Extra_nregs of structure parameters and nr_args can be
added directly at the beginning, and using a flip flag
to identifiy structure parameters. Meantime, renaming
some variables to make them more sense.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230105035026.3091988-1-pulehui@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2023-01-04
We've added 45 non-merge commits during the last 21 day(s) which contain
a total of 50 files changed, 1454 insertions(+), 375 deletions(-).
The main changes are:
1) Fixes, improvements and refactoring of parts of BPF verifier's
state equivalence checks, from Andrii Nakryiko.
2) Fix a few corner cases in libbpf's BTF-to-C converter in particular
around padding handling and enums, also from Andrii Nakryiko.
3) Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better
support decap on GRE tunnel devices not operating in collect metadata,
from Christian Ehrig.
4) Improve x86 JIT's codegen for PROBE_MEM runtime error checks,
from Dave Marchevsky.
5) Remove the need for trace_printk_lock for bpf_trace_printk
and bpf_trace_vprintk helpers, from Jiri Olsa.
6) Add proper documentation for BPF_MAP_TYPE_SOCK{MAP,HASH} maps,
from Maryam Tahhan.
7) Improvements in libbpf's btf_parse_elf error handling, from Changbin Du.
8) Bigger batch of improvements to BPF tracing code samples,
from Daniel T. Lee.
9) Add LoongArch support to libbpf's bpf_tracing helper header,
from Hengqi Chen.
10) Fix a libbpf compiler warning in perf_event_open_probe on arm32,
from Khem Raj.
11) Optimize bpf_local_storage_elem by removing 56 bytes of padding,
from Martin KaFai Lau.
12) Use pkg-config to locate libelf for resolve_btfids build,
from Shen Jiamin.
13) Various libbpf improvements around API documentation and errno
handling, from Xin Liu.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits)
libbpf: Return -ENODATA for missing btf section
libbpf: Add LoongArch support to bpf_tracing.h
libbpf: Restore errno after pr_warn.
libbpf: Added the description of some API functions
libbpf: Fix invalid return address register in s390
samples/bpf: Use BPF_KSYSCALL macro in syscall tracing programs
samples/bpf: Fix tracex2 by using BPF_KSYSCALL macro
samples/bpf: Change _kern suffix to .bpf with syscall tracing program
samples/bpf: Use vmlinux.h instead of implicit headers in syscall tracing program
samples/bpf: Use kyscall instead of kprobe in syscall tracing program
bpf: rename list_head -> graph_root in field info types
libbpf: fix errno is overwritten after being closed.
bpf: fix regs_exact() logic in regsafe() to remap IDs correctly
bpf: perform byte-by-byte comparison only when necessary in regsafe()
bpf: reject non-exact register type matches in regsafe()
bpf: generalize MAYBE_NULL vs non-MAYBE_NULL rule
bpf: reorganize struct bpf_reg_state fields
bpf: teach refsafe() to take into account ID remapping
bpf: Remove unused field initialization in bpf's ctl_table
selftests/bpf: Add jit probe_mem corner case tests to s390x denylist
...
====================
Link: https://lore.kernel.org/r/20230105000926.31350-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch rewrites the runtime PROBE_MEM check insns emitted by the BPF
JIT in order to ensure load safety. The changes in the patch fix two
issues with the previous logic and more generally improve size of
emitted code. Paragraphs between this one and "FIX 1" below explain the
purpose of the runtime check and examine the current implementation.
When a load is marked PROBE_MEM - e.g. due to PTR_UNTRUSTED access - the
address being loaded from is not necessarily valid. The BPF jit sets up
exception handlers for each such load which catch page faults and 0 out
the destination register.
Arbitrary register-relative loads can escape this exception handling
mechanism. Specifically, a load like dst_reg = *(src_reg + off) will not
trigger BPF exception handling if (src_reg + off) is outside of kernel
address space, resulting in an uncaught page fault. A concrete example
of such behavior is a program like:
struct result {
char space[40];
long a;
};
/* if err, returns ERR_PTR(-EINVAL) */
struct result *ptr = get_ptr_maybe_err();
long x = ptr->a;
If get_ptr_maybe_err returns ERR_PTR(-EINVAL) and the result isn't
checked for err, 'result' will be (u64)-EINVAL, a number close to
U64_MAX. The ptr->a load will be > U64_MAX and will wrap over to a small
positive u64, which will be in userspace and thus not covered by BPF
exception handling mechanism.
In order to prevent such loads from occurring, the BPF jit emits some
instructions which do runtime checking of (src_reg + off) and skip the
actual load if it's out of range. As an example, here are instructions
emitted for a %rdi = *(%rdi + 0x10) PROBE_MEM load:
72: movabs $0x800000000010,%r11 --|
7c: cmp %r11,%rdi |- 72 - 7f: Check 1
7f: jb 0x000000000000008d --|
81: mov %rdi,%r11 -----|
84: add $0x0000000000000010,%r11 |- 81-8b: Check 2
8b: jnc 0x0000000000000091 -----|
8d: xor %edi,%edi ---- 0 out dest
8f: jmp 0x0000000000000095
91: mov 0x10(%rdi),%rdi ---- Actual load
95:
The JIT considers kernel address space to start at MAX_TASK_SIZE +
PAGE_SIZE. Determining whether a load will be outside of kernel address
space should be a simple check:
(src_reg + off) >= MAX_TASK_SIZE + PAGE_SIZE
But because there is only one spare register when the checking logic is
emitted, this logic is split into two checks:
Check 1: src_reg >= (MAX_TASK_SIZE + PAGE_SIZE - off)
Check 2: src_reg + off doesn't wrap over U64_MAX and result in small pos u64
Emitted insns implementing Checks 1 and 2 are annotated in the above
example. Check 1 can be done with a single spare register since the
source reg by definition is the left-hand-side of the inequality.
Since adding 'off' to both sides of Check 1's inequality results in the
original inequality we want, it's equivalent to testing that inequality.
Except in the case where src_reg + off wraps past U64_MAX, which is why
Check 2 needs to actually add src_reg + off if Check 1 passes - again
using the single spare reg.
FIX 1: The Check 1 inequality listed above is not what current code is
doing. Current code is a bit more pessimistic, instead checking:
src_reg >= (MAX_TASK_SIZE + PAGE_SIZE + abs(off))
The 0x800000000010 in above example is from this current check. If Check
1 was corrected to use the correct right-hand-side, the value would be
0x7ffffffffff0. This patch changes the checking logic more broadly (FIX
2 below will elaborate), fixing this issue as a side-effect of the
rewrite. Regardless, it's important to understand why Check 1 should've
been doing MAX_TASK_SIZE + PAGE_SIZE - off before proceeding.
FIX 2: Current code relies on a 'jnc' to determine whether src_reg + off
addition wrapped over. For negative offsets this logic is incorrect.
Consider Check 2 insns emitted when off = -0x10:
81: mov %rdi,%r11
84: add 0xfffffffffffffff0,%r11
8b: jnc 0x0000000000000091
2's complement representation of -0x10 is a large positive u64. Any
value of src_reg that passes Check 1 will result in carry flag being set
after (src_reg + off) addition. So a load with any negative offset will
always fail Check 2 at runtime and never do the actual load. This patch
fixes the negative offset issue by rewriting both checks in order to not
rely on carry flag.
The rewrite takes advantage of the fact that, while we only have one
scratch reg to hold arbitrary values, we know the offset at JIT time.
This we can use src_reg as a temporary scratch reg to hold src_reg +
offset since we can return it to its original value by later subtracting
offset. As a result we can directly check the original inequality we
care about:
(src_reg + off) >= MAX_TASK_SIZE + PAGE_SIZE
For a load like %rdi = *(%rsi + -0x10), this results in emitted code:
43: movabs $0x800000000000,%r11
4d: add $0xfffffffffffffff0,%rsi --- src_reg += off
54: cmp %r11,%rsi --- Check original inequality
57: jae 0x000000000000005d
59: xor %edi,%edi
5b: jmp 0x0000000000000061
5d: mov 0x0(%rdi),%rsi --- Actual Load
61: sub $0xfffffffffffffff0,%rsi --- src_reg -= off
Note that the actual load is always done with offset 0, since previous
insns have already done src_reg += off. Regardless of whether the new
check succeeds or fails, insn 61 is always executed, returning src_reg
to its original value.
Because the goal of these checks is to ensure that loaded-from address
will be protected by BPF exception handler, the new check can safely
ignore any wrapover from insn 4d. If such wrapped-over address passes
insn 54 + 57's cmp-and-jmp it will have such protection so the load can
proceed.
IMPROVEMENTS: The above improved logic is 8 insns vs original logic's 9,
and has 1 fewer jmp. The number of checking insns can be further
improved in common scenarios:
If src_reg == dst_reg, the actual load insn will clobber src_reg, so
there's no original src_reg state for the sub insn immediately following
the load to restore, so it can be omitted. In fact, it must be omitted
since it would incorrectly subtract from the result of the load if it
wasn't. So for src_reg == dst_reg, JIT emits these insns:
3c: movabs $0x800000000000,%r11
46: add $0xfffffffffffffff0,%rdi
4d: cmp %r11,%rdi
50: jae 0x0000000000000056
52: xor %edi,%edi
54: jmp 0x000000000000005a
56: mov 0x0(%rdi),%rdi
5a:
The only difference from larger example being the omitted sub, which
would've been insn 5a in this example.
If offset == 0, we can similarly omit the sub as in previous case, since
there's nothing added to subtract. For the same reason we can omit the
addition as well, resulting in JIT emitting these insns:
46: movabs $0x800000000000,%r11
4d: cmp %r11,%rdi
50: jae 0x0000000000000056
52: xor %edi,%edi
54: jmp 0x000000000000005a
56: mov 0x0(%rdi),%rdi
5a:
Although the above example also has src_reg == dst_reg, the same
offset == 0 optimization is valid to apply if src_reg != dst_reg.
To summarize the improvements in emitted insn count for the
check-and-load:
BEFORE: 8 check insns, 3 jmps
AFTER (general case): 7 check insns, 2 jmps (12.5% fewer insn, 33% jmp)
AFTER (src == dst): 6 check insns, 2 jmps (25% fewer insn)
AFTER (offset == 0): 5 check insns, 2 jmps (37.5% fewer insn)
(Above counts don't include the 1 load insn, just checking around it)
Based on BPF bytecode + JITted x86 insn I saw while experimenting with
these improvements, I expect the src_reg == dst_reg case to occur most
often, followed by offset == 0, then the general case.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221216214319.3408356-1-davemarchevsky@fb.com
been long in the making. It is a lighterweight software-only fix for
Skylake-based cores where enabling IBRS is a big hammer and causes a
significant performance impact.
What it basically does is, it aligns all kernel functions to 16 bytes
boundary and adds a 16-byte padding before the function, objtool
collects all functions' locations and when the mitigation gets applied,
it patches a call accounting thunk which is used to track the call depth
of the stack at any time.
When that call depth reaches a magical, microarchitecture-specific value
for the Return Stack Buffer, the code stuffs that RSB and avoids its
underflow which could otherwise lead to the Intel variant of Retbleed.
This software-only solution brings a lot of the lost performance back,
as benchmarks suggest:
https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
That page above also contains a lot more detailed explanation of the
whole mechanism
- Implement a new control flow integrity scheme called FineIBT which is
based on the software kCFI implementation and uses hardware IBT support
where present to annotate and track indirect branches using a hash to
validate them
- Other misc fixes and cleanups
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Merge tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:
- Add the call depth tracking mitigation for Retbleed which has been
long in the making. It is a lighterweight software-only fix for
Skylake-based cores where enabling IBRS is a big hammer and causes a
significant performance impact.
What it basically does is, it aligns all kernel functions to 16 bytes
boundary and adds a 16-byte padding before the function, objtool
collects all functions' locations and when the mitigation gets
applied, it patches a call accounting thunk which is used to track
the call depth of the stack at any time.
When that call depth reaches a magical, microarchitecture-specific
value for the Return Stack Buffer, the code stuffs that RSB and
avoids its underflow which could otherwise lead to the Intel variant
of Retbleed.
This software-only solution brings a lot of the lost performance
back, as benchmarks suggest:
https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
That page above also contains a lot more detailed explanation of the
whole mechanism
- Implement a new control flow integrity scheme called FineIBT which is
based on the software kCFI implementation and uses hardware IBT
support where present to annotate and track indirect branches using a
hash to validate them
- Other misc fixes and cleanups
* tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits)
x86/paravirt: Use common macro for creating simple asm paravirt functions
x86/paravirt: Remove clobber bitmask from .parainstructions
x86/debug: Include percpu.h in debugreg.h to get DECLARE_PER_CPU() et al
x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11, to leave space for WIP X86_FEATURE_SGX_EDECCSSA bit
x86/Kconfig: Enable kernel IBT by default
x86,pm: Force out-of-line memcpy()
objtool: Fix weak hole vs prefix symbol
objtool: Optimize elf_dirty_reloc_sym()
x86/cfi: Add boot time hash randomization
x86/cfi: Boot time selection of CFI scheme
x86/ibt: Implement FineIBT
objtool: Add --cfi to generate the .cfi_sites section
x86: Add prefix symbols for function padding
objtool: Add option to generate prefix symbols
objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf
objtool: Slice up elf_create_section_symbol()
kallsyms: Revert "Take callthunks into account"
x86: Unconfuse CONFIG_ and X86_FEATURE_ namespaces
x86/retpoline: Fix crash printing warning
x86/paravirt: Fix a !PARAVIRT build warning
...
Because __attribute__((patchable_function_entry)) is only available
since GCC-8 this solution fails to build on the minimum required GCC
version.
Undo these changes so we might try again -- without cluttering up the
patches with too many changes.
This is an almost complete revert of:
dbe69b2998 ("bpf: Fix dispatcher patchable function entry to 5 bytes nop")
ceea991a01 ("bpf: Move bpf_dispatcher function out of ftrace locations")
(notably the arch/x86/Kconfig hunk is kept).
Reported-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lkml.kernel.org/r/439d8dc735bb4858875377df67f1b29a@AcuMS.aculab.com
Link: https://lore.kernel.org/bpf/20221103120647.728830733@infradead.org
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2022-11-02
We've added 70 non-merge commits during the last 14 day(s) which contain
a total of 96 files changed, 3203 insertions(+), 640 deletions(-).
The main changes are:
1) Make cgroup local storage available to non-cgroup attached BPF programs
such as tc BPF ones, from Yonghong Song.
2) Avoid unnecessary deadlock detection and failures wrt BPF task storage
helpers, from Martin KaFai Lau.
3) Add LLVM disassembler as default library for dumping JITed code
in bpftool, from Quentin Monnet.
4) Various kprobe_multi_link fixes related to kernel modules,
from Jiri Olsa.
5) Optimize x86-64 JIT with emitting BMI2-based shift instructions,
from Jie Meng.
6) Improve BPF verifier's memory type compatibility for map key/value
arguments, from Dave Marchevsky.
7) Only create mmap-able data section maps in libbpf when data is exposed
via skeletons, from Andrii Nakryiko.
8) Add an autoattach option for bpftool to load all object assets,
from Wang Yufen.
9) Various memory handling fixes for libbpf and BPF selftests,
from Xu Kuohai.
10) Initial support for BPF selftest's vmtest.sh on arm64,
from Manu Bretelle.
11) Improve libbpf's BTF handling to dedup identical structs,
from Alan Maguire.
12) Add BPF CI and denylist documentation for BPF selftests,
from Daniel Müller.
13) Check BPF cpumap max_entries before doing allocation work,
from Florian Lehner.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (70 commits)
samples/bpf: Fix typo in README
bpf: Remove the obsolte u64_stats_fetch_*_irq() users.
bpf: check max_entries before allocating memory
bpf: Fix a typo in comment for DFS algorithm
bpftool: Fix spelling mistake "disasembler" -> "disassembler"
selftests/bpf: Fix bpftool synctypes checking failure
selftests/bpf: Panic on hard/soft lockup
docs/bpf: Add documentation for new cgroup local storage
selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x
selftests/bpf: Add selftests for new cgroup local storage
selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str
bpftool: Support new cgroup local storage
libbpf: Support new cgroup local storage
bpf: Implement cgroup storage available to non-cgroup-attached bpf progs
bpf: Refactor some inode/task/sk storage functions for reuse
bpf: Make struct cgroup btf id global
selftests/bpf: Tracing prog can still do lookup under busy lock
selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to deadlock detection
bpf: Add new bpf_task_storage_delete proto with no deadlock detection
bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check
...
====================
Link: https://lore.kernel.org/r/20221102062120.5724-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The commit 64696c40d0 ("bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline")
removed prog->active check for struct_ops prog. The bpf_lsm
and bpf_iter is also using trampoline. Like struct_ops, the bpf_lsm
and bpf_iter have fixed hooks for the prog to attach. The
kernel does not call the same hook in a recursive way.
This patch also removes the prog->active check for
bpf_lsm and bpf_iter.
A later patch has a test to reproduce the recursion issue
for a sleepable bpf_lsm program.
This patch appends the '_recur' naming to the existing
enter and exit functions that track the prog->active counter.
New __bpf_prog_{enter,exit}[_sleepable] function are
added to skip the prog->active tracking. The '_struct_ops'
version is also removed.
It also moves the decision on picking the enter and exit function to
the new bpf_trampoline_{enter,exit}(). It returns the '_recur' ones
for all tracing progs to use. For bpf_lsm, bpf_iter,
struct_ops (no prog->active tracking after 64696c40d0), and
bpf_lsm_cgroup (no prog->active tracking after 69fd337a97),
it will return the functions that don't track the prog->active.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The patchable_function_entry(5) might output 5 single nop
instructions (depends on toolchain), which will clash with
bpf_arch_text_poke check for 5 bytes nop instruction.
Adding early init call for dispatcher that checks and change
the patchable entry into expected 5 nop instruction if needed.
There's no need to take text_mutex, because we are using it
in early init call which is called at pre-smp time.
Fixes: ceea991a01 ("bpf: Move bpf_dispatcher function out of ftrace locations")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221018075934.574415-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BMI2 provides 3 shift instructions (shrx, sarx and shlx) that use VEX
encoding but target general purpose registers [1]. They allow the shift
count in any general purpose register and have the same performance as
non BMI2 shift instructions [2].
Instead of shr/sar/shl that implicitly use %cl (lowest 8 bit of %rcx),
emit their more flexible alternatives provided in BMI2 when advantageous;
keep using the non BMI2 instructions when shift count is already in
BPF_REG_4/%rcx as non BMI2 instructions are shorter.
To summarize, when BMI2 is available:
-------------------------------------------------
| arbitrary dst
=================================================
src == ecx | shl dst, cl
-------------------------------------------------
src != ecx | shlx dst, dst, src
-------------------------------------------------
And no additional register shuffling is needed.
A concrete example between non BMI2 and BMI2 codegen. To shift %rsi by
%rdi:
Without BMI2:
ef3: push %rcx
51
ef4: mov %rdi,%rcx
48 89 f9
ef7: shl %cl,%rsi
48 d3 e6
efa: pop %rcx
59
With BMI2:
f0b: shlx %rdi,%rsi,%rsi
c4 e2 c1 f7 f6
[1] https://en.wikipedia.org/wiki/X86_Bit_manipulation_instruction_set
[2] https://www.agner.org/optimize/instruction_tables.pdf
Signed-off-by: Jie Meng <jmeng@fb.com>
Link: https://lore.kernel.org/r/20221007202348.1118830-3-jmeng@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
x64 JIT produces redundant instructions when a shift operation's
destination register is BPF_REG_4/ecx and this patch removes them.
Specifically, when dest reg is BPF_REG_4 but the src isn't, we
needn't push and pop ecx around shift only to get it overwritten
by r11 immediately afterwards.
In the rare case when both dest and src registers are BPF_REG_4,
a single shift instruction is sufficient and we don't need the
two MOV instructions around the shift.
To summarize using shift left as an example, without patch:
-------------------------------------------------
| dst == ecx | dst != ecx
=================================================
src == ecx | mov r11, ecx | shl dst, cl
| shl r11, ecx |
| mov ecx, r11 |
-------------------------------------------------
src != ecx | mov r11, ecx | push ecx
| push ecx | mov ecx, src
| mov ecx, src | shl dst, cl
| shl r11, cl | pop ecx
| pop ecx |
| mov ecx, r11 |
-------------------------------------------------
With patch:
-------------------------------------------------
| dst == ecx | dst != ecx
=================================================
src == ecx | shl ecx, cl | shl dst, cl
-------------------------------------------------
src != ecx | mov r11, ecx | push ecx
| mov ecx, src | mov ecx, src
| shl r11, cl | shl dst, cl
| mov ecx, r11 | pop ecx
-------------------------------------------------
Signed-off-by: Jie Meng <jmeng@fb.com>
Link: https://lore.kernel.org/r/20221007202348.1118830-2-jmeng@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since ftrace has trampolines, don't use thunks for the __fentry__ site
but instead require that every function called from there includes
accounting. This very much includes all the direct-call functions.
Additionally, ftrace uses ROP tricks in two places:
- return_to_handler(), and
- ftrace_regs_caller() when pt_regs->orig_ax is set by a direct-call.
return_to_handler() already uses a retpoline to replace an
indirect-jump to defeat IBT, since this is a jump-type retpoline, make
sure there is no accounting done and ALTERNATIVE the RET into a ret.
ftrace_regs_caller() does much the same and gets the same treatment.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.927545073@infradead.org
Ensure that calls in BPF jitted programs are emitting call depth accounting
when enabled to keep the call/return balanced. The return thunk jump is
already injected due to the earlier retbleed mitigations.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.615413406@infradead.org
Ensure that retpolines do the proper call accounting so that the return
accounting works correctly.
Specifically; retpolines are used to replace both 'jmp *%reg' and
'call *%reg', however these two cases do not have the same accounting
requirements. Therefore split things up and provide two different
retpoline arrays for SKL.
The 'jmp *%reg' case needs no accounting, the
__x86_indirect_jump_thunk_array[] covers this. The retpoline is
changed to not use the return thunk; it's a simple call;ret construct.
[ strictly speaking it should do:
andq $(~0x1f), PER_CPU_VAR(__x86_call_depth)
but we can argue this can be covered by the fuzz we already have
in the accounting depth (12) vs the RSB depth (16) ]
The 'call *%reg' case does need accounting, the
__x86_indirect_call_thunk_array[] covers this. Again, this retpoline
avoids the use of the return-thunk, in this case to avoid double
accounting.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.996634749@infradead.org
In preparation for call depth tracking on Intel SKL CPUs, make it possible
to patch in a SKL specific return thunk.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.680469665@infradead.org
SSE2 and hence lfence are architectural in x86-64 and no need to check
whether they're supported in CPU. SSE2's CPUID flag is still set to
maintain backward compatibility with older code or code shared with x86,
but bpf_jit_comp.c is compiled under x86-64 exclusively so the check is
redundant.
Signed-off-by: Jie Meng <jmeng@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20221005170039.3936894-1-jmeng@fb.com
Core
----
- Introduce and use a single page frag cache for allocating small skb
heads, clawing back the 10-20% performance regression in UDP flood
test from previous fixes.
- Run packets which already went thru HW coalescing thru SW GRO.
This significantly improves TCP segment coalescing and simplifies
deployments as different workloads benefit from HW or SW GRO.
- Shrink the size of the base zero-copy send structure.
- Move TCP init under a new slow / sleepable version of DO_ONCE().
BPF
---
- Add BPF-specific, any-context-safe memory allocator.
- Add helpers/kfuncs for PKCS#7 signature verification from BPF
programs.
- Define a new map type and related helpers for user space -> kernel
communication over a ring buffer (BPF_MAP_TYPE_USER_RINGBUF).
- Allow targeting BPF iterators to loop through resources of one
task/thread.
- Add ability to call selected destructive functions.
Expose crash_kexec() to allow BPF to trigger a kernel dump.
Use CAP_SYS_BOOT check on the loading process to judge permissions.
- Enable BPF to collect custom hierarchical cgroup stats efficiently
by integrating with the rstat framework.
- Support struct arguments for trampoline based programs.
Only structs with size <= 16B and x86 are supported.
- Invoke cgroup/connect{4,6} programs for unprivileged ICMP ping
sockets (instead of just TCP and UDP sockets).
- Add a helper for accessing CLOCK_TAI for time sensitive network
related programs.
- Support accessing network tunnel metadata's flags.
- Make TCP SYN ACK RTO tunable by BPF programs with TCP Fast Open.
- Add support for writing to Netfilter's nf_conn:mark.
Protocols
---------
- WiFi: more Extremely High Throughput (EHT) and Multi-Link
Operation (MLO) work (802.11be, WiFi 7).
- vsock: improve support for SO_RCVLOWAT.
- SMC: support SO_REUSEPORT.
- Netlink: define and document how to use netlink in a "modern" way.
Support reporting missing attributes via extended ACK.
- IPSec: support collect metadata mode for xfrm interfaces.
- TCPv6: send consistent autoflowlabel in SYN_RECV state
and RST packets.
- TCP: introduce optional per-netns connection hash table to allow
better isolation between namespaces (opt-in, at the cost of memory
and cache pressure).
- MPTCP: support TCP_FASTOPEN_CONNECT.
- Add NEXT-C-SID support in Segment Routing (SRv6) End behavior.
- Adjust IP_UNICAST_IF sockopt behavior for connected UDP sockets.
- Open vSwitch:
- Allow specifying ifindex of new interfaces.
- Allow conntrack and metering in non-initial user namespace.
- TLS: support the Korean ARIA-GCM crypto algorithm.
- Remove DECnet support.
Driver API
----------
- Allow selecting the conduit interface used by each port
in DSA switches, at runtime.
- Ethernet Power Sourcing Equipment and Power Device support.
- Add tc-taprio support for queueMaxSDU parameter, i.e. setting
per traffic class max frame size for time-based packet schedules.
- Support PHY rate matching - adapting between differing host-side
and link-side speeds.
- Introduce QUSGMII PHY mode and 1000BASE-KX interface mode.
- Validate OF (device tree) nodes for DSA shared ports; make
phylink-related properties mandatory on DSA and CPU ports.
Enforcing more uniformity should allow transitioning to phylink.
- Require that flash component name used during update matches one
of the components for which version is reported by info_get().
- Remove "weight" argument from driver-facing NAPI API as much
as possible. It's one of those magic knobs which seemed like
a good idea at the time but is too indirect to use in practice.
- Support offload of TLS connections with 256 bit keys.
New hardware / drivers
----------------------
- Ethernet:
- Microchip KSZ9896 6-port Gigabit Ethernet Switch
- Renesas Ethernet AVB (EtherAVB-IF) Gen4 SoCs
- Analog Devices ADIN1110 and ADIN2111 industrial single pair
Ethernet (10BASE-T1L) MAC+PHY.
- Rockchip RV1126 Gigabit Ethernet (a version of stmmac IP).
- Ethernet SFPs / modules:
- RollBall / Hilink / Turris 10G copper SFPs
- HALNy GPON module
- WiFi:
- CYW43439 SDIO chipset (brcmfmac)
- CYW89459 PCIe chipset (brcmfmac)
- BCM4378 on Apple platforms (brcmfmac)
Drivers
-------
- CAN:
- gs_usb: HW timestamp support
- Ethernet PHYs:
- lan8814: cable diagnostics
- Ethernet NICs:
- Intel (100G):
- implement control of FCS/CRC stripping
- port splitting via devlink
- L2TPv3 filtering offload
- nVidia/Mellanox:
- tunnel offload for sub-functions
- MACSec offload, w/ Extended packet number and replay
window offload
- significantly restructure, and optimize the AF_XDP support,
align the behavior with other vendors
- Huawei:
- configuring DSCP map for traffic class selection
- querying standard FEC statistics
- querying SerDes lane number via ethtool
- Marvell/Cavium:
- egress priority flow control
- MACSec offload
- AMD/SolarFlare:
- PTP over IPv6 and raw Ethernet
- small / embedded:
- ax88772: convert to phylink (to support SFP cages)
- altera: tse: convert to phylink
- ftgmac100: support fixed link
- enetc: standard Ethtool counters
- macb: ZynqMP SGMII dynamic configuration support
- tsnep: support multi-queue and use page pool
- lan743x: Rx IP & TCP checksum offload
- igc: add xdp frags support to ndo_xdp_xmit
- Ethernet high-speed switches:
- Marvell (prestera):
- support SPAN port features (traffic mirroring)
- nexthop object offloading
- Microchip (sparx5):
- multicast forwarding offload
- QoS queuing offload (tc-mqprio, tc-tbf, tc-ets)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- support RGMII cmode
- NXP (felix):
- standardized ethtool counters
- Microchip (lan966x):
- QoS queuing offload (tc-mqprio, tc-tbf, tc-cbs, tc-ets)
- traffic policing and mirroring
- link aggregation / bonding offload
- QUSGMII PHY mode support
- Qualcomm 802.11ax WiFi (ath11k):
- cold boot calibration support on WCN6750
- support to connect to a non-transmit MBSSID AP profile
- enable remain-on-channel support on WCN6750
- Wake-on-WLAN support for WCN6750
- support to provide transmit power from firmware via nl80211
- support to get power save duration for each client
- spectral scan support for 160 MHz
- MediaTek WiFi (mt76):
- WiFi-to-Ethernet bridging offload for MT7986 chips
- RealTek WiFi (rtw89):
- P2P support
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core:
- Introduce and use a single page frag cache for allocating small skb
heads, clawing back the 10-20% performance regression in UDP flood
test from previous fixes.
- Run packets which already went thru HW coalescing thru SW GRO. This
significantly improves TCP segment coalescing and simplifies
deployments as different workloads benefit from HW or SW GRO.
- Shrink the size of the base zero-copy send structure.
- Move TCP init under a new slow / sleepable version of DO_ONCE().
BPF:
- Add BPF-specific, any-context-safe memory allocator.
- Add helpers/kfuncs for PKCS#7 signature verification from BPF
programs.
- Define a new map type and related helpers for user space -> kernel
communication over a ring buffer (BPF_MAP_TYPE_USER_RINGBUF).
- Allow targeting BPF iterators to loop through resources of one
task/thread.
- Add ability to call selected destructive functions. Expose
crash_kexec() to allow BPF to trigger a kernel dump. Use
CAP_SYS_BOOT check on the loading process to judge permissions.
- Enable BPF to collect custom hierarchical cgroup stats efficiently
by integrating with the rstat framework.
- Support struct arguments for trampoline based programs. Only
structs with size <= 16B and x86 are supported.
- Invoke cgroup/connect{4,6} programs for unprivileged ICMP ping
sockets (instead of just TCP and UDP sockets).
- Add a helper for accessing CLOCK_TAI for time sensitive network
related programs.
- Support accessing network tunnel metadata's flags.
- Make TCP SYN ACK RTO tunable by BPF programs with TCP Fast Open.
- Add support for writing to Netfilter's nf_conn:mark.
Protocols:
- WiFi: more Extremely High Throughput (EHT) and Multi-Link Operation
(MLO) work (802.11be, WiFi 7).
- vsock: improve support for SO_RCVLOWAT.
- SMC: support SO_REUSEPORT.
- Netlink: define and document how to use netlink in a "modern" way.
Support reporting missing attributes via extended ACK.
- IPSec: support collect metadata mode for xfrm interfaces.
- TCPv6: send consistent autoflowlabel in SYN_RECV state and RST
packets.
- TCP: introduce optional per-netns connection hash table to allow
better isolation between namespaces (opt-in, at the cost of memory
and cache pressure).
- MPTCP: support TCP_FASTOPEN_CONNECT.
- Add NEXT-C-SID support in Segment Routing (SRv6) End behavior.
- Adjust IP_UNICAST_IF sockopt behavior for connected UDP sockets.
- Open vSwitch:
- Allow specifying ifindex of new interfaces.
- Allow conntrack and metering in non-initial user namespace.
- TLS: support the Korean ARIA-GCM crypto algorithm.
- Remove DECnet support.
Driver API:
- Allow selecting the conduit interface used by each port in DSA
switches, at runtime.
- Ethernet Power Sourcing Equipment and Power Device support.
- Add tc-taprio support for queueMaxSDU parameter, i.e. setting per
traffic class max frame size for time-based packet schedules.
- Support PHY rate matching - adapting between differing host-side
and link-side speeds.
- Introduce QUSGMII PHY mode and 1000BASE-KX interface mode.
- Validate OF (device tree) nodes for DSA shared ports; make
phylink-related properties mandatory on DSA and CPU ports.
Enforcing more uniformity should allow transitioning to phylink.
- Require that flash component name used during update matches one of
the components for which version is reported by info_get().
- Remove "weight" argument from driver-facing NAPI API as much as
possible. It's one of those magic knobs which seemed like a good
idea at the time but is too indirect to use in practice.
- Support offload of TLS connections with 256 bit keys.
New hardware / drivers:
- Ethernet:
- Microchip KSZ9896 6-port Gigabit Ethernet Switch
- Renesas Ethernet AVB (EtherAVB-IF) Gen4 SoCs
- Analog Devices ADIN1110 and ADIN2111 industrial single pair
Ethernet (10BASE-T1L) MAC+PHY.
- Rockchip RV1126 Gigabit Ethernet (a version of stmmac IP).
- Ethernet SFPs / modules:
- RollBall / Hilink / Turris 10G copper SFPs
- HALNy GPON module
- WiFi:
- CYW43439 SDIO chipset (brcmfmac)
- CYW89459 PCIe chipset (brcmfmac)
- BCM4378 on Apple platforms (brcmfmac)
Drivers:
- CAN:
- gs_usb: HW timestamp support
- Ethernet PHYs:
- lan8814: cable diagnostics
- Ethernet NICs:
- Intel (100G):
- implement control of FCS/CRC stripping
- port splitting via devlink
- L2TPv3 filtering offload
- nVidia/Mellanox:
- tunnel offload for sub-functions
- MACSec offload, w/ Extended packet number and replay window
offload
- significantly restructure, and optimize the AF_XDP support,
align the behavior with other vendors
- Huawei:
- configuring DSCP map for traffic class selection
- querying standard FEC statistics
- querying SerDes lane number via ethtool
- Marvell/Cavium:
- egress priority flow control
- MACSec offload
- AMD/SolarFlare:
- PTP over IPv6 and raw Ethernet
- small / embedded:
- ax88772: convert to phylink (to support SFP cages)
- altera: tse: convert to phylink
- ftgmac100: support fixed link
- enetc: standard Ethtool counters
- macb: ZynqMP SGMII dynamic configuration support
- tsnep: support multi-queue and use page pool
- lan743x: Rx IP & TCP checksum offload
- igc: add xdp frags support to ndo_xdp_xmit
- Ethernet high-speed switches:
- Marvell (prestera):
- support SPAN port features (traffic mirroring)
- nexthop object offloading
- Microchip (sparx5):
- multicast forwarding offload
- QoS queuing offload (tc-mqprio, tc-tbf, tc-ets)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- support RGMII cmode
- NXP (felix):
- standardized ethtool counters
- Microchip (lan966x):
- QoS queuing offload (tc-mqprio, tc-tbf, tc-cbs, tc-ets)
- traffic policing and mirroring
- link aggregation / bonding offload
- QUSGMII PHY mode support
- Qualcomm 802.11ax WiFi (ath11k):
- cold boot calibration support on WCN6750
- support to connect to a non-transmit MBSSID AP profile
- enable remain-on-channel support on WCN6750
- Wake-on-WLAN support for WCN6750
- support to provide transmit power from firmware via nl80211
- support to get power save duration for each client
- spectral scan support for 160 MHz
- MediaTek WiFi (mt76):
- WiFi-to-Ethernet bridging offload for MT7986 chips
- RealTek WiFi (rtw89):
- P2P support"
* tag 'net-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1864 commits)
eth: pse: add missing static inlines
once: rename _SLOW to _SLEEPABLE
net: pse-pd: add regulator based PSE driver
dt-bindings: net: pse-dt: add bindings for regulator based PoDL PSE controller
ethtool: add interface to interact with Ethernet Power Equipment
net: mdiobus: search for PSE nodes by parsing PHY nodes.
net: mdiobus: fwnode_mdiobus_register_phy() rework error handling
net: add framework to support Ethernet PSE and PDs devices
dt-bindings: net: phy: add PoDL PSE property
net: marvell: prestera: Propagate nh state from hw to kernel
net: marvell: prestera: Add neighbour cache accounting
net: marvell: prestera: add stub handler neighbour events
net: marvell: prestera: Add heplers to interact with fib_notifier_info
net: marvell: prestera: Add length macros for prestera_ip_addr
net: marvell: prestera: add delayed wq and flush wq on deinit
net: marvell: prestera: Add strict cleanup of fib arbiter
net: marvell: prestera: Add cleanup of allocated fib_nodes
net: marvell: prestera: Add router nexthops ABI
eth: octeon: fix build after netif_napi_add() changes
net/mlx5: E-Switch, Return EBUSY if can't get mode lock
...
The struct_ops prog is to allow using bpf to implement the functions in
a struct (eg. kernel module). The current usage is to implement the
tcp_congestion. The kernel does not call the tcp-cc's ops (ie.
the bpf prog) in a recursive way.
The struct_ops is sharing the tracing-trampoline's enter/exit
function which tracks prog->active to avoid recursion. It is
needed for tracing prog. However, it turns out the struct_ops
bpf prog will hit this prog->active and unnecessarily skipped
running the struct_ops prog. eg. The '.ssthresh' may run in_task()
and then interrupted by softirq that runs the same '.ssthresh'.
Skip running the '.ssthresh' will end up returning random value
to the caller.
The patch adds __bpf_prog_{enter,exit}_struct_ops for the
struct_ops trampoline. They do not track the prog->active
to detect recursion.
One exception is when the tcp_congestion's '.init' ops is doing
bpf_setsockopt(TCP_CONGESTION) and then recurs to the same
'.init' ops. This will be addressed in the following patches.
Fixes: ca06f55b90 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allocate bpf_dispatcher with bpf_prog_pack_alloc so that bpf_dispatcher
can share pages with bpf programs.
arch_prepare_bpf_dispatcher() is updated to provide a RW buffer as working
area for arch code to write to.
This also fixes CPA W^X warnning like:
CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ...
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220926184739.3512547-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Using function address given at the generation time as the trampoline
ip argument. This way we get directly the function address that we
need, so we don't need to:
- read the ip from the stack
- subtract X86_PATCH_SIZE
- subtract ENDBR_INSN_SIZE if CONFIG_X86_KERNEL_IBT is enabled
which is not even implemented yet ;-)
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Both AMD and Intel recommend using INT3 after an indirect JMP. Make sure
to emit one when rewriting the retpoline JMP irrespective of compiler
SLS options or even CONFIG_SLS.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Link: https://lkml.kernel.org/r/Yxm+QkFPOhrVSH6q@hirez.programming.kicks-ass.net
In C, struct value can be passed as a function argument.
For small structs, struct value may be passed in
one or more registers. For trampoline based bpf programs,
this would cause complication since one-to-one mapping between
function argument and arch argument register is not valid
any more.
The latest llvm16 added bpf support to pass by values
for struct up to 16 bytes ([1]). This is also true for
x86_64 architecture where two registers will hold
the struct value if the struct size is >8 and <= 16.
This may not be true if one of struct member is 'double'
type but in current linux source code we don't have
such instance yet, so we assume all >8 && <= 16 struct
holds two general purpose argument registers.
Also change on-stack nr_args value to the number
of registers holding the arguments. This will
permit bpf_get_func_arg() helper to get all
argument values.
[1] https://reviews.llvm.org/D132144
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152652.2078600-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
bpf-next 2022-07-22
We've added 73 non-merge commits during the last 12 day(s) which contain
a total of 88 files changed, 3458 insertions(+), 860 deletions(-).
The main changes are:
1) Implement BPF trampoline for arm64 JIT, from Xu Kuohai.
2) Add ksyscall/kretsyscall section support to libbpf to simplify tracing kernel
syscalls through kprobe mechanism, from Andrii Nakryiko.
3) Allow for livepatch (KLP) and BPF trampolines to attach to the same kernel
function, from Song Liu & Jiri Olsa.
4) Add new kfunc infrastructure for netfilter's CT e.g. to insert and change
entries, from Kumar Kartikeya Dwivedi & Lorenzo Bianconi.
5) Add a ksym BPF iterator to allow for more flexible and efficient interactions
with kernel symbols, from Alan Maguire.
6) Bug fixes in libbpf e.g. for uprobe binary path resolution, from Dan Carpenter.
7) Fix BPF subprog function names in stack traces, from Alexei Starovoitov.
8) libbpf support for writing custom perf event readers, from Jon Doron.
9) Switch to use SPDX tag for BPF helper man page, from Alejandro Colomar.
10) Fix xsk send-only sockets when in busy poll mode, from Maciej Fijalkowski.
11) Reparent BPF maps and their charging on memcg offlining, from Roman Gushchin.
12) Multiple follow-up fixes around BPF lsm cgroup infra, from Stanislav Fomichev.
13) Use bootstrap version of bpftool where possible to speed up builds, from Pu Lehui.
14) Cleanup BPF verifier's check_func_arg() handling, from Joanne Koong.
15) Make non-prealloced BPF map allocations low priority to play better with
memcg limits, from Yafang Shao.
16) Fix BPF test runner to reject zero-length data for skbs, from Zhengchao Shao.
17) Various smaller cleanups and improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (73 commits)
bpf: Simplify bpf_prog_pack_[size|mask]
bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)
bpf, x64: Allow to use caller address from stack
ftrace: Allow IPMODIFY and DIRECT ops on the same function
ftrace: Add modify_ftrace_direct_multi_nolock
bpf/selftests: Fix couldn't retrieve pinned program in xdp veth test
bpf: Fix build error in case of !CONFIG_DEBUG_INFO_BTF
selftests/bpf: Fix test_verifier failed test in unprivileged mode
selftests/bpf: Add negative tests for new nf_conntrack kfuncs
selftests/bpf: Add tests for new nf_conntrack kfuncs
selftests/bpf: Add verifier tests for trusted kfunc args
net: netfilter: Add kfuncs to set and change CT status
net: netfilter: Add kfuncs to set and change CT timeout
net: netfilter: Add kfuncs to allocate and insert CT
net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup
bpf: Add documentation for kfuncs
bpf: Add support for forcing kfunc args to be trusted
bpf: Switch to new kfunc flags infrastructure
tools/resolve_btfids: Add support for 8-byte BTF sets
bpf: Introduce 8-byte BTF set
...
====================
Link: https://lore.kernel.org/r/20220722221218.29943-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently we call the original function by using the absolute address
given at the JIT generation. That's not usable when having trampoline
attached to multiple functions, or the target address changes dynamically
(in case of live patch). In such cases we need to take the return address
from the stack.
Adding support to retrieve the original function address from the stack
by adding new BPF_TRAMP_F_ORIG_STACK flag for arch_prepare_bpf_trampoline
function.
Basically we take the return address of the 'fentry' call:
function + 0: call fentry # stores 'function + 5' address on stack
function + 5: ...
The 'function + 5' address will be used as the address for the
original function to call.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220720002126.803253-4-song@kernel.org
syzbot reported a few issues with bpf_prog_pack [1], [2]. This only happens
with multiple subprogs. In jit_subprogs(), we first call bpf_int_jit_compile()
on each sub program. And then, we call it on each sub program again. jit_data
is not freed in the first call of bpf_int_jit_compile(). Similarly we don't
call bpf_jit_binary_pack_finalize() in the first call of bpf_int_jit_compile().
If bpf_int_jit_compile() failed for one sub program, we will call
bpf_jit_binary_pack_finalize() for this sub program. However, we don't have a
chance to call it for other sub programs. Then we will hit "goto out_free" in
jit_subprogs(), and call bpf_jit_free on some subprograms that haven't got
bpf_jit_binary_pack_finalize() yet.
At this point, bpf_jit_binary_pack_free() is called and the whole 2MB page is
freed erroneously.
Fix this with a custom bpf_jit_free() for x86_64, which calls
bpf_jit_binary_pack_finalize() if necessary. Also, with custom
bpf_jit_free(), bpf_prog_aux->use_bpf_prog_pack is not needed any more,
remove it.
Fixes: 1022a5498f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
[1] https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f
[2] https://syzkaller.appspot.com/bug?extid=87f65c75f4a72db05445
Reported-by: syzbot+2f649ec6d2eea1495a8f@syzkaller.appspotmail.com
Reported-by: syzbot+87f65c75f4a72db05445@syzkaller.appspotmail.com
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220706002612.4013790-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Before generating bpf trampoline, x86 calls is_valid_bpf_tramp_flags()
to check the input flags. This check is architecture independent.
So, to be consistent with x86, arm64 should also do this check
before generating bpf trampoline.
However, the BPF_TRAMP_F_XXX flags are not used by user code and the
flags argument is almost constant at compile time, so this run time
check is a bit redundant.
Remove is_valid_bpf_tramp_flags() and add some comments to the usage of
BPF_TRAMP_F_XXX flags, as suggested by Alexei.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220711150823.2128542-2-xukuohai@huawei.com
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-07-09
We've added 94 non-merge commits during the last 19 day(s) which contain
a total of 125 files changed, 5141 insertions(+), 6701 deletions(-).
The main changes are:
1) Add new way for performing BTF type queries to BPF, from Daniel Müller.
2) Add inlining of calls to bpf_loop() helper when its function callback is
statically known, from Eduard Zingerman.
3) Implement BPF TCP CC framework usability improvements, from Jörn-Thorben Hinz.
4) Add LSM flavor for attaching per-cgroup BPF programs to existing LSM
hooks, from Stanislav Fomichev.
5) Remove all deprecated libbpf APIs in prep for 1.0 release, from Andrii Nakryiko.
6) Add benchmarks around local_storage to BPF selftests, from Dave Marchevsky.
7) AF_XDP sample removal (given move to libxdp) and various improvements around AF_XDP
selftests, from Magnus Karlsson & Maciej Fijalkowski.
8) Add bpftool improvements for memcg probing and bash completion, from Quentin Monnet.
9) Add arm64 JIT support for BPF-2-BPF coupled with tail calls, from Jakub Sitnicki.
10) Sockmap optimizations around throughput of UDP transmissions which have been
improved by 61%, from Cong Wang.
11) Rework perf's BPF prologue code to remove deprecated functions, from Jiri Olsa.
12) Fix sockmap teardown path to avoid sleepable sk_psock_stop, from John Fastabend.
13) Fix libbpf's cleanup around legacy kprobe/uprobe on error case, from Chuang Wang.
14) Fix libbpf's bpf_helpers.h to work with gcc for the case of its sec/pragma
macro, from James Hilliard.
15) Fix libbpf's pt_regs macros for riscv to use a0 for RC register, from Yixun Lan.
16) Fix bpftool to show the name of type BPF_OBJ_LINK, from Yafang Shao.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (94 commits)
selftests/bpf: Fix xdp_synproxy build failure if CONFIG_NF_CONNTRACK=m/n
bpf: Correctly propagate errors up from bpf_core_composites_match
libbpf: Disable SEC pragma macro on GCC
bpf: Check attach_func_proto more carefully in check_return_code
selftests/bpf: Add test involving restrict type qualifier
bpftool: Add support for KIND_RESTRICT to gen min_core_btf command
MAINTAINERS: Add entry for AF_XDP selftests files
selftests, xsk: Rename AF_XDP testing app
bpf, docs: Remove deprecated xsk libbpf APIs description
selftests/bpf: Add benchmark for local_storage RCU Tasks Trace usage
libbpf, riscv: Use a0 for RC register
libbpf: Remove unnecessary usdt_rel_ip assignments
selftests/bpf: Fix few more compiler warnings
selftests/bpf: Fix bogus uninitialized variable warning
bpftool: Remove zlib feature test from Makefile
libbpf: Cleanup the legacy uprobe_event on failed add/attach_event()
libbpf: Fix wrong variable used in perf_event_uprobe_open_legacy()
libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()
selftests/bpf: Add type match test against kernel's task_struct
selftests/bpf: Add nested type to type based tests
...
====================
Link: https://lore.kernel.org/r/20220708233145.32365-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Allow attaching to lsm hooks in the cgroup context.
Attaching to per-cgroup LSM works exactly like attaching
to other per-cgroup hooks. New BPF_LSM_CGROUP is added
to trigger new mode; the actual lsm hook we attach to is
signaled via existing attach_btf_id.
For the hooks that have 'struct socket' or 'struct sock' as its first
argument, we use the cgroup associated with that socket. For the rest,
we use 'current' cgroup (this is all on default hierarchy == v2 only).
Note that for some hooks that work on 'struct sock' we still
take the cgroup from 'current' because some of them work on the socket
that hasn't been properly initialized yet.
Behind the scenes, we allocate a shim program that is attached
to the trampoline and runs cgroup effective BPF programs array.
This shim has some rudimentary ref counting and can be shared
between several programs attaching to the same lsm hook from
different cgroups.
Note that this patch bloats cgroup size because we add 211
cgroup_bpf_attach_type(s) for simplicity sake. This will be
addressed in the subsequent patch.
Also note that we only add non-sleepable flavor for now. To enable
sleepable use-cases, bpf_prog_run_array_cg has to grab trace rcu,
shim programs have to be freed via trace rcu, cgroup_bpf.effective
should be also trace-rcu-managed + maybe some other changes that
I'm not aware of.
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-4-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
On it's own not much of a cleanup but it prepares for more/similar
code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail
calls for only x86-64. Change the logic to instead rely on a new weak
function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable
JIT backend can override.
Update the x86-64 eBPF JIT to reflect this.
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
[jakub: drop MIPS bits and tweak patch subject]
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com
On x86-64 the tail call count is passed from one BPF function to another
through %rax. Additionally, on function entry, the tail call count value
is stored on stack right after the BPF program stack, due to register
shortage.
The stored count is later loaded from stack either when performing a tail
call - to check if we have not reached the tail call limit - or before
calling another BPF function call in order to pass it via %rax.
In the latter case, we miscalculate the offset at which the tail call count
was stored on function entry. The JIT does not take into account that the
allocated BPF program stack is always a multiple of 8 on x86, while the
actual stack depth does not have to be.
This leads to a load from an offset that belongs to the BPF stack, as shown
in the example below:
SEC("tc")
int entry(struct __sk_buff *skb)
{
/* Have data on stack which size is not a multiple of 8 */
volatile char arr[1] = {};
return subprog_tail(skb);
}
int entry(struct __sk_buff * skb):
0: (b4) w2 = 0
1: (73) *(u8 *)(r10 -1) = r2
2: (85) call pc+1#bpf_prog_ce2f79bb5f3e06dd_F
3: (95) exit
int entry(struct __sk_buff * skb):
0xffffffffa0201788: nop DWORD PTR [rax+rax*1+0x0]
0xffffffffa020178d: xor eax,eax
0xffffffffa020178f: push rbp
0xffffffffa0201790: mov rbp,rsp
0xffffffffa0201793: sub rsp,0x8
0xffffffffa020179a: push rax
0xffffffffa020179b: xor esi,esi
0xffffffffa020179d: mov BYTE PTR [rbp-0x1],sil
0xffffffffa02017a1: mov rax,QWORD PTR [rbp-0x9] !!! tail call count
0xffffffffa02017a8: call 0xffffffffa02017d8 !!! is at rbp-0x10
0xffffffffa02017ad: leave
0xffffffffa02017ae: ret
Fix it by rounding up the BPF stack depth to a multiple of 8, when
calculating the tail call count offset on stack.
Fixes: ebf7d1f508 ("bpf, x64: rework pro/epilogue and tailcall handling in JIT")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220616162037.535469-2-jakub@cloudflare.com
Introduce bpf_arch_text_invalidate and use it to fill unused part of the
bpf_prog_pack with illegal instructions when a BPF program is freed.
Fixes: 57631054fa ("bpf: Introduce bpf_prog_pack allocator")
Fixes: 33c9805860 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220520235758.1858153-4-song@kernel.org
Pass a cookie along with BPF_LINK_CREATE requests.
Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie.
The cookie of a bpf_tracing_link is available by calling
bpf_get_attach_cookie when running the BPF program of the attached
link.
The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com
BPF trampolines will create a bpf_tramp_run_ctx, a bpf_run_ctx, on
stacks and set/reset the current bpf_run_ctx before/after calling a
bpf_prog.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-3-kuifeng@fb.com
Replace struct bpf_tramp_progs with struct bpf_tramp_links to collect
struct bpf_tramp_link(s) for a trampoline. struct bpf_tramp_link
extends bpf_link to act as a linked list node.
arch_prepare_bpf_trampoline() accepts a struct bpf_tramp_links to
collects all bpf_tramp_link(s) that a trampoline should call.
Change BPF trampoline and bpf_struct_ops to pass bpf_tramp_links
instead of bpf_tramp_progs.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-2-kuifeng@fb.com
Clang can inline emit_indirect_jump() and then folds constants, which
results in:
| vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x6a4: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40
| vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x67d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40
| vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x386: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20
| vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x35d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20
Suppress the optimization such that it must emit a code reference to
the __x86_indirect_thunk_array[] base.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lkml.kernel.org/r/20220405075531.GB30877@worktop.programming.kicks-ass.net
coarse grained, hardware based, forward edge Control-Flow-Integrity mechanism
where any indirect CALL/JMP must target an ENDBR instruction or suffer #CP.
Additionally, since Alderlake (12th gen)/Sapphire-Rapids, speculation is
limited to 2 instructions (and typically fewer) on branch targets not starting
with ENDBR. CET-IBT also limits speculation of the next sequential instruction
after the indirect CALL/JMP [1].
CET-IBT is fundamentally incompatible with retpolines, but provides, as
described above, speculation limits itself.
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html
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Merge tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 CET-IBT (Control-Flow-Integrity) support from Peter Zijlstra:
"Add support for Intel CET-IBT, available since Tigerlake (11th gen),
which is a coarse grained, hardware based, forward edge
Control-Flow-Integrity mechanism where any indirect CALL/JMP must
target an ENDBR instruction or suffer #CP.
Additionally, since Alderlake (12th gen)/Sapphire-Rapids, speculation
is limited to 2 instructions (and typically fewer) on branch targets
not starting with ENDBR. CET-IBT also limits speculation of the next
sequential instruction after the indirect CALL/JMP [1].
CET-IBT is fundamentally incompatible with retpolines, but provides,
as described above, speculation limits itself"
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html
* tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
kvm/emulate: Fix SETcc emulation for ENDBR
x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0
x86/Kconfig: Only enable CONFIG_CC_HAS_IBT for clang >= 14.0.0
kbuild: Fixup the IBT kbuild changes
x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
x86: Remove toolchain check for X32 ABI capability
x86/alternative: Use .ibt_endbr_seal to seal indirect calls
objtool: Find unused ENDBR instructions
objtool: Validate IBT assumptions
objtool: Add IBT/ENDBR decoding
objtool: Read the NOENDBR annotation
x86: Annotate idtentry_df()
x86,objtool: Move the ASM_REACHABLE annotation to objtool.h
x86: Annotate call_on_stack()
objtool: Rework ASM_REACHABLE
x86: Mark __invalid_creds() __noreturn
exit: Mark do_group_exit() __noreturn
x86: Mark stop_this_cpu() __noreturn
objtool: Ignore extra-symbol code
objtool: Rename --duplicate to --lto
...
Alexei Starovoitov says:
====================
pull-request: bpf-next 2022-03-21 v2
We've added 137 non-merge commits during the last 17 day(s) which contain
a total of 143 files changed, 7123 insertions(+), 1092 deletions(-).
The main changes are:
1) Custom SEC() handling in libbpf, from Andrii.
2) subskeleton support, from Delyan.
3) Use btf_tag to recognize __percpu pointers in the verifier, from Hao.
4) Fix net.core.bpf_jit_harden race, from Hou.
5) Fix bpf_sk_lookup remote_port on big-endian, from Jakub.
6) Introduce fprobe (multi kprobe) _without_ arch bits, from Masami.
The arch specific bits will come later.
7) Introduce multi_kprobe bpf programs on top of fprobe, from Jiri.
8) Enable non-atomic allocations in local storage, from Joanne.
9) Various var_off ptr_to_btf_id fixed, from Kumar.
10) bpf_ima_file_hash helper, from Roberto.
11) Add "live packet" mode for XDP in BPF_PROG_RUN, from Toke.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (137 commits)
selftests/bpf: Fix kprobe_multi test.
Revert "rethook: x86: Add rethook x86 implementation"
Revert "arm64: rethook: Add arm64 rethook implementation"
Revert "powerpc: Add rethook support"
Revert "ARM: rethook: Add rethook arm implementation"
bpftool: Fix a bug in subskeleton code generation
bpf: Fix bpf_prog_pack when PMU_SIZE is not defined
bpf: Fix bpf_prog_pack for multi-node setup
bpf: Fix warning for cast from restricted gfp_t in verifier
bpf, arm: Fix various typos in comments
libbpf: Close fd in bpf_object__reuse_map
bpftool: Fix print error when show bpf map
bpf: Fix kprobe_multi return probe backtrace
Revert "bpf: Add support to inline bpf_get_func_ip helper on x86"
bpf: Simplify check in btf_parse_hdr()
selftests/bpf/test_lirc_mode2.sh: Exit with proper code
bpf: Check for NULL return from bpf_get_btf_vmlinux
selftests/bpf: Test skipping stacktrace
bpf: Adjust BPF stack helper functions to accommodate skip > 0
bpf: Select proper size for bpf_prog_pack
...
====================
Link: https://lore.kernel.org/r/20220322050159.5507-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Extra pass for subprog jit may fail (e.g. due to bpf_jit_harden race),
but bpf_func is not cleared for the subprog and jit_subprogs will
succeed. The running of the bpf program may lead to oops because the
memory for the jited subprog image has already been freed.
So fall back to interpreter mode by clearing bpf_func/jited/jited_len
when extra pass fails.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220309123321.2400262-2-houtao1@huawei.com
With IBT enabled builds we need ENDBR instructions at indirect jump
target sites, since we start execution of the JIT'ed code through an
indirect jump, the very first instruction needs to be ENDBR.
Similarly, since eBPF tail-calls use indirect branches, their landing
site needs to be an ENDBR too.
The trampolines need similar adjustment.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Fixed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.464998838@infradead.org
On do_jit failure path, the header is freed by bpf_jit_binary_pack_free.
While bpf_jit_binary_pack_free doesn't require proper ro_header->size,
bpf_prog_pack_free still uses it. Set header->size in bpf_int_jit_compile
before calling bpf_jit_binary_pack_free.
Fixes: 1022a5498f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
Fixes: 33c9805860 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]")
Reported-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220302175126.247459-3-song@kernel.org
The RETPOLINE_AMD name is unfortunate since it isn't necessarily
AMD only, in fact Hygon also uses it. Furthermore it will likely be
sufficient for some Intel processors. Therefore rename the thing to
RETPOLINE_LFENCE to better describe what it is.
Add the spectre_v2=retpoline,lfence option as an alias to
spectre_v2=retpoline,amd to preserve existing setups. However, the output
of /sys/devices/system/cpu/vulnerabilities/spectre_v2 will be changed.
[ bp: Fix typos, massage. ]
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Use bpf_jit_binary_pack_alloc in x86_64 jit. The jit engine first writes
the program to the rw buffer. When the jit is done, the program is copied
to the final location with bpf_jit_binary_pack_finalize.
Note that we need to do bpf_tail_call_direct_fixup after finalize.
Therefore, the text_live = false logic in __bpf_arch_text_poke is no
longer needed.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-10-song@kernel.org
This will be used to copy JITed text to RO protected module memory. On
x86, bpf_arch_text_copy is implemented with text_poke_copy.
bpf_arch_text_copy returns pointer to dst on success, and ERR_PTR(errno)
on errors.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-7-song@kernel.org
According to the LLVM commit (https://reviews.llvm.org/D72184),
sync_fetch_and_sub() is implemented as a negation followed by
sync_fetch_and_add(), so there will be no BPF_SUB op, thus just
remove it. BPF_SUB is also rejected by the verifier anyway.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Brendan Jackman <jackmanb@google.com>
Link: https://lore.kernel.org/bpf/20220127083240.1425481-1-houtao1@huawei.com
