Currently, the hyp code cannot make full use of a bss, as the kernel
section is mapped read-only.
While this mapping could simply be changed to read-write, it would
intermingle even more the hyp and kernel state than they currently are.
Instead, introduce a __hyp_bss section, that uses reserved pages, and
create the appropriate RW hyp mappings during KVM init.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-8-qperret@google.com
- Support for userspace to emulate Xen hypercalls
- Raise the maximum number of user memslots
- Scalability improvements for the new MMU. Instead of the complex
"fast page fault" logic that is used in mmu.c, tdp_mmu.c uses an
rwlock so that page faults are concurrent, but the code that can run
against page faults is limited. Right now only page faults take the
lock for reading; in the future this will be extended to some
cases of page table destruction. I hope to switch the default MMU
around 5.12-rc3 (some testing was delayed due to Chinese New Year).
- Cleanups for MAXPHYADDR checks
- Use static calls for vendor-specific callbacks
- On AMD, use VMLOAD/VMSAVE to save and restore host state
- Stop using deprecated jump label APIs
- Workaround for AMD erratum that made nested virtualization unreliable
- Support for LBR emulation in the guest
- Support for communicating bus lock vmexits to userspace
- Add support for SEV attestation command
- Miscellaneous cleanups
PPC:
- Support for second data watchpoint on POWER10
- Remove some complex workarounds for buggy early versions of POWER9
- Guest entry/exit fixes
ARM64
- Make the nVHE EL2 object relocatable
- Cleanups for concurrent translation faults hitting the same page
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Simplification of the early init hypercall handling
Non-KVM changes (with acks):
- Detection of contended rwlocks (implemented only for qrwlocks,
because KVM only needs it for x86)
- Allow __DISABLE_EXPORTS from assembly code
- Provide a saner follow_pfn replacements for modules
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"x86:
- Support for userspace to emulate Xen hypercalls
- Raise the maximum number of user memslots
- Scalability improvements for the new MMU.
Instead of the complex "fast page fault" logic that is used in
mmu.c, tdp_mmu.c uses an rwlock so that page faults are concurrent,
but the code that can run against page faults is limited. Right now
only page faults take the lock for reading; in the future this will
be extended to some cases of page table destruction. I hope to
switch the default MMU around 5.12-rc3 (some testing was delayed
due to Chinese New Year).
- Cleanups for MAXPHYADDR checks
- Use static calls for vendor-specific callbacks
- On AMD, use VMLOAD/VMSAVE to save and restore host state
- Stop using deprecated jump label APIs
- Workaround for AMD erratum that made nested virtualization
unreliable
- Support for LBR emulation in the guest
- Support for communicating bus lock vmexits to userspace
- Add support for SEV attestation command
- Miscellaneous cleanups
PPC:
- Support for second data watchpoint on POWER10
- Remove some complex workarounds for buggy early versions of POWER9
- Guest entry/exit fixes
ARM64:
- Make the nVHE EL2 object relocatable
- Cleanups for concurrent translation faults hitting the same page
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Simplification of the early init hypercall handling
Non-KVM changes (with acks):
- Detection of contended rwlocks (implemented only for qrwlocks,
because KVM only needs it for x86)
- Allow __DISABLE_EXPORTS from assembly code
- Provide a saner follow_pfn replacements for modules"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (192 commits)
KVM: x86/xen: Explicitly pad struct compat_vcpu_info to 64 bytes
KVM: selftests: Don't bother mapping GVA for Xen shinfo test
KVM: selftests: Fix hex vs. decimal snafu in Xen test
KVM: selftests: Fix size of memslots created by Xen tests
KVM: selftests: Ignore recently added Xen tests' build output
KVM: selftests: Add missing header file needed by xAPIC IPI tests
KVM: selftests: Add operand to vmsave/vmload/vmrun in svm.c
KVM: SVM: Make symbol 'svm_gp_erratum_intercept' static
locking/arch: Move qrwlock.h include after qspinlock.h
KVM: PPC: Book3S HV: Fix host radix SLB optimisation with hash guests
KVM: PPC: Book3S HV: Ensure radix guest has no SLB entries
KVM: PPC: Don't always report hash MMU capability for P9 < DD2.2
KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path
KVM: PPC: remove unneeded semicolon
KVM: PPC: Book3S HV: Use POWER9 SLBIA IH=6 variant to clear SLB
KVM: PPC: Book3S HV: No need to clear radix host SLB before loading HPT guest
KVM: PPC: Book3S HV: Fix radix guest SLB side channel
KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support
KVM: PPC: Book3S HV: Introduce new capability for 2nd DAWR
KVM: PPC: Book3S HV: Add infrastructure to support 2nd DAWR
...
Add TRAMP_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and tramp_pg_dir.
Then use TRAMP_SWAPPER_OFFSET to assert that the offset is
correct at link time.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210202123658.22308-3-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Add RESERVED_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and reserved_pg_dir.
Then use RESERVED_SWAPPER_OFFSET to assert that the offset is
correct at link time.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210202123658.22308-2-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Add a post-processing step to compilation of KVM nVHE hyp code which
calls a custom host tool (gen-hyprel) on the partially linked object
file (hyp sections' names prefixed).
The tool lists all R_AARCH64_ABS64 data relocations targeting hyp
sections and generates an assembly file that will form a new section
.hyp.reloc in the kernel binary. The new section contains an array of
32-bit offsets to the positions targeted by these relocations.
Since these addresses of those positions will not be determined until
linking of `vmlinux`, each 32-bit entry carries a R_AARCH64_PREL32
relocation with addend <section_base_sym> + <r_offset>. The linker of
`vmlinux` will therefore fill the slot accordingly.
This relocation data will be used at runtime to convert the kernel VAs
at those positions to hyp VAs.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-5-dbrazdil@google.com
We will need to recognize pointers in .rodata specific to hyp, so
establish a .hyp.rodata ELF section. Merge it with the existing
.hyp.data..ro_after_init as they are treated the same at runtime.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-3-dbrazdil@google.com
* PSCI relay at EL2 when "protected KVM" is enabled
* New exception injection code
* Simplification of AArch32 system register handling
* Fix PMU accesses when no PMU is enabled
* Expose CSV3 on non-Meltdown hosts
* Cache hierarchy discovery fixes
* PV steal-time cleanups
* Allow function pointers at EL2
* Various host EL2 entry cleanups
* Simplification of the EL2 vector allocation
s390:
* memcg accouting for s390 specific parts of kvm and gmap
* selftest for diag318
* new kvm_stat for when async_pf falls back to sync
x86:
* Tracepoints for the new pagetable code from 5.10
* Catch VFIO and KVM irqfd events before userspace
* Reporting dirty pages to userspace with a ring buffer
* SEV-ES host support
* Nested VMX support for wait-for-SIPI activity state
* New feature flag (AVX512 FP16)
* New system ioctl to report Hyper-V-compatible paravirtualization features
Generic:
* Selftest improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Much x86 work was pushed out to 5.12, but ARM more than made up for it.
ARM:
- PSCI relay at EL2 when "protected KVM" is enabled
- New exception injection code
- Simplification of AArch32 system register handling
- Fix PMU accesses when no PMU is enabled
- Expose CSV3 on non-Meltdown hosts
- Cache hierarchy discovery fixes
- PV steal-time cleanups
- Allow function pointers at EL2
- Various host EL2 entry cleanups
- Simplification of the EL2 vector allocation
s390:
- memcg accouting for s390 specific parts of kvm and gmap
- selftest for diag318
- new kvm_stat for when async_pf falls back to sync
x86:
- Tracepoints for the new pagetable code from 5.10
- Catch VFIO and KVM irqfd events before userspace
- Reporting dirty pages to userspace with a ring buffer
- SEV-ES host support
- Nested VMX support for wait-for-SIPI activity state
- New feature flag (AVX512 FP16)
- New system ioctl to report Hyper-V-compatible paravirtualization features
Generic:
- Selftest improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (171 commits)
KVM: SVM: fix 32-bit compilation
KVM: SVM: Add AP_JUMP_TABLE support in prep for AP booting
KVM: SVM: Provide support to launch and run an SEV-ES guest
KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests
KVM: SVM: Provide support for SEV-ES vCPU loading
KVM: SVM: Provide support for SEV-ES vCPU creation/loading
KVM: SVM: Update ASID allocation to support SEV-ES guests
KVM: SVM: Set the encryption mask for the SVM host save area
KVM: SVM: Add NMI support for an SEV-ES guest
KVM: SVM: Guest FPU state save/restore not needed for SEV-ES guest
KVM: SVM: Do not report support for SMM for an SEV-ES guest
KVM: x86: Update __get_sregs() / __set_sregs() to support SEV-ES
KVM: SVM: Add support for CR8 write traps for an SEV-ES guest
KVM: SVM: Add support for CR4 write traps for an SEV-ES guest
KVM: SVM: Add support for CR0 write traps for an SEV-ES guest
KVM: SVM: Add support for EFER write traps for an SEV-ES guest
KVM: SVM: Support string IO operations for an SEV-ES guest
KVM: SVM: Support MMIO for an SEV-ES guest
KVM: SVM: Create trace events for VMGEXIT MSR protocol processing
KVM: SVM: Create trace events for VMGEXIT processing
...
* for-next/kvm-build-fix:
: Fix KVM build issues with 64K pages
KVM: arm64: Fix build error in user_mem_abort()
* for-next/va-refactor:
: VA layout changes
arm64: mm: don't assume struct page is always 64 bytes
Documentation/arm64: fix RST layout of memory.rst
arm64: mm: tidy up top of kernel VA space
arm64: mm: make vmemmap region a projection of the linear region
arm64: mm: extend linear region for 52-bit VA configurations
* for-next/lto:
: Upgrade READ_ONCE() to RCpc acquire on arm64 with LTO
arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y
arm64: alternatives: Remove READ_ONCE() usage during patch operation
arm64: cpufeatures: Add capability for LDAPR instruction
arm64: alternatives: Split up alternative.h
arm64: uaccess: move uao_* alternatives to asm-uaccess.h
* for-next/mem-hotplug:
: Memory hotplug improvements
arm64/mm/hotplug: Ensure early memory sections are all online
arm64/mm/hotplug: Enable MEM_OFFLINE event handling
arm64/mm/hotplug: Register boot memory hot remove notifier earlier
arm64: mm: account for hotplug memory when randomizing the linear region
* for-next/cppc-ffh:
: Add CPPC FFH support using arm64 AMU counters
arm64: abort counter_read_on_cpu() when irqs_disabled()
arm64: implement CPPC FFH support using AMUs
arm64: split counter validation function
arm64: wrap and generalise counter read functions
* for-next/pad-image-header:
: Pad Image header to 64KB and unmap it
arm64: head: tidy up the Image header definition
arm64/head: avoid symbol names pointing into first 64 KB of kernel image
arm64: omit [_text, _stext) from permanent kernel mapping
* for-next/zone-dma-default-32-bit:
: Default to 32-bit wide ZONE_DMA (previously reduced to 1GB for RPi4)
of: unittest: Fix build on architectures without CONFIG_OF_ADDRESS
mm: Remove examples from enum zone_type comment
arm64: mm: Set ZONE_DMA size based on early IORT scan
arm64: mm: Set ZONE_DMA size based on devicetree's dma-ranges
of: unittest: Add test for of_dma_get_max_cpu_address()
of/address: Introduce of_dma_get_max_cpu_address()
arm64: mm: Move zone_dma_bits initialization into zone_sizes_init()
arm64: mm: Move reserve_crashkernel() into mem_init()
arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is required
arm64: Ignore any DMA offsets in the max_zone_phys() calculation
* for-next/signal-tag-bits:
: Expose the FAR_EL1 tag bits in siginfo
arm64: expose FAR_EL1 tag bits in siginfo
signal: define the SA_EXPOSE_TAGBITS bit in sa_flags
signal: define the SA_UNSUPPORTED bit in sa_flags
arch: provide better documentation for the arch-specific SA_* flags
signal: clear non-uapi flag bits when passing/returning sa_flags
arch: move SA_* definitions to generic headers
parisc: start using signal-defs.h
parisc: Drop parisc special case for __sighandler_t
* for-next/cmdline-extended:
: Add support for CONFIG_CMDLINE_EXTENDED
arm64: Extend the kernel command line from the bootloader
arm64: kaslr: Refactor early init command line parsing
Add rules for renaming the .data..ro_after_init ELF section in KVM nVHE
object files to .hyp.data..ro_after_init, linking it into the kernel
and mapping it in hyp at runtime.
The section is RW to the host, then mapped RO in hyp. The expectation is
that the host populates the variables in the section and they are never
changed by hyp afterwards.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-13-dbrazdil@google.com
We currently try to emit *.init.rodata.* twice, once in INIT_DATA, and once
in the line immediately following it. As the two section definitions are
identical, the latter is redundant and can be dropped.
This patch drops the redundant *.init.rodata.* section definition.
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1605750340-910-1-git-send-email-tangyouling@loongson.cn
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In a previous patch, we increased the size of the EFI PE/COFF header
to 64 KB, which resulted in the _stext symbol to appear at a fixed
offset of 64 KB into the image.
Since 64 KB is also the largest page size we support, this completely
removes the need to map the first 64 KB of the kernel image, given that
it only contains the arm64 Image header and the EFI header, neither of
which we ever access again after booting the kernel. More importantly,
we should avoid an executable mapping of non-executable and not entirely
predictable data, to deal with the unlikely event that we inadvertently
emitted something that looks like an opcode that could be used as a
gadget for speculative execution.
So let's limit the kernel mapping of .text to the [_stext, _etext)
region, which matches the view of generic code (such as kallsyms) when
it reasons about the boundaries of the kernel's .text section.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201117124729.12642-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Depending on configuration options and specific code paths, we either
use the empty_zero_page or the configuration-dependent reserved_ttbr0
as a reserved value for TTBR{0,1}_EL1.
To simplify this code, let's always allocate and use the same
reserved_pg_dir, replacing reserved_ttbr0. Note that this is allocated
(and hence pre-zeroed), and is also marked as read-only in the kernel
Image mapping.
Keeping this separate from the empty_zero_page potentially helps with
robustness as the empty_zero_page is used in a number of cases where a
failure to map it read-only could allow it to become corrupted.
The (presently unused) swapper_pg_end symbol is also removed, and
comments are added wherever we rely on the offsets between the
pre-allocated pg_dirs to keep these cases easily identifiable.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201103102229.8542-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When building with LTO, there is an increased risk of the compiler
converting an address dependency headed by a READ_ONCE() invocation
into a control dependency and consequently allowing for harmful
reordering by the CPU.
Ensure that such transformations are harmless by overriding the generic
READ_ONCE() definition with one that provides acquire semantics when
building with LTO.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Now that we started making the linker warn about orphan sections
(input sections that are not explicitly consumed by an output section),
some configurations produce the following warning:
aarch64-linux-gnu-ld: warning: orphan section `.igot.plt' from
`arch/arm64/kernel/head.o' being placed in section `.igot.plt'
It could be any file that triggers this - head.o is simply the first
input file in the link - and the resulting .igot.plt section never
actually appears in vmlinux as it turns out to be empty.
So let's add .igot.plt to our collection of input sections to disregard
unless they are empty.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20201028133332.5571-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
- New page table code for both hypervisor and guest stage-2
- Introduction of a new EL2-private host context
- Allow EL2 to have its own private per-CPU variables
- Support of PMU event filtering
- Complete rework of the Spectre mitigation
PPC:
- Fix for running nested guests with in-kernel IRQ chip
- Fix race condition causing occasional host hard lockup
- Minor cleanups and bugfixes
x86:
- allow trapping unknown MSRs to userspace
- allow userspace to force #GP on specific MSRs
- INVPCID support on AMD
- nested AMD cleanup, on demand allocation of nested SVM state
- hide PV MSRs and hypercalls for features not enabled in CPUID
- new test for MSR_IA32_TSC writes from host and guest
- cleanups: MMU, CPUID, shared MSRs
- LAPIC latency optimizations ad bugfixes
For x86, also included in this pull request is a new alternative and
(in the future) more scalable implementation of extended page tables
that does not need a reverse map from guest physical addresses to
host physical addresses. For now it is disabled by default because
it is still lacking a few of the existing MMU's bells and whistles.
However it is a very solid piece of work and it is already available
for people to hammer on it.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"For x86, there is a new alternative and (in the future) more scalable
implementation of extended page tables that does not need a reverse
map from guest physical addresses to host physical addresses.
For now it is disabled by default because it is still lacking a few of
the existing MMU's bells and whistles. However it is a very solid
piece of work and it is already available for people to hammer on it.
Other updates:
ARM:
- New page table code for both hypervisor and guest stage-2
- Introduction of a new EL2-private host context
- Allow EL2 to have its own private per-CPU variables
- Support of PMU event filtering
- Complete rework of the Spectre mitigation
PPC:
- Fix for running nested guests with in-kernel IRQ chip
- Fix race condition causing occasional host hard lockup
- Minor cleanups and bugfixes
x86:
- allow trapping unknown MSRs to userspace
- allow userspace to force #GP on specific MSRs
- INVPCID support on AMD
- nested AMD cleanup, on demand allocation of nested SVM state
- hide PV MSRs and hypercalls for features not enabled in CPUID
- new test for MSR_IA32_TSC writes from host and guest
- cleanups: MMU, CPUID, shared MSRs
- LAPIC latency optimizations ad bugfixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (232 commits)
kvm: x86/mmu: NX largepage recovery for TDP MMU
kvm: x86/mmu: Don't clear write flooding count for direct roots
kvm: x86/mmu: Support MMIO in the TDP MMU
kvm: x86/mmu: Support write protection for nesting in tdp MMU
kvm: x86/mmu: Support disabling dirty logging for the tdp MMU
kvm: x86/mmu: Support dirty logging for the TDP MMU
kvm: x86/mmu: Support changed pte notifier in tdp MMU
kvm: x86/mmu: Add access tracking for tdp_mmu
kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMU
kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU
kvm: x86/mmu: Add TDP MMU PF handler
kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg
kvm: x86/mmu: Support zapping SPTEs in the TDP MMU
KVM: Cache as_id in kvm_memory_slot
kvm: x86/mmu: Add functions to handle changed TDP SPTEs
kvm: x86/mmu: Allocate and free TDP MMU roots
kvm: x86/mmu: Init / Uninit the TDP MMU
kvm: x86/mmu: Introduce tdp_iter
KVM: mmu: extract spte.h and spte.c
KVM: mmu: Separate updating a PTE from kvm_set_pte_rmapp
...
because the heuristics that various linkers & compilers use to handle them
(include these bits into the output image vs discarding them silently)
are both highly idiosyncratic and also version dependent.
Instead of this historically problematic mess, this tree by Kees Cook (et al)
adds build time asserts and build time warnings if there's any orphan section
in the kernel or if a section is not sized as expected.
And because we relied on so many silent assumptions in this area, fix a metric
ton of dependencies and some outright bugs related to this, before we can
finally enable the checks on the x86, ARM and ARM64 platforms.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull orphan section checking from Ingo Molnar:
"Orphan link sections were a long-standing source of obscure bugs,
because the heuristics that various linkers & compilers use to handle
them (include these bits into the output image vs discarding them
silently) are both highly idiosyncratic and also version dependent.
Instead of this historically problematic mess, this tree by Kees Cook
(et al) adds build time asserts and build time warnings if there's any
orphan section in the kernel or if a section is not sized as expected.
And because we relied on so many silent assumptions in this area, fix
a metric ton of dependencies and some outright bugs related to this,
before we can finally enable the checks on the x86, ARM and ARM64
platforms"
* tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/boot/compressed: Warn on orphan section placement
x86/build: Warn on orphan section placement
arm/boot: Warn on orphan section placement
arm/build: Warn on orphan section placement
arm64/build: Warn on orphan section placement
x86/boot/compressed: Add missing debugging sections to output
x86/boot/compressed: Remove, discard, or assert for unwanted sections
x86/boot/compressed: Reorganize zero-size section asserts
x86/build: Add asserts for unwanted sections
x86/build: Enforce an empty .got.plt section
x86/asm: Avoid generating unused kprobe sections
arm/boot: Handle all sections explicitly
arm/build: Assert for unwanted sections
arm/build: Add missing sections
arm/build: Explicitly keep .ARM.attributes sections
arm/build: Refactor linker script headers
arm64/build: Assert for unwanted sections
arm64/build: Add missing DWARF sections
arm64/build: Use common DISCARDS in linker script
arm64/build: Remove .eh_frame* sections due to unwind tables
...
Add hyp percpu section to linker script and rename the corresponding ELF
sections of hyp/nvhe object files. This moves all nVHE-specific percpu
variables to the new hyp percpu section.
Allocate sufficient amount of memory for all percpu hyp regions at global KVM
init time and create corresponding hyp mappings.
The base addresses of hyp percpu regions are kept in a dynamically allocated
array in the kernel.
Add NULL checks in PMU event-reset code as it may run before KVM memory is
initialized.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-10-dbrazdil@google.com
Minor cleanup that only creates __kvm_ex_table ELF section and
related symbols if CONFIG_KVM is enabled. Also useful as more
hyp-specific sections will be added.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-4-dbrazdil@google.com
Minor cleanup to move all macros related to prefixing nVHE hyp section
and symbol names into one place: hyp_image.h.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-3-dbrazdil@google.com
TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues that require us to revisit that decision, let's get rid of the
macro entirely, along with any references to it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Use the common DISCARDS rule for the linker script in an effort to
regularize the linker script to prepare for warning on orphaned
sections. Additionally clean up left-over no-op macros.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-12-keescook@chromium.org
Avoid .eh_frame* section generation by making sure both CFLAGS and AFLAGS
contain -fno-asychronous-unwind-tables and -fno-unwind-tables.
With all sources of .eh_frame now removed from the build, drop this
DISCARD so we can be alerted in the future if it returns unexpectedly
once orphan section warnings have been enabled.
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-11-keescook@chromium.org
The .comment section doesn't belong in STABS_DEBUG. Split it out into a
new macro named ELF_DETAILS. This will gain other non-debug sections
that need to be accounted for when linking with --orphan-handling=warn.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20200821194310.3089815-5-keescook@chromium.org
KVM has a one instruction window where it will allow an SError exception
to be consumed by the hypervisor without treating it as a hypervisor bug.
This is used to consume asynchronous external abort that were caused by
the guest.
As we are about to add another location that survives unexpected exceptions,
generalise this code to make it behave like the host's extable.
KVM's version has to be mapped to EL2 to be accessible on nVHE systems.
The SError vaxorcism code is a one instruction window, so has two entries
in the extable. Because the KVM code is copied for VHE and nVHE, we end up
with four entries, half of which correspond with code that isn't mapped.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
- Removal of the tremendously unpopular read_barrier_depends() barrier,
which is a NOP on all architectures apart from Alpha, in favour of
allowing architectures to override READ_ONCE() and do whatever dance
they need to do to ensure address dependencies provide LOAD ->
LOAD/STORE ordering. This work also offers a potential solution if
compilers are shown to convert LOAD -> LOAD address dependencies into
control dependencies (e.g. under LTO), as weakly ordered architectures
will effectively be able to upgrade READ_ONCE() to smp_load_acquire().
The latter case is not used yet, but will be discussed further at LPC.
- Make the MSI/IOMMU input/output ID translation PCI agnostic, augment
the MSI/IOMMU ACPI/OF ID mapping APIs to accept an input ID
bus-specific parameter and apply the resulting changes to the device
ID space provided by the Freescale FSL bus.
- arm64 support for TLBI range operations and translation table level
hints (part of the ARMv8.4 architecture version).
- Time namespace support for arm64.
- Export the virtual and physical address sizes in vmcoreinfo for
makedumpfile and crash utilities.
- CPU feature handling cleanups and checks for programmer errors
(overlapping bit-fields).
- ACPI updates for arm64: disallow AML accesses to EFI code regions and
kernel memory.
- perf updates for arm64.
- Miscellaneous fixes and cleanups, most notably PLT counting
optimisation for module loading, recordmcount fix to ignore
relocations other than R_AARCH64_CALL26, CMA areas reserved for
gigantic pages on 16K and 64K configurations.
- Trivial typos, duplicate words.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 and cross-arch updates from Catalin Marinas:
"Here's a slightly wider-spread set of updates for 5.9.
Going outside the usual arch/arm64/ area is the removal of
read_barrier_depends() series from Will and the MSI/IOMMU ID
translation series from Lorenzo.
The notable arm64 updates include ARMv8.4 TLBI range operations and
translation level hint, time namespace support, and perf.
Summary:
- Removal of the tremendously unpopular read_barrier_depends()
barrier, which is a NOP on all architectures apart from Alpha, in
favour of allowing architectures to override READ_ONCE() and do
whatever dance they need to do to ensure address dependencies
provide LOAD -> LOAD/STORE ordering.
This work also offers a potential solution if compilers are shown
to convert LOAD -> LOAD address dependencies into control
dependencies (e.g. under LTO), as weakly ordered architectures will
effectively be able to upgrade READ_ONCE() to smp_load_acquire().
The latter case is not used yet, but will be discussed further at
LPC.
- Make the MSI/IOMMU input/output ID translation PCI agnostic,
augment the MSI/IOMMU ACPI/OF ID mapping APIs to accept an input ID
bus-specific parameter and apply the resulting changes to the
device ID space provided by the Freescale FSL bus.
- arm64 support for TLBI range operations and translation table level
hints (part of the ARMv8.4 architecture version).
- Time namespace support for arm64.
- Export the virtual and physical address sizes in vmcoreinfo for
makedumpfile and crash utilities.
- CPU feature handling cleanups and checks for programmer errors
(overlapping bit-fields).
- ACPI updates for arm64: disallow AML accesses to EFI code regions
and kernel memory.
- perf updates for arm64.
- Miscellaneous fixes and cleanups, most notably PLT counting
optimisation for module loading, recordmcount fix to ignore
relocations other than R_AARCH64_CALL26, CMA areas reserved for
gigantic pages on 16K and 64K configurations.
- Trivial typos, duplicate words"
Link: http://lkml.kernel.org/r/20200710165203.31284-1-will@kernel.org
Link: http://lkml.kernel.org/r/20200619082013.13661-1-lorenzo.pieralisi@arm.com
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (82 commits)
arm64: use IRQ_STACK_SIZE instead of THREAD_SIZE for irq stack
arm64/mm: save memory access in check_and_switch_context() fast switch path
arm64: sigcontext.h: delete duplicated word
arm64: ptrace.h: delete duplicated word
arm64: pgtable-hwdef.h: delete duplicated words
bus: fsl-mc: Add ACPI support for fsl-mc
bus/fsl-mc: Refactor the MSI domain creation in the DPRC driver
of/irq: Make of_msi_map_rid() PCI bus agnostic
of/irq: make of_msi_map_get_device_domain() bus agnostic
dt-bindings: arm: fsl: Add msi-map device-tree binding for fsl-mc bus
of/device: Add input id to of_dma_configure()
of/iommu: Make of_map_rid() PCI agnostic
ACPI/IORT: Add an input ID to acpi_dma_configure()
ACPI/IORT: Remove useless PCI bus walk
ACPI/IORT: Make iort_msi_map_rid() PCI agnostic
ACPI/IORT: Make iort_get_device_domain IRQ domain agnostic
ACPI/IORT: Make iort_match_node_callback walk the ACPI namespace for NC
arm64: enable time namespace support
arm64/vdso: Restrict splitting VVAR VMA
arm64/vdso: Handle faults on timens page
...
Although vmlinux.lds.S smells like an assembly file and is compiled
with __ASSEMBLY__ defined, it's actually just fed to the preprocessor to
create our linker script. This means that any assembly macros defined
by headers that it includes will result in a helpful link error:
| aarch64-linux-gnu-ld:./arch/arm64/kernel/vmlinux.lds:1: syntax error
In preparation for an arm64-private asm/rwonce.h implementation, which
will end up pulling assembly macros into linux/compiler.h, reduce the
number of headers we include directly and transitively in vmlinux.lds.S
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Will Deacon <will@kernel.org>
When building very large kernels, the logic that emits replacement
sequences for alternatives fails when relative branches are present
in the code that is emitted into the .altinstr_replacement section
and patched in at the original site and fixed up. The reason is that
the linker will insert veneers if relative branches go out of range,
and due to the relative distance of the .altinstr_replacement from
the .text section where its branch targets usually live, veneers
may be emitted at the end of the .altinstr_replacement section, with
the relative branches in the sequence pointed at the veneers instead
of the actual target.
The alternatives patching logic will attempt to fix up the branch to
point to its original target, which will be the veneer in this case,
but given that the patch site is likely to be far away as well, it
will be out of range and so patching will fail. There are other cases
where these veneers are problematic, e.g., when the target of the
branch is in .text while the patch site is in .init.text, in which
case putting the replacement sequence inside .text may not help either.
So let's use subsections to emit the replacement code as closely as
possible to the patch site, to ensure that veneers are only likely to
be emitted if they are required at the patch site as well, in which
case they will be in range for the replacement sequence both before
and after it is transported to the patch site.
This will prevent alternative sequences in non-init code from being
released from memory after boot, but this is tolerable given that the
entire section is only 512 KB on an allyesconfig build (which weighs in
at 500+ MB for the entire Image). Also, note that modules today carry
the replacement sequences in non-init sections as well, and any of
those that target init code will be emitted into init sections after
this change.
This fixes an early crash when booting an allyesconfig kernel on a
system where any of the alternatives sequences containing relative
branches are activated at boot (e.g., ARM64_HAS_PAN on TX2)
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Dave P Martin <dave.martin@arm.com>
Link: https://lore.kernel.org/r/20200630081921.13443-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include
of the latter in the middle of asm includes. Fix this up with the aid of
the below script and manual adjustments here and there.
import sys
import re
if len(sys.argv) is not 3:
print "USAGE: %s <file> <header>" % (sys.argv[0])
sys.exit(1)
hdr_to_move="#include <linux/%s>" % sys.argv[2]
moved = False
in_hdrs = False
with open(sys.argv[1], "r") as f:
lines = f.readlines()
for _line in lines:
line = _line.rstrip('
')
if line == hdr_to_move:
continue
if line.startswith("#include <linux/"):
in_hdrs = True
elif not moved and in_hdrs:
moved = True
print hdr_to_move
print line
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The include/linux/pgtable.h is going to be the home of generic page table
manipulation functions.
Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and
make the latter include asm/pgtable.h.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The arm64 kernel's segment alignment is fixed at 64 KB for any page
size, and relocatable kernels are able to fix up any misalignment of
the kernel image with respect to the 2 MB section alignment that is
mandated by the arm64 boot protocol.
Let's increase the PE/COFF section alignment to the same value, so that
kernels loaded by the UEFI PE/COFF loader are guaranteed to end up at
an address that doesn't require any reallocation to be done if the
kernel is relocatable.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200413155521.24698-6-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Prior to commit 8eb7e28d4c ("arm64/mm: move runtime pgds to
rodata"), idmap_pgd_dir, tramp_pg_dir, reserved_ttbr0, swapper_pg_dir,
and init_pg_dir were contiguous at the end of the kernel image. The
maintenance at the end of __create_page_tables assumed these were
contiguous, and affected everything from the start of idmap_pg_dir
to the end of init_pg_dir.
That commit moved all but init_pg_dir into the .rodata section, with
other data placed between idmap_pg_dir and init_pg_dir, but did not
update the maintenance. Hence the maintenance is performed on much
more data than necessary (but as the bootloader previously made this
clean to the PoC there is no functional problem).
As we only alter idmap_pg_dir, and init_pg_dir, we only need to perform
maintenance for these. As the other dirs are in .rodata, the bootloader
will have initialised them as expected and cleaned them to the PoC. The
kernel will initialize them as necessary after enabling the MMU.
This patch reworks the maintenance to only cover the idmap_pg_dir and
init_pg_dir to avoid this unnecessary work.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200427235700.112220-1-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
ARM_EXIT_KEEP and ARM_EXIT_DISCARD are always defined in the same way,
so we don't really need them in the first place.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200416132730.25290-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
For historical reasons, the primary entry routine living somewhere in
the inittext section is called stext(), which is confusing, given that
there is also a section marker called _stext which lives at a fixed
offset in the image (either 64 or 4096 bytes, depending on whether
CONFIG_EFI is enabled)
Let's rename stext to primary_entry(), which is a better description
and reflects the secondary_entry() routine that already exists for
SMP boot.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200326171423.3080-1-ardb@kernel.org
Reviwed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
- ZONE_DMA32 initialisation fix when memblocks fall entirely within the
first GB (used by ZONE_DMA in 5.5 for Raspberry Pi 4).
- Couple of ftrace fixes following the FTRACE_WITH_REGS patchset.
- access_ok() fix for the Tagged Address ABI when called from from a
kernel thread (asynchronous I/O): the kthread does not have the TIF
flags of the mm owner, so untag the user address unconditionally.
- KVM compute_layout() called before the alternatives code patching.
- Minor clean-ups.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas:
- ZONE_DMA32 initialisation fix when memblocks fall entirely within the
first GB (used by ZONE_DMA in 5.5 for Raspberry Pi 4).
- Couple of ftrace fixes following the FTRACE_WITH_REGS patchset.
- access_ok() fix for the Tagged Address ABI when called from from a
kernel thread (asynchronous I/O): the kthread does not have the TIF
flags of the mm owner, so untag the user address unconditionally.
- KVM compute_layout() called before the alternatives code patching.
- Minor clean-ups.
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: entry: refine comment of stack overflow check
arm64: ftrace: fix ifdeffery
arm64: KVM: Invoke compute_layout() before alternatives are applied
arm64: Validate tagged addresses in access_ok() called from kernel threads
arm64: mm: Fix column alignment for UXN in kernel_page_tables
arm64: insn: consistently handle exit text
arm64: mm: Fix initialisation of DMA zones on non-NUMA systems
A kernel built with KASAN && FTRACE_WITH_REGS && !MODULES, produces a
boot-time splat in the bowels of ftrace:
| [ 0.000000] ftrace: allocating 32281 entries in 127 pages
| [ 0.000000] ------------[ cut here ]------------
| [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2019 ftrace_bug+0x27c/0x328
| [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.0-rc3-00008-g7f08ae53a7e3 #13
| [ 0.000000] Hardware name: linux,dummy-virt (DT)
| [ 0.000000] pstate: 60000085 (nZCv daIf -PAN -UAO)
| [ 0.000000] pc : ftrace_bug+0x27c/0x328
| [ 0.000000] lr : ftrace_init+0x640/0x6cc
| [ 0.000000] sp : ffffa000120e7e00
| [ 0.000000] x29: ffffa000120e7e00 x28: ffff00006ac01b10
| [ 0.000000] x27: ffff00006ac898c0 x26: dfffa00000000000
| [ 0.000000] x25: ffffa000120ef290 x24: ffffa0001216df40
| [ 0.000000] x23: 000000000000018d x22: ffffa0001244c700
| [ 0.000000] x21: ffffa00011bf393c x20: ffff00006ac898c0
| [ 0.000000] x19: 00000000ffffffff x18: 0000000000001584
| [ 0.000000] x17: 0000000000001540 x16: 0000000000000007
| [ 0.000000] x15: 0000000000000000 x14: ffffa00010432770
| [ 0.000000] x13: ffff940002483519 x12: 1ffff40002483518
| [ 0.000000] x11: 1ffff40002483518 x10: ffff940002483518
| [ 0.000000] x9 : dfffa00000000000 x8 : 0000000000000001
| [ 0.000000] x7 : ffff940002483519 x6 : ffffa0001241a8c0
| [ 0.000000] x5 : ffff940002483519 x4 : ffff940002483519
| [ 0.000000] x3 : ffffa00011780870 x2 : 0000000000000001
| [ 0.000000] x1 : 1fffe0000d591318 x0 : 0000000000000000
| [ 0.000000] Call trace:
| [ 0.000000] ftrace_bug+0x27c/0x328
| [ 0.000000] ftrace_init+0x640/0x6cc
| [ 0.000000] start_kernel+0x27c/0x654
| [ 0.000000] random: get_random_bytes called from print_oops_end_marker+0x30/0x60 with crng_init=0
| [ 0.000000] ---[ end trace 0000000000000000 ]---
| [ 0.000000] ftrace faulted on writing
| [ 0.000000] [<ffffa00011bf393c>] _GLOBAL__sub_D_65535_0___tracepoint_initcall_level+0x4/0x28
| [ 0.000000] Initializing ftrace call sites
| [ 0.000000] ftrace record flags: 0
| [ 0.000000] (0)
| [ 0.000000] expected tramp: ffffa000100b3344
This is due to an unfortunate combination of several factors.
Building with KASAN results in the compiler generating anonymous
functions to register/unregister global variables against the shadow
memory. These functions are placed in .text.startup/.text.exit, and
given mangled names like _GLOBAL__sub_{I,D}_65535_0_$OTHER_SYMBOL. The
kernel linker script places these in .init.text and .exit.text
respectively, which are both discarded at runtime as part of initmem.
Building with FTRACE_WITH_REGS uses -fpatchable-function-entry=2, which
also instruments KASAN's anonymous functions. When these are discarded
with the rest of initmem, ftrace removes dangling references to these
call sites.
Building without MODULES implicitly disables STRICT_MODULE_RWX, and
causes arm64's patch_map() function to treat any !core_kernel_text()
symbol as something that can be modified in-place. As core_kernel_text()
is only true for .text and .init.text, with the latter depending on
system_state < SYSTEM_RUNNING, we'll treat .exit.text as something that
can be patched in-place. However, .exit.text is mapped read-only.
Hence in this configuration the ftrace init code blows up while trying
to patch one of the functions generated by KASAN.
We could try to filter out the call sites in .exit.text rather than
initializing them, but this would be inconsistent with how we handle
.init.text, and requires hooking into core bits of ftrace. The behaviour
of patch_map() is also inconsistent today, so instead let's clean that
up and have it consistently handle .exit.text.
This patch teaches patch_map() to handle .exit.text at init time,
preventing the boot-time splat above. The flow of patch_map() is
reworked to make the logic clearer and minimize redundant
conditionality.
Fixes: 3b23e4991f ("arm64: implement ftrace with regs")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Torsten Duwe <duwe@suse.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were:
- Cross-arch changes to move the linker sections for NOTES and
EXCEPTION_TABLE into the RO_DATA area, where they belong on most
architectures. (Kees Cook)
- Switch the x86 linker fill byte from x90 (NOP) to 0xcc (INT3), to
trap jumps into the middle of those padding areas instead of
sliding execution. (Kees Cook)
- A thorough cleanup of symbol definitions within x86 assembler code.
The rather randomly named macros got streamlined around a
(hopefully) straightforward naming scheme:
SYM_START(name, linkage, align...)
SYM_END(name, sym_type)
SYM_FUNC_START(name)
SYM_FUNC_END(name)
SYM_CODE_START(name)
SYM_CODE_END(name)
SYM_DATA_START(name)
SYM_DATA_END(name)
etc - with about three times of these basic primitives with some
label, local symbol or attribute variant, expressed via postfixes.
No change in functionality intended. (Jiri Slaby)
- Misc other changes, cleanups and smaller fixes"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits)
x86/entry/64: Remove pointless jump in paranoid_exit
x86/entry/32: Remove unused resume_userspace label
x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o
m68k: Convert missed RODATA to RO_DATA
x86/vmlinux: Use INT3 instead of NOP for linker fill bytes
x86/mm: Report actual image regions in /proc/iomem
x86/mm: Report which part of kernel image is freed
x86/mm: Remove redundant address-of operators on addresses
xtensa: Move EXCEPTION_TABLE to RO_DATA segment
powerpc: Move EXCEPTION_TABLE to RO_DATA segment
parisc: Move EXCEPTION_TABLE to RO_DATA segment
microblaze: Move EXCEPTION_TABLE to RO_DATA segment
ia64: Move EXCEPTION_TABLE to RO_DATA segment
h8300: Move EXCEPTION_TABLE to RO_DATA segment
c6x: Move EXCEPTION_TABLE to RO_DATA segment
arm64: Move EXCEPTION_TABLE to RO_DATA segment
alpha: Move EXCEPTION_TABLE to RO_DATA segment
x86/vmlinux: Move EXCEPTION_TABLE to RO_DATA segment
x86/vmlinux: Actually use _etext for the end of the text segment
vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
...
Since the EXCEPTION_TABLE is read-only, collapse it into RO_DATA. Also
removes the redundant ALIGN, which is already present at the end of the
RO_DATA macro.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Will Deacon <will@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: x86-ml <x86@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20191029211351.13243-19-keescook@chromium.org
Since commit 7326749801 ("arm64: unwind: reference pt_regs via embedded
stack frame") arm64 has not used the __exception annotation to dump
the pt_regs during stack tracing. in_exception_text() has no callers.
This annotation is only used to blacklist kprobes, it means the same as
__kprobes.
Section annotations like this require the functions to be grouped
together between the start/end markers, and placed according to
the linker script. For kprobes we also have NOKPROBE_SYMBOL() which
logs the symbol address in a section that kprobes parses and
blacklists at boot.
Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of
blacklisted symbols, and saves us from having an arm64 specific
spelling of __kprobes.
do_debug_exception() already has a NOKPROBE_SYMBOL() annotation.
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
It seems that LLVM's linker does not correctly handle variable assignments
involving section positions that are updated during the SECTIONS
parsing. Commit aa69fb62be ("arm64/efi: Mark __efistub_stext_offset as
an absolute symbol explicitly") ran into this too, but found a different
workaround.
However, this was not enough, as other variables were also miscalculated
which manifested as boot failures under UEFI where __efistub__end was
not taking the correct _end value (they should be the same):
$ ld.lld -EL -maarch64elf --no-undefined -X -shared \
-Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \
-o vmlinux.lld -T poc.lds --whole-archive vmlinux.o && \
readelf -Ws vmlinux.lld | egrep '\b(__efistub_|)_end\b'
368272: ffff000002218000 0 NOTYPE LOCAL HIDDEN 38 __efistub__end
368322: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 38 _end
$ aarch64-linux-gnu-ld.bfd -EL -maarch64elf --no-undefined -X -shared \
-Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \
-o vmlinux.bfd -T poc.lds --whole-archive vmlinux.o && \
readelf -Ws vmlinux.bfd | egrep '\b(__efistub_|)_end\b'
338124: ffff000012318000 0 NOTYPE LOCAL DEFAULT ABS __efistub__end
383812: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 15325 _end
To work around this, all of the __efistub_-prefixed variable assignments
need to be moved after the linker script's SECTIONS entry. As it turns
out, this also solves the problem fixed in commit aa69fb62be, so those
changes are reverted here.
Link: https://github.com/ClangBuiltLinux/linux/issues/634
Link: https://bugs.llvm.org/show_bug.cgi?id=42990
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will@kernel.org>
RELR is a relocation packing format for relative relocations.
The format is described in a generic-abi proposal:
https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion
The LLD linker can be instructed to pack relocations in the RELR
format by passing the flag --pack-dyn-relocs=relr.
This patch adds a new config option, CONFIG_RELR. Enabling this option
instructs the linker to pack vmlinux's relative relocations in the RELR
format, and causes the kernel to apply the relocations at startup along
with the RELA relocations. RELA relocations still need to be applied
because the linker will emit RELA relative relocations if they are
unrepresentable in the RELR format (i.e. address not a multiple of 2).
Enabling CONFIG_RELR reduces the size of a defconfig kernel image
with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5%
compressed (lz4).
Signed-off-by: Peter Collingbourne <pcc@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
readelf complains about the section layout of vmlinux when building
with CONFIG_RELOCATABLE=y (for KASLR):
readelf: Warning: [21]: Link field (0) should index a symtab section.
readelf: Warning: [21]: Info field (0) should index a relocatable section.
Also, it seems that our use of '-pie -shared' is contradictory, and
thus ambiguous. In general, the way KASLR is wired up at the moment
is highly tailored to how ld.bfd happens to implement (and conflate)
PIE executables and shared libraries, so given the current effort to
support other toolchains, let's fix some of these issues as well.
- Drop the -pie linker argument and just leave -shared. In ld.bfd,
the differences between them are unclear (except for the ELF type
of the produced image [0]) but lld chokes on seeing both at the
same time.
- Rename the .rela output section to .rela.dyn, as is customary for
shared libraries and PIE executables, so that it is not misidentified
by readelf as a static relocation section (producing the warnings
above).
- Pass the -z notext and -z norelro options to explicitly instruct the
linker to permit text relocations, and to omit the RELRO program
header (which requires a certain section layout that we don't adhere
to in the kernel). These are the defaults for current versions of
ld.bfd.
- Discard .eh_frame and .gnu.hash sections to avoid them from being
emitted between .head.text and .text, screwing up the section layout.
These changes only affect the ELF image, and produce the same binary
image.
[0] b9dce7f1ba ("arm64: kernel: force ET_DYN ELF type for ...")
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Smith <peter.smith@linaro.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Pull security subsystem updates from James Morris:
"In this patchset, there are a couple of minor updates, as well as some
reworking of the LSM initialization code from Kees Cook (these prepare
the way for ordered stackable LSMs, but are a valuable cleanup on
their own)"
* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
LSM: Don't ignore initialization failures
LSM: Provide init debugging infrastructure
LSM: Record LSM name in struct lsm_info
LSM: Convert security_initcall() into DEFINE_LSM()
vmlinux.lds.h: Move LSM_TABLE into INIT_DATA
LSM: Convert from initcall to struct lsm_info
LSM: Remove initcall tracing
LSM: Rename .security_initcall section to .lsm_info
vmlinux.lds.h: Avoid copy/paste of security_init section
LSM: Correctly announce start of LSM initialization
security: fix LSM description location
keys: Fix the use of the C++ keyword "private" in uapi/linux/keyctl.h
seccomp: remove unnecessary unlikely()
security: tomoyo: Fix obsolete function
security/capabilities: remove check for -EINVAL
Since the struct lsm_info table is not an initcall, we can just move it
into INIT_DATA like all the other tables.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Now that deliberate writes to swapper_pg_dir are made via the fixmap, we
can defend against errant writes by moving it into the rodata section.
Since tramp_pg_dir and reserved_ttbr0 must be at a fixed offset from
swapper_pg_dir, and are not modified at runtime, these are also moved
into the rodata section. Likewise, idmap_pg_dir is not modified at
runtime, and is moved into rodata.
Signed-off-by: Jun Yao <yaojun8558363@gmail.com>
Reviewed-by: James Morse <james.morse@arm.com>
[Mark: simplify linker script, commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Since the address of swapper_pg_dir is fixed for a given kernel image,
it is an attractive target for manipulation via an arbitrary write. To
mitigate this we'd like to make it read-only by moving it into the
rodata section.
We require that swapper_pg_dir is at a fixed offset from tramp_pg_dir
and reserved_ttbr0, so these will also need to move into rodata.
However, swapper_pg_dir is allocated along with some transient page
tables used for boot which we do not want to move into rodata.
As a step towards this, this patch separates the boot-time page tables
into a new init_pg_dir, and reduces swapper_pg_dir to the single page it
needs to be. This allows us to retain the relationship between
swapper_pg_dir, tramp_pg_dir, and swapper_pg_dir, while cleanly
separating these from the boot-time page tables.
The init_pg_dir holds all of the pgd/pud/pmd/pte levels needed during
boot, and all of these levels will be freed when we switch to the
swapper_pg_dir, which is initialized by the existing code in
paging_init(). Since we start off on the init_pg_dir, we no longer need
to allocate a transient page table in paging_init() in order to ensure
that swapper_pg_dir isn't live while we initialize it.
There should be no functional change as a result of this patch.
Signed-off-by: Jun Yao <yaojun8558363@gmail.com>
Reviewed-by: James Morse <james.morse@arm.com>
[Mark: place init_pg_dir after BSS, fold mm changes, commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
