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LoongArch: Add kernel livepatching support

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The arch-specified function ftrace_regs_set_instruction_pointer() has
been implemented in arch/loongarch/include/asm/ftrace.h, so here only
implement arch_stack_walk_reliable() function.

Here are the test logs:

[root@linux fedora]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-6.8.0-rc2 root=/dev/sda3

[root@linux fedora]# modprobe livepatch-sample
[root@linux fedora]# cat /proc/cmdline
this has been live patched

[root@linux fedora]# echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
[root@linux fedora]# rmmod livepatch_sample
[root@linux fedora]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-6.8.0-rc2 root=/dev/sda3

[root@linux fedora]# dmesg -t | tail -5
livepatch: enabling patch 'livepatch_sample'
livepatch: 'livepatch_sample': starting patching transition
livepatch: 'livepatch_sample': patching complete
livepatch: 'livepatch_sample': starting unpatching transition
livepatch: 'livepatch_sample': unpatching complete

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Jinyang He 2024-03-11 22:23:47 +08:00 committed by Huacai Chen
parent cb8a2ef084
commit 199cc14cb4
3 changed files with 46 additions and 0 deletions
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4
arch/loongarch/Kconfig
View file

@ -134,6 +134,7 @@ config LOONGARCH
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
select HAVE_KVM
select HAVE_LIVEPATCH
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS
@ -143,6 +144,7 @@ config LOONGARCH
select HAVE_PERF_USER_STACK_DUMP
select HAVE_PREEMPT_DYNAMIC_KEY
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC
select HAVE_RETHOOK
select HAVE_RSEQ
select HAVE_RUST
@ -636,6 +638,8 @@ config RANDOMIZE_BASE_MAX_OFFSET
This is limited by the size of the lower address memory, 256MB.
source "kernel/livepatch/Kconfig"
endmenu
config ARCH_SELECT_MEMORY_MODEL

2
arch/loongarch/include/asm/thread_info.h
View file

@ -86,6 +86,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
#define TIF_LASX_CTX_LIVE 18 /* LASX context must be preserved */
#define TIF_USEDLBT 19 /* LBT was used by this task this quantum (SMP) */
#define TIF_LBT_CTX_LIVE 20 /* LBT context must be preserved */
#define TIF_PATCH_PENDING 21 /* pending live patching update */
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
@ -105,6 +106,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
#define _TIF_LASX_CTX_LIVE (1<<TIF_LASX_CTX_LIVE)
#define _TIF_USEDLBT (1<<TIF_USEDLBT)
#define _TIF_LBT_CTX_LIVE (1<<TIF_LBT_CTX_LIVE)
#define _TIF_PATCH_PENDING (1<<TIF_PATCH_PENDING)
#endif /* __KERNEL__ */
#endif /* _ASM_THREAD_INFO_H */

40
arch/loongarch/kernel/stacktrace.c
View file

@ -40,6 +40,46 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
}
}
int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
void *cookie, struct task_struct *task)
{
unsigned long addr;
struct pt_regs dummyregs;
struct pt_regs *regs = &dummyregs;
struct unwind_state state;
if (task == current) {
regs->regs[3] = (unsigned long)__builtin_frame_address(0);
regs->csr_era = (unsigned long)__builtin_return_address(0);
} else {
regs->regs[3] = thread_saved_fp(task);
regs->csr_era = thread_saved_ra(task);
}
regs->regs[1] = 0;
regs->regs[22] = 0;
for (unwind_start(&state, task, regs);
!unwind_done(&state) && !unwind_error(&state); unwind_next_frame(&state)) {
addr = unwind_get_return_address(&state);
/*
* A NULL or invalid return address probably means there's some
* generated code which __kernel_text_address() doesn't know about.
*/
if (!addr)
return -EINVAL;
if (!consume_entry(cookie, addr))
return -EINVAL;
}
/* Check for stack corruption */
if (unwind_error(&state))
return -EINVAL;
return 0;
}
static int
copy_stack_frame(unsigned long fp, struct stack_frame *frame)
{