diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 16:30:30 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 10:32:37 +0100 |
| commit | d15cb3dab1e4f00e29599a4f5e1f6678a530d270 (patch) | |
| tree | 0a1cdf9129615771da2f0f2cabc00274b60e2ce4 | |
| parent | x86/ibt,ftrace: Search for __fentry__ location (diff) | |
| download | linux-d15cb3dab1e4f00e29599a4f5e1f6678a530d270.tar.xz linux-d15cb3dab1e4f00e29599a4f5e1f6678a530d270.zip | |
x86/livepatch: Validate __fentry__ location
Currently livepatch assumes __fentry__ lives at func+0, which is most
likely untrue with IBT on. Instead make it use ftrace_location() by
default which both validates and finds the actual ip if there is any
in the same symbol.
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.285971256@infradead.org
| -rw-r--r-- | arch/powerpc/include/asm/livepatch.h | 10 | ||||
| -rw-r--r-- | kernel/livepatch/patch.c | 19 |
2 files changed, 2 insertions, 27 deletions
diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h index 4fe018cc207b..7b9dcd51af32 100644 --- a/arch/powerpc/include/asm/livepatch.h +++ b/arch/powerpc/include/asm/livepatch.h @@ -19,16 +19,6 @@ static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip) regs_set_return_ip(regs, ip); } -#define klp_get_ftrace_location klp_get_ftrace_location -static inline unsigned long klp_get_ftrace_location(unsigned long faddr) -{ - /* - * Live patch works only with -mprofile-kernel on PPC. In this case, - * the ftrace location is always within the first 16 bytes. - */ - return ftrace_location_range(faddr, faddr + 16); -} - static inline void klp_init_thread_info(struct task_struct *p) { /* + 1 to account for STACK_END_MAGIC */ diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c index fe316c021d73..c172bf92b576 100644 --- a/kernel/livepatch/patch.c +++ b/kernel/livepatch/patch.c @@ -124,19 +124,6 @@ unlock: ftrace_test_recursion_unlock(bit); } -/* - * Convert a function address into the appropriate ftrace location. - * - * Usually this is just the address of the function, but on some architectures - * it's more complicated so allow them to provide a custom behaviour. - */ -#ifndef klp_get_ftrace_location -static unsigned long klp_get_ftrace_location(unsigned long faddr) -{ - return faddr; -} -#endif - static void klp_unpatch_func(struct klp_func *func) { struct klp_ops *ops; @@ -153,8 +140,7 @@ static void klp_unpatch_func(struct klp_func *func) if (list_is_singular(&ops->func_stack)) { unsigned long ftrace_loc; - ftrace_loc = - klp_get_ftrace_location((unsigned long)func->old_func); + ftrace_loc = ftrace_location((unsigned long)func->old_func); if (WARN_ON(!ftrace_loc)) return; @@ -186,8 +172,7 @@ static int klp_patch_func(struct klp_func *func) if (!ops) { unsigned long ftrace_loc; - ftrace_loc = - klp_get_ftrace_location((unsigned long)func->old_func); + ftrace_loc = ftrace_location((unsigned long)func->old_func); if (!ftrace_loc) { pr_err("failed to find location for function '%s'\n", func->old_name); |