From c0e16ab3b5887e86cd45b95e28cf66498b161ee1 Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Thu, 6 Aug 2020 23:24:50 -0700 Subject: [PATCH] kasan: remove kasan_unpoison_stack_above_sp_to() kasan_unpoison_stack_above_sp_to() is defined in kasan code but never used. The function was introduced as part of the commit: commit 9f7d416c36124667 ("kprobes: Unpoison stack in jprobe_return() for KASAN") ... where it was necessary because x86's jprobe_return() would leave stale shadow on the stack, and was an oddity in that regard. Since then, jprobes were removed entirely, and as of commit: commit 80006dbee674f9fa ("kprobes/x86: Remove jprobe implementation") ... there have been no callers of this function. Remove the declaration and the implementation. Signed-off-by: Vincenzo Frascino Signed-off-by: Andrew Morton Reviewed-by: Mark Rutland Reviewed-by: Andrey Konovalov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Link: http://lkml.kernel.org/r/20200706143505.23299-1-vincenzo.frascino@arm.com Signed-off-by: Linus Torvalds --- include/linux/kasan.h | 2 -- mm/kasan/common.c | 15 --------------- 2 files changed, 17 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 18452e35e7b2..087fba34b209 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -38,7 +38,6 @@ extern void kasan_disable_current(void); void kasan_unpoison_shadow(const void *address, size_t size); void kasan_unpoison_task_stack(struct task_struct *task); -void kasan_unpoison_stack_above_sp_to(const void *watermark); void kasan_alloc_pages(struct page *page, unsigned int order); void kasan_free_pages(struct page *page, unsigned int order); @@ -101,7 +100,6 @@ void kasan_restore_multi_shot(bool enabled); static inline void kasan_unpoison_shadow(const void *address, size_t size) {} static inline void kasan_unpoison_task_stack(struct task_struct *task) {} -static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {} static inline void kasan_enable_current(void) {} static inline void kasan_disable_current(void) {} diff --git a/mm/kasan/common.c b/mm/kasan/common.c index f18067736f7c..950fd372a07e 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -180,21 +180,6 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) kasan_unpoison_shadow(base, watermark - base); } -/* - * Clear all poison for the region between the current SP and a provided - * watermark value, as is sometimes required prior to hand-crafted asm function - * returns in the middle of functions. - */ -void kasan_unpoison_stack_above_sp_to(const void *watermark) -{ - const void *sp = __builtin_frame_address(0); - size_t size = watermark - sp; - - if (WARN_ON(sp > watermark)) - return; - kasan_unpoison_shadow(sp, size); -} - void kasan_alloc_pages(struct page *page, unsigned int order) { u8 tag;