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kasan: clean up comments in internal kasan.h 

Clean up comments in mm/kasan/kasan.h: clarify, unify styles, fix
punctuation, etc.

Link: https://lkml.kernel.org/r/a0680ff30035b56cb7bdd5f59fd400e71712ceb5.1652111464.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2022-05-12 20:23:08 -07:00 committed by Andrew Morton
parent 3f80492001
commit fc0e5b91df
1 changed files with 33 additions and 41 deletions
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74
mm/kasan/kasan.h
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@ -42,6 +42,7 @@ static inline bool kasan_sync_fault_possible(void)
{
return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM;
}
#else
static inline bool kasan_stack_collection_enabled(void)
@ -73,47 +74,41 @@ static inline bool kasan_sync_fault_possible(void)
#define KASAN_MEMORY_PER_SHADOW_PAGE (KASAN_GRANULE_SIZE << PAGE_SHIFT)
#ifdef CONFIG_KASAN_GENERIC
#define KASAN_FREE_PAGE 0xFF /* page was freed */
#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
#define KASAN_KMALLOC_REDZONE 0xFC /* redzone inside slub object */
#define KASAN_KMALLOC_FREE 0xFB /* object was freed (kmem_cache_free/kfree) */
#define KASAN_VMALLOC_INVALID 0xF8 /* unallocated space in vmapped page */
#define KASAN_FREE_PAGE 0xFF /* freed page */
#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocation */
#define KASAN_KMALLOC_REDZONE 0xFC /* redzone for slab object */
#define KASAN_KMALLOC_FREE 0xFB /* freed slab object */
#define KASAN_VMALLOC_INVALID 0xF8 /* inaccessible space in vmap area */
#else
#define KASAN_FREE_PAGE KASAN_TAG_INVALID
#define KASAN_PAGE_REDZONE KASAN_TAG_INVALID
#define KASAN_KMALLOC_REDZONE KASAN_TAG_INVALID
#define KASAN_KMALLOC_FREE KASAN_TAG_INVALID
#define KASAN_VMALLOC_INVALID KASAN_TAG_INVALID /* only for SW_TAGS */
#define KASAN_VMALLOC_INVALID KASAN_TAG_INVALID /* only used for SW_TAGS */
#endif
#ifdef CONFIG_KASAN_GENERIC
#define KASAN_KMALLOC_FREETRACK 0xFA /* object was freed and has free track set */
#define KASAN_KMALLOC_FREETRACK 0xFA /* freed slab object with free track */
#define KASAN_GLOBAL_REDZONE 0xF9 /* redzone for global variable */
/*
* Stack redzone shadow values
* (Those are compiler's ABI, don't change them)
*/
/* Stack redzone shadow values. Compiler ABI, do not change. */
#define KASAN_STACK_LEFT 0xF1
#define KASAN_STACK_MID 0xF2
#define KASAN_STACK_RIGHT 0xF3
#define KASAN_STACK_PARTIAL 0xF4
/*
* alloca redzone shadow values
*/
/* alloca redzone shadow values. */
#define KASAN_ALLOCA_LEFT 0xCA
#define KASAN_ALLOCA_RIGHT 0xCB
/* alloca redzone size. Compiler ABI, do not change. */
#define KASAN_ALLOCA_REDZONE_SIZE 32
/*
* Stack frame marker (compiler ABI).
*/
/* Stack frame marker. Compiler ABI, do not change. */
#define KASAN_CURRENT_STACK_FRAME_MAGIC 0x41B58AB3
/* Don't break randconfig/all*config builds */
/* Dummy value to avoid breaking randconfig/all*config builds. */
#ifndef KASAN_ABI_VERSION
#define KASAN_ABI_VERSION 1
#endif
@ -141,21 +136,21 @@ struct kasan_report_info {
unsigned long ip;
};
/* The layout of struct dictated by compiler */
/* Do not change the struct layout: compiler ABI. */
struct kasan_source_location {
const char *filename;
int line_no;
int column_no;
};
/* The layout of struct dictated by compiler */
/* Do not change the struct layout: compiler ABI. */
struct kasan_global {
const void *beg; /* Address of the beginning of the global variable. */
size_t size; /* Size of the global variable. */
size_t size_with_redzone; /* Size of the variable + size of the red zone. 32 bytes aligned */
size_t size_with_redzone; /* Size of the variable + size of the redzone. 32 bytes aligned. */
const void *name;
const void *module_name; /* Name of the module where the global variable is declared. */
unsigned long has_dynamic_init; /* This needed for C++ */
unsigned long has_dynamic_init; /* This is needed for C++. */
#if KASAN_ABI_VERSION >= 4
struct kasan_source_location *location;
#endif
@ -164,9 +159,7 @@ struct kasan_global {
#endif
};
/**
* Structures to keep alloc and free tracks *
*/
/* Structures for keeping alloc and free tracks. */
#define KASAN_STACK_DEPTH 64
@ -183,11 +176,8 @@ struct kasan_track {
struct kasan_alloc_meta {
struct kasan_track alloc_track;
/* Generic mode stores free track in kasan_free_meta. */
#ifdef CONFIG_KASAN_GENERIC
/*
* The auxiliary stack is stored into struct kasan_alloc_meta.
* The free stack is stored into struct kasan_free_meta.
*/
depot_stack_handle_t aux_stack[2];
#else
struct kasan_track free_track[KASAN_NR_FREE_STACKS];
@ -203,18 +193,18 @@ struct qlist_node {
};
/*
* Generic mode either stores free meta in the object itself or in the redzone
* after the object. In the former case free meta offset is 0, in the latter
* case it has some sane value smaller than INT_MAX. Use INT_MAX as free meta
* offset when free meta isn't present.
* Free meta is stored either in the object itself or in the redzone after the
* object. In the former case, free meta offset is 0. In the latter case, the
* offset is between 0 and INT_MAX. INT_MAX marks that free meta is not present.
*/
#define KASAN_NO_FREE_META INT_MAX
/*
* Free meta is only used by Generic mode while the object is in quarantine.
* After that, slab allocator stores the freelist pointer in the object.
*/
struct kasan_free_meta {
#ifdef CONFIG_KASAN_GENERIC
/* This field is used while the object is in the quarantine.
* Otherwise it might be used for the allocator freelist.
*/
struct qlist_node quarantine_link;
struct kasan_track free_track;
#endif
@ -417,9 +407,10 @@ static inline void kasan_unpoison(const void *addr, size_t size, bool init)
return;
/*
* Explicitly initialize the memory with the precise object size to
* avoid overwriting the SLAB redzone. This disables initialization in
* the arch code and may thus lead to performance penalty. The penalty
* is accepted since SLAB redzones aren't enabled in production builds.
* avoid overwriting the slab redzone. This disables initialization in
* the arch code and may thus lead to performance penalty. This penalty
* does not affect production builds, as slab redzones are not enabled
* there.
*/
if (__slub_debug_enabled() &&
init && ((unsigned long)size & KASAN_GRANULE_MASK)) {
@ -503,8 +494,9 @@ void kasan_restore_multi_shot(bool enabled);
/*
* Exported functions for interfaces called from assembly or from generated
* code. Declarations here to avoid warning about missing declarations.
* code. Declared here to avoid warnings about missing declarations.
*/
asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
void __asan_register_globals(struct kasan_global *globals, size_t size);
void __asan_unregister_globals(struct kasan_global *globals, size_t size);
@ -573,4 +565,4 @@ void __hwasan_storeN_noabort(unsigned long addr, size_t size);
void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);
#endif
#endif /* __MM_KASAN_KASAN_H */