diff options
author | Mark Rutland <mark.rutland@arm.com> | 2021-07-14 15:38:43 +0100 |
---|---|---|
committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-08-02 18:15:28 +0100 |
commit | 767215030150d9d01ff65fbc1c5dff515ffdcfe3 (patch) | |
tree | 722c4250af594120161913ab8fadc744b94aaa6e /arch | |
parent | 82868247897bea2d69a83dca9a6a557e2c96dac4 (diff) | |
download | linux-767215030150d9d01ff65fbc1c5dff515ffdcfe3.tar.bz2 |
arm64: kasan: mte: remove redundant mte_report_once logic
We have special logic to suppress MTE tag check fault reporting, based
on a global `mte_report_once` and `reported` variables. These can be
used to suppress calling kasan_report() when taking a tag check fault,
but do not prevent taking the fault in the first place, nor does they
affect the way we disable tag checks upon taking a fault.
The core KASAN code already defaults to reporting a single fault, and
has a `multi_shot` control to permit reporting multiple faults. The only
place we transiently alter `mte_report_once` is in lib/test_kasan.c,
where we also the `multi_shot` state as the same time. Thus
`mte_report_once` and `reported` are redundant, and can be removed.
When a tag check fault is taken, tag checking will be disabled by
`do_tag_recovery` and must be explicitly re-enabled if desired. The test
code does this by calling kasan_enable_tagging_sync().
This patch removes the redundant mte_report_once() logic and associated
variables.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20210714143843.56537-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm64/include/asm/memory.h | 1 | ||||
-rw-r--r-- | arch/arm64/include/asm/mte-kasan.h | 12 | ||||
-rw-r--r-- | arch/arm64/kernel/mte.c | 12 | ||||
-rw-r--r-- | arch/arm64/mm/fault.c | 15 |
4 files changed, 1 insertions, 39 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 7f4e6a923aa6..f1745a843414 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -243,7 +243,6 @@ static inline const void *__tag_set(const void *addr, u8 tag) #ifdef CONFIG_KASAN_HW_TAGS #define arch_enable_tagging_sync() mte_enable_kernel_sync() #define arch_enable_tagging_async() mte_enable_kernel_async() -#define arch_set_tagging_report_once(state) mte_set_report_once(state) #define arch_force_async_tag_fault() mte_check_tfsr_exit() #define arch_get_random_tag() mte_get_random_tag() #define arch_get_mem_tag(addr) mte_get_mem_tag(addr) diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h index 82fa4ac4ad4e..22420e1f8c03 100644 --- a/arch/arm64/include/asm/mte-kasan.h +++ b/arch/arm64/include/asm/mte-kasan.h @@ -131,9 +131,6 @@ static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag, void mte_enable_kernel_sync(void); void mte_enable_kernel_async(void); -void mte_set_report_once(bool state); -bool mte_report_once(void); - #else /* CONFIG_ARM64_MTE */ static inline u8 mte_get_ptr_tag(void *ptr) @@ -164,15 +161,6 @@ static inline void mte_enable_kernel_async(void) { } -static inline void mte_set_report_once(bool state) -{ -} - -static inline bool mte_report_once(void) -{ - return false; -} - #endif /* CONFIG_ARM64_MTE */ #endif /* __ASSEMBLY__ */ diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index b538ff27a912..9d314a3bad3b 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -23,8 +23,6 @@ #include <asm/ptrace.h> #include <asm/sysreg.h> -static bool report_fault_once = true; - static DEFINE_PER_CPU_READ_MOSTLY(u64, mte_tcf_preferred); #ifdef CONFIG_KASAN_HW_TAGS @@ -141,16 +139,6 @@ void mte_enable_kernel_async(void) } #endif -void mte_set_report_once(bool state) -{ - WRITE_ONCE(report_fault_once, state); -} - -bool mte_report_once(void) -{ - return READ_ONCE(report_fault_once); -} - #ifdef CONFIG_KASAN_HW_TAGS void mte_check_tfsr_el1(void) { diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 349c488765ca..9ae24e3b72be 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -309,24 +309,11 @@ static void die_kernel_fault(const char *msg, unsigned long addr, static void report_tag_fault(unsigned long addr, unsigned int esr, struct pt_regs *regs) { - static bool reported; - bool is_write; - - if (READ_ONCE(reported)) - return; - - /* - * This is used for KASAN tests and assumes that no MTE faults - * happened before running the tests. - */ - if (mte_report_once()) - WRITE_ONCE(reported, true); - /* * SAS bits aren't set for all faults reported in EL1, so we can't * find out access size. */ - is_write = !!(esr & ESR_ELx_WNR); + bool is_write = !!(esr & ESR_ELx_WNR); kasan_report(addr, 0, is_write, regs->pc); } #else |