diff options
author | Catalin Marinas <catalin.marinas@arm.com> | 2019-11-27 10:30:15 +0000 |
---|---|---|
committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-09-04 12:46:07 +0100 |
commit | 1c101da8b971a36695319dce7a24711dc567a0dd (patch) | |
tree | c791523a3008b05b4c47267da585568bd3622b3f /arch/arm64/include/asm/mte.h | |
parent | 51b0bff2f703f7ecfeb228eaa3d8f6090c18c9c1 (diff) |
arm64: mte: Allow user control of the tag check mode via prctl()
By default, even if PROT_MTE is set on a memory range, there is no tag
check fault reporting (SIGSEGV). Introduce a set of option to the
exiting prctl(PR_SET_TAGGED_ADDR_CTRL) to allow user control of the tag
check fault mode:
PR_MTE_TCF_NONE - no reporting (default)
PR_MTE_TCF_SYNC - synchronous tag check fault reporting
PR_MTE_TCF_ASYNC - asynchronous tag check fault reporting
These options translate into the corresponding SCTLR_EL1.TCF0 bitfield,
context-switched by the kernel. Note that the kernel accesses to the
user address space (e.g. read() system call) are not checked if the user
thread tag checking mode is PR_MTE_TCF_NONE or PR_MTE_TCF_ASYNC. If the
tag checking mode is PR_MTE_TCF_SYNC, the kernel makes a best effort to
check its user address accesses, however it cannot always guarantee it.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm/mte.h')
-rw-r--r-- | arch/arm64/include/asm/mte.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index b2577eee62c2..df2efbc9f8f1 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -21,6 +21,9 @@ void mte_clear_page_tags(void *addr); void mte_sync_tags(pte_t *ptep, pte_t pte); void mte_copy_page_tags(void *kto, const void *kfrom); void flush_mte_state(void); +void mte_thread_switch(struct task_struct *next); +long set_mte_ctrl(unsigned long arg); +long get_mte_ctrl(void); #else @@ -36,6 +39,17 @@ static inline void mte_copy_page_tags(void *kto, const void *kfrom) static inline void flush_mte_state(void) { } +static inline void mte_thread_switch(struct task_struct *next) +{ +} +static inline long set_mte_ctrl(unsigned long arg) +{ + return 0; +} +static inline long get_mte_ctrl(void) +{ + return 0; +} #endif |