Commit 6c4e0198 authored by Vincenzo Frascino's avatar Vincenzo Frascino
Browse files

arm64: mte: Add asynchronous mode support

MTE provides an asynchronous mode for detecting tag exceptions. In
particular instead of triggering a fault the arm64 core updates a
register which is checked by the kernel after the asynchronous tag
check fault has occurred.

Add support for MTE asynchronous mode.

The exception handling mechanism will be added with a future patch.

Note: KASAN HW activates async mode via kasan.mode kernel parameter.
The default mode is set to synchronous.
The code that verifies the status of TFSR_EL1 will be added with a
future patch.

Cc: Catalin Marinas <>
Cc: Will Deacon <>
Reviewed-by: Catalin Marinas's avatarCatalin Marinas <>
Reviewed-by: default avatarAndrey Konovalov <>
Signed-off-by: Vincenzo Frascino's avatarVincenzo Frascino <>
parent fb3825cb
......@@ -243,7 +243,8 @@ static inline const void *__tag_set(const void *addr, u8 tag)
#define arch_enable_tagging() mte_enable_kernel()
#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_init_tags(max_tag) mte_init_tags(max_tag)
#define arch_get_random_tag() mte_get_random_tag()
......@@ -77,7 +77,8 @@ static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
} while (curr != end);
void mte_enable_kernel(void);
void mte_enable_kernel_sync(void);
void mte_enable_kernel_async(void);
void mte_init_tags(u64 max_tag);
void mte_set_report_once(bool state);
......@@ -104,7 +105,11 @@ static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
static inline void mte_enable_kernel(void)
static inline void mte_enable_kernel_sync(void)
static inline void mte_enable_kernel_async(void)
......@@ -107,13 +107,26 @@ void mte_init_tags(u64 max_tag)
write_sysreg_s(SYS_GCR_EL1_RRND | gcr_kernel_excl, SYS_GCR_EL1);
void mte_enable_kernel(void)
static inline void __mte_enable_kernel(const char *mode, unsigned long tcf)
/* Enable MTE Sync Mode for EL1. */
sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC);
sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, tcf);
pr_info_once("MTE: enabled in %s mode at EL1\n", mode);
void mte_enable_kernel_sync(void)
__mte_enable_kernel("synchronous", SCTLR_ELx_TCF_SYNC);
void mte_enable_kernel_async(void)
__mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC);
void mte_set_report_once(bool state)
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