f3b7deef8d
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: Will Deacon <will@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210315132019.33202-2-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
134 lines
2.4 KiB
C
134 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2020 ARM Ltd.
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*/
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#ifndef __ASM_MTE_KASAN_H
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#define __ASM_MTE_KASAN_H
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#include <asm/mte-def.h>
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#ifdef CONFIG_ARM64_MTE
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/*
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* These functions are meant to be only used from KASAN runtime through
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* the arch_*() interface defined in asm/memory.h.
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* These functions don't include system_supports_mte() checks,
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* as KASAN only calls them when MTE is supported and enabled.
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*/
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static inline u8 mte_get_ptr_tag(void *ptr)
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{
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/* Note: The format of KASAN tags is 0xF<x> */
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u8 tag = 0xF0 | (u8)(((u64)(ptr)) >> MTE_TAG_SHIFT);
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return tag;
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}
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/* Get allocation tag for the address. */
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static inline u8 mte_get_mem_tag(void *addr)
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{
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asm(__MTE_PREAMBLE "ldg %0, [%0]"
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: "+r" (addr));
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return mte_get_ptr_tag(addr);
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}
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/* Generate a random tag. */
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static inline u8 mte_get_random_tag(void)
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{
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void *addr;
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asm(__MTE_PREAMBLE "irg %0, %0"
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: "=r" (addr));
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return mte_get_ptr_tag(addr);
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}
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/*
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* Assign allocation tags for a region of memory based on the pointer tag.
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* Note: The address must be non-NULL and MTE_GRANULE_SIZE aligned and
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* size must be non-zero and MTE_GRANULE_SIZE aligned.
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*/
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static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
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{
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u64 curr, end;
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if (!size)
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return;
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curr = (u64)__tag_set(addr, tag);
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end = curr + size;
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do {
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/*
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* 'asm volatile' is required to prevent the compiler to move
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* the statement outside of the loop.
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*/
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asm volatile(__MTE_PREAMBLE "stg %0, [%0]"
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:
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: "r" (curr)
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: "memory");
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curr += MTE_GRANULE_SIZE;
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} while (curr != end);
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}
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void mte_enable_kernel_sync(void);
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void mte_enable_kernel_async(void);
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void mte_init_tags(u64 max_tag);
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void mte_set_report_once(bool state);
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bool mte_report_once(void);
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#else /* CONFIG_ARM64_MTE */
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static inline u8 mte_get_ptr_tag(void *ptr)
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{
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return 0xFF;
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}
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static inline u8 mte_get_mem_tag(void *addr)
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{
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return 0xFF;
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}
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static inline u8 mte_get_random_tag(void)
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{
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return 0xFF;
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}
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static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
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{
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}
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static inline void mte_enable_kernel_sync(void)
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{
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}
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static inline void mte_enable_kernel_async(void)
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{
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}
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static inline void mte_init_tags(u64 max_tag)
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{
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}
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static inline void mte_set_report_once(bool state)
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{
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}
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static inline bool mte_report_once(void)
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{
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return false;
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}
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#endif /* CONFIG_ARM64_MTE */
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_MTE_KASAN_H */
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