Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Vincenzo Frascino | 338 | 60.90% | 10 | 50.00% |
Evgenii Stepanov | 125 | 22.52% | 1 | 5.00% |
Andrey Konovalov | 48 | 8.65% | 2 | 10.00% |
Reiji Watanabe | 23 | 4.14% | 1 | 5.00% |
Catalin Marinas | 15 | 2.70% | 4 | 20.00% |
Peter Collingbourne | 3 | 0.54% | 1 | 5.00% |
Paul Semel | 3 | 0.54% | 1 | 5.00% |
Total | 555 | 20 |
/* SPDX-License-Identifier: GPL-2.0 */ /* * Copyright (C) 2020 ARM Ltd. */ #ifndef __ASM_MTE_KASAN_H #define __ASM_MTE_KASAN_H #include <asm/compiler.h> #include <asm/cputype.h> #include <asm/mte-def.h> #ifndef __ASSEMBLY__ #include <linux/types.h> #ifdef CONFIG_KASAN_HW_TAGS /* Whether the MTE asynchronous mode is enabled. */ DECLARE_STATIC_KEY_FALSE(mte_async_or_asymm_mode); static inline bool system_uses_mte_async_or_asymm_mode(void) { return static_branch_unlikely(&mte_async_or_asymm_mode); } #else /* CONFIG_KASAN_HW_TAGS */ static inline bool system_uses_mte_async_or_asymm_mode(void) { return false; } #endif /* CONFIG_KASAN_HW_TAGS */ #ifdef CONFIG_ARM64_MTE /* * The Tag Check Flag (TCF) mode for MTE is per EL, hence TCF0 * affects EL0 and TCF affects EL1 irrespective of which TTBR is * used. * The kernel accesses TTBR0 usually with LDTR/STTR instructions * when UAO is available, so these would act as EL0 accesses using * TCF0. * However futex.h code uses exclusives which would be executed as * EL1, this can potentially cause a tag check fault even if the * user disables TCF0. * * To address the problem we set the PSTATE.TCO bit in uaccess_enable() * and reset it in uaccess_disable(). * * The Tag check override (TCO) bit disables temporarily the tag checking * preventing the issue. */ static inline void mte_disable_tco(void) { asm volatile(ALTERNATIVE("nop", SET_PSTATE_TCO(0), ARM64_MTE, CONFIG_KASAN_HW_TAGS)); } static inline void mte_enable_tco(void) { asm volatile(ALTERNATIVE("nop", SET_PSTATE_TCO(1), ARM64_MTE, CONFIG_KASAN_HW_TAGS)); } /* * These functions disable tag checking only if in MTE async mode * since the sync mode generates exceptions synchronously and the * nofault or load_unaligned_zeropad can handle them. */ static inline void __mte_disable_tco_async(void) { if (system_uses_mte_async_or_asymm_mode()) mte_disable_tco(); } static inline void __mte_enable_tco_async(void) { if (system_uses_mte_async_or_asymm_mode()) mte_enable_tco(); } /* * These functions are meant to be only used from KASAN runtime through * the arch_*() interface defined in asm/memory.h. * These functions don't include system_supports_mte() checks, * as KASAN only calls them when MTE is supported and enabled. */ static inline u8 mte_get_ptr_tag(void *ptr) { /* Note: The format of KASAN tags is 0xF<x> */ u8 tag = 0xF0 | (u8)(((u64)(ptr)) >> MTE_TAG_SHIFT); return tag; } /* Get allocation tag for the address. */ static inline u8 mte_get_mem_tag(void *addr) { asm(__MTE_PREAMBLE "ldg %0, [%0]" : "+r" (addr)); return mte_get_ptr_tag(addr); } /* Generate a random tag. */ static inline u8 mte_get_random_tag(void) { void *addr; asm(__MTE_PREAMBLE "irg %0, %0" : "=r" (addr)); return mte_get_ptr_tag(addr); } static inline u64 __stg_post(u64 p) { asm volatile(__MTE_PREAMBLE "stg %0, [%0], #16" : "+r"(p) : : "memory"); return p; } static inline u64 __stzg_post(u64 p) { asm volatile(__MTE_PREAMBLE "stzg %0, [%0], #16" : "+r"(p) : : "memory"); return p; } static inline void __dc_gva(u64 p) { asm volatile(__MTE_PREAMBLE "dc gva, %0" : : "r"(p) : "memory"); } static inline void __dc_gzva(u64 p) { asm volatile(__MTE_PREAMBLE "dc gzva, %0" : : "r"(p) : "memory"); } /* * Assign allocation tags for a region of memory based on the pointer tag. * Note: The address must be non-NULL and MTE_GRANULE_SIZE aligned and * size must be MTE_GRANULE_SIZE aligned. */ static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag, bool init) { u64 curr, mask, dczid, dczid_bs, dczid_dzp, end1, end2, end3; /* Read DC G(Z)VA block size from the system register. */ dczid = read_cpuid(DCZID_EL0); dczid_bs = 4ul << (dczid & 0xf); dczid_dzp = (dczid >> 4) & 1; curr = (u64)__tag_set(addr, tag); mask = dczid_bs - 1; /* STG/STZG up to the end of the first block. */ end1 = curr | mask; end3 = curr + size; /* DC GVA / GZVA in [end1, end2) */ end2 = end3 & ~mask; /* * The following code uses STG on the first DC GVA block even if the * start address is aligned - it appears to be faster than an alignment * check + conditional branch. Also, if the range size is at least 2 DC * GVA blocks, the first two loops can use post-condition to save one * branch each. */ #define SET_MEMTAG_RANGE(stg_post, dc_gva) \ do { \ if (!dczid_dzp && size >= 2 * dczid_bs) {\ do { \ curr = stg_post(curr); \ } while (curr < end1); \ \ do { \ dc_gva(curr); \ curr += dczid_bs; \ } while (curr < end2); \ } \ \ while (curr < end3) \ curr = stg_post(curr); \ } while (0) if (init) SET_MEMTAG_RANGE(__stzg_post, __dc_gzva); else SET_MEMTAG_RANGE(__stg_post, __dc_gva); #undef SET_MEMTAG_RANGE } void mte_enable_kernel_sync(void); void mte_enable_kernel_async(void); void mte_enable_kernel_asymm(void); #else /* CONFIG_ARM64_MTE */ static inline void mte_disable_tco(void) { } static inline void mte_enable_tco(void) { } static inline void __mte_disable_tco_async(void) { } static inline void __mte_enable_tco_async(void) { } static inline u8 mte_get_ptr_tag(void *ptr) { return 0xFF; } static inline u8 mte_get_mem_tag(void *addr) { return 0xFF; } static inline u8 mte_get_random_tag(void) { return 0xFF; } static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag, bool init) { } static inline void mte_enable_kernel_sync(void) { } static inline void mte_enable_kernel_async(void) { } static inline void mte_enable_kernel_asymm(void) { } #endif /* CONFIG_ARM64_MTE */ #endif /* __ASSEMBLY__ */ #endif /* __ASM_MTE_KASAN_H */
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