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Diffstat (limited to 'target/arm/mte_helper.c')
| -rw-r--r-- | target/arm/mte_helper.c | 940 |
1 files changed, 940 insertions, 0 deletions
diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c new file mode 100644 index 000000000..e09b7e46a --- /dev/null +++ b/target/arm/mte_helper.c @@ -0,0 +1,940 @@ +/* + * ARM v8.5-MemTag Operations + * + * Copyright (c) 2020 Linaro, Ltd. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ + +#include "qemu/osdep.h" +#include "cpu.h" +#include "internals.h" +#include "exec/exec-all.h" +#include "exec/ram_addr.h" +#include "exec/cpu_ldst.h" +#include "exec/helper-proto.h" +#include "qapi/error.h" +#include "qemu/guest-random.h" + + +static int choose_nonexcluded_tag(int tag, int offset, uint16_t exclude) +{ + if (exclude == 0xffff) { + return 0; + } + if (offset == 0) { + while (exclude & (1 << tag)) { + tag = (tag + 1) & 15; + } + } else { + do { + do { + tag = (tag + 1) & 15; + } while (exclude & (1 << tag)); + } while (--offset > 0); + } + return tag; +} + +/** + * allocation_tag_mem: + * @env: the cpu environment + * @ptr_mmu_idx: the addressing regime to use for the virtual address + * @ptr: the virtual address for which to look up tag memory + * @ptr_access: the access to use for the virtual address + * @ptr_size: the number of bytes in the normal memory access + * @tag_access: the access to use for the tag memory + * @tag_size: the number of bytes in the tag memory access + * @ra: the return address for exception handling + * + * Our tag memory is formatted as a sequence of little-endian nibbles. + * That is, the byte at (addr >> (LOG2_TAG_GRANULE + 1)) contains two + * tags, with the tag at [3:0] for the lower addr and the tag at [7:4] + * for the higher addr. + * + * Here, resolve the physical address from the virtual address, and return + * a pointer to the corresponding tag byte. Exit with exception if the + * virtual address is not accessible for @ptr_access. + * + * The @ptr_size and @tag_size values may not have an obvious relation + * due to the alignment of @ptr, and the number of tag checks required. + * + * If there is no tag storage corresponding to @ptr, return NULL. + */ +static uint8_t *allocation_tag_mem(CPUARMState *env, int ptr_mmu_idx, + uint64_t ptr, MMUAccessType ptr_access, + int ptr_size, MMUAccessType tag_access, + int tag_size, uintptr_t ra) +{ +#ifdef CONFIG_USER_ONLY + uint64_t clean_ptr = useronly_clean_ptr(ptr); + int flags = page_get_flags(clean_ptr); + uint8_t *tags; + uintptr_t index; + + if (!(flags & (ptr_access == MMU_DATA_STORE ? PAGE_WRITE_ORG : PAGE_READ))) { + cpu_loop_exit_sigsegv(env_cpu(env), ptr, ptr_access, + !(flags & PAGE_VALID), ra); + } + + /* Require both MAP_ANON and PROT_MTE for the page. */ + if (!(flags & PAGE_ANON) || !(flags & PAGE_MTE)) { + return NULL; + } + + tags = page_get_target_data(clean_ptr); + if (tags == NULL) { + size_t alloc_size = TARGET_PAGE_SIZE >> (LOG2_TAG_GRANULE + 1); + tags = page_alloc_target_data(clean_ptr, alloc_size); + assert(tags != NULL); + } + + index = extract32(ptr, LOG2_TAG_GRANULE + 1, + TARGET_PAGE_BITS - LOG2_TAG_GRANULE - 1); + return tags + index; +#else + uintptr_t index; + CPUIOTLBEntry *iotlbentry; + int in_page, flags; + ram_addr_t ptr_ra; + hwaddr ptr_paddr, tag_paddr, xlat; + MemoryRegion *mr; + ARMASIdx tag_asi; + AddressSpace *tag_as; + void *host; + + /* + * Probe the first byte of the virtual address. This raises an + * exception for inaccessible pages, and resolves the virtual address + * into the softmmu tlb. + * + * When RA == 0, this is for mte_probe. The page is expected to be + * valid. Indicate to probe_access_flags no-fault, then assert that + * we received a valid page. + */ + flags = probe_access_flags(env, ptr, ptr_access, ptr_mmu_idx, + ra == 0, &host, ra); + assert(!(flags & TLB_INVALID_MASK)); + + /* + * Find the iotlbentry for ptr. This *must* be present in the TLB + * because we just found the mapping. + * TODO: Perhaps there should be a cputlb helper that returns a + * matching tlb entry + iotlb entry. + */ + index = tlb_index(env, ptr_mmu_idx, ptr); +# ifdef CONFIG_DEBUG_TCG + { + CPUTLBEntry *entry = tlb_entry(env, ptr_mmu_idx, ptr); + target_ulong comparator = (ptr_access == MMU_DATA_LOAD + ? entry->addr_read + : tlb_addr_write(entry)); + g_assert(tlb_hit(comparator, ptr)); + } +# endif + iotlbentry = &env_tlb(env)->d[ptr_mmu_idx].iotlb[index]; + + /* If the virtual page MemAttr != Tagged, access unchecked. */ + if (!arm_tlb_mte_tagged(&iotlbentry->attrs)) { + return NULL; + } + + /* + * If not backed by host ram, there is no tag storage: access unchecked. + * This is probably a guest os bug though, so log it. + */ + if (unlikely(flags & TLB_MMIO)) { + qemu_log_mask(LOG_GUEST_ERROR, + "Page @ 0x%" PRIx64 " indicates Tagged Normal memory " + "but is not backed by host ram\n", ptr); + return NULL; + } + + /* + * The Normal memory access can extend to the next page. E.g. a single + * 8-byte access to the last byte of a page will check only the last + * tag on the first page. + * Any page access exception has priority over tag check exception. + */ + in_page = -(ptr | TARGET_PAGE_MASK); + if (unlikely(ptr_size > in_page)) { + void *ignore; + flags |= probe_access_flags(env, ptr + in_page, ptr_access, + ptr_mmu_idx, ra == 0, &ignore, ra); + assert(!(flags & TLB_INVALID_MASK)); + } + + /* Any debug exception has priority over a tag check exception. */ + if (unlikely(flags & TLB_WATCHPOINT)) { + int wp = ptr_access == MMU_DATA_LOAD ? BP_MEM_READ : BP_MEM_WRITE; + assert(ra != 0); + cpu_check_watchpoint(env_cpu(env), ptr, ptr_size, + iotlbentry->attrs, wp, ra); + } + + /* + * Find the physical address within the normal mem space. + * The memory region lookup must succeed because TLB_MMIO was + * not set in the cputlb lookup above. + */ + mr = memory_region_from_host(host, &ptr_ra); + tcg_debug_assert(mr != NULL); + tcg_debug_assert(memory_region_is_ram(mr)); + ptr_paddr = ptr_ra; + do { + ptr_paddr += mr->addr; + mr = mr->container; + } while (mr); + + /* Convert to the physical address in tag space. */ + tag_paddr = ptr_paddr >> (LOG2_TAG_GRANULE + 1); + + /* Look up the address in tag space. */ + tag_asi = iotlbentry->attrs.secure ? ARMASIdx_TagS : ARMASIdx_TagNS; + tag_as = cpu_get_address_space(env_cpu(env), tag_asi); + mr = address_space_translate(tag_as, tag_paddr, &xlat, NULL, + tag_access == MMU_DATA_STORE, + iotlbentry->attrs); + + /* + * Note that @mr will never be NULL. If there is nothing in the address + * space at @tag_paddr, the translation will return the unallocated memory + * region. For our purposes, the result must be ram. + */ + if (unlikely(!memory_region_is_ram(mr))) { + /* ??? Failure is a board configuration error. */ + qemu_log_mask(LOG_UNIMP, + "Tag Memory @ 0x%" HWADDR_PRIx " not found for " + "Normal Memory @ 0x%" HWADDR_PRIx "\n", + tag_paddr, ptr_paddr); + return NULL; + } + + /* + * Ensure the tag memory is dirty on write, for migration. + * Tag memory can never contain code or display memory (vga). + */ + if (tag_access == MMU_DATA_STORE) { + ram_addr_t tag_ra = memory_region_get_ram_addr(mr) + xlat; + cpu_physical_memory_set_dirty_flag(tag_ra, DIRTY_MEMORY_MIGRATION); + } + + return memory_region_get_ram_ptr(mr) + xlat; +#endif +} + +uint64_t HELPER(irg)(CPUARMState *env, uint64_t rn, uint64_t rm) +{ + uint16_t exclude = extract32(rm | env->cp15.gcr_el1, 0, 16); + int rrnd = extract32(env->cp15.gcr_el1, 16, 1); + int start = extract32(env->cp15.rgsr_el1, 0, 4); + int seed = extract32(env->cp15.rgsr_el1, 8, 16); + int offset, i, rtag; + + /* + * Our IMPDEF choice for GCR_EL1.RRND==1 is to continue to use the + * deterministic algorithm. Except that with RRND==1 the kernel is + * not required to have set RGSR_EL1.SEED != 0, which is required for + * the deterministic algorithm to function. So we force a non-zero + * SEED for that case. + */ + if (unlikely(seed == 0) && rrnd) { + do { + Error *err = NULL; + uint16_t two; + + if (qemu_guest_getrandom(&two, sizeof(two), &err) < 0) { + /* + * Failed, for unknown reasons in the crypto subsystem. + * Best we can do is log the reason and use a constant seed. + */ + qemu_log_mask(LOG_UNIMP, "IRG: Crypto failure: %s\n", + error_get_pretty(err)); + error_free(err); + two = 1; + } + seed = two; + } while (seed == 0); + } + + /* RandomTag */ + for (i = offset = 0; i < 4; ++i) { + /* NextRandomTagBit */ + int top = (extract32(seed, 5, 1) ^ extract32(seed, 3, 1) ^ + extract32(seed, 2, 1) ^ extract32(seed, 0, 1)); + seed = (top << 15) | (seed >> 1); + offset |= top << i; + } + rtag = choose_nonexcluded_tag(start, offset, exclude); + env->cp15.rgsr_el1 = rtag | (seed << 8); + + return address_with_allocation_tag(rn, rtag); +} + +uint64_t HELPER(addsubg)(CPUARMState *env, uint64_t ptr, + int32_t offset, uint32_t tag_offset) +{ + int start_tag = allocation_tag_from_addr(ptr); + uint16_t exclude = extract32(env->cp15.gcr_el1, 0, 16); + int rtag = choose_nonexcluded_tag(start_tag, tag_offset, exclude); + + return address_with_allocation_tag(ptr + offset, rtag); +} + +static int load_tag1(uint64_t ptr, uint8_t *mem) +{ + int ofs = extract32(ptr, LOG2_TAG_GRANULE, 1) * 4; + return extract32(*mem, ofs, 4); +} + +uint64_t HELPER(ldg)(CPUARMState *env, uint64_t ptr, uint64_t xt) +{ + int mmu_idx = cpu_mmu_index(env, false); + uint8_t *mem; + int rtag = 0; + + /* Trap if accessing an invalid page. */ + mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_LOAD, 1, + MMU_DATA_LOAD, 1, GETPC()); + + /* Load if page supports tags. */ + if (mem) { + rtag = load_tag1(ptr, mem); + } + + return address_with_allocation_tag(xt, rtag); +} + +static void check_tag_aligned(CPUARMState *env, uint64_t ptr, uintptr_t ra) +{ + if (unlikely(!QEMU_IS_ALIGNED(ptr, TAG_GRANULE))) { + arm_cpu_do_unaligned_access(env_cpu(env), ptr, MMU_DATA_STORE, + cpu_mmu_index(env, false), ra); + g_assert_not_reached(); + } +} + +/* For use in a non-parallel context, store to the given nibble. */ +static void store_tag1(uint64_t ptr, uint8_t *mem, int tag) +{ + int ofs = extract32(ptr, LOG2_TAG_GRANULE, 1) * 4; + *mem = deposit32(*mem, ofs, 4, tag); +} + +/* For use in a parallel context, atomically store to the given nibble. */ +static void store_tag1_parallel(uint64_t ptr, uint8_t *mem, int tag) +{ + int ofs = extract32(ptr, LOG2_TAG_GRANULE, 1) * 4; + uint8_t old = qatomic_read(mem); + + while (1) { + uint8_t new = deposit32(old, ofs, 4, tag); + uint8_t cmp = qatomic_cmpxchg(mem, old, new); + if (likely(cmp == old)) { + return; + } + old = cmp; + } +} + +typedef void stg_store1(uint64_t, uint8_t *, int); + +static inline void do_stg(CPUARMState *env, uint64_t ptr, uint64_t xt, + uintptr_t ra, stg_store1 store1) +{ + int mmu_idx = cpu_mmu_index(env, false); + uint8_t *mem; + + check_tag_aligned(env, ptr, ra); + + /* Trap if accessing an invalid page. */ + mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE, TAG_GRANULE, + MMU_DATA_STORE, 1, ra); + + /* Store if page supports tags. */ + if (mem) { + store1(ptr, mem, allocation_tag_from_addr(xt)); + } +} + +void HELPER(stg)(CPUARMState *env, uint64_t ptr, uint64_t xt) +{ + do_stg(env, ptr, xt, GETPC(), store_tag1); +} + +void HELPER(stg_parallel)(CPUARMState *env, uint64_t ptr, uint64_t xt) +{ + do_stg(env, ptr, xt, GETPC(), store_tag1_parallel); +} + +void HELPER(stg_stub)(CPUARMState *env, uint64_t ptr) +{ + int mmu_idx = cpu_mmu_index(env, false); + uintptr_t ra = GETPC(); + + check_tag_aligned(env, ptr, ra); + probe_write(env, ptr, TAG_GRANULE, mmu_idx, ra); +} + +static inline void do_st2g(CPUARMState *env, uint64_t ptr, uint64_t xt, + uintptr_t ra, stg_store1 store1) +{ + int mmu_idx = cpu_mmu_index(env, false); + int tag = allocation_tag_from_addr(xt); + uint8_t *mem1, *mem2; + + check_tag_aligned(env, ptr, ra); + + /* + * Trap if accessing an invalid page(s). + * This takes priority over !allocation_tag_access_enabled. + */ + if (ptr & TAG_GRANULE) { + /* Two stores unaligned mod TAG_GRANULE*2 -- modify two bytes. */ + mem1 = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE, + TAG_GRANULE, MMU_DATA_STORE, 1, ra); + mem2 = allocation_tag_mem(env, mmu_idx, ptr + TAG_GRANULE, + MMU_DATA_STORE, TAG_GRANULE, + MMU_DATA_STORE, 1, ra); + + /* Store if page(s) support tags. */ + if (mem1) { + store1(TAG_GRANULE, mem1, tag); + } + if (mem2) { + store1(0, mem2, tag); + } + } else { + /* Two stores aligned mod TAG_GRANULE*2 -- modify one byte. */ + mem1 = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE, + 2 * TAG_GRANULE, MMU_DATA_STORE, 1, ra); + if (mem1) { + tag |= tag << 4; + qatomic_set(mem1, tag); + } + } +} + +void HELPER(st2g)(CPUARMState *env, uint64_t ptr, uint64_t xt) +{ + do_st2g(env, ptr, xt, GETPC(), store_tag1); +} + +void HELPER(st2g_parallel)(CPUARMState *env, uint64_t ptr, uint64_t xt) +{ + do_st2g(env, ptr, xt, GETPC(), store_tag1_parallel); +} + +void HELPER(st2g_stub)(CPUARMState *env, uint64_t ptr) +{ + int mmu_idx = cpu_mmu_index(env, false); + uintptr_t ra = GETPC(); + int in_page = -(ptr | TARGET_PAGE_MASK); + + check_tag_aligned(env, ptr, ra); + + if (likely(in_page >= 2 * TAG_GRANULE)) { + probe_write(env, ptr, 2 * TAG_GRANULE, mmu_idx, ra); + } else { + probe_write(env, ptr, TAG_GRANULE, mmu_idx, ra); + probe_write(env, ptr + TAG_GRANULE, TAG_GRANULE, mmu_idx, ra); + } +} + +#define LDGM_STGM_SIZE (4 << GMID_EL1_BS) + +uint64_t HELPER(ldgm)(CPUARMState *env, uint64_t ptr) +{ + int mmu_idx = cpu_mmu_index(env, false); + uintptr_t ra = GETPC(); + void *tag_mem; + + ptr = QEMU_ALIGN_DOWN(ptr, LDGM_STGM_SIZE); + + /* Trap if accessing an invalid page. */ + tag_mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_LOAD, + LDGM_STGM_SIZE, MMU_DATA_LOAD, + LDGM_STGM_SIZE / (2 * TAG_GRANULE), ra); + + /* The tag is squashed to zero if the page does not support tags. */ + if (!tag_mem) { + return 0; + } + + QEMU_BUILD_BUG_ON(GMID_EL1_BS != 6); + /* + * We are loading 64-bits worth of tags. The ordering of elements + * within the word corresponds to a 64-bit little-endian operation. + */ + return ldq_le_p(tag_mem); +} + +void HELPER(stgm)(CPUARMState *env, uint64_t ptr, uint64_t val) +{ + int mmu_idx = cpu_mmu_index(env, false); + uintptr_t ra = GETPC(); + void *tag_mem; + + ptr = QEMU_ALIGN_DOWN(ptr, LDGM_STGM_SIZE); + + /* Trap if accessing an invalid page. */ + tag_mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE, + LDGM_STGM_SIZE, MMU_DATA_LOAD, + LDGM_STGM_SIZE / (2 * TAG_GRANULE), ra); + + /* + * Tag store only happens if the page support tags, + * and if the OS has enabled access to the tags. + */ + if (!tag_mem) { + return; + } + + QEMU_BUILD_BUG_ON(GMID_EL1_BS != 6); + /* + * We are storing 64-bits worth of tags. The ordering of elements + * within the word corresponds to a 64-bit little-endian operation. + */ + stq_le_p(tag_mem, val); +} + +void HELPER(stzgm_tags)(CPUARMState *env, uint64_t ptr, uint64_t val) +{ + uintptr_t ra = GETPC(); + int mmu_idx = cpu_mmu_index(env, false); + int log2_dcz_bytes, log2_tag_bytes; + intptr_t dcz_bytes, tag_bytes; + uint8_t *mem; + + /* + * In arm_cpu_realizefn, we assert that dcz > LOG2_TAG_GRANULE+1, + * i.e. 32 bytes, which is an unreasonably small dcz anyway, + * to make sure that we can access one complete tag byte here. + */ + log2_dcz_bytes = env_archcpu(env)->dcz_blocksize + 2; + log2_tag_bytes = log2_dcz_bytes - (LOG2_TAG_GRANULE + 1); + dcz_bytes = (intptr_t)1 << log2_dcz_bytes; + tag_bytes = (intptr_t)1 << log2_tag_bytes; + ptr &= -dcz_bytes; + + mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE, dcz_bytes, + MMU_DATA_STORE, tag_bytes, ra); + if (mem) { + int tag_pair = (val & 0xf) * 0x11; + memset(mem, tag_pair, tag_bytes); + } +} + +static void mte_sync_check_fail(CPUARMState *env, uint32_t desc, + uint64_t dirty_ptr, uintptr_t ra) +{ + int is_write, syn; + + env->exception.vaddress = dirty_ptr; + + is_write = FIELD_EX32(desc, MTEDESC, WRITE); + syn = syn_data_abort_no_iss(arm_current_el(env) != 0, 0, 0, 0, 0, is_write, + 0x11); + raise_exception_ra(env, EXCP_DATA_ABORT, syn, exception_target_el(env), ra); + g_assert_not_reached(); +} + +static void mte_async_check_fail(CPUARMState *env, uint64_t dirty_ptr, + uintptr_t ra, ARMMMUIdx arm_mmu_idx, int el) +{ + int select; + + if (regime_has_2_ranges(arm_mmu_idx)) { + select = extract64(dirty_ptr, 55, 1); + } else { + select = 0; + } + env->cp15.tfsr_el[el] |= 1 << select; +#ifdef CONFIG_USER_ONLY + /* + * Stand in for a timer irq, setting _TIF_MTE_ASYNC_FAULT, + * which then sends a SIGSEGV when the thread is next scheduled. + * This cpu will return to the main loop at the end of the TB, + * which is rather sooner than "normal". But the alternative + * is waiting until the next syscall. + */ + qemu_cpu_kick(env_cpu(env)); +#endif +} + +/* Record a tag check failure. */ +static void mte_check_fail(CPUARMState *env, uint32_t desc, + uint64_t dirty_ptr, uintptr_t ra) +{ + int mmu_idx = FIELD_EX32(desc, MTEDESC, MIDX); + ARMMMUIdx arm_mmu_idx = core_to_aa64_mmu_idx(mmu_idx); + int el, reg_el, tcf; + uint64_t sctlr; + + reg_el = regime_el(env, arm_mmu_idx); + sctlr = env->cp15.sctlr_el[reg_el]; + + switch (arm_mmu_idx) { + case ARMMMUIdx_E10_0: + case ARMMMUIdx_E20_0: + el = 0; + tcf = extract64(sctlr, 38, 2); + break; + default: + el = reg_el; + tcf = extract64(sctlr, 40, 2); + } + + switch (tcf) { + case 1: + /* Tag check fail causes a synchronous exception. */ + mte_sync_check_fail(env, desc, dirty_ptr, ra); + break; + + case 0: + /* + * Tag check fail does not affect the PE. + * We eliminate this case by not setting MTE_ACTIVE + * in tb_flags, so that we never make this runtime call. + */ + g_assert_not_reached(); + + case 2: + /* Tag check fail causes asynchronous flag set. */ + mte_async_check_fail(env, dirty_ptr, ra, arm_mmu_idx, el); + break; + + case 3: + /* + * Tag check fail causes asynchronous flag set for stores, or + * a synchronous exception for loads. + */ + if (FIELD_EX32(desc, MTEDESC, WRITE)) { + mte_async_check_fail(env, dirty_ptr, ra, arm_mmu_idx, el); + } else { + mte_sync_check_fail(env, desc, dirty_ptr, ra); + } + break; + } +} + +/** + * checkN: + * @tag: tag memory to test + * @odd: true to begin testing at tags at odd nibble + * @cmp: the tag to compare against + * @count: number of tags to test + * + * Return the number of successful tests. + * Thus a return value < @count indicates a failure. + * + * A note about sizes: count is expected to be small. + * + * The most common use will be LDP/STP of two integer registers, + * which means 16 bytes of memory touching at most 2 tags, but + * often the access is aligned and thus just 1 tag. + * + * Using AdvSIMD LD/ST (multiple), one can access 64 bytes of memory, + * touching at most 5 tags. SVE LDR/STR (vector) with the default + * vector length is also 64 bytes; the maximum architectural length + * is 256 bytes touching at most 9 tags. + * + * The loop below uses 7 logical operations and 1 memory operation + * per tag pair. An implementation that loads an aligned word and + * uses masking to ignore adjacent tags requires 18 logical operations + * and thus does not begin to pay off until 6 tags. + * Which, according to the survey above, is unlikely to be common. + */ +static int checkN(uint8_t *mem, int odd, int cmp, int count) +{ + int n = 0, diff; + + /* Replicate the test tag and compare. */ + cmp *= 0x11; + diff = *mem++ ^ cmp; + + if (odd) { + goto start_odd; + } + + while (1) { + /* Test even tag. */ + if (unlikely((diff) & 0x0f)) { + break; + } + if (++n == count) { + break; + } + + start_odd: + /* Test odd tag. */ + if (unlikely((diff) & 0xf0)) { + break; + } + if (++n == count) { + break; + } + + diff = *mem++ ^ cmp; + } + return n; +} + +/** + * mte_probe_int() - helper for mte_probe and mte_check + * @env: CPU environment + * @desc: MTEDESC descriptor + * @ptr: virtual address of the base of the access + * @fault: return virtual address of the first check failure + * + * Internal routine for both mte_probe and mte_check. + * Return zero on failure, filling in *fault. + * Return negative on trivial success for tbi disabled. + * Return positive on success with tbi enabled. + */ +static int mte_probe_int(CPUARMState *env, uint32_t desc, uint64_t ptr, + uintptr_t ra, uint64_t *fault) +{ + int mmu_idx, ptr_tag, bit55; + uint64_t ptr_last, prev_page, next_page; + uint64_t tag_first, tag_last; + uint64_t tag_byte_first, tag_byte_last; + uint32_t sizem1, tag_count, tag_size, n, c; + uint8_t *mem1, *mem2; + MMUAccessType type; + + bit55 = extract64(ptr, 55, 1); + *fault = ptr; + + /* If TBI is disabled, the access is unchecked, and ptr is not dirty. */ + if (unlikely(!tbi_check(desc, bit55))) { + return -1; + } + + ptr_tag = allocation_tag_from_addr(ptr); + + if (tcma_check(desc, bit55, ptr_tag)) { + return 1; + } + + mmu_idx = FIELD_EX32(desc, MTEDESC, MIDX); + type = FIELD_EX32(desc, MTEDESC, WRITE) ? MMU_DATA_STORE : MMU_DATA_LOAD; + sizem1 = FIELD_EX32(desc, MTEDESC, SIZEM1); + + /* Find the addr of the end of the access */ + ptr_last = ptr + sizem1; + + /* Round the bounds to the tag granule, and compute the number of tags. */ + tag_first = QEMU_ALIGN_DOWN(ptr, TAG_GRANULE); + tag_last = QEMU_ALIGN_DOWN(ptr_last, TAG_GRANULE); + tag_count = ((tag_last - tag_first) / TAG_GRANULE) + 1; + + /* Round the bounds to twice the tag granule, and compute the bytes. */ + tag_byte_first = QEMU_ALIGN_DOWN(ptr, 2 * TAG_GRANULE); + tag_byte_last = QEMU_ALIGN_DOWN(ptr_last, 2 * TAG_GRANULE); + + /* Locate the page boundaries. */ + prev_page = ptr & TARGET_PAGE_MASK; + next_page = prev_page + TARGET_PAGE_SIZE; + + if (likely(tag_last - prev_page < TARGET_PAGE_SIZE)) { + /* Memory access stays on one page. */ + tag_size = ((tag_byte_last - tag_byte_first) / (2 * TAG_GRANULE)) + 1; + mem1 = allocation_tag_mem(env, mmu_idx, ptr, type, sizem1 + 1, + MMU_DATA_LOAD, tag_size, ra); + if (!mem1) { + return 1; + } + /* Perform all of the comparisons. */ + n = checkN(mem1, ptr & TAG_GRANULE, ptr_tag, tag_count); + } else { + /* Memory access crosses to next page. */ + tag_size = (next_page - tag_byte_first) / (2 * TAG_GRANULE); + mem1 = allocation_tag_mem(env, mmu_idx, ptr, type, next_page - ptr, + MMU_DATA_LOAD, tag_size, ra); + + tag_size = ((tag_byte_last - next_page) / (2 * TAG_GRANULE)) + 1; + mem2 = allocation_tag_mem(env, mmu_idx, next_page, type, + ptr_last - next_page + 1, + MMU_DATA_LOAD, tag_size, ra); + + /* + * Perform all of the comparisons. + * Note the possible but unlikely case of the operation spanning + * two pages that do not both have tagging enabled. + */ + n = c = (next_page - tag_first) / TAG_GRANULE; + if (mem1) { + n = checkN(mem1, ptr & TAG_GRANULE, ptr_tag, c); + } + if (n == c) { + if (!mem2) { + return 1; + } + n += checkN(mem2, 0, ptr_tag, tag_count - c); + } + } + + if (likely(n == tag_count)) { + return 1; + } + + /* + * If we failed, we know which granule. For the first granule, the + * failure address is @ptr, the first byte accessed. Otherwise the + * failure address is the first byte of the nth granule. + */ + if (n > 0) { + *fault = tag_first + n * TAG_GRANULE; + } + return 0; +} + +uint64_t mte_check(CPUARMState *env, uint32_t desc, uint64_t ptr, uintptr_t ra) +{ + uint64_t fault; + int ret = mte_probe_int(env, desc, ptr, ra, &fault); + + if (unlikely(ret == 0)) { + mte_check_fail(env, desc, fault, ra); + } else if (ret < 0) { + return ptr; + } + return useronly_clean_ptr(ptr); +} + +uint64_t HELPER(mte_check)(CPUARMState *env, uint32_t desc, uint64_t ptr) +{ + return mte_check(env, desc, ptr, GETPC()); +} + +/* + * No-fault version of mte_check, to be used by SVE for MemSingleNF. + * Returns false if the access is Checked and the check failed. This + * is only intended to probe the tag -- the validity of the page must + * be checked beforehand. + */ +bool mte_probe(CPUARMState *env, uint32_t desc, uint64_t ptr) +{ + uint64_t fault; + int ret = mte_probe_int(env, desc, ptr, 0, &fault); + + return ret != 0; +} + +/* + * Perform an MTE checked access for DC_ZVA. + */ +uint64_t HELPER(mte_check_zva)(CPUARMState *env, uint32_t desc, uint64_t ptr) +{ + uintptr_t ra = GETPC(); + int log2_dcz_bytes, log2_tag_bytes; + int mmu_idx, bit55; + intptr_t dcz_bytes, tag_bytes, i; + void *mem; + uint64_t ptr_tag, mem_tag, align_ptr; + + bit55 = extract64(ptr, 55, 1); + + /* If TBI is disabled, the access is unchecked, and ptr is not dirty. */ + if (unlikely(!tbi_check(desc, bit55))) { + return ptr; + } + + ptr_tag = allocation_tag_from_addr(ptr); + + if (tcma_check(desc, bit55, ptr_tag)) { + goto done; + } + + /* + * In arm_cpu_realizefn, we asserted that dcz > LOG2_TAG_GRANULE+1, + * i.e. 32 bytes, which is an unreasonably small dcz anyway, to make + * sure that we can access one complete tag byte here. + */ + log2_dcz_bytes = env_archcpu(env)->dcz_blocksize + 2; + log2_tag_bytes = log2_dcz_bytes - (LOG2_TAG_GRANULE + 1); + dcz_bytes = (intptr_t)1 << log2_dcz_bytes; + tag_bytes = (intptr_t)1 << log2_tag_bytes; + align_ptr = ptr & -dcz_bytes; + + /* + * Trap if accessing an invalid page. DC_ZVA requires that we supply + * the original pointer for an invalid page. But watchpoints require + * that we probe the actual space. So do both. + */ + mmu_idx = FIELD_EX32(desc, MTEDESC, MIDX); + (void) probe_write(env, ptr, 1, mmu_idx, ra); + mem = allocation_tag_mem(env, mmu_idx, align_ptr, MMU_DATA_STORE, + dcz_bytes, MMU_DATA_LOAD, tag_bytes, ra); + if (!mem) { + goto done; + } + + /* + * Unlike the reasoning for checkN, DC_ZVA is always aligned, and thus + * it is quite easy to perform all of the comparisons at once without + * any extra masking. + * + * The most common zva block size is 64; some of the thunderx cpus use + * a block size of 128. For user-only, aarch64_max_initfn will set the + * block size to 512. Fill out the other cases for future-proofing. + * + * In order to be able to find the first miscompare later, we want the + * tag bytes to be in little-endian order. + */ + switch (log2_tag_bytes) { + case 0: /* zva_blocksize 32 */ + mem_tag = *(uint8_t *)mem; + ptr_tag *= 0x11u; + break; + case 1: /* zva_blocksize 64 */ + mem_tag = cpu_to_le16(*(uint16_t *)mem); + ptr_tag *= 0x1111u; + break; + case 2: /* zva_blocksize 128 */ + mem_tag = cpu_to_le32(*(uint32_t *)mem); + ptr_tag *= 0x11111111u; + break; + case 3: /* zva_blocksize 256 */ + mem_tag = cpu_to_le64(*(uint64_t *)mem); + ptr_tag *= 0x1111111111111111ull; + break; + + default: /* zva_blocksize 512, 1024, 2048 */ + ptr_tag *= 0x1111111111111111ull; + i = 0; + do { + mem_tag = cpu_to_le64(*(uint64_t *)(mem + i)); + if (unlikely(mem_tag != ptr_tag)) { + goto fail; + } + i += 8; + align_ptr += 16 * TAG_GRANULE; + } while (i < tag_bytes); + goto done; + } + + if (likely(mem_tag == ptr_tag)) { + goto done; + } + + fail: + /* Locate the first nibble that differs. */ + i = ctz64(mem_tag ^ ptr_tag) >> 4; + mte_check_fail(env, desc, align_ptr + i * TAG_GRANULE, ra); + + done: + return useronly_clean_ptr(ptr); +} |