| /* |
| * 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 "qemu/log.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); |
| |
| index = extract32(ptr, LOG2_TAG_GRANULE + 1, |
| TARGET_PAGE_BITS - LOG2_TAG_GRANULE - 1); |
| return tags + index; |
| #else |
| CPUTLBEntryFull *full; |
| MemTxAttrs attrs; |
| int in_page, flags; |
| 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_full(env, ptr, 0, ptr_access, ptr_mmu_idx, |
| ra == 0, &host, &full, ra); |
| assert(!(flags & TLB_INVALID_MASK)); |
| |
| /* If the virtual page MemAttr != Tagged, access unchecked. */ |
| if (full->pte_attrs != 0xf0) { |
| 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; |
| } |
| |
| /* |
| * Remember these values across the second lookup below, |
| * which may invalidate this pointer via tlb resize. |
| */ |
| ptr_paddr = full->phys_addr | (ptr & ~TARGET_PAGE_MASK); |
| attrs = full->attrs; |
| full = 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)) { |
| flags |= probe_access_full(env, ptr + in_page, 0, ptr_access, |
| ptr_mmu_idx, ra == 0, &host, &full, 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, attrs, wp, ra); |
| } |
| |
| /* 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 = 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, 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); |
| } |
