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[2001:8b0:1d0::2]) by smtp.gmail.com with ESMTPSA id d1-20020adfa401000000b0031980294e9fsm20256241wra.116.2023.09.07.09.03.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Sep 2023 09:03:46 -0700 (PDT) From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Subject: [PATCH 08/14] target/arm: Implement MTE tag-checking functions for FEAT_MOPS Date: Thu, 7 Sep 2023 17:03:34 +0100 Message-Id: <20230907160340.260094-9-peter.maydell@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230907160340.260094-1-peter.maydell@linaro.org> References: <20230907160340.260094-1-peter.maydell@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::433; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x433.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The FEAT_MOPS instructions need a couple of helper routines that check for MTE tag failures: * mte_mops_probe() checks whether there is going to be a tag error in the next up-to-a-page worth of data * mte_check_fail() is an existing function to record the fact of a tag failure, which we need to make global so we can call it from helper-a64.c Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- target/arm/internals.h | 28 +++++++++++++++++++ target/arm/tcg/mte_helper.c | 54 +++++++++++++++++++++++++++++++++++-- 2 files changed, 80 insertions(+), 2 deletions(-) diff --git a/target/arm/internals.h b/target/arm/internals.h index 5f5393b25c4..a70a7fd50f6 100644 --- a/target/arm/internals.h +++ b/target/arm/internals.h @@ -1272,6 +1272,34 @@ FIELD(MTEDESC, SIZEM1, 12, SIMD_DATA_BITS - 12) /* size - 1 */ bool mte_probe(CPUARMState *env, uint32_t desc, uint64_t ptr); uint64_t mte_check(CPUARMState *env, uint32_t desc, uint64_t ptr, uintptr_t ra); +/** + * mte_mops_probe: Check where the next MTE failure is for a FEAT_MOPS operation + * @env: CPU env + * @ptr: start address of memory region (dirty pointer) + * @size: length of region (guaranteed not to cross a page boundary) + * @desc: MTEDESC descriptor word (0 means no MTE checks) + * Returns: the size of the region that can be copied without hitting + * an MTE tag failure + * + * Note that we assume that the caller has already checked the TBI + * and TCMA bits with mte_checks_needed() and an MTE check is definitely + * required. + */ +uint64_t mte_mops_probe(CPUARMState *env, uint64_t ptr, uint64_t size, + uint32_t desc); + +/** + * mte_check_fail: Record an MTE tag check failure + * @env: CPU env + * @desc: MTEDESC descriptor word + * @dirty_ptr: Failing dirty address + * @ra: TCG retaddr + * + * This may never return (if the MTE tag checks are configured to fault). + */ +void mte_check_fail(CPUARMState *env, uint32_t desc, + uint64_t dirty_ptr, uintptr_t ra); + static inline int allocation_tag_from_addr(uint64_t ptr) { return extract64(ptr, 56, 4); diff --git a/target/arm/tcg/mte_helper.c b/target/arm/tcg/mte_helper.c index 884d88848aa..0065012be19 100644 --- a/target/arm/tcg/mte_helper.c +++ b/target/arm/tcg/mte_helper.c @@ -616,8 +616,8 @@ static void mte_async_check_fail(CPUARMState *env, uint64_t dirty_ptr, } /* Record a tag check failure. */ -static void mte_check_fail(CPUARMState *env, uint32_t desc, - uint64_t dirty_ptr, uintptr_t ra) +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); @@ -990,3 +990,53 @@ uint64_t HELPER(mte_check_zva)(CPUARMState *env, uint32_t desc, uint64_t ptr) done: return useronly_clean_ptr(ptr); } + +uint64_t mte_mops_probe(CPUARMState *env, uint64_t ptr, uint64_t size, + uint32_t desc) +{ + int mmu_idx, tag_count; + uint64_t ptr_tag, tag_first, tag_last; + void *mem; + bool w = FIELD_EX32(desc, MTEDESC, WRITE); + uint32_t n; + + mmu_idx = FIELD_EX32(desc, MTEDESC, MIDX); + /* True probe; this will never fault */ + mem = allocation_tag_mem_probe(env, mmu_idx, ptr, + w ? MMU_DATA_STORE : MMU_DATA_LOAD, + size, MMU_DATA_LOAD, true, 0); + if (!mem) { + return size; + } + + /* + * TODO: checkN() is not designed for checks of the size we expect + * for FEAT_MOPS operations, so we should implement this differently. + * Maybe we should do something like + * if (region start and size are aligned nicely) { + * do direct loads of 64 tag bits at a time; + * } else { + * call checkN() + * } + */ + /* Round the bounds to the tag granule, and compute the number of tags. */ + ptr_tag = allocation_tag_from_addr(ptr); + tag_first = QEMU_ALIGN_DOWN(ptr, TAG_GRANULE); + tag_last = QEMU_ALIGN_DOWN(ptr + size - 1, TAG_GRANULE); + tag_count = ((tag_last - tag_first) / TAG_GRANULE) + 1; + n = checkN(mem, ptr & TAG_GRANULE, ptr_tag, tag_count); + if (likely(n == tag_count)) { + return size; + } + + /* + * Failure; for the first granule, it's at @ptr. Otherwise + * it's at the first byte of the nth granule. Calculate how + * many bytes we can access without hitting that failure. + */ + if (n == 0) { + return 0; + } else { + return n * TAG_GRANULE - (ptr - tag_first); + } +}