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authorRichard Henderson <richard.henderson@linaro.org>2020-06-25 20:31:13 -0700
committerPeter Maydell <peter.maydell@linaro.org>2020-06-26 14:31:12 +0100
commitc15294c1e36a7dd9b25bd54d98178e80f4b64bc1 (patch)
tree703622337a307f90aaff93e97f151d46f51338a1 /target/arm/mte_helper.c
parent0d1762e931f8a694f261c604daba605bcda70928 (diff)
downloadqemu-arm-c15294c1e36a7dd9b25bd54d98178e80f4b64bc1.tar.gz
target/arm: Implement LDG, STG, ST2G instructions
Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20200626033144.790098-16-richard.henderson@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'target/arm/mte_helper.c')
-rw-r--r--target/arm/mte_helper.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 9ab9ed749d..7ec7930dfc 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -44,6 +44,40 @@ static int choose_nonexcluded_tag(int tag, int offset, uint16_t exclude)
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)
+{
+ /* Tag storage not implemented. */
+ return NULL;
+}
+
uint64_t HELPER(irg)(CPUARMState *env, uint64_t rn, uint64_t rm)
{
int rtag;
@@ -80,3 +114,163 @@ uint64_t HELPER(addsubg)(CPUARMState *env, uint64_t ptr,
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 = atomic_read(mem);
+
+ while (1) {
+ uint8_t new = deposit32(old, ofs, 4, tag);
+ uint8_t cmp = atomic_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;
+ atomic_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);
+ }
+}