target/arm: Replace MTEDESC ESIZE+TSIZE with SIZEM1

After recent changes, mte_checkN does not use ESIZE,
and mte_check1 never used TSIZE.  We can combine the
two into a single field: SIZEM1.

Choose to pass size - 1 because size == 0 is never used,
our immediate need in mte_probe_int is for the address
of the last byte (ptr + size - 1), and since almost all
operations are powers of 2, this makes the immediate
constant one bit smaller.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210416183106.1516563-6-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 14 insertions, 18 deletions

diff --git a/target/arm/internals.h b/target/arm/internals.h
index f11bd32..2c77f2d 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -26,6 +26,7 @@
 #define TARGET_ARM_INTERNALS_H
 
 #include "hw/registerfields.h"
+#include "tcg/tcg-gvec-desc.h"
 #include "syndrome.h"
 
 /* register banks for CPU modes */
@@ -1142,8 +1143,7 @@ FIELD(MTEDESC, MIDX,  0, 4)
 FIELD(MTEDESC, TBI,   4, 2)
 FIELD(MTEDESC, TCMA,  6, 2)
 FIELD(MTEDESC, WRITE, 8, 1)
-FIELD(MTEDESC, ESIZE, 9, 5)
-FIELD(MTEDESC, TSIZE, 14, 10)  /* mte_checkN only */
+FIELD(MTEDESC, SIZEM1, 9, SIMD_DATA_BITS - 9)  /* size - 1 */
 
 bool mte_probe1(CPUARMState *env, uint32_t desc, uint64_t ptr);
 uint64_t mte_check1(CPUARMState *env, uint32_t desc,
diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 0ee0397..804057d 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -692,13 +692,13 @@ static int checkN(uint8_t *mem, int odd, int cmp, int count)
  * Return positive on success with tbi enabled.
  */
 static int mte_probe_int(CPUARMState *env, uint32_t desc, uint64_t ptr,
-                         uintptr_t ra, uint32_t total, uint64_t *fault)
+                         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 tag_count, tag_size, n, c;
+    uint32_t sizem1, tag_count, tag_size, n, c;
     uint8_t *mem1, *mem2;
     MMUAccessType type;
 
@@ -718,9 +718,10 @@ static int mte_probe_int(CPUARMState *env, uint32_t desc, uint64_t ptr,
 
     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 + total - 1;
+    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);
@@ -738,7 +739,7 @@ static int mte_probe_int(CPUARMState *env, uint32_t desc, uint64_t ptr,
     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, total,
+        mem1 = allocation_tag_mem(env, mmu_idx, ptr, type, sizem1 + 1,
                                   MMU_DATA_LOAD, tag_size, ra);
         if (!mem1) {
             return 1;
@@ -792,8 +793,7 @@ uint64_t mte_checkN(CPUARMState *env, uint32_t desc,
                     uint64_t ptr, uintptr_t ra)
 {
     uint64_t fault;
-    uint32_t total = FIELD_EX32(desc, MTEDESC, TSIZE);
-    int ret = mte_probe_int(env, desc, ptr, ra, total, &fault);
+    int ret = mte_probe_int(env, desc, ptr, ra, &fault);
 
     if (unlikely(ret == 0)) {
         mte_check_fail(env, desc, fault, ra);
@@ -812,8 +812,7 @@ uint64_t mte_check1(CPUARMState *env, uint32_t desc,
                     uint64_t ptr, uintptr_t ra)
 {
     uint64_t fault;
-    uint32_t total = FIELD_EX32(desc, MTEDESC, ESIZE);
-    int ret = mte_probe_int(env, desc, ptr, ra, total, &fault);
+    int ret = mte_probe_int(env, desc, ptr, ra, &fault);
 
     if (unlikely(ret == 0)) {
         mte_check_fail(env, desc, fault, ra);
@@ -837,8 +836,7 @@ uint64_t HELPER(mte_check1)(CPUARMState *env, uint32_t desc, uint64_t ptr)
 bool mte_probe1(CPUARMState *env, uint32_t desc, uint64_t ptr)
 {
     uint64_t fault;
-    uint32_t total = FIELD_EX32(desc, MTEDESC, ESIZE);
-    int ret = mte_probe_int(env, desc, ptr, 0, total, &fault);
+    int ret = mte_probe_int(env, desc, ptr, 0, &fault);
 
     return ret != 0;
 }
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 0b42e53..3af00ae 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -272,7 +272,7 @@ static TCGv_i64 gen_mte_check1_mmuidx(DisasContext *s, TCGv_i64 addr,
         desc = FIELD_DP32(desc, MTEDESC, TBI, s->tbid);
         desc = FIELD_DP32(desc, MTEDESC, TCMA, s->tcma);
         desc = FIELD_DP32(desc, MTEDESC, WRITE, is_write);
-        desc = FIELD_DP32(desc, MTEDESC, ESIZE, 1 << log2_size);
+        desc = FIELD_DP32(desc, MTEDESC, SIZEM1, (1 << log2_size) - 1);
         tcg_desc = tcg_const_i32(desc);
 
         ret = new_tmp_a64(s);
@@ -306,8 +306,7 @@ TCGv_i64 gen_mte_checkN(DisasContext *s, TCGv_i64 addr, bool is_write,
         desc = FIELD_DP32(desc, MTEDESC, TBI, s->tbid);
         desc = FIELD_DP32(desc, MTEDESC, TCMA, s->tcma);
         desc = FIELD_DP32(desc, MTEDESC, WRITE, is_write);
-        desc = FIELD_DP32(desc, MTEDESC, ESIZE, 1 << log2_esize);
-        desc = FIELD_DP32(desc, MTEDESC, TSIZE, total_size);
+        desc = FIELD_DP32(desc, MTEDESC, SIZEM1, total_size - 1);
         tcg_desc = tcg_const_i32(desc);
 
         ret = new_tmp_a64(s);
diff --git a/target/arm/translate-sve.c b/target/arm/translate-sve.c
index 0eefb61..5179c1f 100644
--- a/target/arm/translate-sve.c
+++ b/target/arm/translate-sve.c
@@ -4509,8 +4509,7 @@ static void do_mem_zpa(DisasContext *s, int zt, int pg, TCGv_i64 addr,
         desc = FIELD_DP32(desc, MTEDESC, TBI, s->tbid);
         desc = FIELD_DP32(desc, MTEDESC, TCMA, s->tcma);
         desc = FIELD_DP32(desc, MTEDESC, WRITE, is_write);
-        desc = FIELD_DP32(desc, MTEDESC, ESIZE, 1 << msz);
-        desc = FIELD_DP32(desc, MTEDESC, TSIZE, mte_n << msz);
+        desc = FIELD_DP32(desc, MTEDESC, SIZEM1, (mte_n << msz) - 1);
         desc <<= SVE_MTEDESC_SHIFT;
     } else {
         addr = clean_data_tbi(s, addr);
@@ -5189,7 +5188,7 @@ static void do_mem_zpz(DisasContext *s, int zt, int pg, int zm,
         desc = FIELD_DP32(desc, MTEDESC, TBI, s->tbid);
         desc = FIELD_DP32(desc, MTEDESC, TCMA, s->tcma);
         desc = FIELD_DP32(desc, MTEDESC, WRITE, is_write);
-        desc = FIELD_DP32(desc, MTEDESC, ESIZE, 1 << msz);
+        desc = FIELD_DP32(desc, MTEDESC, SIZEM1, (1 << msz) - 1);
         desc <<= SVE_MTEDESC_SHIFT;
     }
     desc = simd_desc(vsz, vsz, desc | scale);