[PATCH v2 06/10] gdbstub: Use specific MMU index when probing MTE addresses

["Alex Bennée" <alex.bennee@linaro.org>]

From: Gustavo Romero <gustavo.romero@linaro.org>

Use cpu_mmu_index() to determine the specific translation regime (MMU
index) before probing addresses using allocation_tag_mem_probe().

Currently, the MMU index is hardcoded to 0 and only works for user mode.
By obtaining the specific MMU index according to the translation regime,
future use of the stubs relying on allocation_tag_mem_probe in other
regimes will be possible, like in EL1.

This commit also changes the ptr_size value passed to
allocation_tag_mem_probe() from 8 to 1. The ptr_size parameter actually
represents the number of bytes in the memory access (which can be as
small as 1 byte), rather than the number of bits used in the address
space pointed to by ptr.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240906143316.657436-2-gustavo.romero@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 target/arm/gdbstub64.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/target/arm/gdbstub64.c b/target/arm/gdbstub64.c
index 5221381cc8..85a19c14c7 100644
--- a/target/arm/gdbstub64.c
+++ b/target/arm/gdbstub64.c
@@ -435,6 +435,7 @@ static void handle_q_memtag(GArray *params, void *user_ctx)
 {
     ARMCPU *cpu = ARM_CPU(user_ctx);
     CPUARMState *env = &cpu->env;
+    uint32_t mmu_index;
 
     uint64_t addr = gdb_get_cmd_param(params, 0)->val_ull;
     uint64_t len = gdb_get_cmd_param(params, 1)->val_ul;
@@ -458,8 +459,10 @@ static void handle_q_memtag(GArray *params, void *user_ctx)
         gdb_put_packet("E03");
     }
 
+    /* Find out the current translation regime for probe. */
+    mmu_index = cpu_mmu_index(env_cpu(env), false);
     /* Note that tags are packed here (2 tags packed in one byte). */
-    tags = allocation_tag_mem_probe(env, 0, addr, MMU_DATA_LOAD, 8 /* 64-bit */,
+    tags = allocation_tag_mem_probe(env, mmu_index, addr, MMU_DATA_LOAD, 1,
                                     MMU_DATA_LOAD, true, 0);
     if (!tags) {
         /* Address is not in a tagged region. */
@@ -478,13 +481,16 @@ static void handle_q_isaddresstagged(GArray *params, void *user_ctx)
 {
     ARMCPU *cpu = ARM_CPU(user_ctx);
     CPUARMState *env = &cpu->env;
+    uint32_t mmu_index;
 
     uint64_t addr = gdb_get_cmd_param(params, 0)->val_ull;
 
     uint8_t *tags;
     const char *reply;
 
-    tags = allocation_tag_mem_probe(env, 0, addr, MMU_DATA_LOAD, 8 /* 64-bit */,
+    /* Find out the current translation regime for probe. */
+    mmu_index = cpu_mmu_index(env_cpu(env), false);
+    tags = allocation_tag_mem_probe(env, mmu_index, addr, MMU_DATA_LOAD, 1,
                                     MMU_DATA_LOAD, true, 0);
     reply = tags ? "01" : "00";
 
@@ -495,6 +501,7 @@ static void handle_Q_memtag(GArray *params, void *user_ctx)
 {
     ARMCPU *cpu = ARM_CPU(user_ctx);
     CPUARMState *env = &cpu->env;
+    uint32_t mmu_index;
 
     uint64_t start_addr = gdb_get_cmd_param(params, 0)->val_ull;
     uint64_t len = gdb_get_cmd_param(params, 1)->val_ul;
@@ -527,8 +534,10 @@ static void handle_Q_memtag(GArray *params, void *user_ctx)
      * Get all tags in the page starting from the tag of the start address.
      * Note that there are two tags packed into a single byte here.
      */
-    tags = allocation_tag_mem_probe(env, 0, start_addr, MMU_DATA_STORE,
-                                    8 /* 64-bit */, MMU_DATA_STORE, true, 0);
+    /* Find out the current translation regime for probe. */
+    mmu_index = cpu_mmu_index(env_cpu(env), false);
+    tags = allocation_tag_mem_probe(env, mmu_index, start_addr, MMU_DATA_STORE,
+                                    1, MMU_DATA_STORE, true, 0);
     if (!tags) {
         /* Address is not in a tagged region. */
         gdb_put_packet("E04");
-- 
2.39.2