kselftest/arm64/mte: Add verification for address tag in signal handler

Add the address tag [63:60] verification when synchronous mte fault is happen.
when signal handler is registered with SA_EXPOSE_TAGBITS,
address includes not only memory tag [59:56] but also address tag.
Therefore, when verify fault address location, remove both tags

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250618084513.1761345-9-yeoreum.yun@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index d9702a542cb63559847c24aeed340eb58b27bad8..10dcbc37e3792702f4f782ccd1818831bb82d194 100644 (file)
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -33,12 +33,25 @@ static unsigned int mte_cur_pstate_tco;
 
 void mte_default_handler(int signum, siginfo_t *si, void *uc)
 {
+       struct sigaction sa;
        unsigned long addr = (unsigned long)si->si_addr;
+       unsigned char si_tag, si_atag;
+
+       sigaction(signum, NULL, &sa);
+
+       if (sa.sa_flags & SA_EXPOSE_TAGBITS) {
+               si_tag = MT_FETCH_TAG(addr);
+               si_atag = MT_FETCH_ATAG(addr);
+               addr = MT_CLEAR_TAGS(addr);
+       } else {
+               si_tag = 0;
+               si_atag = 0;
+       }
 
        if (signum == SIGSEGV) {
 #ifdef DEBUG
-               ksft_print_msg("INFO: SIGSEGV signal at pc=%lx, fault addr=%lx, si_code=%lx\n",
-                               ((ucontext_t *)uc)->uc_mcontext.pc, addr, si->si_code);
+               ksft_print_msg("INFO: SIGSEGV signal at pc=%lx, fault addr=%lx, si_code=%lx, si_tag=%x, si_atag=%x\n",
+                               ((ucontext_t *)uc)->uc_mcontext.pc, addr, si->si_code, si_tag, si_atag);
 #endif
                if (si->si_code == SEGV_MTEAERR) {
                        if (cur_mte_cxt.trig_si_code == si->si_code)
@@ -51,13 +64,18 @@ void mte_default_handler(int signum, siginfo_t *si, void *uc)
                }
                /* Compare the context for precise error */
                else if (si->si_code == SEGV_MTESERR) {
+                       if ((!mtefar_support && si_atag) || (si_atag != MT_FETCH_ATAG(cur_mte_cxt.trig_addr))) {
+                               ksft_print_msg("Invalid MTE synchronous exception caught for address tag! si_tag=%x, si_atag: %x\n", si_tag, si_atag);
+                               exit(KSFT_FAIL);
+                       }
+
                        if (cur_mte_cxt.trig_si_code == si->si_code &&
                            ((cur_mte_cxt.trig_range >= 0 &&
-                             addr >= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
-                             addr <= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)) ||
+                             addr >= MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) &&
+                             addr <= (MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)) ||
                             (cur_mte_cxt.trig_range < 0 &&
-                             addr <= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
-                             addr >= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)))) {
+                             addr <= MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) &&
+                             addr >= (MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)))) {
                                cur_mte_cxt.fault_valid = true;
                                /* Adjust the pc by 4 */
                                ((ucontext_t *)uc)->uc_mcontext.pc += 4;
@@ -73,11 +91,11 @@ void mte_default_handler(int signum, siginfo_t *si, void *uc)
                ksft_print_msg("INFO: SIGBUS signal at pc=%llx, fault addr=%lx, si_code=%x\n",
                                ((ucontext_t *)uc)->uc_mcontext.pc, addr, si->si_code);
                if ((cur_mte_cxt.trig_range >= 0 &&
-                    addr >= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
-                    addr <= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)) ||
+                    addr >= MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) &&
+                    addr <= (MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)) ||
                    (cur_mte_cxt.trig_range < 0 &&
-                    addr <= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
-                    addr >= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range))) {
+                    addr <= MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) &&
+                    addr >= (MT_CLEAR_TAGS(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range))) {
                        cur_mte_cxt.fault_valid = true;
                        /* Adjust the pc by 4 */
                        ((ucontext_t *)uc)->uc_mcontext.pc += 4;