target/arm: Report pauth information to gdb as 'pauth_v2'

So that we can avoid the "older gdb crashes" problem described in
commit 5787d17a42f7af4 and which caused us to disable reporting pauth
information via the gdbstub, newer gdb is going to implement support
for recognizing the pauth information via a new feature name:
 org.gnu.gdb.aarch64.pauth_v2

Older gdb won't recognize this feature name, so we can re-enable the
pauth support under the new name without risking them crashing.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230406150827.3322670-1-peter.maydell@linaro.org

diff --git a/gdb-xml/aarch64-pauth.xml b/gdb-xml/aarch64-pauth.xml
index 24af5f903c191e46b4221d5e47688633691da217..0a5c566d66847f710cdeec27f979e1cf72844f15 100644 (file)
--- a/gdb-xml/aarch64-pauth.xml
+++ b/gdb-xml/aarch64-pauth.xml
@@ -6,7 +6,7 @@
      notice and this notice are preserved.  -->
 
 <!DOCTYPE feature SYSTEM "gdb-target.dtd">
-<feature name="org.gnu.gdb.aarch64.pauth">
+<feature name="org.gnu.gdb.aarch64.pauth_v2">
   <reg name="pauth_dmask" bitsize="64"/>
   <reg name="pauth_cmask" bitsize="64"/>
   <reg name="pauth_dmask_high" bitsize="64"/>

diff --git a/target/arm/gdbstub.c b/target/arm/gdbstub.c
index 13fbe9b0d7e4e6ee0244a9ee05bc1cda052fda0b..03b17c814f68690b26b0c148c8315e5be1f64dcc 100644 (file)
--- a/target/arm/gdbstub.c
+++ b/target/arm/gdbstub.c
@@ -521,18 +521,17 @@ void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)
                                      aarch64_gdb_set_fpu_reg,
                                      34, "aarch64-fpu.xml", 0);
         }
-#if 0
         /*
-         * GDB versions 9 through 12 have a bug which means they will
-         * crash if they see this XML from QEMU; disable it for the 8.0
-         * release, pending a better solution.
+         * Note that we report pauth information via the feature name
+         * org.gnu.gdb.aarch64.pauth_v2, not org.gnu.gdb.aarch64.pauth.
+         * GDB versions 9 through 12 have a bug where they will crash
+         * if they see the latter XML from QEMU.
          */
         if (isar_feature_aa64_pauth(&cpu->isar)) {
             gdb_register_coprocessor(cs, aarch64_gdb_get_pauth_reg,
                                      aarch64_gdb_set_pauth_reg,
                                      4, "aarch64-pauth.xml", 0);
         }
-#endif
 #endif
     } else {
         if (arm_feature(env, ARM_FEATURE_NEON)) {