@@ -165,6 +165,7 @@
#define AARCH64_ZA_MAGIC 0x54366345
#define AARCH64_TPIDR2_MAGIC 0x54504902
#define AARCH64_ZT_MAGIC 0x5a544e01
+#define AARCH64_GCS_MAGIC 0x47435300
/* Defines for the extra_context that follows an AARCH64_EXTRA_MAGIC. */
#define AARCH64_EXTRA_DATAP_OFFSET 8
@@ -206,6 +207,11 @@
the signal context state. */
#define AARCH64_SME2_CONTEXT_REGS_OFFSET 16
+/* GCSPR register value offset in the GCS signal frame context. */
+#define AARCH64_GCS_CONTEXT_GCSPR_OFFSET 8
+/* features_enabled value offset in the GCS signal frame context. */
+#define AARCH64_GCS_CONTEXT_FEATURES_ENABLED_OFFSET 16
+
/* Holds information about the signal frame. */
struct aarch64_linux_sigframe
{
@@ -246,6 +252,13 @@ struct aarch64_linux_sigframe
bool za_payload = false;
/* True if we have a ZT entry in the signal context, false otherwise. */
bool zt_available = false;
+
+ /* True if we have a GCS entry in the signal context, false otherwise. */
+ bool gcs_availabe = false;
+ /* The Guarded Control Stack Pointer Register. */
+ uint64_t gcspr;
+ /* Flags indicating which GCS features are enabled for the thread. */
+ uint64_t gcs_features_enabled;
};
/* Read an aarch64_ctx, returning the magic value, and setting *SIZE to the
@@ -526,6 +539,39 @@ aarch64_linux_read_signal_frame_info (const frame_info_ptr &this_frame,
signal_frame.zt_section = section;
signal_frame.zt_available = true;
+ section += size;
+ break;
+ }
+ case AARCH64_GCS_MAGIC:
+ {
+ gdb_byte buf[8];
+
+ /* Extract the GCSPR. */
+ if (target_read_memory (section + AARCH64_GCS_CONTEXT_GCSPR_OFFSET,
+ buf, 8) != 0)
+ {
+ warning (_("Failed to read the GCSPR from the GCS signal frame"
+ " context."));
+ section += size;
+ break;
+ }
+
+ signal_frame.gcspr = extract_unsigned_integer (buf, byte_order);
+
+ /* Extract the features_enabled field. */
+ if (target_read_memory (section
+ + AARCH64_GCS_CONTEXT_FEATURES_ENABLED_OFFSET,
+ buf, sizeof (buf)) != 0)
+ {
+ warning (_("Failed to read the enabled features from the GCS"
+ " signal frame context."));
+ section += size;
+ break;
+ }
+
+ signal_frame.gcs_features_enabled
+ = extract_unsigned_integer (buf, byte_order);
+ signal_frame.gcs_availabe = true;
section += size;
break;
}
@@ -703,6 +749,19 @@ aarch64_linux_sigframe_init (const struct tramp_frame *self,
+ AARCH64_TPIDR2_CONTEXT_TPIDR2_OFFSET);
}
+ /* Restore the GCS registers, if the target supports it and if there is
+ an entry for them. */
+ if (signal_frame.gcs_availabe && tdep->has_gcs ())
+ {
+ /* Restore GCSPR. */
+ trad_frame_set_reg_value (this_cache, tdep->gcs_reg_base,
+ signal_frame.gcspr);
+ /* Restore gcs_features_enabled. */
+ trad_frame_set_reg_value (this_cache, tdep->gcs_linux_reg_base,
+ signal_frame.gcs_features_enabled);
+ /* gcs_features_locked isn't present in the GCS signal context. */
+ }
+
trad_frame_set_id (this_cache, frame_id_build (signal_frame.sp, func));
}
@@ -2486,17 +2545,18 @@ aarch64_linux_report_signal_info (struct gdbarch *gdbarch,
{
aarch64_gdbarch_tdep *tdep = gdbarch_tdep<aarch64_gdbarch_tdep> (gdbarch);
- if (!tdep->has_mte () || siggnal != GDB_SIGNAL_SEGV)
+ if (!(tdep->has_mte () || tdep->has_gcs ()) || siggnal != GDB_SIGNAL_SEGV)
return;
CORE_ADDR fault_addr = 0;
- long si_code = 0;
+ long si_code = 0, si_errno = 0;
try
{
/* Sigcode tells us if the segfault is actually a memory tag
violation. */
si_code = parse_and_eval_long ("$_siginfo.si_code");
+ si_errno = parse_and_eval_long ("$_siginfo.si_errno");
fault_addr
= parse_and_eval_long ("$_siginfo._sifields._sigfault.si_addr");
@@ -2507,13 +2567,18 @@ aarch64_linux_report_signal_info (struct gdbarch *gdbarch,
return;
}
- /* If this is not a memory tag violation, just return. */
- if (si_code != SEGV_MTEAERR && si_code != SEGV_MTESERR)
+ const char *meaning;
+
+ if (si_code == SEGV_MTEAERR || si_code == SEGV_MTESERR)
+ meaning = _("Memory tag violation");
+ else if (si_code == SEGV_CPERR && si_errno == 0)
+ meaning = _("Guarded Control Stack error");
+ else
return;
uiout->text ("\n");
- uiout->field_string ("sigcode-meaning", _("Memory tag violation"));
+ uiout->field_string ("sigcode-meaning", meaning);
/* For synchronous faults, show additional information. */
if (si_code == SEGV_MTESERR)
@@ -2539,7 +2604,7 @@ aarch64_linux_report_signal_info (struct gdbarch *gdbarch,
uiout->field_string ("logical-tag", hex_string (ltag));
}
}
- else
+ else if (si_code != SEGV_CPERR)
{
uiout->text ("\n");
uiout->text (_("Fault address unavailable"));
@@ -2838,9 +2903,6 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
/* Register a hook for checking if an address is tagged or not. */
set_gdbarch_tagged_address_p (gdbarch, aarch64_linux_tagged_address_p);
- set_gdbarch_report_signal_info (gdbarch,
- aarch64_linux_report_signal_info);
-
/* Core file helpers. */
/* Core file helper to create a memory tag section for a particular
@@ -2857,6 +2919,9 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
aarch64_linux_decode_memtag_section);
}
+ if (tdep->has_mte () || tdep->has_gcs ())
+ set_gdbarch_report_signal_info (gdbarch, aarch64_linux_report_signal_info);
+
/* Initialize the aarch64_linux_record_tdep. */
/* These values are the size of the type that will be used in a system
call. They are obtained from Linux Kernel source. */
@@ -41,4 +41,8 @@ struct user_gcs
#endif /* GCS_MAGIC */
+#ifndef SEGV_CPERR
+#define SEGV_CPERR 10 /* Control protection error. */
+#endif
+
#endif /* ARCH_AARCH64_GCS_LINUX_H */
@@ -26994,6 +26994,14 @@ information, see the
@uref{https://www.kernel.org/doc/html/latest/arch/arm64/gcs.html,ignored,
documentation} in the Linux kernel.
+To aid debugging, @value{GDBN} will note when SIGSEGV signals are generated
+as a result of a Guarded Control Stack error:
+
+@smallexample
+Program received signal SIGSEGV, Segmentation fault
+Guarded Control Stack error.
+@end smallexample
+
@node x86
@subsection x86