gdb/aarch64: signal frame support for fpmr

Add support for FPMR in signal frames and restore contents of FPMR.

Approved-By: Luis Machado <luis.machado.foss@gmail.com>

diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index 10b44d978af18efd9e474e36e5cc9e6d8c17660e..5346ae39eda13fa5d97f814cdc8af37620d8b7d8 100644 (file)
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -167,6 +167,7 @@
 #define AARCH64_TPIDR2_MAGIC                   0x54504902
 #define AARCH64_ZT_MAGIC                       0x5a544e01
 #define AARCH64_GCS_MAGIC                      0x47435300
+#define AARCH64_FPMR_MAGIC                     0x46504d52
 
 /* Defines for the extra_context that follows an AARCH64_EXTRA_MAGIC.  */
 #define AARCH64_EXTRA_DATAP_OFFSET             8
@@ -213,6 +214,9 @@
 /* features_enabled value offset in the GCS signal frame context.  */
 #define AARCH64_GCS_CONTEXT_FEATURES_ENABLED_OFFSET    16
 
+/* FPMR constants.  */
+#define AARCH64_FPMR_OFFSET                    8
+
 /* Holds information about the signal frame.  */
 struct aarch64_linux_sigframe
 {
@@ -260,6 +264,12 @@ struct aarch64_linux_sigframe
   uint64_t gcspr;
   /* Flags indicating which GCS features are enabled for the thread.  */
   uint64_t gcs_features_enabled;
+
+  /* True if we have an FPMR entry in the signal context, false otherwise.  */
+  bool fpmr_available = false;
+  /* FPMR value.  */
+  CORE_ADDR fpmr = 0;
+
 };
 
 /* Read an aarch64_ctx, returning the magic value, and setting *SIZE to the
@@ -576,6 +586,22 @@ aarch64_linux_read_signal_frame_info (const frame_info_ptr &this_frame,
            section += size;
            break;
          }
+       case AARCH64_FPMR_MAGIC:
+         {
+           gdb_byte buf[8];
+           if (target_read_memory (section + AARCH64_FPMR_OFFSET,
+                                   buf, 8) != 0)
+             {
+               warning (_("Failed to read the FPMR section address from the"
+                          " signal frame context."));
+               section += size;
+               break;
+             }
+           signal_frame.fpmr = extract_unsigned_integer (buf, 8, byte_order);
+           signal_frame.fpmr_available = true;
+           section += size;
+           break;
+         }
        case AARCH64_EXTRA_MAGIC:
          {
            /* Extra is always the last valid section in reserved and points to
@@ -739,6 +765,13 @@ aarch64_linux_sigframe_init (const struct tramp_frame *self,
        }
     }
 
+  /* Handle FPMR.  */
+  if (tdep->has_fpmr () && signal_frame.fpmr_available != 0)
+  {
+    trad_frame_set_reg_value (this_cache, tdep->fpmr_regnum,
+                             signal_frame.fpmr);
+  }
+
   /* Restore the tpidr2 register, if the target supports it and if there is
      an entry for it.  */
   if (signal_frame.tpidr2_section != 0 && tdep->has_tls ()
@@ -791,6 +824,7 @@ aarch64_linux_sigframe_prev_arch (const frame_info_ptr &this_frame,
   aarch64_features features = aarch64_features_from_target_desc (tdesc);
   features.vq = sve_vq_from_vl (signal_frame.vl);
   features.svq = (uint8_t) sve_vq_from_vl (signal_frame.svl);
+  features.fpmr = signal_frame.fpmr_available;
 
   struct gdbarch_info info;
   info.bfd_arch_info = bfd_lookup_arch (bfd_arch_aarch64, bfd_mach_aarch64);