AArch64: gdbserver: read pauth registers

Add the pauth registers to the regset lists.

Add a new regset type OPTIONAL_REGS which allows for the regset read to fail.
Once the read fails, it will not be checked again.  This allows targets with
optional features to keep a single static regset_info structure.

gdb/ChangeLog:

	* arch/aarch64.h (AARCH64_PAUTH_REGS_SIZE): New define.

gdb/gdbserver/ChangeLog:

	* linux-aarch64-low.c (aarch64_store_pauthregset): New function.
	* linux-low.c (regsets_store_inferior_registers): Allow optional reads
	to fail.
	* linux-low.h (enum regset_type): Add OPTIONAL_REGS.

Author: a74nh

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2019-03-22  Alan Hayward  <alan.hayward@arm.com>
+	    Jiong Wang  <jiong.wang@arm.com>
+
+	* arch/aarch64.h (AARCH64_PAUTH_REGS_SIZE): New define.
+
 2019-03-22  Alan Hayward  <alan.hayward@arm.com>
 	    Jiong Wang  <jiong.wang@arm.com>
 

gdb/arch/aarch64.h

@@ -68,6 +68,7 @@ enum aarch64_regnum
 
 #define AARCH64_PAUTH_DMASK_REGNUM(pauth_reg_base) (pauth_reg_base)
 #define AARCH64_PAUTH_CMASK_REGNUM(pauth_reg_base) (pauth_reg_base + 1)
+#define AARCH64_PAUTH_REGS_SIZE (16)
 
 #define AARCH64_X_REGS_NUM 31
 #define AARCH64_V_REGS_NUM 32

gdb/gdbserver/ChangeLog

@@ -1,3 +1,11 @@
+2019-03-22  Alan Hayward  <alan.hayward@arm.com>
+	    Jiong Wang  <jiong.wang@arm.com>
+
+	* linux-aarch64-low.c (aarch64_store_pauthregset): New function.
+	* linux-low.c (regsets_store_inferior_registers): Allow optional reads
+	to fail.
+	* linux-low.h (enum regset_type): Add OPTIONAL_REGS.
+
 2019-03-22  Alan Hayward  <alan.hayward@arm.com>
 	    Jiong Wang  <jiong.wang@arm.com>
 

gdb/gdbserver/linux-aarch64-low.c

@@ -135,6 +135,23 @@ aarch64_store_fpregset (struct regcache *regcache, const void *buf)
   supply_register (regcache, AARCH64_FPCR_REGNUM, &regset->fpcr);
 }
 
+/* Store the pauth registers to regcache.  */
+
+static void
+aarch64_store_pauthregset (struct regcache *regcache, const void *buf)
+{
+  uint64_t *pauth_regset = (uint64_t *) buf;
+  int pauth_base = find_regno (regcache->tdesc, "pauth_dmask");
+
+  if (pauth_base == 0)
+    return;
+
+  supply_register (regcache, AARCH64_PAUTH_DMASK_REGNUM (pauth_base),
+		   &pauth_regset[0]);
+  supply_register (regcache, AARCH64_PAUTH_CMASK_REGNUM (pauth_base),
+		   &pauth_regset[1]);
+}
+
 /* Enable miscellaneous debugging output.  The name is historical - it
    was originally used to debug LinuxThreads support.  */
 extern int debug_threads;
@@ -564,6 +581,9 @@ static struct regset_info aarch64_regsets[] =
     sizeof (struct user_fpsimd_state), FP_REGS,
     aarch64_fill_fpregset, aarch64_store_fpregset
   },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_ARM_PAC_MASK,
+    AARCH64_PAUTH_REGS_SIZE, OPTIONAL_REGS,
+    NULL, aarch64_store_pauthregset },
   NULL_REGSET
 };
 
@@ -590,6 +610,9 @@ static struct regset_info aarch64_sve_regsets[] =
     SVE_PT_SIZE (AARCH64_MAX_SVE_VQ, SVE_PT_REGS_SVE), EXTENDED_REGS,
     aarch64_sve_regs_copy_from_regcache, aarch64_sve_regs_copy_to_regcache
   },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_ARM_PAC_MASK,
+    AARCH64_PAUTH_REGS_SIZE, OPTIONAL_REGS,
+    NULL, aarch64_store_pauthregset },
   NULL_REGSET
 };
 

gdb/gdbserver/linux-low.c

@@ -5358,10 +5358,11 @@ regsets_fetch_inferior_registers (struct regsets_info *regsets_info,
 #endif
       if (res < 0)
 	{
-	  if (errno == EIO)
+	  if (errno == EIO
+	      || (errno == EINVAL && regset->type == OPTIONAL_REGS))
 	    {
-	      /* If we get EIO on a regset, do not try it again for
-		 this process mode.  */
+	      /* If we get EIO on a regset, or an EINVAL and the regset is
+		 optional, do not try it again for this process mode.  */
 	      disable_regset (regsets_info, regset);
 	    }
 	  else if (errno == ENODATA)
@@ -5456,10 +5457,11 @@ regsets_store_inferior_registers (struct regsets_info *regsets_info,
 
       if (res < 0)
 	{
-	  if (errno == EIO)
+	  if (errno == EIO
+	      || (errno == EINVAL && regset->type == OPTIONAL_REGS))
 	    {
-	      /* If we get EIO on a regset, do not try it again for
-		 this process mode.  */
+	      /* If we get EIO on a regset, or an EINVAL and the regset is
+		 optional, do not try it again for this process mode.  */
 	      disable_regset (regsets_info, regset);
 	    }
 	  else if (errno == ESRCH)

gdb/gdbserver/linux-low.h

@@ -40,6 +40,7 @@ enum regset_type {
   GENERAL_REGS,
   FP_REGS,
   EXTENDED_REGS,
+  OPTIONAL_REGS, /* Do not error if the regset cannot be accessed.  */
 };
 
 /* The arch's regsets array initializer must be terminated with a NULL