[PATCH v2 4/8] AArch64: gdbserver: read pauth registers

[Alan Hayward <Alan.Hayward@arm.com>]

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:

2019-03-06  Alan Hayward  <alan.hayward@arm.com>
	    Jiong Wang  <jiong.wang@arm.com>

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

gdb/gdbserver/ChangeLog:

2019-03-06  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.
---
 gdb/arch/aarch64.h                |  1 +
 gdb/gdbserver/linux-aarch64-low.c | 23 +++++++++++++++++++++++
 gdb/gdbserver/linux-low.c         | 14 ++++++++------
 gdb/gdbserver/linux-low.h         |  1 +
 4 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/gdb/arch/aarch64.h b/gdb/arch/aarch64.h
index 8c80b7be62..309fe75273 100644
--- a/gdb/arch/aarch64.h
+++ b/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
diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
index e2e25f0e27..20c75493b0 100644
--- a/gdb/gdbserver/linux-aarch64-low.c
+++ b/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
 };
 
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 8c5a51f23c..e1cb7fcfbc 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -5359,10 +5359,11 @@ 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)
@@ -5457,10 +5458,11 @@ 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)
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index d09390dd99..1ade35d648 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/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
-- 
2.17.2 (Apple Git-113)