Re: [PATCH] Improve the fetch/store of general-purpose and floating-point PowerPC registers

["Sérgio Durigan Júnior" <sergiodj@linux.vnet.ibm.com>]

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Hi Luis,

This version of the patch fixes what you suggested. Also, I removed some
unecessary checks regarding PPC32/64.

Regards,

-- 
Sérgio Durigan Júnior
Linux on Power Toolchain - Software Engineer
Linux Technology Center - LTC
IBM Brazil

2009-01-21  Sergio Durigan Junior <sergiodj@linux.vnet.ibm.com>

	* ppc-linux-nat.c (have_ptrace_getsetregs): New variable.
	(have_ptrace_getsetfpregs): Likewise.
	fetch_all_gp_regs): New function.
	(fetch_gp_regs): New function.
	(fetch_all_fp_regs): Likewise.
	(fetch_fp_regs): New function.
	(fetch_ppc_registers): Using the new methods to fetch general-
	purpose and floating-pointer registers.
	(store_all_gp_regs): New function.
	(store_gp_regs): Likewise.
	(store_all_fp_regs): New function.
	(store_fp_regs): Likewise.
	(store_ppc_registers): Using the new methods to store general-
	purpose and floating-pointer registers.


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diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index b946093..bc1b767 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -108,6 +108,21 @@
 #define PTRACE_GETSIGINFO    0x4202
 #endif
 
+/* Similarly for the general-purpose (gp0 -- gp31)
+   and floating-point registers (fp0 -- fp31).  */
+#ifndef PTRACE_GETREGS
+#define PTRACE_GETREGS 12
+#endif
+#ifndef PTRACE_SETREGS
+#define PTRACE_SETREGS 13
+#endif
+#ifndef PTRACE_GETFPREGS
+#define PTRACE_GETFPREGS 14
+#endif
+#ifndef PTRACE_SETFPREGS
+#define PTRACE_SETFPREGS 15
+#endif
+
 /* This oddity is because the Linux kernel defines elf_vrregset_t as
    an array of 33 16 bytes long elements.  I.e. it leaves out vrsave.
    However the PTRACE_GETVRREGS and PTRACE_SETVRREGS requests return
@@ -218,6 +233,18 @@ int have_ptrace_getvrregs = 1;
    error.  */
 int have_ptrace_getsetevrregs = 1;
 
+/* Non-zero if our kernel may support the PTRACE_GETREGS and
+   PTRACE_SETREGS requests, for reading and writing the
+   general-purpose registers.  Zero if we've tried one of
+   them and gotten an error.  */
+int have_ptrace_getsetregs = 1;
+
+/* Non-zero if our kernel may support the PTRACE_GETFPREGS and
+   PTRACE_SETFPREGS requests, for reading and writing the
+   floating-pointers registers.  Zero if we've tried one of
+   them and gotten an error.  */
+int have_ptrace_getsetfpregs = 1;
+
 /* *INDENT-OFF* */
 /* registers layout, as presented by the ptrace interface:
 PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
@@ -601,6 +628,84 @@ fetch_altivec_registers (struct regcache *regcache, int tid)
   supply_vrregset (regcache, &regs);
 }
 
+static int
+fetch_all_gp_regs (struct regcache *regcache, int tid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  gdb_gregset_t gregset;
+
+  if (ptrace (PTRACE_GETREGS, tid, 0, (void *) &gregset) < 0)
+    {
+      if (errno == EIO)
+        {
+          have_ptrace_getsetregs = 0;
+          return 0;
+        }
+      perror_with_name (_("Couldn't get general-purpose registers."));
+    }
+
+  supply_gregset (regcache, (const gdb_gregset_t *) &gregset);
+
+  return 1;
+}
+
+static void
+fetch_gp_regs (struct regcache *regcache, int tid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int i;
+
+  if (have_ptrace_getsetregs)
+    if (fetch_all_gp_regs (regcache, tid))
+      return;
+
+  /* If we've hit this point, it doesn't really matter which
+     architecture we are using.  We just need to read the
+     registers in the "old-fashioned way".  */
+  for (i = 0; i < ppc_num_gprs; i++)
+    fetch_register (regcache, tid, tdep->ppc_gp0_regnum + i);
+}
+
+static int
+fetch_all_fp_regs (struct regcache *regcache, int tid)
+{
+  gdb_fpregset_t fpregs;
+
+  if (ptrace (PTRACE_GETFPREGS, tid, 0, (void *) &fpregs) < 0)
+    {
+      if (errno == EIO)
+        {
+          have_ptrace_getsetfpregs = 0;
+          return 0;
+        }
+      perror_with_name (_("Couldn't get floating-point registers."));
+    }
+
+  supply_fpregset (regcache, (const gdb_fpregset_t *) &fpregs);
+
+  return 1;
+}
+
+static void
+fetch_fp_regs (struct regcache *regcache, int tid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int i;
+
+  if (have_ptrace_getsetfpregs)
+    if (fetch_all_fp_regs (regcache, tid))
+      return;
+ 
+  /* If we've hit this point, it doesn't really matter which
+     architecture we are using.  We just need to read the
+     registers in the "old-fashioned way".  */
+  for (i = 0; i < ppc_num_fprs; i++)
+    fetch_register (regcache, tid, tdep->ppc_fp0_regnum + i);
+}
+
 static void 
 fetch_ppc_registers (struct regcache *regcache, int tid)
 {
@@ -608,11 +713,9 @@ fetch_ppc_registers (struct regcache *regcache, int tid)
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 
-  for (i = 0; i < ppc_num_gprs; i++)
-    fetch_register (regcache, tid, tdep->ppc_gp0_regnum + i);
+  fetch_gp_regs (regcache, tid);
   if (tdep->ppc_fp0_regnum >= 0)
-    for (i = 0; i < ppc_num_fprs; i++)
-      fetch_register (regcache, tid, tdep->ppc_fp0_regnum + i);
+    fetch_fp_regs (regcache, tid);
   fetch_register (regcache, tid, gdbarch_pc_regnum (gdbarch));
   if (tdep->ppc_ps_regnum != -1)
     fetch_register (regcache, tid, tdep->ppc_ps_regnum);
@@ -969,18 +1072,114 @@ store_altivec_registers (const struct regcache *regcache, int tid)
     perror_with_name (_("Couldn't write AltiVec registers"));
 }
 
+static int
+store_all_gp_regs (const struct regcache *regcache, int tid, int regno)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  gdb_gregset_t gregset;
+
+  if (ptrace (PTRACE_GETREGS, tid, 0, (void *) &gregset) < 0)
+    {
+      if (errno == EIO)
+        {
+          have_ptrace_getsetregs = 0;
+          return 0;
+        }
+      perror_with_name (_("Couldn't get general-purpose registers."));
+    }
+
+  fill_gregset (regcache, &gregset, regno);
+
+  if (ptrace (PTRACE_SETREGS, tid, 0, (void *) &gregset) < 0)
+    {
+      if (errno == EIO)
+        {
+          have_ptrace_getsetregs = 0;
+          return 0;
+        }
+      perror_with_name (_("Couldn't set general-purpose registers."));
+    }
+
+  return 1;
+}
+
 static void
-store_ppc_registers (const struct regcache *regcache, int tid)
+store_gp_regs (const struct regcache *regcache, int tid, int regno)
 {
-  int i;
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-  
+  int i;
+
+  if (have_ptrace_getsetregs)
+    if (store_all_gp_regs (regcache, tid, regno))
+      return;
+
+  /* If we hit this point, it doesn't really matter which
+     architecture we are using.  We just need to store the
+     registers in the "old-fashioned way".  */
   for (i = 0; i < ppc_num_gprs; i++)
     store_register (regcache, tid, tdep->ppc_gp0_regnum + i);
+}
+
+static int
+store_all_fp_regs (const struct regcache *regcache, int tid, int regno)
+{
+  gdb_fpregset_t fpregs;
+
+  if (ptrace (PTRACE_GETFPREGS, tid, 0, (void *) &fpregs) < 0)
+    {
+      if (errno == EIO)
+        {
+          have_ptrace_getsetfpregs = 0;
+          return 0;
+        }
+      perror_with_name (_("Couldn't get floating-point registers."));
+    }
+
+  fill_fpregset (regcache, &fpregs, regno);
+
+  if (ptrace (PTRACE_SETFPREGS, tid, 0, (void *) &fpregs) < 0)
+    {
+      if (errno == EIO)
+        {
+          have_ptrace_getsetfpregs = 0;
+          return 0;
+        }
+      perror_with_name (_("Couldn't set floating-point registers."));
+    }
+
+  return 1;
+}
+
+static void
+store_fp_regs (const struct regcache *regcache, int tid, int regno)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int i;
+
+  if (have_ptrace_getsetfpregs)
+    if (store_all_fp_regs (regcache, tid, regno))
+      return;
+
+  /* If we hit this point, it doesn't really matter which
+     architecture we are using.  We just need to store the
+     registers in the "old-fashioned way".  */
+  for (i = 0; i < ppc_num_fprs; i++)
+    store_register (regcache, tid, tdep->ppc_fp0_regnum + i);
+}
+
+static void
+store_ppc_registers (const struct regcache *regcache, int tid)
+{
+  int i;
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+ 
+  store_gp_regs (regcache, tid, -1);
   if (tdep->ppc_fp0_regnum >= 0)
-    for (i = 0; i < ppc_num_fprs; i++)
-      store_register (regcache, tid, tdep->ppc_fp0_regnum + i);
+    store_fp_regs (regcache, tid, -1);
   store_register (regcache, tid, gdbarch_pc_regnum (gdbarch));
   if (tdep->ppc_ps_regnum != -1)
     store_register (regcache, tid, tdep->ppc_ps_regnum);