Blame SOURCES/gdb-6.3-ppc64syscall-20040622.patch

7bc85d
From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
7bc85d
From: Andrew Cagney <cagney@gnu.org>
7bc85d
Date: Fri, 27 Oct 2017 21:07:50 +0200
7bc85d
Subject: gdb-6.3-ppc64syscall-20040622.patch
7bc85d
7bc85d
;; Better parse 64-bit PPC system call prologues.
7bc85d
;;=push: Write new testcase.
7bc85d
7bc85d
2004-06-22  Andrew Cagney  <cagney@gnu.org>
7bc85d
7bc85d
	* rs6000-tdep.c (struct rs6000_framedata): Add field "func_start".
7bc85d
	(skip_prologue): Delete local variable "orig_pc", use
7bc85d
	"func_start".  Add local variable "num_skip_linux_syscall_insn",
7bc85d
	use to skip over first half of a GNU/Linux syscall and update
7bc85d
	"func_start".
7bc85d
7bc85d
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
7bc85d
--- a/gdb/rs6000-tdep.c
7bc85d
+++ b/gdb/rs6000-tdep.c
7bc85d
@@ -134,6 +134,7 @@ static const char *powerpc_vector_abi_string = "auto";
7bc85d
 
7bc85d
 struct rs6000_framedata
7bc85d
   {
7bc85d
+    CORE_ADDR func_start;	/* True function start.  */
7bc85d
     int offset;			/* total size of frame --- the distance
7bc85d
 				   by which we decrement sp to allocate
7bc85d
 				   the frame */
7bc85d
@@ -1426,7 +1427,6 @@ static CORE_ADDR
7bc85d
 skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
7bc85d
 	       struct rs6000_framedata *fdata)
7bc85d
 {
7bc85d
-  CORE_ADDR orig_pc = pc;
7bc85d
   CORE_ADDR last_prologue_pc = pc;
7bc85d
   CORE_ADDR li_found_pc = 0;
7bc85d
   gdb_byte buf[4];
7bc85d
@@ -1445,12 +1445,14 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
7bc85d
   int minimal_toc_loaded = 0;
7bc85d
   int prev_insn_was_prologue_insn = 1;
7bc85d
   int num_skip_non_prologue_insns = 0;
7bc85d
+  int num_skip_ppc64_gnu_linux_syscall_insn = 0;
7bc85d
   int r0_contains_arg = 0;
7bc85d
   const struct bfd_arch_info *arch_info = gdbarch_bfd_arch_info (gdbarch);
7bc85d
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
7bc85d
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
7bc85d
 
7bc85d
   memset (fdata, 0, sizeof (struct rs6000_framedata));
7bc85d
+  fdata->func_start = pc;
7bc85d
   fdata->saved_gpr = -1;
7bc85d
   fdata->saved_fpr = -1;
7bc85d
   fdata->saved_vr = -1;
7bc85d
@@ -1484,6 +1486,55 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
7bc85d
 	break;
7bc85d
       op = extract_unsigned_integer (buf, 4, byte_order);
7bc85d
 
7bc85d
+      /* A PPC64 GNU/Linux system call function is split into two
7bc85d
+	 sub-functions: a non-threaded fast-path (__NAME_nocancel)
7bc85d
+	 which does not use a frame; and a threaded slow-path
7bc85d
+	 (Lpseudo_cancel) that does create a frame.  Ref:
7bc85d
+	 nptl/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h
7bc85d
+
7bc85d
+	 *INDENT-OFF*
7bc85d
+	 NAME:
7bc85d
+	 	SINGLE_THREAD_P
7bc85d
+	 	bne- .Lpseudo_cancel
7bc85d
+	 __NAME_nocancel:
7bc85d
+	 	li r0,162
7bc85d
+	 	sc
7bc85d
+	 	bnslr+
7bc85d
+	 	b 0x7fe014ef64 <.__syscall_error>
7bc85d
+	 Lpseudo_cancel:
7bc85d
+	 	stdu r1,-128(r1)
7bc85d
+	 	...
7bc85d
+	 *INDENT-ON*
7bc85d
+
7bc85d
+	 Unfortunatly, because the latter case uses a local label (not
7bc85d
+	 in the symbol table) a PC in "Lpseudo_cancel" appears to be
7bc85d
+	 in "__NAME_nocancel".  The following code recognizes this,
7bc85d
+	 adjusting FUNC_START to point to where "Lpseudo_cancel"
7bc85d
+	 should be, and parsing the prologue sequence as if
7bc85d
+	 "Lpseudo_cancel" was the entry point.  */
7bc85d
+
7bc85d
+      if (((op & 0xffff0000) == 0x38000000 /* li r0,N */
7bc85d
+	   && pc == fdata->func_start + 0
7bc85d
+	   && num_skip_ppc64_gnu_linux_syscall_insn == 0)
7bc85d
+	  || (op == 0x44000002 /* sc */
7bc85d
+	      && pc == fdata->func_start + 4
7bc85d
+	      && num_skip_ppc64_gnu_linux_syscall_insn == 1)
7bc85d
+	  || (op == 0x4ca30020 /* bnslr+ */
7bc85d
+	      && pc == fdata->func_start + 8
7bc85d
+	      && num_skip_ppc64_gnu_linux_syscall_insn == 2))
7bc85d
+	{
7bc85d
+	  num_skip_ppc64_gnu_linux_syscall_insn++;
7bc85d
+	  continue;
7bc85d
+	}
7bc85d
+      else if ((op & 0xfc000003) == 0x48000000 /* b __syscall_error */
7bc85d
+	       && pc == fdata->func_start + 12
7bc85d
+	       && num_skip_ppc64_gnu_linux_syscall_insn == 3)
7bc85d
+	{
7bc85d
+	  num_skip_ppc64_gnu_linux_syscall_insn = -1;
7bc85d
+	  fdata->func_start = pc;
7bc85d
+	  continue;
7bc85d
+	}
7bc85d
+
7bc85d
       if ((op & 0xfc1fffff) == 0x7c0802a6)
7bc85d
 	{			/* mflr Rx */
7bc85d
 	  /* Since shared library / PIC code, which needs to get its
7bc85d
@@ -1673,9 +1724,9 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
7bc85d
 	     we have no line table information or the line info tells
7bc85d
 	     us that the subroutine call is not part of the line
7bc85d
 	     associated with the prologue.  */
7bc85d
-	  if ((pc - orig_pc) > 8)
7bc85d
+	  if ((pc - fdata->func_start) > 8)
7bc85d
 	    {
7bc85d
-	      struct symtab_and_line prologue_sal = find_pc_line (orig_pc, 0);
7bc85d
+	      struct symtab_and_line prologue_sal = find_pc_line (fdata->func_start, 0);
7bc85d
 	      struct symtab_and_line this_sal = find_pc_line (pc, 0);
7bc85d
 
7bc85d
 	      if ((prologue_sal.line == 0)