2006-11-29 Daniel Jacobowitz <dan@codesourcery.com>

Jakub Jelinek  <jakub@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* sysdeps/unix/sysv/linux/x86_64/sigaction.c (restore_rt): Add correct
	unwind information.
	* sysdeps/unix/sysv/linux/x86_64/Makefile: Provide symbols for
	'restore_rt' even in the 'signal' directory.
	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym: Extend the regs list.

ChangeLog

@@ -1,3 +1,13 @@
+2006-11-29  Daniel Jacobowitz  <dan@codesourcery.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+	    Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* sysdeps/unix/sysv/linux/x86_64/sigaction.c (restore_rt): Add correct
+	unwind information.
+	* sysdeps/unix/sysv/linux/x86_64/Makefile: Provide symbols for
+	'restore_rt' even in the 'signal' directory.
+	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym: Extend the regs list.
+
 2006-11-27  Jakub Jelinek  <jakub@redhat.com>
 
 	[BZ #3559]

sysdeps/unix/sysv/linux/x86_64/Makefile

@@ -10,6 +10,6 @@ ifeq ($(subdir),stdlib)
 sysdep_routines += __start_context
 endif
 
-ifeq ($(subdir),stdlib)
+ifeq ($(subdir),csu)
 gen-as-const-headers += ucontext_i.sym
 endif

sysdeps/unix/sysv/linux/x86_64/sigaction.c

@@ -33,6 +33,8 @@
    translate it here.  */
 #include <kernel_sigaction.h>
 
+#include "ucontext_i.h"
+
 /* We do not globally define the SA_RESTORER flag so do it here.  */
 #define SA_RESTORER 0x04000000
 
@@ -90,18 +92,94 @@ weak_alias (__libc_sigaction, sigaction)
    signal handlers work right.  Important are both the names
    (__restore_rt) and the exact instruction sequence.
    If you ever feel the need to make any changes, please notify the
-   appropriate GDB maintainer.  */
+   appropriate GDB maintainer.
+
+   The unwind information starts a byte before __restore_rt, so that
+   it is found when unwinding, to get an address the unwinder assumes
+   will be in the middle of a call instruction.  See the Linux kernel
+   (the i386 vsyscall, in particular) for an explanation of the complex
+   unwind information used here in order to get the traditional CFA.
+   We do not restore cs - it's only stored as two bytes here so that's
+   a bit tricky.  We don't use the gas cfi directives, so that we can
+   reliably add .cfi_signal_frame.  */
+
+#define do_cfa_expr						\
+  "	.byte 0x0f\n"		/* DW_CFA_def_cfa_expression */	\
+  "	.uleb128 2f-1f\n"	/* length */			\
+  "1:	.byte 0x77\n"		/* DW_OP_breg7 */		\
+  "	.sleb128 " CFI_STRINGIFY (oRSP) "\n"			\
+  "	.byte 0x06\n"		/* DW_OP_deref */		\
+  "2:"
+
+#define do_expr(regno, offset)					\
+  "	.byte 0x10\n"		/* DW_CFA_expression */		\
+  "	.uleb128 " CFI_STRINGIFY (regno) "\n"			\
+  "	.uleb128 2f-1f\n"	/* length */			\
+  "1:	.byte 0x77\n"		/* DW_OP_breg7 */		\
+  "	.sleb128 " CFI_STRINGIFY (offset) "\n"			\
+  "2:"
 
 #define RESTORE(name, syscall) RESTORE2 (name, syscall)
 # define RESTORE2(name, syscall) \
-asm						\
+asm									\
-  (						\
+  (									\
-   ".align 16\n"				\
+   /* `nop' for debuggers assuming `call' should not disalign the code.  */ \
-   CFI_STARTPROC "\n"				\
+   "	nop\n"								\
-   "__" #name ":\n"				\
+   ".align 16\n"							\
-   "	movq $" #syscall ", %rax\n"		\
+   ".LSTART_" #name ":\n"						\
-   "	syscall\n"				\
+   "	.type __" #name ",@function\n"					\
-   CFI_ENDPROC "\n"				\
+   "__" #name ":\n"							\
+   "	movq $" #syscall ", %rax\n"					\
+   "	syscall\n"							\
+   ".LEND_" #name ":\n"							\
+   ".section .eh_frame,\"a\",@progbits\n"				\
+   ".LSTARTFRAME_" #name ":\n"						\
+   "	.long .LENDCIE_" #name "-.LSTARTCIE_" #name "\n"		\
+   ".LSTARTCIE_" #name ":\n"						\
+   "	.long 0\n"	/* CIE ID */					\
+   "	.byte 1\n"	/* Version number */				\
+   "	.string \"zRS\"\n" /* NUL-terminated augmentation string */	\
+   "	.uleb128 1\n"	/* Code alignment factor */			\
+   "	.sleb128 -8\n"	/* Data alignment factor */			\
+   "	.uleb128 16\n"	/* Return address register column (rip) */	\
+   /* Augmentation value length */					\
+   "	.uleb128 .LENDAUGMNT_" #name "-.LSTARTAUGMNT_" #name "\n"	\
+   ".LSTARTAUGMNT_" #name ":\n"						\
+   "	.byte 0x1b\n"	/* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */		\
+   ".LENDAUGMNT_" #name ":\n"						\
+   "	.align 8\n"							\
+   ".LENDCIE_" #name ":\n"						\
+   "	.long .LENDFDE_" #name "-.LSTARTFDE_" #name "\n" /* FDE len */	\
+   ".LSTARTFDE_" #name ":\n"						\
+   "	.long .LSTARTFDE_" #name "-.LSTARTFRAME_" #name "\n" /* CIE */	\
+   /* `LSTART_' is subtracted 1 as debuggers assume a `call' here.  */	\
+   "	.long (.LSTART_" #name "-1)-.\n" /* PC-relative start addr.  */	\
+   "	.long .LEND_" #name "-(.LSTART_" #name "-1)\n"			\
+   "	.uleb128 0\n"			/* FDE augmentation length */	\
+   do_cfa_expr								\
+   do_expr (8 /* r8 */, oR8)						\
+   do_expr (9 /* r9 */, oR9)						\
+   do_expr (10 /* r10 */, oR10)						\
+   do_expr (11 /* r11 */, oR11)						\
+   do_expr (12 /* r12 */, oR12)						\
+   do_expr (13 /* r13 */, oR13)						\
+   do_expr (14 /* r14 */, oR14)						\
+   do_expr (15 /* r15 */, oR15)						\
+   do_expr (5 /* rdi */, oRDI)						\
+   do_expr (4 /* rsi */, oRSI)						\
+   do_expr (6 /* rbp */, oRBP)						\
+   do_expr (3 /* rbx */, oRBX)						\
+   do_expr (1 /* rdx */, oRDX)						\
+   do_expr (0 /* rax */, oRAX)						\
+   do_expr (2 /* rcx */, oRCX)						\
+   do_expr (7 /* rsp */, oRSP)						\
+   do_expr (16 /* rip */, oRIP)						\
+   do_expr (49 /* rflags */, oEFL)					\
+   /* `cs'/`ds'/`fs' are unaligned and a different size.  */		\
+   /* gas: Error: register save offset not a multiple of 8  */		\
+   "	.align 8\n"							\
+   ".LENDFDE_" #name ":\n"						\
+   "	.previous\n"							\
    );
 /* The return code for realtime-signals.  */
 RESTORE (restore_rt, __NR_rt_sigreturn)

sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym

@@ -18,6 +18,8 @@ oRSP		mreg (RSP)
 oRBX		mreg (RBX)
 oR8		mreg (R8)
 oR9		mreg (R9)
+oR10		mreg (R10)
+oR11		mreg (R11)
 oR12		mreg (R12)
 oR13		mreg (R13)
 oR14		mreg (R14)
@@ -28,6 +30,7 @@ oRDX		mreg (RDX)
 oRAX		mreg (RAX)
 oRCX		mreg (RCX)
 oRIP		mreg (RIP)
+oEFL		mreg (EFL)
 oFPREGS		mcontext (fpregs)
 oSIGMASK	ucontext (uc_sigmask)
 oFPREGSMEM	ucontext (__fpregs_mem)