[PATCH] x86-64: Fix CFI information

Being the foundation for reliable stack unwinding, this fixes CFI unwind
annotations in many low-level x86_64 routines, plus a config option
(available to all architectures, and also present in the previously sent
patch adding such annotations to i386 code) to enable them separatly
rather than only along with adding full debug information.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/ia32/ia32entry.S

@@ -55,20 +55,34 @@
  * with the int 0x80 path.
  */ 	
 ENTRY(ia32_sysenter_target)
-	CFI_STARTPROC
+	CFI_STARTPROC	simple
+	CFI_DEF_CFA	rsp,0
+	CFI_REGISTER	rsp,rbp
 	swapgs
 	movq	%gs:pda_kernelstack, %rsp
 	addq	$(PDA_STACKOFFSET),%rsp	
 	sti	
  	movl	%ebp,%ebp		/* zero extension */
 	pushq	$__USER32_DS
+	CFI_ADJUST_CFA_OFFSET 8
+	/*CFI_REL_OFFSET ss,0*/
 	pushq	%rbp
+	CFI_ADJUST_CFA_OFFSET 8
+	CFI_REL_OFFSET rsp,0
 	pushfq
+	CFI_ADJUST_CFA_OFFSET 8
+	/*CFI_REL_OFFSET rflags,0*/
 	movl	$VSYSCALL32_SYSEXIT, %r10d
+	CFI_REGISTER rip,r10
 	pushq	$__USER32_CS
+	CFI_ADJUST_CFA_OFFSET 8
+	/*CFI_REL_OFFSET cs,0*/
 	movl	%eax, %eax
 	pushq	%r10
+	CFI_ADJUST_CFA_OFFSET 8
+	CFI_REL_OFFSET rip,0
 	pushq	%rax
+	CFI_ADJUST_CFA_OFFSET 8
 	cld
 	SAVE_ARGS 0,0,1
  	/* no need to do an access_ok check here because rbp has been
@@ -79,6 +93,7 @@ ENTRY(ia32_sysenter_target)
  	.previous	
 	GET_THREAD_INFO(%r10)
 	testl  $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
+	CFI_REMEMBER_STATE
 	jnz  sysenter_tracesys
 sysenter_do_call:	
 	cmpl	$(IA32_NR_syscalls),%eax
@@ -94,14 +109,20 @@ sysenter_do_call:
 	andl  $~0x200,EFLAGS-R11(%rsp) 
 	RESTORE_ARGS 1,24,1,1,1,1
 	popfq
+	CFI_ADJUST_CFA_OFFSET -8
+	/*CFI_RESTORE rflags*/
 	popq	%rcx				/* User %esp */
+	CFI_ADJUST_CFA_OFFSET -8
+	CFI_REGISTER rsp,rcx
 	movl	$VSYSCALL32_SYSEXIT,%edx	/* User %eip */
+	CFI_REGISTER rip,rdx
 	swapgs
 	sti		/* sti only takes effect after the next instruction */
 	/* sysexit */
 	.byte	0xf, 0x35
 
 sysenter_tracesys:
+	CFI_RESTORE_STATE
 	SAVE_REST
 	CLEAR_RREGS
 	movq	$-ENOSYS,RAX(%rsp)	/* really needed? */
@@ -140,21 +161,28 @@ sysenter_tracesys:
  * with the int 0x80 path.	
  */ 	
 ENTRY(ia32_cstar_target)
-	CFI_STARTPROC
+	CFI_STARTPROC	simple
+	CFI_DEF_CFA	rsp,0
+	CFI_REGISTER	rip,rcx
+	/*CFI_REGISTER	rflags,r11*/
 	swapgs
 	movl	%esp,%r8d
+	CFI_REGISTER	rsp,r8
 	movq	%gs:pda_kernelstack,%rsp
 	sti
 	SAVE_ARGS 8,1,1
 	movl 	%eax,%eax	/* zero extension */
 	movq	%rax,ORIG_RAX-ARGOFFSET(%rsp)
 	movq	%rcx,RIP-ARGOFFSET(%rsp)
+	CFI_REL_OFFSET rip,RIP-ARGOFFSET
 	movq	%rbp,RCX-ARGOFFSET(%rsp) /* this lies slightly to ptrace */
 	movl	%ebp,%ecx
 	movq	$__USER32_CS,CS-ARGOFFSET(%rsp)
 	movq	$__USER32_DS,SS-ARGOFFSET(%rsp)
 	movq	%r11,EFLAGS-ARGOFFSET(%rsp)
+	/*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/
 	movq	%r8,RSP-ARGOFFSET(%rsp)	
+	CFI_REL_OFFSET rsp,RSP-ARGOFFSET
 	/* no need to do an access_ok check here because r8 has been
 	   32bit zero extended */ 
 	/* hardware stack frame is complete now */	
@@ -164,6 +192,7 @@ ENTRY(ia32_cstar_target)
 	.previous	
 	GET_THREAD_INFO(%r10)
 	testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
+	CFI_REMEMBER_STATE
 	jnz   cstar_tracesys
 cstar_do_call:	
 	cmpl $IA32_NR_syscalls,%eax
@@ -177,12 +206,16 @@ cstar_do_call:
 	jnz  int_ret_from_sys_call
 	RESTORE_ARGS 1,-ARG_SKIP,1,1,1
 	movl RIP-ARGOFFSET(%rsp),%ecx
+	CFI_REGISTER rip,rcx
 	movl EFLAGS-ARGOFFSET(%rsp),%r11d	
+	/*CFI_REGISTER rflags,r11*/
 	movl RSP-ARGOFFSET(%rsp),%esp
+	CFI_RESTORE rsp
 	swapgs
 	sysretl
 
 cstar_tracesys:	
+	CFI_RESTORE_STATE
 	SAVE_REST
 	CLEAR_RREGS
 	movq $-ENOSYS,RAX(%rsp)	/* really needed? */
@@ -226,11 +259,18 @@ ia32_badarg:
  */ 				
 
 ENTRY(ia32_syscall)
-	CFI_STARTPROC
+	CFI_STARTPROC	simple
+	CFI_DEF_CFA	rsp,SS+8-RIP
+	/*CFI_REL_OFFSET	ss,SS-RIP*/
+	CFI_REL_OFFSET	rsp,RSP-RIP
+	/*CFI_REL_OFFSET	rflags,EFLAGS-RIP*/
+	/*CFI_REL_OFFSET	cs,CS-RIP*/
+	CFI_REL_OFFSET	rip,RIP-RIP
 	swapgs	
 	sti
 	movl %eax,%eax
 	pushq %rax
+	CFI_ADJUST_CFA_OFFSET 8
 	cld
 	/* note the registers are not zero extended to the sf.
 	   this could be a problem. */
@@ -278,6 +318,8 @@ quiet_ni_syscall:
 	jmp  ia32_ptregs_common	
 	.endm
 
+	CFI_STARTPROC
+
 	PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn, %rdi
 	PTREGSCALL stub32_sigreturn, sys32_sigreturn, %rdi
 	PTREGSCALL stub32_sigaltstack, sys32_sigaltstack, %rdx
@@ -290,8 +332,9 @@ quiet_ni_syscall:
 	PTREGSCALL stub32_rt_sigsuspend, sys_rt_sigsuspend, %rdx
 
 ENTRY(ia32_ptregs_common)
-	CFI_STARTPROC
 	popq %r11
+	CFI_ADJUST_CFA_OFFSET -8
+	CFI_REGISTER rip, r11
 	SAVE_REST
 	call *%rax
 	RESTORE_REST