[PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinder

Current gcc generates calls not jumps to noreturn functions. When that happens the return address can point to the next function, which confuses the unwinder. This patch works around it by marking asynchronous exception frames in contrast normal call frames in the unwind information. Then teach the unwinder to decode this. For normal call frames the unwinder now subtracts one from the address which avoids this problem. The standard libgcc unwinder uses the same trick. It doesn't include adjustment of the printed address (i.e. for the original example, it'd still be kernel_math_error+0 that gets displayed, but the unwinder wouldn't get confused anymore. This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16 unfortunately because earlier binutils don't support .cfi_signal_frame [AK: added automatic detection of the new binutils and wrote description] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>

[PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinder
Current gcc generates calls not jumps to noreturn functions. When that happens the return address can point to the next function, which confuses the unwinder. This patch works around it by marking asynchronous exception frames in contrast normal call frames in the unwind information. Then teach the unwinder to decode this. For normal call frames the unwinder now subtracts one from the address which avoids this problem. The standard libgcc unwinder uses the same trick. It doesn't include adjustment of the printed address (i.e. for the original example, it'd still be kernel_math_error+0 that gets displayed, but the unwinder wouldn't get confused anymore. This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16 unfortunately because earlier binutils don't support .cfi_signal_frame [AK: added automatic detection of the new binutils and wrote description] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
Jan Beulich · Andi Kleen
1 parent ab2e0b46cb
Showing 11 changed files with 73 additions and 9 deletions Side-by-side Diff
arch/i386/Makefile
arch/i386/kernel/entry.S
arch/x86_64/Makefile
arch/x86_64/ia32/ia32entry.S
arch/x86_64/kernel/entry.S
include/asm-i386/dwarf2.h
include/asm-i386/unwind.h
include/asm-x86_64/dwarf2.h
include/asm-x86_64/unwind.h
kernel/unwind.c
scripts/Kbuild.include
@@ -50,6 +50,10 @@
 cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
 AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
  
+# is .cfi_signal_frame supported too?
+cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
+AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
+
 CFLAGS += $(cflags-y)
  
 # Default subarch .c files
@@ -183,18 +183,21 @@
  
 #define RING0_INT_FRAME \
 	CFI_STARTPROC simple;\
+	CFI_SIGNAL_FRAME;\
 	CFI_DEF_CFA esp, 3*4;\
 	/*CFI_OFFSET cs, -2*4;*/\
 	CFI_OFFSET eip, -3*4
  
 #define RING0_EC_FRAME \
 	CFI_STARTPROC simple;\
+	CFI_SIGNAL_FRAME;\
 	CFI_DEF_CFA esp, 4*4;\
 	/*CFI_OFFSET cs, -2*4;*/\
 	CFI_OFFSET eip, -3*4
  
 #define RING0_PTREGS_FRAME \
 	CFI_STARTPROC simple;\
+	CFI_SIGNAL_FRAME;\
 	CFI_DEF_CFA esp, OLDESP-EBX;\
 	/*CFI_OFFSET cs, CS-OLDESP;*/\
 	CFI_OFFSET eip, EIP-OLDESP;\
@@ -275,6 +278,7 @@
 	# sysenter call handler stub
 ENTRY(sysenter_entry)
 	CFI_STARTPROC simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA esp, 0
 	CFI_REGISTER esp, ebp
 	movl TSS_sysenter_esp0(%esp),%esp
@@ -58,6 +58,10 @@
 cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
 AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
  
+# is .cfi_signal_frame supported too?
+cflags-y += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
+AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
+
 cflags-$(CONFIG_CC_STACKPROTECTOR) += $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) -fstack-protector )
 cflags-$(CONFIG_CC_STACKPROTECTOR_ALL) += $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) -fstack-protector-all )
  
@@ -71,6 +71,7 @@
  */ 	
 ENTRY(ia32_sysenter_target)
 	CFI_STARTPROC32	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,0
 	CFI_REGISTER	rsp,rbp
 	swapgs
@@ -186,6 +187,7 @@
  */ 	
 ENTRY(ia32_cstar_target)
 	CFI_STARTPROC32	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,PDA_STACKOFFSET
 	CFI_REGISTER	rip,rcx
 	/*CFI_REGISTER	rflags,r11*/
@@ -293,6 +295,7 @@
  
 ENTRY(ia32_syscall)
 	CFI_STARTPROC	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,SS+8-RIP
 	/*CFI_REL_OFFSET	ss,SS-RIP*/
 	CFI_REL_OFFSET	rsp,RSP-RIP
@@ -370,6 +373,7 @@
 	popq %r11
 	CFI_ENDPROC
 	CFI_STARTPROC32	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,SS+8-ARGOFFSET
 	CFI_REL_OFFSET	rax,RAX-ARGOFFSET
 	CFI_REL_OFFSET	rcx,RCX-ARGOFFSET
@@ -123,6 +123,7 @@
 	.macro	CFI_DEFAULT_STACK start=1
 	.if \start
 	CFI_STARTPROC	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,SS+8
 	.else
 	CFI_DEF_CFA_OFFSET SS+8
@@ -207,6 +208,7 @@
  
 ENTRY(system_call)
 	CFI_STARTPROC	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,PDA_STACKOFFSET
 	CFI_REGISTER	rip,rcx
 	/*CFI_REGISTER	rflags,r11*/
@@ -324,6 +326,7 @@
  */ 	
 ENTRY(int_ret_from_sys_call)
 	CFI_STARTPROC	simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA	rsp,SS+8-ARGOFFSET
 	/*CFI_REL_OFFSET	ss,SS-ARGOFFSET*/
 	CFI_REL_OFFSET	rsp,RSP-ARGOFFSET
@@ -484,6 +487,7 @@
  */
 	.macro _frame ref
 	CFI_STARTPROC simple
+	CFI_SIGNAL_FRAME
 	CFI_DEF_CFA rsp,SS+8-\ref
 	/*CFI_REL_OFFSET ss,SS-\ref*/
 	CFI_REL_OFFSET rsp,RSP-\ref
@@ -28,8 +28,14 @@
 #define CFI_RESTORE_STATE .cfi_restore_state
 #define CFI_UNDEFINED .cfi_undefined
  
+#ifdef CONFIG_AS_CFI_SIGNAL_FRAME
+#define CFI_SIGNAL_FRAME .cfi_signal_frame
 #else
+#define CFI_SIGNAL_FRAME
+#endif
  
+#else
+
 /* Due to the structure of pre-exisiting code, don't use assembler line
    comment character # to ignore the arguments. Instead, use a dummy macro. */
 .macro ignore a=0, b=0, c=0, d=0
@@ -48,6 +54,7 @@
 #define CFI_REMEMBER_STATE ignore
 #define CFI_RESTORE_STATE ignore
 #define CFI_UNDEFINED ignore
+#define CFI_SIGNAL_FRAME ignore
  
 #endif
  
@@ -18,6 +18,7 @@
 {
 	struct pt_regs regs;
 	struct task_struct *task;
+	unsigned call_frame:1;
 };
  
 #define UNW_PC(frame)        (frame)->regs.eip
@@ -43,6 +44,10 @@
 	PTREGS_INFO(esi), \
 	PTREGS_INFO(edi), \
 	PTREGS_INFO(eip)
+
+#define UNW_DEFAULT_RA(raItem, dataAlign) \
+	((raItem).where == Memory && \
+	 !((raItem).value * (dataAlign) + 4))
  
 static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
                                             /*const*/ struct pt_regs *regs)
@@ -28,6 +28,11 @@
 #define CFI_REMEMBER_STATE .cfi_remember_state
 #define CFI_RESTORE_STATE .cfi_restore_state
 #define CFI_UNDEFINED .cfi_undefined
+#ifdef CONFIG_AS_CFI_SIGNAL_FRAME
+#define CFI_SIGNAL_FRAME .cfi_signal_frame
+#else
+#define CFI_SIGNAL_FRAME
+#endif
  
 #else
  
@@ -45,6 +50,7 @@
 #define CFI_REMEMBER_STATE	#
 #define CFI_RESTORE_STATE	#
 #define CFI_UNDEFINED	#
+#define CFI_SIGNAL_FRAME	#
  
 #endif
  
@@ -18,6 +18,7 @@
 {
 	struct pt_regs regs;
 	struct task_struct *task;
+	unsigned call_frame:1;
 };
  
 #define UNW_PC(frame)        (frame)->regs.rip
@@ -56,6 +57,10 @@
 	PTREGS_INFO(r14), \
 	PTREGS_INFO(r15), \
 	PTREGS_INFO(rip)
+
+#define UNW_DEFAULT_RA(raItem, dataAlign) \
+	((raItem).where == Memory && \
+	 !((raItem).value * (dataAlign) + 8))
  
 static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
                                             /*const*/ struct pt_regs *regs)
@@ -603,6 +603,7 @@
 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
 	const u32 *fde = NULL, *cie = NULL;
 	const u8 *ptr = NULL, *end = NULL;
+	unsigned long pc = UNW_PC(frame) - frame->call_frame;
 	unsigned long startLoc = 0, endLoc = 0, cfa;
 	unsigned i;
 	signed ptrType = -1;
@@ -612,7 +613,7 @@
  
 	if (UNW_PC(frame) == 0)
 		return -EINVAL;
-	if ((table = find_table(UNW_PC(frame))) != NULL
+	if ((table = find_table(pc)) != NULL
 	    && !(table->size & (sizeof(*fde) - 1))) {
 		unsigned long tableSize = table->size;
  
@@ -647,7 +648,7 @@
 			                        ptrType & DW_EH_PE_indirect
 			                        ? ptrType
 			                        : ptrType & (DW_EH_PE_FORM|DW_EH_PE_signed));
-			if (UNW_PC(frame) >= startLoc && UNW_PC(frame) < endLoc)
+			if (pc >= startLoc && pc < endLoc)
 				break;
 			cie = NULL;
 		}
  
  
@@ -657,16 +658,28 @@
 		state.cieEnd = ptr; /* keep here temporarily */
 		ptr = (const u8 *)(cie + 2);
 		end = (const u8 *)(cie + 1) + *cie;
+		frame->call_frame = 1;
 		if ((state.version = *ptr) != 1)
 			cie = NULL; /* unsupported version */
 		else if (*++ptr) {
 			/* check if augmentation size is first (and thus present) */
 			if (*ptr == 'z') {
-				/* check for ignorable (or already handled)
-				 * nul-terminated augmentation string */
-				while (++ptr < end && *ptr)
-					if (strchr("LPR", *ptr) == NULL)
+				while (++ptr < end && *ptr) {
+					switch(*ptr) {
+					/* check for ignorable (or already handled)
+					 * nul-terminated augmentation string */
+					case 'L':
+					case 'P':
+					case 'R':
+						continue;
+					case 'S':
+						frame->call_frame = 0;
+						continue;
+					default:
 						break;
+					}
+					break;
+				}
 			}
 			if (ptr >= end || *ptr)
 				cie = NULL;
@@ -755,7 +768,7 @@
 	state.org = startLoc;
 	memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
 	/* process instructions */
-	if (!processCFI(ptr, end, UNW_PC(frame), ptrType, &state)
+	if (!processCFI(ptr, end, pc, ptrType, &state)
 	   || state.loc > endLoc
 	   || state.regs[retAddrReg].where == Nowhere
 	   || state.cfa.reg >= ARRAY_SIZE(reg_info)
@@ -763,6 +776,11 @@
 	   || state.cfa.offs % sizeof(unsigned long))
 		return -EIO;
 	/* update frame */
+#ifndef CONFIG_AS_CFI_SIGNAL_FRAME
+	if(frame->call_frame
+	   && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
+		frame->call_frame = 0;
+#endif
 	cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
 	startLoc = min((unsigned long)UNW_SP(frame), cfa);
 	endLoc = max((unsigned long)UNW_SP(frame), cfa);
@@ -866,6 +884,7 @@
                            /*const*/ struct pt_regs *regs)
 {
 	info->task = tsk;
+	info->call_frame = 0;
 	arch_unw_init_frame_info(info, regs);
  
 	return 0;
@@ -879,6 +898,7 @@
                         struct task_struct *tsk)
 {
 	info->task = tsk;
+	info->call_frame = 0;
 	arch_unw_init_blocked(info);
  
 	return 0;
@@ -894,6 +914,7 @@
                         void *arg)
 {
 	info->task = current;
+	info->call_frame = 0;
  
 	return arch_unwind_init_running(info, callback, arg);
 }
@@ -66,8 +66,8 @@
 # as-instr
 # Usage: cflags-y += $(call as-instr, instr, option1, option2)
  
-as-instr = $(shell if echo -e "$(1)" | $(AS) -Z -o astest$$$$.out \
-		   2>&1 >/dev/null ; then echo "$(2)"; else echo "$(3)"; fi; \
+as-instr = $(shell if echo -e "$(1)" | $(AS) >/dev/null 2>&1 -W -Z -o astest$$$$.out ; \
+		   then echo "$(2)"; else echo "$(3)"; fi; \
 	           rm -f astest$$$$.out)
  
 # cc-option
...	...	@@ -50,6 +50,10 @@
50	50	cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
51	51	AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
52	52
	53	+# is .cfi_signal_frame supported too?
	54	+cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
	55	+AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
	56	+
53	57	CFLAGS += $(cflags-y)
54	58
55	59	# Default subarch .c files
...	...	@@ -183,18 +183,21 @@
183	183
184	184	#define RING0_INT_FRAME \
185	185	CFI_STARTPROC simple;\
	186	+ CFI_SIGNAL_FRAME;\
186	187	CFI_DEF_CFA esp, 3*4;\
187	188	/CFI_OFFSET cs, -24;*/\
188	189	CFI_OFFSET eip, -3*4
189	190
190	191	#define RING0_EC_FRAME \
191	192	CFI_STARTPROC simple;\
	193	+ CFI_SIGNAL_FRAME;\
192	194	CFI_DEF_CFA esp, 4*4;\
193	195	/CFI_OFFSET cs, -24;*/\
194	196	CFI_OFFSET eip, -3*4
195	197
196	198	#define RING0_PTREGS_FRAME \
197	199	CFI_STARTPROC simple;\
	200	+ CFI_SIGNAL_FRAME;\
198	201	CFI_DEF_CFA esp, OLDESP-EBX;\
199	202	/CFI_OFFSET cs, CS-OLDESP;/\
200	203	CFI_OFFSET eip, EIP-OLDESP;\
...	...	@@ -275,6 +278,7 @@
275	278	# sysenter call handler stub
276	279	ENTRY(sysenter_entry)
277	280	CFI_STARTPROC simple
	281	+ CFI_SIGNAL_FRAME
278	282	CFI_DEF_CFA esp, 0
279	283	CFI_REGISTER esp, ebp
280	284	movl TSS_sysenter_esp0(%esp),%esp
...	...	@@ -58,6 +58,10 @@
58	58	cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
59	59	AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,)
60	60
	61	+# is .cfi_signal_frame supported too?
	62	+cflags-y += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
	63	+AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1,)
	64	+
61	65	cflags-$(CONFIG_CC_STACKPROTECTOR) += $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) -fstack-protector )
62	66	cflags-$(CONFIG_CC_STACKPROTECTOR_ALL) += $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) -fstack-protector-all )
63	67
...	...	@@ -71,6 +71,7 @@
71	71	*/
72	72	ENTRY(ia32_sysenter_target)
73	73	CFI_STARTPROC32 simple
	74	+ CFI_SIGNAL_FRAME
74	75	CFI_DEF_CFA rsp,0
75	76	CFI_REGISTER rsp,rbp
76	77	swapgs
...	...	@@ -186,6 +187,7 @@
186	187	*/
187	188	ENTRY(ia32_cstar_target)
188	189	CFI_STARTPROC32 simple
	190	+ CFI_SIGNAL_FRAME
189	191	CFI_DEF_CFA rsp,PDA_STACKOFFSET
190	192	CFI_REGISTER rip,rcx
191	193	/CFI_REGISTER rflags,r11/
...	...	@@ -293,6 +295,7 @@
293	295
294	296	ENTRY(ia32_syscall)
295	297	CFI_STARTPROC simple
	298	+ CFI_SIGNAL_FRAME
296	299	CFI_DEF_CFA rsp,SS+8-RIP
297	300	/CFI_REL_OFFSET ss,SS-RIP/
298	301	CFI_REL_OFFSET rsp,RSP-RIP
...	...	@@ -370,6 +373,7 @@
370	373	popq %r11
371	374	CFI_ENDPROC
372	375	CFI_STARTPROC32 simple
	376	+ CFI_SIGNAL_FRAME
373	377	CFI_DEF_CFA rsp,SS+8-ARGOFFSET
374	378	CFI_REL_OFFSET rax,RAX-ARGOFFSET
375	379	CFI_REL_OFFSET rcx,RCX-ARGOFFSET
...	...	@@ -123,6 +123,7 @@
123	123	.macro CFI_DEFAULT_STACK start=1
124	124	.if \start
125	125	CFI_STARTPROC simple
	126	+ CFI_SIGNAL_FRAME
126	127	CFI_DEF_CFA rsp,SS+8
127	128	.else
128	129	CFI_DEF_CFA_OFFSET SS+8
...	...	@@ -207,6 +208,7 @@
207	208
208	209	ENTRY(system_call)
209	210	CFI_STARTPROC simple
	211	+ CFI_SIGNAL_FRAME
210	212	CFI_DEF_CFA rsp,PDA_STACKOFFSET
211	213	CFI_REGISTER rip,rcx
212	214	/CFI_REGISTER rflags,r11/
...	...	@@ -324,6 +326,7 @@
324	326	*/
325	327	ENTRY(int_ret_from_sys_call)
326	328	CFI_STARTPROC simple
	329	+ CFI_SIGNAL_FRAME
327	330	CFI_DEF_CFA rsp,SS+8-ARGOFFSET
328	331	/CFI_REL_OFFSET ss,SS-ARGOFFSET/
329	332	CFI_REL_OFFSET rsp,RSP-ARGOFFSET
...	...	@@ -484,6 +487,7 @@
484	487	*/
485	488	.macro _frame ref
486	489	CFI_STARTPROC simple
	490	+ CFI_SIGNAL_FRAME
487	491	CFI_DEF_CFA rsp,SS+8-\ref
488	492	/CFI_REL_OFFSET ss,SS-\ref/
489	493	CFI_REL_OFFSET rsp,RSP-\ref
...	...	@@ -28,8 +28,14 @@
28	28	#define CFI_RESTORE_STATE .cfi_restore_state
29	29	#define CFI_UNDEFINED .cfi_undefined
30	30
	31	+#ifdef CONFIG_AS_CFI_SIGNAL_FRAME
	32	+#define CFI_SIGNAL_FRAME .cfi_signal_frame
31	33	#else
	34	+#define CFI_SIGNAL_FRAME
	35	+#endif
32	36
	37	+#else
	38	+
33	39	/* Due to the structure of pre-exisiting code, don't use assembler line
34	40	comment character # to ignore the arguments. Instead, use a dummy macro. */
35	41	.macro ignore a=0, b=0, c=0, d=0
...	...	@@ -48,6 +54,7 @@
48	54	#define CFI_REMEMBER_STATE ignore
49	55	#define CFI_RESTORE_STATE ignore
50	56	#define CFI_UNDEFINED ignore
	57	+#define CFI_SIGNAL_FRAME ignore
51	58
52	59	#endif
53	60
...	...	@@ -18,6 +18,7 @@
18	18	{
19	19	struct pt_regs regs;
20	20	struct task_struct *task;
	21	+ unsigned call_frame:1;
21	22	};
22	23
23	24	#define UNW_PC(frame) (frame)->regs.eip
...	...	@@ -43,6 +44,10 @@
43	44	PTREGS_INFO(esi), \
44	45	PTREGS_INFO(edi), \
45	46	PTREGS_INFO(eip)
	47	+
	48	+#define UNW_DEFAULT_RA(raItem, dataAlign) \
	49	+ ((raItem).where == Memory && \
	50	+ !((raItem).value * (dataAlign) + 4))
46	51
47	52	static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
48	53	/const/ struct pt_regs *regs)
...	...	@@ -28,6 +28,11 @@
28	28	#define CFI_REMEMBER_STATE .cfi_remember_state
29	29	#define CFI_RESTORE_STATE .cfi_restore_state
30	30	#define CFI_UNDEFINED .cfi_undefined
	31	+#ifdef CONFIG_AS_CFI_SIGNAL_FRAME
	32	+#define CFI_SIGNAL_FRAME .cfi_signal_frame
	33	+#else
	34	+#define CFI_SIGNAL_FRAME
	35	+#endif
31	36
32	37	#else
33	38
...	...	@@ -45,6 +50,7 @@
45	50	#define CFI_REMEMBER_STATE #
46	51	#define CFI_RESTORE_STATE #
47	52	#define CFI_UNDEFINED #
	53	+#define CFI_SIGNAL_FRAME #
48	54
49	55	#endif
50	56
...	...	@@ -603,6 +603,7 @@
603	603	#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
604	604	const u32 fde = NULL, cie = NULL;
605	605	const u8 ptr = NULL, end = NULL;
	606	+ unsigned long pc = UNW_PC(frame) - frame->call_frame;
606	607	unsigned long startLoc = 0, endLoc = 0, cfa;
607	608	unsigned i;
608	609	signed ptrType = -1;
...	...	@@ -612,7 +613,7 @@
612	613
613	614	if (UNW_PC(frame) == 0)
614	615	return -EINVAL;
615		- if ((table = find_table(UNW_PC(frame))) != NULL
	616	+ if ((table = find_table(pc)) != NULL
616	617	&& !(table->size & (sizeof(*fde) - 1))) {
617	618	unsigned long tableSize = table->size;
618	619
...	...	@@ -647,7 +648,7 @@
647	648	ptrType & DW_EH_PE_indirect
648	649	? ptrType
649	650	: ptrType & (DW_EH_PE_FORM\|DW_EH_PE_signed));
650		- if (UNW_PC(frame) >= startLoc && UNW_PC(frame) < endLoc)
	651	+ if (pc >= startLoc && pc < endLoc)
651	652	break;
652	653	cie = NULL;
653	654	}
654	655
655	656
...	...	@@ -657,16 +658,28 @@
657	658	state.cieEnd = ptr; /* keep here temporarily */
658	659	ptr = (const u8 *)(cie + 2);
659	660	end = (const u8 )(cie + 1) + cie;
	661	+ frame->call_frame = 1;
660	662	if ((state.version = *ptr) != 1)
661	663	cie = NULL; /* unsupported version */
662	664	else if (*++ptr) {
663	665	/* check if augmentation size is first (and thus present) */
664	666	if (*ptr == 'z') {
665		- /* check for ignorable (or already handled)
666		- * nul-terminated augmentation string */
667		- while (++ptr < end && *ptr)
668		- if (strchr("LPR", *ptr) == NULL)
	667	+ while (++ptr < end && *ptr) {
	668	+ switch(*ptr) {
	669	+ /* check for ignorable (or already handled)
	670	+ * nul-terminated augmentation string */
	671	+ case 'L':
	672	+ case 'P':
	673	+ case 'R':
	674	+ continue;
	675	+ case 'S':
	676	+ frame->call_frame = 0;
	677	+ continue;
	678	+ default:
669	679	break;
	680	+ }
	681	+ break;
	682	+ }
670	683	}
671	684	if (ptr >= end \|\| *ptr)
672	685	cie = NULL;
...	...	@@ -755,7 +768,7 @@
755	768	state.org = startLoc;
756	769	memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
757	770	/* process instructions */
758		- if (!processCFI(ptr, end, UNW_PC(frame), ptrType, &state)
	771	+ if (!processCFI(ptr, end, pc, ptrType, &state)
759	772	\|\| state.loc > endLoc
760	773	\|\| state.regs[retAddrReg].where == Nowhere
761	774	\|\| state.cfa.reg >= ARRAY_SIZE(reg_info)
...	...	@@ -763,6 +776,11 @@
763	776	\|\| state.cfa.offs % sizeof(unsigned long))
764	777	return -EIO;
765	778	/* update frame */
	779	+#ifndef CONFIG_AS_CFI_SIGNAL_FRAME
	780	+ if(frame->call_frame
	781	+ && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
	782	+ frame->call_frame = 0;
	783	+#endif
766	784	cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
767	785	startLoc = min((unsigned long)UNW_SP(frame), cfa);
768	786	endLoc = max((unsigned long)UNW_SP(frame), cfa);
...	...	@@ -866,6 +884,7 @@
866	884	/const/ struct pt_regs *regs)
867	885	{
868	886	info->task = tsk;
	887	+ info->call_frame = 0;
869	888	arch_unw_init_frame_info(info, regs);
870	889
871	890	return 0;
...	...	@@ -879,6 +898,7 @@
879	898	struct task_struct *tsk)
880	899	{
881	900	info->task = tsk;
	901	+ info->call_frame = 0;
882	902	arch_unw_init_blocked(info);
883	903
884	904	return 0;
...	...	@@ -894,6 +914,7 @@
894	914	void *arg)
895	915	{
896	916	info->task = current;
	917	+ info->call_frame = 0;
897	918
898	919	return arch_unwind_init_running(info, callback, arg);
899	920	}
...	...	@@ -66,8 +66,8 @@
66	66	# as-instr
67	67	# Usage: cflags-y += $(call as-instr, instr, option1, option2)
68	68
69		-as-instr = $(shell if echo -e "$(1)" \| $(AS) -Z -o astest$$$$.out \
70		- 2>&1 >/dev/null ; then echo "$(2)"; else echo "$(3)"; fi; \
	69	+as-instr = $(shell if echo -e "$(1)" \| $(AS) >/dev/null 2>&1 -W -Z -o astest$$$$.out ; \
	70	+ then echo "$(2)"; else echo "$(3)"; fi; \
71	71	rm -f astest$$$$.out)
72	72
73	73	# cc-option