x86/debug: Remove perpetually broken, unmaintainable dwarf annotations

So the dwarf2 annotations in low level assembly code have
become an increasing hindrance: unreadable, messy macros
mixed into some of the most security sensitive code paths
of the Linux kernel.

These debug info annotations don't even buy the upstream
kernel anything: dwarf driven stack unwinding has caused
problems in the past so it's out of tree, and the upstream
kernel only uses the much more robust framepointers based
stack unwinding method.

In addition to that there's a steady, slow bitrot going
on with these annotations, requiring frequent fixups.
There's no tooling and no functionality upstream that
keeps it correct.

So burn down the sick forest, allowing new, healthier growth:

   27 files changed, 350 insertions(+), 1101 deletions(-)

Someone who has the willingness and time to do this
properly can attempt to reintroduce dwarf debuginfo in x86
assembly code plus dwarf unwinding from first principles,
with the following conditions:

 - it should be maximally readable, and maximally low-key to
   'ordinary' code reading and maintenance.

 - find a build time method to insert dwarf annotations
   automatically in the most common cases, for pop/push
   instructions that manipulate the stack pointer. This could
   be done for example via a preprocessing step that just
   looks for common patterns - plus special annotations for
   the few cases where we want to depart from the default.
   We have hundreds of CFI annotations, so automating most of
   that makes sense.

 - it should come with build tooling checks that ensure that
   CFI annotations are sensible. We've seen such efforts from
   the framepointer side, and there's no reason it couldn't be
   done on the dwarf side.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 48 insertions, 240 deletions

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 47b95813dc37..b84cec50c8cf 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -19,8 +19,6 @@
  * at the top of the kernel process stack.
  *
  * Some macro usage:
- * - CFI macros are used to generate dwarf2 unwind information for better
- * backtraces. They don't change any code.
  * - ENTRY/END Define functions in the symbol table.
  * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.
  * - idtentry - Define exception entry points.
@@ -30,7 +28,6 @@
 #include <asm/segment.h>
 #include <asm/cache.h>
 #include <asm/errno.h>
-#include <asm/dwarf2.h>
 #include <asm/calling.h>
 #include <asm/asm-offsets.h>
 #include <asm/msr.h>
@@ -113,61 +110,6 @@ ENDPROC(native_usergs_sysret64)
 #endif
 
 /*
- * empty frame
- */
-	.macro EMPTY_FRAME start=1 offset=0
-	.if \start
-	CFI_STARTPROC simple
-	CFI_SIGNAL_FRAME
-	CFI_DEF_CFA rsp,8+\offset
-	.else
-	CFI_DEF_CFA_OFFSET 8+\offset
-	.endif
-	.endm
-
-/*
- * initial frame state for interrupts (and exceptions without error code)
- */
-	.macro INTR_FRAME start=1 offset=0
-	EMPTY_FRAME \start, 5*8+\offset
-	/*CFI_REL_OFFSET ss, 4*8+\offset*/
-	CFI_REL_OFFSET rsp, 3*8+\offset
-	/*CFI_REL_OFFSET rflags, 2*8+\offset*/
-	/*CFI_REL_OFFSET cs, 1*8+\offset*/
-	CFI_REL_OFFSET rip, 0*8+\offset
-	.endm
-
-/*
- * initial frame state for exceptions with error code (and interrupts
- * with vector already pushed)
- */
-	.macro XCPT_FRAME start=1 offset=0
-	INTR_FRAME \start, 1*8+\offset
-	.endm
-
-/*
- * frame that enables passing a complete pt_regs to a C function.
- */
-	.macro DEFAULT_FRAME start=1 offset=0
-	XCPT_FRAME \start, ORIG_RAX+\offset
-	CFI_REL_OFFSET rdi, RDI+\offset
-	CFI_REL_OFFSET rsi, RSI+\offset
-	CFI_REL_OFFSET rdx, RDX+\offset
-	CFI_REL_OFFSET rcx, RCX+\offset
-	CFI_REL_OFFSET rax, RAX+\offset
-	CFI_REL_OFFSET r8, R8+\offset
-	CFI_REL_OFFSET r9, R9+\offset
-	CFI_REL_OFFSET r10, R10+\offset
-	CFI_REL_OFFSET r11, R11+\offset
-	CFI_REL_OFFSET rbx, RBX+\offset
-	CFI_REL_OFFSET rbp, RBP+\offset
-	CFI_REL_OFFSET r12, R12+\offset
-	CFI_REL_OFFSET r13, R13+\offset
-	CFI_REL_OFFSET r14, R14+\offset
-	CFI_REL_OFFSET r15, R15+\offset
-	.endm
-
-/*
  * 64bit SYSCALL instruction entry. Up to 6 arguments in registers.
  *
  * 64bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
@@ -196,12 +138,6 @@ ENDPROC(native_usergs_sysret64)
  */
 
 ENTRY(system_call)
-	CFI_STARTPROC	simple
-	CFI_SIGNAL_FRAME
-	CFI_DEF_CFA	rsp,0
-	CFI_REGISTER	rip,rcx
-	/*CFI_REGISTER	rflags,r11*/
-
 	/*
 	 * Interrupts are off on entry.
 	 * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
@@ -219,8 +155,8 @@ GLOBAL(system_call_after_swapgs)
 	movq	PER_CPU_VAR(cpu_current_top_of_stack),%rsp
 
 	/* Construct struct pt_regs on stack */
-	pushq_cfi $__USER_DS			/* pt_regs->ss */
-	pushq_cfi PER_CPU_VAR(rsp_scratch)	/* pt_regs->sp */
+	pushq $__USER_DS			/* pt_regs->ss */
+	pushq PER_CPU_VAR(rsp_scratch)	/* pt_regs->sp */
 	/*
 	 * Re-enable interrupts.
 	 * We use 'rsp_scratch' as a scratch space, hence irq-off block above
@@ -229,22 +165,20 @@ GLOBAL(system_call_after_swapgs)
 	 * with using rsp_scratch:
 	 */
 	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq_cfi	%r11			/* pt_regs->flags */
-	pushq_cfi	$__USER_CS		/* pt_regs->cs */
-	pushq_cfi	%rcx			/* pt_regs->ip */
-	CFI_REL_OFFSET rip,0
-	pushq_cfi_reg	rax			/* pt_regs->orig_ax */
-	pushq_cfi_reg	rdi			/* pt_regs->di */
-	pushq_cfi_reg	rsi			/* pt_regs->si */
-	pushq_cfi_reg	rdx			/* pt_regs->dx */
-	pushq_cfi_reg	rcx			/* pt_regs->cx */
-	pushq_cfi	$-ENOSYS		/* pt_regs->ax */
-	pushq_cfi_reg	r8			/* pt_regs->r8 */
-	pushq_cfi_reg	r9			/* pt_regs->r9 */
-	pushq_cfi_reg	r10			/* pt_regs->r10 */
-	pushq_cfi_reg	r11			/* pt_regs->r11 */
+	pushq	%r11			/* pt_regs->flags */
+	pushq	$__USER_CS		/* pt_regs->cs */
+	pushq	%rcx			/* pt_regs->ip */
+	pushq	%rax			/* pt_regs->orig_ax */
+	pushq	%rdi			/* pt_regs->di */
+	pushq	%rsi			/* pt_regs->si */
+	pushq	%rdx			/* pt_regs->dx */
+	pushq	%rcx			/* pt_regs->cx */
+	pushq	$-ENOSYS		/* pt_regs->ax */
+	pushq	%r8			/* pt_regs->r8 */
+	pushq	%r9			/* pt_regs->r9 */
+	pushq	%r10			/* pt_regs->r10 */
+	pushq	%r11			/* pt_regs->r11 */
 	sub	$(6*8),%rsp /* pt_regs->bp,bx,r12-15 not saved */
-	CFI_ADJUST_CFA_OFFSET 6*8
 
 	testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
 	jnz tracesys
@@ -282,13 +216,9 @@ system_call_fastpath:
 	testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
 	jnz int_ret_from_sys_call_irqs_off	/* Go to the slow path */
 
-	CFI_REMEMBER_STATE
-
 	RESTORE_C_REGS_EXCEPT_RCX_R11
 	movq	RIP(%rsp),%rcx
-	CFI_REGISTER	rip,rcx
 	movq	EFLAGS(%rsp),%r11
-	/*CFI_REGISTER	rflags,r11*/
 	movq	RSP(%rsp),%rsp
 	/*
 	 * 64bit SYSRET restores rip from rcx,
@@ -307,8 +237,6 @@ system_call_fastpath:
 	 */
 	USERGS_SYSRET64
 
-	CFI_RESTORE_STATE
-
 	/* Do syscall entry tracing */
 tracesys:
 	movq %rsp, %rdi
@@ -374,9 +302,9 @@ int_careful:
 	jnc  int_very_careful
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq_cfi %rdi
+	pushq %rdi
 	SCHEDULE_USER
-	popq_cfi %rdi
+	popq %rdi
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 	jmp int_with_check
@@ -389,10 +317,10 @@ int_very_careful:
 	/* Check for syscall exit trace */
 	testl $_TIF_WORK_SYSCALL_EXIT,%edx
 	jz int_signal
-	pushq_cfi %rdi
+	pushq %rdi
 	leaq 8(%rsp),%rdi	# &ptregs -> arg1
 	call syscall_trace_leave
-	popq_cfi %rdi
+	popq %rdi
 	andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
 	jmp int_restore_rest
 
@@ -475,27 +403,21 @@ syscall_return:
 	 * perf profiles.  Nothing jumps here.
 	 */
 syscall_return_via_sysret:
-	CFI_REMEMBER_STATE
 	/* rcx and r11 are already restored (see code above) */
 	RESTORE_C_REGS_EXCEPT_RCX_R11
 	movq RSP(%rsp),%rsp
 	USERGS_SYSRET64
-	CFI_RESTORE_STATE
 
 opportunistic_sysret_failed:
 	SWAPGS
 	jmp	restore_c_regs_and_iret
-	CFI_ENDPROC
 END(system_call)
 
 
 	.macro FORK_LIKE func
 ENTRY(stub_\func)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8		/* offset 8: return address */
 	SAVE_EXTRA_REGS 8
 	jmp sys_\func
-	CFI_ENDPROC
 END(stub_\func)
 	.endm
 
@@ -504,8 +426,6 @@ END(stub_\func)
 	FORK_LIKE  vfork
 
 ENTRY(stub_execve)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8
 	call	sys_execve
 return_from_execve:
 	testl	%eax, %eax
@@ -515,11 +435,9 @@ return_from_execve:
 1:
 	/* must use IRET code path (pt_regs->cs may have changed) */
 	addq	$8, %rsp
-	CFI_ADJUST_CFA_OFFSET -8
 	ZERO_EXTRA_REGS
 	movq	%rax,RAX(%rsp)
 	jmp	int_ret_from_sys_call
-	CFI_ENDPROC
 END(stub_execve)
 /*
  * Remaining execve stubs are only 7 bytes long.
@@ -527,32 +445,23 @@ END(stub_execve)
  */
 	.align	8
 GLOBAL(stub_execveat)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8
 	call	sys_execveat
 	jmp	return_from_execve
-	CFI_ENDPROC
 END(stub_execveat)
 
 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
 	.align	8
 GLOBAL(stub_x32_execve)
 GLOBAL(stub32_execve)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8
 	call	compat_sys_execve
 	jmp	return_from_execve
-	CFI_ENDPROC
 END(stub32_execve)
 END(stub_x32_execve)
 	.align	8
 GLOBAL(stub_x32_execveat)
 GLOBAL(stub32_execveat)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8
 	call	compat_sys_execveat
 	jmp	return_from_execve
-	CFI_ENDPROC
 END(stub32_execveat)
 END(stub_x32_execveat)
 #endif
@@ -562,8 +471,6 @@ END(stub_x32_execveat)
  * This cannot be done with SYSRET, so use the IRET return path instead.
  */
 ENTRY(stub_rt_sigreturn)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8
 	/*
 	 * SAVE_EXTRA_REGS result is not normally needed:
 	 * sigreturn overwrites all pt_regs->GPREGS.
@@ -575,21 +482,16 @@ ENTRY(stub_rt_sigreturn)
 	call sys_rt_sigreturn
 return_from_stub:
 	addq	$8, %rsp
-	CFI_ADJUST_CFA_OFFSET -8
 	RESTORE_EXTRA_REGS
 	movq %rax,RAX(%rsp)
 	jmp int_ret_from_sys_call
-	CFI_ENDPROC
 END(stub_rt_sigreturn)
 
 #ifdef CONFIG_X86_X32_ABI
 ENTRY(stub_x32_rt_sigreturn)
-	CFI_STARTPROC
-	DEFAULT_FRAME 0, 8
 	SAVE_EXTRA_REGS 8
 	call sys32_x32_rt_sigreturn
 	jmp  return_from_stub
-	CFI_ENDPROC
 END(stub_x32_rt_sigreturn)
 #endif
 
@@ -599,12 +501,11 @@ END(stub_x32_rt_sigreturn)
  * rdi: prev task we switched from
  */
 ENTRY(ret_from_fork)
-	DEFAULT_FRAME
 
 	LOCK ; btr $TIF_FORK,TI_flags(%r8)
 
-	pushq_cfi $0x0002
-	popfq_cfi				# reset kernel eflags
+	pushq $0x0002
+	popfq				# reset kernel eflags
 
 	call schedule_tail			# rdi: 'prev' task parameter
 
@@ -628,7 +529,6 @@ ENTRY(ret_from_fork)
 	movl $0, RAX(%rsp)
 	RESTORE_EXTRA_REGS
 	jmp int_ret_from_sys_call
-	CFI_ENDPROC
 END(ret_from_fork)
 
 /*
@@ -637,16 +537,13 @@ END(ret_from_fork)
  */
 	.align 8
 ENTRY(irq_entries_start)
-	INTR_FRAME
     vector=FIRST_EXTERNAL_VECTOR
     .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
-	pushq_cfi $(~vector+0x80)	/* Note: always in signed byte range */
+	pushq $(~vector+0x80)	/* Note: always in signed byte range */
     vector=vector+1
 	jmp	common_interrupt
-	CFI_ADJUST_CFA_OFFSET -8
 	.align	8
     .endr
-	CFI_ENDPROC
 END(irq_entries_start)
 
 /*
@@ -688,17 +585,7 @@ END(irq_entries_start)
 	movq %rsp, %rsi
 	incl PER_CPU_VAR(irq_count)
 	cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
-	CFI_DEF_CFA_REGISTER	rsi
 	pushq %rsi
-	/*
-	 * For debugger:
-	 * "CFA (Current Frame Address) is the value on stack + offset"
-	 */
-	CFI_ESCAPE	0x0f /* DW_CFA_def_cfa_expression */, 6, \
-			0x77 /* DW_OP_breg7 (rsp) */, 0, \
-			0x06 /* DW_OP_deref */, \
-			0x08 /* DW_OP_const1u */, SIZEOF_PTREGS-RBP, \
-			0x22 /* DW_OP_plus */
 	/* We entered an interrupt context - irqs are off: */
 	TRACE_IRQS_OFF
 
@@ -711,7 +598,6 @@ END(irq_entries_start)
 	 */
 	.p2align CONFIG_X86_L1_CACHE_SHIFT
 common_interrupt:
-	XCPT_FRAME
 	ASM_CLAC
 	addq $-0x80,(%rsp)		/* Adjust vector to [-256,-1] range */
 	interrupt do_IRQ
@@ -723,11 +609,8 @@ ret_from_intr:
 
 	/* Restore saved previous stack */
 	popq %rsi
-	CFI_DEF_CFA rsi,SIZEOF_PTREGS-RBP /* reg/off reset after def_cfa_expr */
 	/* return code expects complete pt_regs - adjust rsp accordingly: */
 	leaq -RBP(%rsi),%rsp
-	CFI_DEF_CFA_REGISTER	rsp
-	CFI_ADJUST_CFA_OFFSET	RBP
 
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
@@ -743,7 +626,6 @@ retint_check:
 	LOCKDEP_SYS_EXIT_IRQ
 	movl TI_flags(%rcx),%edx
 	andl %edi,%edx
-	CFI_REMEMBER_STATE
 	jnz  retint_careful
 
 retint_swapgs:		/* return to user-space */
@@ -807,8 +689,8 @@ native_irq_return_iret:
 
 #ifdef CONFIG_X86_ESPFIX64
 native_irq_return_ldt:
-	pushq_cfi %rax
-	pushq_cfi %rdi
+	pushq %rax
+	pushq %rdi
 	SWAPGS
 	movq PER_CPU_VAR(espfix_waddr),%rdi
 	movq %rax,(0*8)(%rdi)	/* RAX */
@@ -823,24 +705,23 @@ native_irq_return_ldt:
 	movq (5*8)(%rsp),%rax	/* RSP */
 	movq %rax,(4*8)(%rdi)
 	andl $0xffff0000,%eax
-	popq_cfi %rdi
+	popq %rdi
 	orq PER_CPU_VAR(espfix_stack),%rax
 	SWAPGS
 	movq %rax,%rsp
-	popq_cfi %rax
+	popq %rax
 	jmp native_irq_return_iret
 #endif
 
 	/* edi: workmask, edx: work */
 retint_careful:
-	CFI_RESTORE_STATE
 	bt    $TIF_NEED_RESCHED,%edx
 	jnc   retint_signal
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq_cfi %rdi
+	pushq %rdi
 	SCHEDULE_USER
-	popq_cfi %rdi
+	popq %rdi
 	GET_THREAD_INFO(%rcx)
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
@@ -862,7 +743,6 @@ retint_signal:
 	GET_THREAD_INFO(%rcx)
 	jmp retint_with_reschedule
 
-	CFI_ENDPROC
 END(common_interrupt)
 
 /*
@@ -870,13 +750,11 @@ END(common_interrupt)
  */
 .macro apicinterrupt3 num sym do_sym
 ENTRY(\sym)
-	INTR_FRAME
 	ASM_CLAC
-	pushq_cfi $~(\num)
+	pushq $~(\num)
 .Lcommon_\sym:
 	interrupt \do_sym
 	jmp ret_from_intr
-	CFI_ENDPROC
 END(\sym)
 .endm
 
@@ -959,24 +837,17 @@ ENTRY(\sym)
 	.error "using shift_ist requires paranoid=1"
 	.endif
 
-	.if \has_error_code
-	XCPT_FRAME
-	.else
-	INTR_FRAME
-	.endif
-
 	ASM_CLAC
 	PARAVIRT_ADJUST_EXCEPTION_FRAME
 
 	.ifeq \has_error_code
-	pushq_cfi $-1			/* ORIG_RAX: no syscall to restart */
+	pushq $-1			/* ORIG_RAX: no syscall to restart */
 	.endif
 
 	ALLOC_PT_GPREGS_ON_STACK
 
 	.if \paranoid
 	.if \paranoid == 1
-	CFI_REMEMBER_STATE
 	testb	$3, CS(%rsp)		/* If coming from userspace, switch */
 	jnz 1f				/* stacks. */
 	.endif
@@ -986,8 +857,6 @@ ENTRY(\sym)
 	.endif
 	/* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */
 
-	DEFAULT_FRAME 0
-
 	.if \paranoid
 	.if \shift_ist != -1
 	TRACE_IRQS_OFF_DEBUG		/* reload IDT in case of recursion */
@@ -1023,7 +892,6 @@ ENTRY(\sym)
 	.endif
 
 	.if \paranoid == 1
-	CFI_RESTORE_STATE
 	/*
 	 * Paranoid entry from userspace.  Switch stacks and treat it
 	 * as a normal entry.  This means that paranoid handlers
@@ -1032,7 +900,6 @@ ENTRY(\sym)
 1:
 	call error_entry
 
-	DEFAULT_FRAME 0
 
 	movq %rsp,%rdi			/* pt_regs pointer */
 	call sync_regs
@@ -1051,8 +918,6 @@ ENTRY(\sym)
 
 	jmp error_exit			/* %ebx: no swapgs flag */
 	.endif
-
-	CFI_ENDPROC
 END(\sym)
 .endm
 
@@ -1085,17 +950,15 @@ idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0
 	/* Reload gs selector with exception handling */
 	/* edi:  new selector */
 ENTRY(native_load_gs_index)
-	CFI_STARTPROC
-	pushfq_cfi
+	pushfq
 	DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
 	SWAPGS
 gs_change:
 	movl %edi,%gs
 2:	mfence		/* workaround */
 	SWAPGS
-	popfq_cfi
+	popfq
 	ret
-	CFI_ENDPROC
 END(native_load_gs_index)
 
 	_ASM_EXTABLE(gs_change,bad_gs)
@@ -1110,22 +973,15 @@ bad_gs:
 
 /* Call softirq on interrupt stack. Interrupts are off. */
 ENTRY(do_softirq_own_stack)
-	CFI_STARTPROC
-	pushq_cfi %rbp
-	CFI_REL_OFFSET rbp,0
+	pushq %rbp
 	mov  %rsp,%rbp
-	CFI_DEF_CFA_REGISTER rbp
 	incl PER_CPU_VAR(irq_count)
 	cmove PER_CPU_VAR(irq_stack_ptr),%rsp
 	push  %rbp			# backlink for old unwinder
 	call __do_softirq
 	leaveq
-	CFI_RESTORE		rbp
-	CFI_DEF_CFA_REGISTER	rsp
-	CFI_ADJUST_CFA_OFFSET   -8
 	decl PER_CPU_VAR(irq_count)
 	ret
-	CFI_ENDPROC
 END(do_softirq_own_stack)
 
 #ifdef CONFIG_XEN
@@ -1145,28 +1001,22 @@ idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0
  * activation and restart the handler using the previous one.
  */
 ENTRY(xen_do_hypervisor_callback)   # do_hypervisor_callback(struct *pt_regs)
-	CFI_STARTPROC
 /*
  * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
  * see the correct pointer to the pt_regs
  */
 	movq %rdi, %rsp            # we don't return, adjust the stack frame
-	CFI_ENDPROC
-	DEFAULT_FRAME
 11:	incl PER_CPU_VAR(irq_count)
 	movq %rsp,%rbp
-	CFI_DEF_CFA_REGISTER rbp
 	cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
 	pushq %rbp			# backlink for old unwinder
 	call xen_evtchn_do_upcall
 	popq %rsp
-	CFI_DEF_CFA_REGISTER rsp
 	decl PER_CPU_VAR(irq_count)
 #ifndef CONFIG_PREEMPT
 	call xen_maybe_preempt_hcall
 #endif
 	jmp  error_exit
-	CFI_ENDPROC
 END(xen_do_hypervisor_callback)
 
 /*
@@ -1183,16 +1033,8 @@ END(xen_do_hypervisor_callback)
  * with its current contents: any discrepancy means we in category 1.
  */
 ENTRY(xen_failsafe_callback)
-	INTR_FRAME 1 (6*8)
-	/*CFI_REL_OFFSET gs,GS*/
-	/*CFI_REL_OFFSET fs,FS*/
-	/*CFI_REL_OFFSET es,ES*/
-	/*CFI_REL_OFFSET ds,DS*/
-	CFI_REL_OFFSET r11,8
-	CFI_REL_OFFSET rcx,0
 	movl %ds,%ecx
 	cmpw %cx,0x10(%rsp)
-	CFI_REMEMBER_STATE
 	jne 1f
 	movl %es,%ecx
 	cmpw %cx,0x18(%rsp)
@@ -1205,29 +1047,21 @@ ENTRY(xen_failsafe_callback)
 	jne 1f
 	/* All segments match their saved values => Category 2 (Bad IRET). */
 	movq (%rsp),%rcx
-	CFI_RESTORE rcx
 	movq 8(%rsp),%r11
-	CFI_RESTORE r11
 	addq $0x30,%rsp
-	CFI_ADJUST_CFA_OFFSET -0x30
-	pushq_cfi $0	/* RIP */
-	pushq_cfi %r11
-	pushq_cfi %rcx
+	pushq $0	/* RIP */
+	pushq %r11
+	pushq %rcx
 	jmp general_protection
-	CFI_RESTORE_STATE
 1:	/* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
 	movq (%rsp),%rcx
-	CFI_RESTORE rcx
 	movq 8(%rsp),%r11
-	CFI_RESTORE r11
 	addq $0x30,%rsp
-	CFI_ADJUST_CFA_OFFSET -0x30
-	pushq_cfi $-1 /* orig_ax = -1 => not a system call */
+	pushq $-1 /* orig_ax = -1 => not a system call */
 	ALLOC_PT_GPREGS_ON_STACK
 	SAVE_C_REGS
 	SAVE_EXTRA_REGS
 	jmp error_exit
-	CFI_ENDPROC
 END(xen_failsafe_callback)
 
 apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
@@ -1263,7 +1097,6 @@ idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(
  * Return: ebx=0: need swapgs on exit, ebx=1: otherwise
  */
 ENTRY(paranoid_entry)
-	XCPT_FRAME 1 15*8
 	cld
 	SAVE_C_REGS 8
 	SAVE_EXTRA_REGS 8
@@ -1275,7 +1108,6 @@ ENTRY(paranoid_entry)
 	SWAPGS
 	xorl %ebx,%ebx
 1:	ret
-	CFI_ENDPROC
 END(paranoid_entry)
 
 /*
@@ -1290,7 +1122,6 @@ END(paranoid_entry)
  */
 /* On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) */
 ENTRY(paranoid_exit)
-	DEFAULT_FRAME
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF_DEBUG
 	testl %ebx,%ebx				/* swapgs needed? */
@@ -1305,7 +1136,6 @@ paranoid_exit_restore:
 	RESTORE_C_REGS
 	REMOVE_PT_GPREGS_FROM_STACK 8
 	INTERRUPT_RETURN
-	CFI_ENDPROC
 END(paranoid_exit)
 
 /*
@@ -1313,7 +1143,6 @@ END(paranoid_exit)
  * Return: ebx=0: need swapgs on exit, ebx=1: otherwise
  */
 ENTRY(error_entry)
-	XCPT_FRAME 1 15*8
 	cld
 	SAVE_C_REGS 8
 	SAVE_EXTRA_REGS 8
@@ -1333,7 +1162,6 @@ error_sti:
 	 * for these here too.
 	 */
 error_kernelspace:
-	CFI_REL_OFFSET rcx, RCX+8
 	incl %ebx
 	leaq native_irq_return_iret(%rip),%rcx
 	cmpq %rcx,RIP+8(%rsp)
@@ -1357,13 +1185,11 @@ error_bad_iret:
 	mov %rax,%rsp
 	decl %ebx	/* Return to usergs */
 	jmp error_sti
-	CFI_ENDPROC
 END(error_entry)
 
 
 /* On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) */
 ENTRY(error_exit)
-	DEFAULT_FRAME
 	movl %ebx,%eax
 	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
@@ -1377,12 +1203,10 @@ ENTRY(error_exit)
 	andl %edi,%edx
 	jnz retint_careful
 	jmp retint_swapgs
-	CFI_ENDPROC
 END(error_exit)
 
 /* Runs on exception stack */
 ENTRY(nmi)
-	INTR_FRAME
 	PARAVIRT_ADJUST_EXCEPTION_FRAME
 	/*
 	 * We allow breakpoints in NMIs. If a breakpoint occurs, then
@@ -1417,8 +1241,7 @@ ENTRY(nmi)
 	 */
 
 	/* Use %rdx as our temp variable throughout */
-	pushq_cfi %rdx
-	CFI_REL_OFFSET rdx, 0
+	pushq %rdx
 
 	/*
 	 * If %cs was not the kernel segment, then the NMI triggered in user
@@ -1452,8 +1275,6 @@ ENTRY(nmi)
 	jb	first_nmi
 	/* Ah, it is within the NMI stack, treat it as nested */
 
-	CFI_REMEMBER_STATE
-
 nested_nmi:
 	/*
 	 * Do nothing if we interrupted the fixup in repeat_nmi.
@@ -1471,26 +1292,22 @@ nested_nmi:
 	/* Set up the interrupted NMIs stack to jump to repeat_nmi */
 	leaq -1*8(%rsp), %rdx
 	movq %rdx, %rsp
-	CFI_ADJUST_CFA_OFFSET 1*8
 	leaq -10*8(%rsp), %rdx
-	pushq_cfi $__KERNEL_DS
-	pushq_cfi %rdx
-	pushfq_cfi
-	pushq_cfi $__KERNEL_CS
-	pushq_cfi $repeat_nmi
+	pushq $__KERNEL_DS
+	pushq %rdx
+	pushfq
+	pushq $__KERNEL_CS
+	pushq $repeat_nmi
 
 	/* Put stack back */
 	addq $(6*8), %rsp
-	CFI_ADJUST_CFA_OFFSET -6*8
 
 nested_nmi_out:
-	popq_cfi %rdx
-	CFI_RESTORE rdx
+	popq %rdx
 
 	/* No need to check faults here */
 	INTERRUPT_RETURN
 
-	CFI_RESTORE_STATE
 first_nmi:
 	/*
 	 * Because nested NMIs will use the pushed location that we
@@ -1529,22 +1346,19 @@ first_nmi:
 	 */
 	/* Do not pop rdx, nested NMIs will corrupt that part of the stack */
 	movq (%rsp), %rdx
-	CFI_RESTORE rdx
 
 	/* Set the NMI executing variable on the stack. */
-	pushq_cfi $1
+	pushq $1
 
 	/*
 	 * Leave room for the "copied" frame
 	 */
 	subq $(5*8), %rsp
-	CFI_ADJUST_CFA_OFFSET 5*8
 
 	/* Copy the stack frame to the Saved frame */
 	.rept 5
-	pushq_cfi 11*8(%rsp)
+	pushq 11*8(%rsp)
 	.endr
-	CFI_DEF_CFA_OFFSET 5*8
 
 	/* Everything up to here is safe from nested NMIs */
 
@@ -1567,12 +1381,10 @@ repeat_nmi:
 
 	/* Make another copy, this one may be modified by nested NMIs */
 	addq $(10*8), %rsp
-	CFI_ADJUST_CFA_OFFSET -10*8
 	.rept 5
-	pushq_cfi -6*8(%rsp)
+	pushq -6*8(%rsp)
 	.endr
 	subq $(5*8), %rsp
-	CFI_DEF_CFA_OFFSET 5*8
 end_repeat_nmi:
 
 	/*
@@ -1580,7 +1392,7 @@ end_repeat_nmi:
 	 * NMI if the first NMI took an exception and reset our iret stack
 	 * so that we repeat another NMI.
 	 */
-	pushq_cfi $-1		/* ORIG_RAX: no syscall to restart */
+	pushq $-1		/* ORIG_RAX: no syscall to restart */
 	ALLOC_PT_GPREGS_ON_STACK
 
 	/*
@@ -1591,7 +1403,6 @@ end_repeat_nmi:
 	 * exceptions might do.
 	 */
 	call paranoid_entry
-	DEFAULT_FRAME 0
 
 	/*
 	 * Save off the CR2 register. If we take a page fault in the NMI then
@@ -1628,13 +1439,10 @@ nmi_restore:
 	/* Clear the NMI executing stack variable */
 	movq $0, 5*8(%rsp)
 	jmp irq_return
-	CFI_ENDPROC
 END(nmi)
 
 ENTRY(ignore_sysret)
-	CFI_STARTPROC
 	mov $-ENOSYS,%eax
 	sysret
-	CFI_ENDPROC
 END(ignore_sysret)