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Subject[PATCH] x86-64: fix unwind info for incomplete frames
Commit 76f5df43ca ('x86/asm/entry/64: Always allocate a complete
"struct pt_regs" on the kernel stack') deleted PARTIAL_FRAME without
considering that while a full frame is now being allocated, not all
registers get always saved into it. Instead of restoring that macro,
simply make DEFAULT_FRAME capable of expressing both.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
---
arch/x86/kernel/entry_64.S | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

--- 4.1-rc5/arch/x86/kernel/entry_64.S
+++ 4.1-rc5-x86_64-unwind-info/arch/x86/kernel/entry_64.S
@@ -148,7 +148,7 @@ ENDPROC(native_usergs_sysret64)
/*
* frame that enables passing a complete pt_regs to a C function.
*/
- .macro DEFAULT_FRAME start=1 offset=0
+ .macro DEFAULT_FRAME start=1 offset=0 extra=1
XCPT_FRAME \start, ORIG_RAX+\offset
CFI_REL_OFFSET rdi, RDI+\offset
CFI_REL_OFFSET rsi, RSI+\offset
@@ -159,12 +159,14 @@ ENDPROC(native_usergs_sysret64)
CFI_REL_OFFSET r9, R9+\offset
CFI_REL_OFFSET r10, R10+\offset
CFI_REL_OFFSET r11, R11+\offset
+ .if \extra
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
+ .endif
.endm

/*
@@ -491,7 +493,7 @@ END(system_call)
.macro FORK_LIKE func
ENTRY(stub_\func)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8 /* offset 8: return address */
+ DEFAULT_FRAME 0, 8, 0 /* offset 8: return address */
SAVE_EXTRA_REGS 8
jmp sys_\func
CFI_ENDPROC
@@ -504,7 +506,7 @@ END(stub_\func)

ENTRY(stub_execve)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8
+ DEFAULT_FRAME 0, 8, 0
call sys_execve
return_from_execve:
testl %eax, %eax
@@ -527,7 +529,7 @@ END(stub_execve)
.align 8
GLOBAL(stub_execveat)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8
+ DEFAULT_FRAME 0, 8, 0
call sys_execveat
jmp return_from_execve
CFI_ENDPROC
@@ -537,7 +539,7 @@ END(stub_execveat)
.align 8
GLOBAL(stub_x32_execve)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8
+ DEFAULT_FRAME 0, 8, 0
call compat_sys_execve
jmp return_from_execve
CFI_ENDPROC
@@ -545,7 +547,7 @@ END(stub_x32_execve)
.align 8
GLOBAL(stub_x32_execveat)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8
+ DEFAULT_FRAME 0, 8, 0
call compat_sys_execveat
jmp return_from_execve
CFI_ENDPROC
@@ -575,7 +577,7 @@ END(stub32_execveat)
*/
ENTRY(stub_rt_sigreturn)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8
+ DEFAULT_FRAME 0, 8, 0
/*
* SAVE_EXTRA_REGS result is not normally needed:
* sigreturn overwrites all pt_regs->GPREGS.
@@ -597,7 +599,7 @@ END(stub_rt_sigreturn)
#ifdef CONFIG_X86_X32_ABI
ENTRY(stub_x32_rt_sigreturn)
CFI_STARTPROC
- DEFAULT_FRAME 0, 8
+ DEFAULT_FRAME 0, 8, 0
SAVE_EXTRA_REGS 8
call sys32_x32_rt_sigreturn
jmp return_from_stub




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