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[PATCH] x86-64: miscellaneous entry.S adjustments 

This patch:
- makes ret_from_sys_call no longer global (all external users were
  previously switched to use int_ret_from_sys_call)
- adjusts placement of a CFI_{REMEMBER,RESTORE}_STATE pair to better
  fit logic flow
- eliminates an unnecessary pair of CFI_{REMEMBER,RESTORE}_STATE
- glues together function- and unwinder-wise the previously separate
  system_call and int_ret_from_sys_call function fragments

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Jan Beulich 2006-12-07 02:14:02 +01:00 committed by Andi Kleen
parent da68933e0a
commit bcddc0155f
1 changed files with 6 additions and 30 deletions
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36
arch/x86_64/kernel/entry.S
View File

@ -230,7 +230,6 @@ ENTRY(system_call)
CFI_REL_OFFSET rip,RIP-ARGOFFSET
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%rcx)
CFI_REMEMBER_STATE
jnz tracesys
cmpq $__NR_syscall_max,%rax
ja badsys
@ -241,7 +240,6 @@ ENTRY(system_call)
* Syscall return path ending with SYSRET (fast path)
* Has incomplete stack frame and undefined top of stack.
*/
.globl ret_from_sys_call
ret_from_sys_call:
movl $_TIF_ALLWORK_MASK,%edi
/* edi: flagmask */
@ -251,8 +249,8 @@ sysret_check:
TRACE_IRQS_OFF
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
CFI_REMEMBER_STATE
jnz sysret_careful
CFI_REMEMBER_STATE
/*
* sysretq will re-enable interrupts:
*/
@ -265,10 +263,10 @@ sysret_check:
swapgs
sysretq
CFI_RESTORE_STATE
/* Handle reschedules */
/* edx: work, edi: workmask */
sysret_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc sysret_signal
TRACE_IRQS_ON
@ -306,7 +304,6 @@ badsys:
/* Do syscall tracing */
tracesys:
CFI_RESTORE_STATE
SAVE_REST
movq $-ENOSYS,RAX(%rsp)
FIXUP_TOP_OF_STACK %rdi
@ -322,32 +319,13 @@ tracesys:
call *sys_call_table(,%rax,8)
1: movq %rax,RAX-ARGOFFSET(%rsp)
/* Use IRET because user could have changed frame */
jmp int_ret_from_sys_call
CFI_ENDPROC
END(system_call)
/*
* Syscall return path ending with IRET.
* Has correct top of stack, but partial stack frame.
*/
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
/*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/
/*CFI_REL_OFFSET cs,CS-ARGOFFSET*/
CFI_REL_OFFSET rip,RIP-ARGOFFSET
CFI_REL_OFFSET rdx,RDX-ARGOFFSET
CFI_REL_OFFSET rcx,RCX-ARGOFFSET
CFI_REL_OFFSET rax,RAX-ARGOFFSET
CFI_REL_OFFSET rdi,RDI-ARGOFFSET
CFI_REL_OFFSET rsi,RSI-ARGOFFSET
CFI_REL_OFFSET r8,R8-ARGOFFSET
CFI_REL_OFFSET r9,R9-ARGOFFSET
CFI_REL_OFFSET r10,R10-ARGOFFSET
CFI_REL_OFFSET r11,R11-ARGOFFSET
*/
.globl int_ret_from_sys_call
int_ret_from_sys_call:
cli
TRACE_IRQS_OFF
testl $3,CS-ARGOFFSET(%rsp)
@ -394,8 +372,6 @@ int_very_careful:
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi
cli
TRACE_IRQS_OFF
jmp int_restore_rest
int_signal:
@ -411,7 +387,7 @@ int_restore_rest:
TRACE_IRQS_OFF
jmp int_with_check
CFI_ENDPROC
END(int_ret_from_sys_call)
END(system_call)
/*
* Certain special system calls that need to save a complete full stack frame.