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x86: introduce save_rest and restructure the PTREGSCALL macro in entry_64.S 

Impact: cleanup

The save_rest function completes a partial stack frame for use
by the PTREGSCALL macro. This also avoids the indirect call in
PTREGSCALLs.

This adds the macro movq_cfi_restore to hide the CFI_RESTORE
annotation when restoring a register from the stack frame.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Alexander van Heukelum 2008-11-21 16:41:55 +01:00 committed by Ingo Molnar
parent 14ae22ba2b
commit c002a1e6b6
1 changed files with 53 additions and 38 deletions
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85
arch/x86/kernel/entry_64.S
View File

@ -78,6 +78,11 @@
CFI_REL_OFFSET \reg, \offset
.endm
.macro movq_cfi_restore offset reg
movq \offset(%rsp), %\reg
CFI_RESTORE \reg
.endm
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(mcount)
@ -186,21 +191,21 @@ ENTRY(native_usergs_sysret64)
*/
/* %rsp:at FRAMEEND */
.macro FIXUP_TOP_OF_STACK tmp
.macro FIXUP_TOP_OF_STACK tmp offset=0
movq %gs:pda_oldrsp,\tmp
movq \tmp,RSP(%rsp)
movq $__USER_DS,SS(%rsp)
movq $__USER_CS,CS(%rsp)
movq $-1,RCX(%rsp)
movq R11(%rsp),\tmp /* get eflags */
movq \tmp,EFLAGS(%rsp)
movq \tmp,RSP+\offset(%rsp)
movq $__USER_DS,SS+\offset(%rsp)
movq $__USER_CS,CS+\offset(%rsp)
movq $-1,RCX+\offset(%rsp)
movq R11+\offset(%rsp),\tmp /* get eflags */
movq \tmp,EFLAGS+\offset(%rsp)
.endm
.macro RESTORE_TOP_OF_STACK tmp,offset=0
movq RSP-\offset(%rsp),\tmp
.macro RESTORE_TOP_OF_STACK tmp offset=0
movq RSP+\offset(%rsp),\tmp
movq \tmp,%gs:pda_oldrsp
movq EFLAGS-\offset(%rsp),\tmp
movq \tmp,R11-\offset(%rsp)
movq EFLAGS+\offset(%rsp),\tmp
movq \tmp,R11+\offset(%rsp)
.endm
.macro FAKE_STACK_FRAME child_rip
@ -333,6 +338,21 @@ ENTRY(save_args)
CFI_ENDPROC
END(save_args)
ENTRY(save_rest)
PARTIAL_FRAME 1 REST_SKIP+8
movq 5*8+16(%rsp), %r11 /* save return address */
movq_cfi rbx, RBX+16
movq_cfi rbp, RBP+16
movq_cfi r12, R12+16
movq_cfi r13, R13+16
movq_cfi r14, R14+16
movq_cfi r15, R15+16
movq %r11, 8(%rsp) /* return address */
FIXUP_TOP_OF_STACK %r11, 16
ret
CFI_ENDPROC
END(save_rest)
/*
* A newly forked process directly context switches into this.
*/
@ -353,7 +373,7 @@ rff_action:
je int_ret_from_sys_call
testl $_TIF_IA32,TI_flags(%rcx)
jnz int_ret_from_sys_call
RESTORE_TOP_OF_STACK %rdi,ARGOFFSET
RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
jmp ret_from_sys_call
rff_trace:
movq %rsp,%rdi
@ -626,18 +646,20 @@ END(system_call)
/*
* Certain special system calls that need to save a complete full stack frame.
*/
.macro PTREGSCALL label,func,arg
.globl \label
\label:
leaq \func(%rip),%rax
leaq -ARGOFFSET+8(%rsp),\arg /* 8 for return address */
ENTRY(\label)
PARTIAL_FRAME 1 8 /* offset 8: return address */
subq $REST_SKIP, %rsp
CFI_ADJUST_CFA_OFFSET REST_SKIP
call save_rest
DEFAULT_FRAME 0 8 /* offset 8: return address */
leaq 8(%rsp), \arg /* pt_regs pointer */
call \func
jmp ptregscall_common
CFI_ENDPROC
END(\label)
.endm
CFI_STARTPROC
PTREGSCALL stub_clone, sys_clone, %r8
PTREGSCALL stub_fork, sys_fork, %rdi
PTREGSCALL stub_vfork, sys_vfork, %rdi
@ -645,22 +667,15 @@ END(\label)
PTREGSCALL stub_iopl, sys_iopl, %rsi
ENTRY(ptregscall_common)
popq %r11
CFI_ADJUST_CFA_OFFSET -8
CFI_REGISTER rip, r11
SAVE_REST
movq %r11, %r15
CFI_REGISTER rip, r15
FIXUP_TOP_OF_STACK %r11
call *%rax
RESTORE_TOP_OF_STACK %r11
movq %r15, %r11
CFI_REGISTER rip, r11
RESTORE_REST
pushq %r11
CFI_ADJUST_CFA_OFFSET 8
CFI_REL_OFFSET rip, 0
ret
DEFAULT_FRAME 1 8 /* offset 8: return address */
RESTORE_TOP_OF_STACK %r11, 8
movq_cfi_restore R15+8, r15
movq_cfi_restore R14+8, r14
movq_cfi_restore R13+8, r13
movq_cfi_restore R12+8, r12
movq_cfi_restore RBP+8, rbp
movq_cfi_restore RBX+8, rbx
ret $REST_SKIP /* pop extended registers */
CFI_ENDPROC
END(ptregscall_common)