|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/3] x86: use MOV instead of PUSH/POP when saving/restoring register state
On Tue, Oct 02, 2012 at 04:26:23PM +0100, Jan Beulich wrote: > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> What's the reasoning behind it? Just that mov's are faster than pop/push? > > --- a/xen/arch/x86/x86_64/compat/entry.S > +++ b/xen/arch/x86/x86_64/compat/entry.S > @@ -21,8 +21,7 @@ ENTRY(compat_hypercall) > UNLIKELY_START(ne, msi_check) > movl $HYPERCALL_VECTOR,%edi > call check_for_unexpected_msi > - RESTORE_ALL > - SAVE_ALL > + LOAD_C_CLOBBERED > UNLIKELY_END(msi_check) > > GET_CURRENT(%rbx) > @@ -173,8 +172,7 @@ compat_bad_hypercall: > /* %rbx: struct vcpu, interrupts disabled */ > compat_restore_all_guest: > ASSERT_INTERRUPTS_DISABLED > - RESTORE_ALL > - addq $8,%rsp > + RESTORE_ALL adj=8 > .Lft0: iretq > > .section .fixup,"ax" > --- a/xen/arch/x86/x86_64/entry.S > +++ b/xen/arch/x86/x86_64/entry.S > @@ -47,12 +47,10 @@ restore_all_guest: > cmpl $1,%ecx > ja .Lforce_iret > > - addq $8,%rsp > - popq %rcx # RIP > - popq %r11 # CS > - cmpw $FLAT_USER_CS32,%r11 > - popq %r11 # RFLAGS > - popq %rsp # RSP > + cmpw $FLAT_USER_CS32,16(%rsp)# CS > + movq 8(%rsp),%rcx # RIP > + movq 24(%rsp),%r11 # RFLAGS > + movq 32(%rsp),%rsp # RSP > je 1f > sysretq > 1: sysretl > @@ -101,8 +99,7 @@ failsafe_callback: > ALIGN > /* No special register assumptions. */ > restore_all_xen: > - RESTORE_ALL > - addq $8,%rsp > + RESTORE_ALL adj=8 > iretq > > /* > @@ -311,8 +308,7 @@ ENTRY(int80_direct_trap) > UNLIKELY_START(ne, msi_check) > movl $0x80,%edi > call check_for_unexpected_msi > - RESTORE_ALL > - SAVE_ALL > + LOAD_C_CLOBBERED > UNLIKELY_END(msi_check) > > GET_CURRENT(%rbx) > --- a/xen/include/asm-x86/x86_64/asm_defns.h > +++ b/xen/include/asm-x86/x86_64/asm_defns.h > @@ -5,11 +5,11 @@ > > #ifdef CONFIG_FRAME_POINTER > /* Indicate special exception stack frame by inverting the frame pointer. */ > -#define SETUP_EXCEPTION_FRAME_POINTER \ > - movq %rsp,%rbp; \ > +#define SETUP_EXCEPTION_FRAME_POINTER(offs) \ > + leaq offs(%rsp),%rbp; \ > notq %rbp > #else > -#define SETUP_EXCEPTION_FRAME_POINTER > +#define SETUP_EXCEPTION_FRAME_POINTER(off) > #endif > > #ifndef NDEBUG > @@ -27,40 +27,49 @@ > #define ASSERT_INTERRUPTS_DISABLED ASSERT_INTERRUPT_STATUS(z) > > #define SAVE_ALL \ > + addq $-(UREGS_error_code-UREGS_r15), %rsp; \ > cld; \ > - pushq %rdi; \ > - pushq %rsi; \ > - pushq %rdx; \ > - pushq %rcx; \ > - pushq %rax; \ > - pushq %r8; \ > - pushq %r9; \ > - pushq %r10; \ > - pushq %r11; \ > - pushq %rbx; \ > - pushq %rbp; \ > - SETUP_EXCEPTION_FRAME_POINTER; \ > - pushq %r12; \ > - pushq %r13; \ > - pushq %r14; \ > - pushq %r15; > - > -#define RESTORE_ALL \ > - popq %r15; \ > - popq %r14; \ > - popq %r13; \ > - popq %r12; \ > - popq %rbp; \ > - popq %rbx; \ > - popq %r11; \ > - popq %r10; \ > - popq %r9; \ > - popq %r8; \ > - popq %rax; \ > - popq %rcx; \ > - popq %rdx; \ > - popq %rsi; \ > - popq %rdi; > + movq %rdi,UREGS_rdi(%rsp); \ > + movq %rsi,UREGS_rsi(%rsp); \ > + movq %rdx,UREGS_rdx(%rsp); \ > + movq %rcx,UREGS_rcx(%rsp); \ > + movq %rax,UREGS_rax(%rsp); \ > + movq %r8,UREGS_r8(%rsp); \ > + movq %r9,UREGS_r9(%rsp); \ > + movq %r10,UREGS_r10(%rsp); \ > + movq %r11,UREGS_r11(%rsp); \ > + movq %rbx,UREGS_rbx(%rsp); \ > + movq %rbp,UREGS_rbp(%rsp); \ > + SETUP_EXCEPTION_FRAME_POINTER(UREGS_rbp); \ > + movq %r12,UREGS_r12(%rsp); \ > + movq %r13,UREGS_r13(%rsp); \ > + movq %r14,UREGS_r14(%rsp); \ > + movq %r15,UREGS_r15(%rsp); \ > + > +#ifdef __ASSEMBLY__ > +.macro LOAD_C_CLOBBERED > + movq UREGS_r11(%rsp),%r11 > + movq UREGS_r10(%rsp),%r10 > + movq UREGS_r9(%rsp),%r9 > + movq UREGS_r8(%rsp),%r8 > + movq UREGS_rax(%rsp),%rax > + movq UREGS_rcx(%rsp),%rcx > + movq UREGS_rdx(%rsp),%rdx > + movq UREGS_rsi(%rsp),%rsi > + movq UREGS_rdi(%rsp),%rdi > +.endm > + > +.macro RESTORE_ALL adj=0 > + movq UREGS_r15(%rsp),%r15 > + movq UREGS_r14(%rsp),%r14 > + movq UREGS_r13(%rsp),%r13 > + movq UREGS_r12(%rsp),%r12 > + movq UREGS_rbp(%rsp),%rbp > + movq UREGS_rbx(%rsp),%rbx > + LOAD_C_CLOBBERED > + subq $-(UREGS_error_code-UREGS_r15+\adj), %rsp > +.endm > +#endif > > #ifdef PERF_COUNTERS > #define PERFC_INCR(_name,_idx,_cur) \ > @@ -94,7 +103,7 @@ > __asm__( \ > "\n" __ALIGN_STR"\n" \ > "common_interrupt:\n\t" \ > - STR(SAVE_ALL) \ > + STR(SAVE_ALL) "\n\t" \ > "movq %rsp,%rdi\n\t" \ > "callq " STR(do_IRQ) "\n\t" \ > "jmp ret_from_intr\n"); > > > x86: use MOV instead of PUSH/POP when saving/restoring register state > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > > --- a/xen/arch/x86/x86_64/compat/entry.S > +++ b/xen/arch/x86/x86_64/compat/entry.S > @@ -21,8 +21,7 @@ ENTRY(compat_hypercall) > UNLIKELY_START(ne, msi_check) > movl $HYPERCALL_VECTOR,%edi > call check_for_unexpected_msi > - RESTORE_ALL > - SAVE_ALL > + LOAD_C_CLOBBERED > UNLIKELY_END(msi_check) > > GET_CURRENT(%rbx) > @@ -173,8 +172,7 @@ compat_bad_hypercall: > /* %rbx: struct vcpu, interrupts disabled */ > compat_restore_all_guest: > ASSERT_INTERRUPTS_DISABLED > - RESTORE_ALL > - addq $8,%rsp > + RESTORE_ALL adj=8 > .Lft0: iretq > > .section .fixup,"ax" > --- a/xen/arch/x86/x86_64/entry.S > +++ b/xen/arch/x86/x86_64/entry.S > @@ -47,12 +47,10 @@ restore_all_guest: > cmpl $1,%ecx > ja .Lforce_iret > > - addq $8,%rsp > - popq %rcx # RIP > - popq %r11 # CS > - cmpw $FLAT_USER_CS32,%r11 > - popq %r11 # RFLAGS > - popq %rsp # RSP > + cmpw $FLAT_USER_CS32,16(%rsp)# CS > + movq 8(%rsp),%rcx # RIP > + movq 24(%rsp),%r11 # RFLAGS > + movq 32(%rsp),%rsp # RSP > je 1f > sysretq > 1: sysretl > @@ -101,8 +99,7 @@ failsafe_callback: > ALIGN > /* No special register assumptions. */ > restore_all_xen: > - RESTORE_ALL > - addq $8,%rsp > + RESTORE_ALL adj=8 > iretq > > /* > @@ -311,8 +308,7 @@ ENTRY(int80_direct_trap) > UNLIKELY_START(ne, msi_check) > movl $0x80,%edi > call check_for_unexpected_msi > - RESTORE_ALL > - SAVE_ALL > + LOAD_C_CLOBBERED > UNLIKELY_END(msi_check) > > GET_CURRENT(%rbx) > --- a/xen/include/asm-x86/x86_64/asm_defns.h > +++ b/xen/include/asm-x86/x86_64/asm_defns.h > @@ -5,11 +5,11 @@ > > #ifdef CONFIG_FRAME_POINTER > /* Indicate special exception stack frame by inverting the frame pointer. */ > -#define SETUP_EXCEPTION_FRAME_POINTER \ > - movq %rsp,%rbp; \ > +#define SETUP_EXCEPTION_FRAME_POINTER(offs) \ > + leaq offs(%rsp),%rbp; \ > notq %rbp > #else > -#define SETUP_EXCEPTION_FRAME_POINTER > +#define SETUP_EXCEPTION_FRAME_POINTER(off) > #endif > > #ifndef NDEBUG > @@ -27,40 +27,49 @@ > #define ASSERT_INTERRUPTS_DISABLED ASSERT_INTERRUPT_STATUS(z) > > #define SAVE_ALL \ > + addq $-(UREGS_error_code-UREGS_r15), %rsp; \ > cld; \ > - pushq %rdi; \ > - pushq %rsi; \ > - pushq %rdx; \ > - pushq %rcx; \ > - pushq %rax; \ > - pushq %r8; \ > - pushq %r9; \ > - pushq %r10; \ > - pushq %r11; \ > - pushq %rbx; \ > - pushq %rbp; \ > - SETUP_EXCEPTION_FRAME_POINTER; \ > - pushq %r12; \ > - pushq %r13; \ > - pushq %r14; \ > - pushq %r15; > - > -#define RESTORE_ALL \ > - popq %r15; \ > - popq %r14; \ > - popq %r13; \ > - popq %r12; \ > - popq %rbp; \ > - popq %rbx; \ > - popq %r11; \ > - popq %r10; \ > - popq %r9; \ > - popq %r8; \ > - popq %rax; \ > - popq %rcx; \ > - popq %rdx; \ > - popq %rsi; \ > - popq %rdi; > + movq %rdi,UREGS_rdi(%rsp); \ > + movq %rsi,UREGS_rsi(%rsp); \ > + movq %rdx,UREGS_rdx(%rsp); \ > + movq %rcx,UREGS_rcx(%rsp); \ > + movq %rax,UREGS_rax(%rsp); \ > + movq %r8,UREGS_r8(%rsp); \ > + movq %r9,UREGS_r9(%rsp); \ > + movq %r10,UREGS_r10(%rsp); \ > + movq %r11,UREGS_r11(%rsp); \ > + movq %rbx,UREGS_rbx(%rsp); \ > + movq %rbp,UREGS_rbp(%rsp); \ > + SETUP_EXCEPTION_FRAME_POINTER(UREGS_rbp); \ > + movq %r12,UREGS_r12(%rsp); \ > + movq %r13,UREGS_r13(%rsp); \ > + movq %r14,UREGS_r14(%rsp); \ > + movq %r15,UREGS_r15(%rsp); \ > + > +#ifdef __ASSEMBLY__ > +.macro LOAD_C_CLOBBERED > + movq UREGS_r11(%rsp),%r11 > + movq UREGS_r10(%rsp),%r10 > + movq UREGS_r9(%rsp),%r9 > + movq UREGS_r8(%rsp),%r8 > + movq UREGS_rax(%rsp),%rax > + movq UREGS_rcx(%rsp),%rcx > + movq UREGS_rdx(%rsp),%rdx > + movq UREGS_rsi(%rsp),%rsi > + movq UREGS_rdi(%rsp),%rdi > +.endm > + > +.macro RESTORE_ALL adj=0 > + movq UREGS_r15(%rsp),%r15 > + movq UREGS_r14(%rsp),%r14 > + movq UREGS_r13(%rsp),%r13 > + movq UREGS_r12(%rsp),%r12 > + movq UREGS_rbp(%rsp),%rbp > + movq UREGS_rbx(%rsp),%rbx > + LOAD_C_CLOBBERED > + subq $-(UREGS_error_code-UREGS_r15+\adj), %rsp > +.endm > +#endif > > #ifdef PERF_COUNTERS > #define PERFC_INCR(_name,_idx,_cur) \ > @@ -94,7 +103,7 @@ > __asm__( \ > "\n" __ALIGN_STR"\n" \ > "common_interrupt:\n\t" \ > - STR(SAVE_ALL) \ > + STR(SAVE_ALL) "\n\t" \ > "movq %rsp,%rdi\n\t" \ > "callq " STR(do_IRQ) "\n\t" \ > "jmp ret_from_intr\n"); > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxx > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |