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x86/paravirt: selectively save/restore regs around pvops calls
Impact: Optimization Each asm paravirt-ops call says what registers are available for clobbering. This patch makes use of this to selectively save/restore registers around each pvops call. In many cases this significantly shrinks code size. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Jeremy Fitzhardinge
H. Peter Anvin
parent
b8aa287f77
commit
9104a18dcd
@ -12,19 +12,29 @@
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#define CLBR_EAX (1 << 0)
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#define CLBR_ECX (1 << 1)
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#define CLBR_EDX (1 << 2)
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#define CLBR_EDI (1 << 3)
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#ifdef CONFIG_X86_64
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#define CLBR_RSI (1 << 3)
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#define CLBR_RDI (1 << 4)
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#ifdef CONFIG_X86_32
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/* CLBR_ANY should match all regs platform has. For i386, that's just it */
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#define CLBR_ANY ((1 << 4) - 1)
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#else
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#define CLBR_RAX CLBR_EAX
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#define CLBR_RCX CLBR_ECX
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#define CLBR_RDX CLBR_EDX
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#define CLBR_RDI CLBR_EDI
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#define CLBR_RSI (1 << 4)
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#define CLBR_R8 (1 << 5)
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#define CLBR_R9 (1 << 6)
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#define CLBR_R10 (1 << 7)
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#define CLBR_R11 (1 << 8)
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#define CLBR_ANY ((1 << 9) - 1)
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#define CLBR_ARG_REGS (CLBR_RDI | CLBR_RSI | CLBR_RDX | \
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CLBR_RCX | CLBR_R8 | CLBR_R9)
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#define CLBR_RET_REG (CLBR_RAX | CLBR_RDX)
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#define CLBR_SCRATCH (CLBR_R10 | CLBR_R11)
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#include <asm/desc_defs.h>
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#else
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/* CLBR_ANY should match all regs platform has. For i386, that's just it */
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#define CLBR_ANY ((1 << 3) - 1)
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#endif /* X86_64 */
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#ifndef __ASSEMBLY__
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@ -1530,33 +1540,49 @@ static inline unsigned long __raw_local_irq_save(void)
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.popsection
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#define COND_PUSH(set, mask, reg) \
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.if ((~set) & mask); push %reg; .endif
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#define COND_POP(set, mask, reg) \
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.if ((~set) & mask); pop %reg; .endif
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#ifdef CONFIG_X86_64
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#define PV_SAVE_REGS \
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push %rax; \
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push %rcx; \
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push %rdx; \
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push %rsi; \
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push %rdi; \
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push %r8; \
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push %r9; \
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push %r10; \
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push %r11
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#define PV_RESTORE_REGS \
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pop %r11; \
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pop %r10; \
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pop %r9; \
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pop %r8; \
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pop %rdi; \
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pop %rsi; \
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pop %rdx; \
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pop %rcx; \
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pop %rax
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#define PV_SAVE_REGS(set) \
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COND_PUSH(set, CLBR_RAX, rax); \
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COND_PUSH(set, CLBR_RCX, rcx); \
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COND_PUSH(set, CLBR_RDX, rdx); \
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COND_PUSH(set, CLBR_RSI, rsi); \
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COND_PUSH(set, CLBR_RDI, rdi); \
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COND_PUSH(set, CLBR_R8, r8); \
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COND_PUSH(set, CLBR_R9, r9); \
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COND_PUSH(set, CLBR_R10, r10); \
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COND_PUSH(set, CLBR_R11, r11)
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#define PV_RESTORE_REGS(set) \
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COND_POP(set, CLBR_R11, r11); \
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COND_POP(set, CLBR_R10, r10); \
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COND_POP(set, CLBR_R9, r9); \
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COND_POP(set, CLBR_R8, r8); \
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COND_POP(set, CLBR_RDI, rdi); \
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COND_POP(set, CLBR_RSI, rsi); \
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COND_POP(set, CLBR_RDX, rdx); \
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COND_POP(set, CLBR_RCX, rcx); \
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COND_POP(set, CLBR_RAX, rax)
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#define PARA_PATCH(struct, off) ((PARAVIRT_PATCH_##struct + (off)) / 8)
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#define PARA_SITE(ptype, clobbers, ops) _PVSITE(ptype, clobbers, ops, .quad, 8)
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#define PARA_INDIRECT(addr) *addr(%rip)
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#else
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#define PV_SAVE_REGS pushl %eax; pushl %edi; pushl %ecx; pushl %edx
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#define PV_RESTORE_REGS popl %edx; popl %ecx; popl %edi; popl %eax
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#define PV_SAVE_REGS(set) \
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COND_PUSH(set, CLBR_EAX, eax); \
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COND_PUSH(set, CLBR_EDI, edi); \
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COND_PUSH(set, CLBR_ECX, ecx); \
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COND_PUSH(set, CLBR_EDX, edx)
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#define PV_RESTORE_REGS(set) \
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COND_POP(set, CLBR_EDX, edx); \
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COND_POP(set, CLBR_ECX, ecx); \
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COND_POP(set, CLBR_EDI, edi); \
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COND_POP(set, CLBR_EAX, eax)
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#define PARA_PATCH(struct, off) ((PARAVIRT_PATCH_##struct + (off)) / 4)
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#define PARA_SITE(ptype, clobbers, ops) _PVSITE(ptype, clobbers, ops, .long, 4)
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#define PARA_INDIRECT(addr) *%cs:addr
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@ -1568,15 +1594,15 @@ static inline unsigned long __raw_local_irq_save(void)
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#define DISABLE_INTERRUPTS(clobbers) \
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PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_irq_disable), clobbers, \
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PV_SAVE_REGS; \
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PV_SAVE_REGS(clobbers); \
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call PARA_INDIRECT(pv_irq_ops+PV_IRQ_irq_disable); \
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PV_RESTORE_REGS;) \
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PV_RESTORE_REGS(clobbers);)
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#define ENABLE_INTERRUPTS(clobbers) \
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PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_irq_enable), clobbers, \
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PV_SAVE_REGS; \
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PV_SAVE_REGS(clobbers); \
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call PARA_INDIRECT(pv_irq_ops+PV_IRQ_irq_enable); \
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PV_RESTORE_REGS;)
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PV_RESTORE_REGS(clobbers);)
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#define USERGS_SYSRET32 \
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PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret32), \
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@ -1606,11 +1632,15 @@ static inline unsigned long __raw_local_irq_save(void)
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PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_swapgs), CLBR_NONE, \
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swapgs)
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/*
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* Note: swapgs is very special, and in practise is either going to be
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* implemented with a single "swapgs" instruction or something very
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* special. Either way, we don't need to save any registers for
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* it.
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*/
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#define SWAPGS \
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PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_swapgs), CLBR_NONE, \
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PV_SAVE_REGS; \
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call PARA_INDIRECT(pv_cpu_ops+PV_CPU_swapgs); \
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PV_RESTORE_REGS \
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call PARA_INDIRECT(pv_cpu_ops+PV_CPU_swapgs) \
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)
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#define GET_CR2_INTO_RCX \
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