diff options
Diffstat (limited to 'include/asm-i386/paravirt.h')
| -rw-r--r-- | include/asm-i386/paravirt.h | 189 |
1 files changed, 153 insertions, 36 deletions
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h index a7551a44686..081194751ad 100644 --- a/include/asm-i386/paravirt.h +++ b/include/asm-i386/paravirt.h @@ -3,8 +3,26 @@ /* Various instructions on x86 need to be replaced for * para-virtualization: those hooks are defined here. */ #include <linux/linkage.h> +#include <linux/stringify.h> #ifdef CONFIG_PARAVIRT +/* These are the most performance critical ops, so we want to be able to patch + * callers */ +#define PARAVIRT_IRQ_DISABLE 0 +#define PARAVIRT_IRQ_ENABLE 1 +#define PARAVIRT_RESTORE_FLAGS 2 +#define PARAVIRT_SAVE_FLAGS 3 +#define PARAVIRT_SAVE_FLAGS_IRQ_DISABLE 4 +#define PARAVIRT_INTERRUPT_RETURN 5 +#define PARAVIRT_STI_SYSEXIT 6 + +/* Bitmask of what can be clobbered: usually at least eax. */ +#define CLBR_NONE 0x0 +#define CLBR_EAX 0x1 +#define CLBR_ECX 0x2 +#define CLBR_EDX 0x4 +#define CLBR_ANY 0x7 + #ifndef __ASSEMBLY__ struct thread_struct; struct Xgt_desc_struct; @@ -15,6 +33,15 @@ struct paravirt_ops int paravirt_enabled; const char *name; + /* + * Patch may replace one of the defined code sequences with arbitrary + * code, subject to the same register constraints. This generally + * means the code is not free to clobber any registers other than EAX. + * The patch function should return the number of bytes of code + * generated, as we nop pad the rest in generic code. + */ + unsigned (*patch)(u8 type, u16 clobber, void *firstinsn, unsigned len); + void (*arch_setup)(void); char *(*memory_setup)(void); void (*init_IRQ)(void); @@ -147,35 +174,6 @@ static inline void __cpuid(unsigned int *eax, unsigned int *ebx, #define read_cr4_safe(x) paravirt_ops.read_cr4_safe() #define write_cr4(x) paravirt_ops.write_cr4(x) -static inline unsigned long __raw_local_save_flags(void) -{ - return paravirt_ops.save_fl(); -} - -static inline void raw_local_irq_restore(unsigned long flags) -{ - return paravirt_ops.restore_fl(flags); -} - -static inline void raw_local_irq_disable(void) -{ - paravirt_ops.irq_disable(); -} - -static inline void raw_local_irq_enable(void) -{ - paravirt_ops.irq_enable(); -} - -static inline unsigned long __raw_local_irq_save(void) -{ - unsigned long flags = paravirt_ops.save_fl(); - - paravirt_ops.irq_disable(); - - return flags; -} - static inline void raw_safe_halt(void) { paravirt_ops.safe_halt(); @@ -267,15 +265,134 @@ static inline void slow_down_io(void) { #endif } -#define CLI_STRING "pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_disable; popl %edx; popl %ecx; popl %eax" -#define STI_STRING "pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_enable; popl %edx; popl %ecx; popl %eax" +/* These all sit in the .parainstructions section to tell us what to patch. */ +struct paravirt_patch { + u8 *instr; /* original instructions */ + u8 instrtype; /* type of this instruction */ + u8 len; /* length of original instruction */ + u16 clobbers; /* what registers you may clobber */ +}; + +#define paravirt_alt(insn_string, typenum, clobber) \ + "771:\n\t" insn_string "\n" "772:\n" \ + ".pushsection .parainstructions,\"a\"\n" \ + " .long 771b\n" \ + " .byte " __stringify(typenum) "\n" \ + " .byte 772b-771b\n" \ + " .short " __stringify(clobber) "\n" \ + ".popsection" + +static inline unsigned long __raw_local_save_flags(void) +{ + unsigned long f; + + __asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;" + "call *%1;" + "popl %%edx; popl %%ecx", + PARAVIRT_SAVE_FLAGS, CLBR_NONE) + : "=a"(f): "m"(paravirt_ops.save_fl) + : "memory", "cc"); + return f; +} + +static inline void raw_local_irq_restore(unsigned long f) +{ + __asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;" + "call *%1;" + "popl %%edx; popl %%ecx", + PARAVIRT_RESTORE_FLAGS, CLBR_EAX) + : "=a"(f) : "m" (paravirt_ops.restore_fl), "0"(f) + : "memory", "cc"); +} + +static inline void raw_local_irq_disable(void) +{ + __asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;" + "call *%0;" + "popl %%edx; popl %%ecx", + PARAVIRT_IRQ_DISABLE, CLBR_EAX) + : : "m" (paravirt_ops.irq_disable) + : "memory", "eax", "cc"); +} + +static inline void raw_local_irq_enable(void) +{ + __asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;" + "call *%0;" + "popl %%edx; popl %%ecx", + PARAVIRT_IRQ_ENABLE, CLBR_EAX) + : : "m" (paravirt_ops.irq_enable) + : "memory", "eax", "cc"); +} + +static inline unsigned long __raw_local_irq_save(void) +{ + unsigned long f; + + __asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;" + "call *%1; pushl %%eax;" + "call *%2; popl %%eax;" + "popl %%edx; popl %%ecx", + PARAVIRT_SAVE_FLAGS_IRQ_DISABLE, + CLBR_NONE) + : "=a"(f) + : "m" (paravirt_ops.save_fl), + "m" (paravirt_ops.irq_disable) + : "memory", "cc"); + return f; +} + +#define CLI_STRING paravirt_alt("pushl %%ecx; pushl %%edx;" \ + "call *paravirt_ops+%c[irq_disable];" \ + "popl %%edx; popl %%ecx", \ + PARAVIRT_IRQ_DISABLE, CLBR_EAX) + +#define STI_STRING paravirt_alt("pushl %%ecx; pushl %%edx;" \ + "call *paravirt_ops+%c[irq_enable];" \ + "popl %%edx; popl %%ecx", \ + PARAVIRT_IRQ_ENABLE, CLBR_EAX) +#define CLI_STI_CLOBBERS , "%eax" +#define CLI_STI_INPUT_ARGS \ + , \ + [irq_disable] "i" (offsetof(struct paravirt_ops, irq_disable)), \ + [irq_enable] "i" (offsetof(struct paravirt_ops, irq_enable)) + #else /* __ASSEMBLY__ */ -#define INTERRUPT_RETURN jmp *%cs:paravirt_ops+PARAVIRT_iret -#define DISABLE_INTERRUPTS pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_disable; popl %edx; popl %ecx; popl %eax -#define ENABLE_INTERRUPTS pushl %eax; pushl %ecx; pushl %edx; call *%cs:paravirt_ops+PARAVIRT_irq_enable; popl %edx; popl %ecx; popl %eax -#define ENABLE_INTERRUPTS_SYSEXIT jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit -#define GET_CR0_INTO_EAX call *paravirt_ops+PARAVIRT_read_cr0 +#define PARA_PATCH(ptype, clobbers, ops) \ +771:; \ + ops; \ +772:; \ + .pushsection .parainstructions,"a"; \ + .long 771b; \ + .byte ptype; \ + .byte 772b-771b; \ + .short clobbers; \ + .popsection + +#define INTERRUPT_RETURN \ + PARA_PATCH(PARAVIRT_INTERRUPT_RETURN, CLBR_ANY, \ + jmp *%cs:paravirt_ops+PARAVIRT_iret) + +#define DISABLE_INTERRUPTS(clobbers) \ + PARA_PATCH(PARAVIRT_IRQ_DISABLE, clobbers, \ + pushl %ecx; pushl %edx; \ + call *paravirt_ops+PARAVIRT_irq_disable; \ + popl %edx; popl %ecx) \ + +#define ENABLE_INTERRUPTS(clobbers) \ + PARA_PATCH(PARAVIRT_IRQ_ENABLE, clobbers, \ + pushl %ecx; pushl %edx; \ + call *%cs:paravirt_ops+PARAVIRT_irq_enable; \ + popl %edx; popl %ecx) + +#define ENABLE_INTERRUPTS_SYSEXIT \ + PARA_PATCH(PARAVIRT_STI_SYSEXIT, CLBR_ANY, \ + jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit) + +#define GET_CR0_INTO_EAX \ + call *paravirt_ops+PARAVIRT_read_cr0 + #endif /* __ASSEMBLY__ */ #endif /* CONFIG_PARAVIRT */ #endif /* __ASM_PARAVIRT_H */ |