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-rw-r--r--include/asm-i386/paravirt.h189
1 files changed, 153 insertions, 36 deletions
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index a7551a4..0811947 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 */