Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d582203578a1f3d408e27bb9042e8635954cd320
Commit:     d582203578a1f3d408e27bb9042e8635954cd320
Parent:     98de032b681d8a7532d44dfc66aa5c0c1c755a9d
Author:     Jeremy Fitzhardinge <[EMAIL PROTECTED]>
AuthorDate: Wed May 2 19:27:14 2007 +0200
Committer:  Andi Kleen <[EMAIL PROTECTED]>
CommitDate: Wed May 2 19:27:14 2007 +0200

    [PATCH] i386: PARAVIRT: Use patch site IDs computed from offset in 
paravirt_ops structure
    
    Use patch type identifiers derived from the offset of the operation in
    the paravirt_ops structure.  This avoids having to maintain a separate
    enum for patch site types.
    
    Also, since the identifier is derived from the offset into
    paravirt_ops, the offset can be derived from the identifier.  This is
    used to remove replicated information in the various callsite macros,
    which has been a source of bugs in the past.
    
    This patch also drops the fused save_fl+cli operation, which doesn't
    really add much and makes things more complex - specifically because
    it breaks the 1:1 relationship between identifiers and offsets.  If
    this operation turns out to be particularly beneficial, then the right
    answer is to define a new entrypoint for it.
    
    Signed-off-by: Jeremy Fitzhardinge <[EMAIL PROTECTED]>
    Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
    Cc: Rusty Russell <[EMAIL PROTECTED]>
    Cc: Zachary Amsden <[EMAIL PROTECTED]>
---
 arch/i386/kernel/paravirt.c |   14 ++--
 arch/i386/kernel/vmi.c      |   39 ++--------
 include/asm-i386/paravirt.h |  177 ++++++++++++++++++++++---------------------
 3 files changed, 104 insertions(+), 126 deletions(-)

diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
index 54cc14d..f298283 100644
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -58,7 +58,6 @@ DEF_NATIVE(cli, "cli");
 DEF_NATIVE(sti, "sti");
 DEF_NATIVE(popf, "push %eax; popf");
 DEF_NATIVE(pushf, "pushf; pop %eax");
-DEF_NATIVE(pushf_cli, "pushf; pop %eax; cli");
 DEF_NATIVE(iret, "iret");
 DEF_NATIVE(sti_sysexit, "sti; sysexit");
 
@@ -66,13 +65,12 @@ static const struct native_insns
 {
        const char *start, *end;
 } native_insns[] = {
-       [PARAVIRT_IRQ_DISABLE] = { start_cli, end_cli },
-       [PARAVIRT_IRQ_ENABLE] = { start_sti, end_sti },
-       [PARAVIRT_RESTORE_FLAGS] = { start_popf, end_popf },
-       [PARAVIRT_SAVE_FLAGS] = { start_pushf, end_pushf },
-       [PARAVIRT_SAVE_FLAGS_IRQ_DISABLE] = { start_pushf_cli, end_pushf_cli },
-       [PARAVIRT_INTERRUPT_RETURN] = { start_iret, end_iret },
-       [PARAVIRT_STI_SYSEXIT] = { start_sti_sysexit, end_sti_sysexit },
+       [PARAVIRT_PATCH(irq_disable)] = { start_cli, end_cli },
+       [PARAVIRT_PATCH(irq_enable)] = { start_sti, end_sti },
+       [PARAVIRT_PATCH(restore_fl)] = { start_popf, end_popf },
+       [PARAVIRT_PATCH(save_fl)] = { start_pushf, end_pushf },
+       [PARAVIRT_PATCH(iret)] = { start_iret, end_iret },
+       [PARAVIRT_PATCH(irq_enable_sysexit)] = { start_sti_sysexit, 
end_sti_sysexit },
 };
 
 static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len)
diff --git a/arch/i386/kernel/vmi.c b/arch/i386/kernel/vmi.c
index ea77d93..b8d01c3 100644
--- a/arch/i386/kernel/vmi.c
+++ b/arch/i386/kernel/vmi.c
@@ -83,11 +83,6 @@ extern struct paravirt_patch __start_parainstructions[],
 #define MNEM_JMP  0xe9
 #define MNEM_RET  0xc3
 
-static char irq_save_disable_callout[] = {
-       MNEM_CALL, 0, 0, 0, 0,
-       MNEM_CALL, 0, 0, 0, 0,
-       MNEM_RET
-};
 #define IRQ_PATCH_INT_MASK 0
 #define IRQ_PATCH_DISABLE  5
 
@@ -135,33 +130,17 @@ static unsigned patch_internal(int call, unsigned len, 
void *insns)
 static unsigned vmi_patch(u8 type, u16 clobbers, void *insns, unsigned len)
 {
        switch (type) {
-               case PARAVIRT_IRQ_DISABLE:
+               case PARAVIRT_PATCH(irq_disable):
                        return patch_internal(VMI_CALL_DisableInterrupts, len, 
insns);
-               case PARAVIRT_IRQ_ENABLE:
+               case PARAVIRT_PATCH(irq_enable):
                        return patch_internal(VMI_CALL_EnableInterrupts, len, 
insns);
-               case PARAVIRT_RESTORE_FLAGS:
+               case PARAVIRT_PATCH(restore_fl):
                        return patch_internal(VMI_CALL_SetInterruptMask, len, 
insns);
-               case PARAVIRT_SAVE_FLAGS:
+               case PARAVIRT_PATCH(save_fl):
                        return patch_internal(VMI_CALL_GetInterruptMask, len, 
insns);
-               case PARAVIRT_SAVE_FLAGS_IRQ_DISABLE:
-                       if (len >= 10) {
-                               patch_internal(VMI_CALL_GetInterruptMask, len, 
insns);
-                               patch_internal(VMI_CALL_DisableInterrupts, 
len-5, insns+5);
-                               return 10;
-                       } else {
-                               /*
-                                * You bastards didn't leave enough room to
-                                * patch save_flags_irq_disable inline.  Patch
-                                * to a helper
-                                */
-                               BUG_ON(len < 5);
-                               *(char *)insns = MNEM_CALL;
-                               patch_offset(insns, irq_save_disable_callout);
-                               return 5;
-                       }
-               case PARAVIRT_INTERRUPT_RETURN:
+               case PARAVIRT_PATCH(iret):
                        return patch_internal(VMI_CALL_IRET, len, insns);
-               case PARAVIRT_STI_SYSEXIT:
+               case PARAVIRT_PATCH(irq_enable_sysexit):
                        return patch_internal(VMI_CALL_SYSEXIT, len, insns);
                default:
                        break;
@@ -796,12 +775,6 @@ static inline int __init activate_vmi(void)
        para_fill(irq_disable, DisableInterrupts);
        para_fill(irq_enable, EnableInterrupts);
 
-       /* irq_save_disable !!! sheer pain */
-       patch_offset(&irq_save_disable_callout[IRQ_PATCH_INT_MASK],
-                    (char *)paravirt_ops.save_fl);
-       patch_offset(&irq_save_disable_callout[IRQ_PATCH_DISABLE],
-                    (char *)paravirt_ops.irq_disable);
-
        para_fill(wbinvd, WBINVD);
        para_fill(read_tsc, RDTSC);
 
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index b4cc2fc..1dbc01f 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -4,19 +4,8 @@
  * para-virtualization: those hooks are defined here. */
 
 #ifdef CONFIG_PARAVIRT
-#include <linux/stringify.h>
 #include <asm/page.h>
 
-/* 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
@@ -191,6 +180,28 @@ struct paravirt_ops
 
 extern struct paravirt_ops paravirt_ops;
 
+#define PARAVIRT_PATCH(x)                                      \
+       (offsetof(struct paravirt_ops, x) / sizeof(void *))
+
+#define paravirt_type(type)                                    \
+       [paravirt_typenum] "i" (PARAVIRT_PATCH(type))
+#define paravirt_clobber(clobber)              \
+       [paravirt_clobber] "i" (clobber)
+
+#define PARAVIRT_CALL  "call *paravirt_ops+%c[paravirt_typenum]*4;"
+
+#define _paravirt_alt(insn_string, type, clobber)      \
+       "771:\n\t" insn_string "\n" "772:\n"            \
+       ".pushsection .parainstructions,\"a\"\n"        \
+       "  .long 771b\n"                                \
+       "  .byte " type "\n"                            \
+       "  .byte 772b-771b\n"                           \
+       "  .short " clobber "\n"                        \
+       ".popsection\n"
+
+#define paravirt_alt(insn_string)                              \
+       _paravirt_alt(insn_string, "%c[paravirt_typenum]", 
"%c[paravirt_clobber]")
+
 #define paravirt_enabled() (paravirt_ops.paravirt_enabled)
 
 static inline void load_esp0(struct tss_struct *tss,
@@ -515,93 +526,89 @@ struct paravirt_patch_site {
 extern struct paravirt_patch_site __parainstructions[],
        __parainstructions_end[];
 
-#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");
+       asm volatile(paravirt_alt("pushl %%ecx; pushl %%edx;"
+                                 PARAVIRT_CALL
+                                 "popl %%edx; popl %%ecx")
+                    : "=a"(f)
+                    : paravirt_type(save_fl),
+                      paravirt_clobber(CLBR_NONE)
+                    : "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");
+       asm volatile(paravirt_alt("pushl %%ecx; pushl %%edx;"
+                                 PARAVIRT_CALL
+                                 "popl %%edx; popl %%ecx")
+                    : "=a"(f)
+                    : "0"(f),
+                      paravirt_type(restore_fl),
+                      paravirt_clobber(CLBR_EAX)
+                    : "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");
+       asm volatile(paravirt_alt("pushl %%ecx; pushl %%edx;"
+                                 PARAVIRT_CALL
+                                 "popl %%edx; popl %%ecx")
+                    :
+                    : paravirt_type(irq_disable),
+                      paravirt_clobber(CLBR_EAX)
+                    : "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");
+       asm volatile(paravirt_alt("pushl %%ecx; pushl %%edx;"
+                                 PARAVIRT_CALL
+                                 "popl %%edx; popl %%ecx")
+                    :
+                    : paravirt_type(irq_enable),
+                      paravirt_clobber(CLBR_EAX)
+                    : "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");
+       f = __raw_local_save_flags();
+       raw_local_irq_disable();
        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 CLI_STRING                                                     \
+       _paravirt_alt("pushl %%ecx; pushl %%edx;"                       \
+                     "call *paravirt_ops+%c[paravirt_cli_type]*4;"     \
+                     "popl %%edx; popl %%ecx",                         \
+                     "%c[paravirt_cli_type]", "%c[paravirt_clobber]")
+
+#define STI_STRING                                                     \
+       _paravirt_alt("pushl %%ecx; pushl %%edx;"                       \
+                     "call *paravirt_ops+%c[paravirt_sti_type]*4;"     \
+                     "popl %%edx; popl %%ecx",                         \
+                     "%c[paravirt_sti_type]", "%c[paravirt_clobber]")
 
-#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 \
+#define CLI_STI_INPUT_ARGS                                             \
        ,                                                               \
-       [irq_disable] "i" (offsetof(struct paravirt_ops, irq_disable)), \
-       [irq_enable] "i" (offsetof(struct paravirt_ops, irq_enable))
+       [paravirt_cli_type] "i" (PARAVIRT_PATCH(irq_disable)),          \
+       [paravirt_sti_type] "i" (PARAVIRT_PATCH(irq_enable)),           \
+       paravirt_clobber(CLBR_EAX)
+
+#undef PARAVIRT_CALL
 
 #else  /* __ASSEMBLY__ */
 
-#define PARA_PATCH(ptype, clobbers, ops)       \
+#define PARA_PATCH(off)        ((off) / 4)
+
+#define PARA_SITE(ptype, clobbers, ops)                \
 771:;                                          \
        ops;                                    \
 772:;                                          \
@@ -612,25 +619,25 @@ static inline unsigned long __raw_local_irq_save(void)
         .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 INTERRUPT_RETURN                                       \
+       PARA_SITE(PARA_PATCH(PARAVIRT_iret), CLBR_ANY,          \
+                 jmp *%cs:paravirt_ops+PARAVIRT_iret)
+
+#define DISABLE_INTERRUPTS(clobbers)                                   \
+       PARA_SITE(PARA_PATCH(PARAVIRT_irq_disable), clobbers,           \
+                 pushl %ecx; pushl %edx;                               \
+                 call *%cs:paravirt_ops+PARAVIRT_irq_disable;          \
+                 popl %edx; popl %ecx)                                 \
+
+#define ENABLE_INTERRUPTS(clobbers)                                    \
+       PARA_SITE(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_SITE(PARA_PATCH(PARAVIRT_irq_enable_sysexit), CLBR_ANY,    \
+                 jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit)
 
 #define GET_CR0_INTO_EAX                       \
        call *paravirt_ops+PARAVIRT_read_cr0
-
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