[patch 11/26] Xen-paravirt_ops: Use patch site IDs computed from offset in paravirt_ops structure

From: Jeremy Fitzhardinge
Date: Tue Feb 27 2007 - 03:48:19 EST

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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.

This patch also drops the fused save_fl+cli operation, which doesn't
really add much and makes things more complex.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Zachary Amsden <zach@xxxxxxxxxx>

---
arch/i386/kernel/asm-offsets.c | 5 +
arch/i386/kernel/paravirt.c | 14 ++---
arch/i386/kernel/vmi.c | 38 ++------------
include/asm-i386/paravirt.h | 106 ++++++++++++++++++++--------------------
4 files changed, 70 insertions(+), 93 deletions(-)

===================================================================
--- a/arch/i386/kernel/asm-offsets.c
+++ b/arch/i386/kernel/asm-offsets.c
@@ -110,5 +110,10 @@ void foo(void)
OFFSET(PARAVIRT_irq_enable_sysexit, paravirt_ops, irq_enable_sysexit);
OFFSET(PARAVIRT_iret, paravirt_ops, iret);
OFFSET(PARAVIRT_read_cr0, paravirt_ops, read_cr0);
+
+ DEFINE(PARAVIRT_IRQ_DISABLE, PARAVIRT_PATCH(irq_disable));
+ DEFINE(PARAVIRT_IRQ_ENABLE, PARAVIRT_PATCH(irq_enable));
+ DEFINE(PARAVIRT_STI_SYSEXIT, PARAVIRT_PATCH(irq_enable_sysexit));
+ DEFINE(PARAVIRT_INTERRUPT_RETURN, PARAVIRT_PATCH(iret));
#endif
}
===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -57,7 +57,6 @@ DEF_NATIVE(sti, "sti");
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");

@@ -65,13 +64,12 @@ 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)
===================================================================
--- a/arch/i386/kernel/vmi.c
+++ b/arch/i386/kernel/vmi.c
@@ -78,11 +78,6 @@ struct {
#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

@@ -130,33 +125,17 @@ static unsigned vmi_patch(u8 type, u16 c
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;
@@ -733,11 +712,6 @@ static inline int __init activate_vmi(vo
para_fill(restore_fl, SetInterruptMask);
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);
#ifndef CONFIG_NO_IDLE_HZ
para_fill(safe_halt, Halt);
#else
===================================================================
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -3,19 +3,9 @@
/* Various instructions on x86 need to be replaced for
* para-virtualization: those hooks are defined here. */
#include <linux/linkage.h>
-#include <linux/stringify.h>
#include <asm/page.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
@@ -26,6 +16,23 @@

#ifndef __ASSEMBLY__
#include <linux/types.h>
+
+#define paravirt_type(type) [paravirt_typenum] "i" (type)
+#define paravirt_clobber(clobber) [paravirt_clobber] "i" (clobber)
+
+#define PARAVIRT_PATCH(x) (offsetof(struct paravirt_ops, x) / sizeof(void *))
+
+#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]")

struct thread_struct;
struct Xgt_desc_struct;
@@ -540,24 +547,16 @@ extern struct paravirt_patch_site __star
extern struct paravirt_patch_site __start_parainstructions[],
__stop_parainstructions[];

-#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)
+ "popl %%edx; popl %%ecx")
+ : "=a"(f): "m"(paravirt_ops.save_fl),
+ paravirt_type(PARAVIRT_PATCH(save_fl)),
+ paravirt_clobber(CLBR_NONE)
: "memory", "cc");
return f;
}
@@ -566,9 +565,10 @@ static inline void raw_local_irq_restore
{
__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)
+ "popl %%edx; popl %%ecx")
+ : "=a"(f) : "m" (paravirt_ops.restore_fl), "0"(f),
+ paravirt_type(PARAVIRT_PATCH(restore_fl)),
+ paravirt_clobber(CLBR_EAX)
: "memory", "cc");
}

@@ -576,9 +576,10 @@ static inline void raw_local_irq_disable
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%0;"
- "popl %%edx; popl %%ecx",
- PARAVIRT_IRQ_DISABLE, CLBR_EAX)
- : : "m" (paravirt_ops.irq_disable)
+ "popl %%edx; popl %%ecx")
+ : : "m" (paravirt_ops.irq_disable),
+ paravirt_type(PARAVIRT_PATCH(irq_disable)),
+ paravirt_clobber(CLBR_EAX)
: "memory", "eax", "cc");
}

@@ -586,9 +587,10 @@ static inline void raw_local_irq_enable(
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
"call *%0;"
- "popl %%edx; popl %%ecx",
- PARAVIRT_IRQ_ENABLE, CLBR_EAX)
- : : "m" (paravirt_ops.irq_enable)
+ "popl %%edx; popl %%ecx")
+ : : "m" (paravirt_ops.irq_enable),
+ paravirt_type(PARAVIRT_PATCH(irq_enable)),
+ paravirt_clobber(CLBR_EAX)
: "memory", "eax", "cc");
}

@@ -596,33 +598,31 @@ static inline unsigned long __raw_local_
{
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 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_STRING _paravirt_alt("pushl %%ecx; pushl %%edx;" \
+ "call *paravirt_ops+%c[irq_disable];" \
+ "popl %%edx; popl %%ecx", \
+ "%c[paravirt_cli_type]", "%c[paravirt_clobber]")
+
+#define STI_STRING _paravirt_alt("pushl %%ecx; pushl %%edx;" \
+ "call *paravirt_ops+%c[irq_enable];" \
+ "popl %%edx; popl %%ecx", \
+ "%c[paravirt_cli_type]", "%c[paravirt_clobber]")
+
+
#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))
+ [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_disable)), \
+ paravirt_clobber(CLBR_NONE)

#else /* __ASSEMBLY__ */

--

-
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Next message: Jeremy Fitzhardinge: "[patch 12/26] Xen-paravirt_ops: Fix patch site clobbers to include return register"
Previous message: Jeremy Fitzhardinge: "[patch 02/26] Xen-paravirt_ops: ignore vgacon if hardware not present"
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Next in thread: Jeremy Fitzhardinge: "[patch 12/26] Xen-paravirt_ops: Fix patch site clobbers to include return register"
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