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

[Jeremy Fitzhardinge <jeremy@goop.org>]

[-- Attachment #1: paravirt-use-offset-site-ids.patch --]
[-- Type: text/plain, Size: 10827 bytes --]

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@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>

---
 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__ */
 

--