[PATCH 08/13] x86/paravirt: Clean up paravirt_types.h

From: Josh Poimboeuf <jpoimboe@redhat.com>
To: x86@kernel.org
Cc: Juergen Gross <jgross@suse.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	xen-devel@lists.xenproject.org,
	Peter Zijlstra <peterz@infradead.org>,
	Jiri Slaby <jslaby@suse.cz>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Mike Galbraith <efault@gmx.de>,
	linux-kernel@vger.kernel.org,
	Sasha Levin <alexander.levin@verizon.com>,
	Chris Wright <chrisw@sous-sol.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
	live-patching@vger.kernel.org, Alok Kataria <akataria@vmware.com>,
	virtualization@lists.linux-foundation.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: [PATCH 08/13] x86/paravirt: Clean up paravirt_types.h
Date: Wed,  4 Oct 2017 10:58:29 -0500	[thread overview]
Message-ID: <38b16ecbfa88b41239e8a87ce1d8330fea7a2b3a.1507128293.git.jpoimboe__18009.184781886$1509079646$gmane$org@redhat.com> (raw)
In-Reply-To: <cover.1507128293.git.jpoimboe@redhat.com>

Make paravirt_types.h more understandable:

- Use more consistent and logical naming
- Simplify interfaces
- Put related macros together
- Improve whitespace

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/include/asm/paravirt_types.h | 104 ++++++++++++++++++----------------
 1 file changed, 54 insertions(+), 50 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 01f9e10983c1..5656aea79412 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -331,33 +331,6 @@ extern struct pv_irq_ops pv_irq_ops;
 extern struct pv_mmu_ops pv_mmu_ops;
 extern struct pv_lock_ops pv_lock_ops;
 
-#define PARAVIRT_PATCH(x)					\
-	(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
-
-#define paravirt_type(op)				\
-	[paravirt_typenum] "i" (PARAVIRT_PATCH(op)),	\
-	[paravirt_opptr] "i" (&(op))
-#define paravirt_clobber(clobber)		\
-	[paravirt_clobber] "i" (clobber)
-
-/*
- * Generate some code, and mark it as patchable by the
- * apply_paravirt() alternate instruction patcher.
- */
-#define _paravirt_alt(insn_string, type, clobber)	\
-	"771:\n\t" insn_string "\n" "772:\n"		\
-	".pushsection .parainstructions,\"a\"\n"	\
-	_ASM_ALIGN "\n"					\
-	_ASM_PTR " 771b\n"				\
-	"  .byte " type "\n"				\
-	"  .byte 772b-771b\n"				\
-	"  .short " clobber "\n"			\
-	".popsection\n"
-
-/* Generate patchable code, with the default asm parameters. */
-#define paravirt_alt(insn_string)					\
-	_paravirt_alt(insn_string, "%c[paravirt_typenum]", "%c[paravirt_clobber]")
-
 /* Simple instruction patching code. */
 #define NATIVE_LABEL(a,x,b) "\n" a #x "_" #b ":\n\t"
 
@@ -388,13 +361,46 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
 
 int paravirt_disable_iospace(void);
 
+
 /*
- * This generates an indirect call based on the operation type number.
- * The type number, computed in PARAVIRT_PATCH, is derived from the
- * offset into the paravirt_patch_template structure, and can therefore be
- * freely converted back into a structure offset.
+ * Generate some code, and mark it as patchable by apply_paravirt().
  */
-#define PARAVIRT_CALL	"call *%c[paravirt_opptr];"
+#define _PV_SITE(insn_string, type, clobber)				\
+	"771:\n\t" insn_string "\n" "772:\n"				\
+	".pushsection .parainstructions,\"a\"\n"			\
+	_ASM_ALIGN "\n"							\
+	_ASM_PTR " 771b\n"						\
+	"  .byte " type "\n"						\
+	"  .byte 772b-771b\n"						\
+	"  .short " clobber "\n"					\
+	".popsection\n"
+
+#define PARAVIRT_PATCH(x)						\
+	(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
+
+#define PV_STRINGIFY(constraint)	"%c[" __stringify(constraint) "]"
+
+#define PV_CALL_CONSTRAINT		pv_op_ptr
+#define PV_TYPE_CONSTRAINT		pv_typenum
+#define PV_CLBR_CONSTRAINT		pv_clobber
+
+#define PV_CALL_CONSTRAINT_STR		PV_STRINGIFY(PV_CALL_CONSTRAINT)
+#define PV_TYPE_CONSTRAINT_STR		PV_STRINGIFY(PV_TYPE_CONSTRAINT)
+#define PV_CLBR_CONSTRAINT_STR		PV_STRINGIFY(PV_CLBR_CONSTRAINT)
+
+#define PV_CALL_STR			"call *" PV_CALL_CONSTRAINT_STR ";"
+
+#define PV_INPUT_CONSTRAINTS(op, clobber)				\
+	[PV_TYPE_CONSTRAINT] "i" (PARAVIRT_PATCH(op)),			\
+	[PV_CALL_CONSTRAINT] "i" (&(op)),				\
+	[PV_CLBR_CONSTRAINT] "i" (clobber)
+
+#define PV_SITE(insn_string)						\
+	_PV_SITE(insn_string, PV_TYPE_CONSTRAINT_STR, PV_CLBR_CONSTRAINT_STR)
+
+#define PV_ALT_SITE(oldinstr, newinstr)					\
+	_PV_ALT_SITE(oldinstr, newinstr, PV_TYPE_CONSTRAINT_STR,	\
+		     PV_CLBR_CONSTRAINT_STR)
 
 /*
  * These macros are intended to wrap calls through one of the paravirt
@@ -525,25 +531,24 @@ int paravirt_disable_iospace(void);
 
 #define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr,		\
 		      pre, post, ...)					\
-	({								\
-		rettype __ret;						\
-		PVOP_CALL_ARGS;						\
-		PVOP_TEST_NULL(op);					\
+({									\
+	rettype __ret;							\
+	PVOP_CALL_ARGS;							\
+	PVOP_TEST_NULL(op);						\
 		asm volatile(pre					\
-			     paravirt_alt(PARAVIRT_CALL)		\
+			     PV_SITE(PV_CALL_STR)			\
 			     post					\
 			     : call_clbr, ASM_CALL_CONSTRAINT		\
-			     : paravirt_type(op),			\
-			       paravirt_clobber(clbr),			\
+			     : PV_INPUT_CONSTRAINTS(op, clbr),		\
 			       ##__VA_ARGS__				\
 			     : "memory", "cc" extra_clbr);		\
-		if (IS_ENABLED(CONFIG_X86_32) &&			\
-		    sizeof(rettype) > sizeof(unsigned long))		\
-			__ret = (rettype)((((u64)__edx) << 32) | __eax);\
-		else							\
-			__ret = (rettype)(__eax & PVOP_RETMASK(rettype));\
-		__ret;							\
-	})
+	if (IS_ENABLED(CONFIG_X86_32) &&				\
+	    sizeof(rettype) > sizeof(unsigned long))			\
+		__ret = (rettype)((((u64)__edx) << 32) | __eax);	\
+	else								\
+		__ret = (rettype)(__eax & PVOP_RETMASK(rettype));	\
+	__ret;								\
+})
 
 #define __PVOP_CALL(rettype, op, pre, post, ...)			\
 	____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_OUTPUTS,		\
@@ -560,11 +565,10 @@ int paravirt_disable_iospace(void);
 		PVOP_VCALL_ARGS;					\
 		PVOP_TEST_NULL(op);					\
 		asm volatile(pre					\
-			     paravirt_alt(PARAVIRT_CALL)		\
+			     PV_SITE(PV_CALL_STR)			\
 			     post					\
 			     : call_clbr, ASM_CALL_CONSTRAINT		\
-			     : paravirt_type(op),			\
-			       paravirt_clobber(clbr),			\
+			     : PV_INPUT_CONSTRAINTS(op, clbr),		\
 			       ##__VA_ARGS__				\
 			     : "memory", "cc" extra_clbr);		\
 	})
@@ -671,7 +675,7 @@ u64 _paravirt_ident_64(u64);
 
 /* These all sit in the .parainstructions section to tell us what to patch. */
 struct paravirt_patch_site {
-	u8 *instr; 		/* original instructions */
+	u8 *instr;		/* original instructions */
 	u8 instrtype;		/* type of this instruction */
 	u8 len;			/* length of original instruction */
 	u16 clobbers;		/* what registers you may clobber */
-- 
2.13.6
