[tip: x86/core] x86/paravirt: Remove clobber bitmask from .parainstructions

tip-bot2 for Kees Cook posted 1 patch 1 week, 2 days ago
arch/x86/include/asm/paravirt_types.h | 61 +++++---------------------
1 file changed, 12 insertions(+), 49 deletions(-)
[tip: x86/core] x86/paravirt: Remove clobber bitmask from .parainstructions
Posted by tip-bot2 for Kees Cook 1 week, 2 days ago
The following commit has been merged into the x86/core branch of tip:

Commit-ID:     5736b1b70170e15d66ec02e500db917ef42ade83
Gitweb:        https://git.kernel.org/tip/5736b1b70170e15d66ec02e500db917ef42ade83
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Sat, 03 Sep 2022 00:37:06 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 24 Nov 2022 13:53:54 +01:00

x86/paravirt: Remove clobber bitmask from .parainstructions

The u16 "clobber" value is not used in .parainstructions since commit
27876f3882fd ("x86/paravirt: Remove clobbers from struct paravirt_patch_site")

Remove the u16 from the section macro, the argument from all macros, and
all now-unused CLBR_* macros.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220903073706.3193746-1-keescook@chromium.org
---
 arch/x86/include/asm/paravirt_types.h | 61 +++++---------------------
 1 file changed, 12 insertions(+), 49 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 27c6927..8c1da41 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -20,37 +20,6 @@ enum paravirt_lazy_mode {
 
 #ifdef CONFIG_PARAVIRT
 
-/* Bitmask of what can be clobbered: usually at least eax. */
-#define CLBR_EAX  (1 << 0)
-#define CLBR_ECX  (1 << 1)
-#define CLBR_EDX  (1 << 2)
-#define CLBR_EDI  (1 << 3)
-
-#ifdef CONFIG_X86_32
-/* CLBR_ANY should match all regs platform has. For i386, that's just it */
-#define CLBR_ANY  ((1 << 4) - 1)
-
-#define CLBR_ARG_REGS	(CLBR_EAX | CLBR_EDX | CLBR_ECX)
-#define CLBR_RET_REG	(CLBR_EAX | CLBR_EDX)
-#else
-#define CLBR_RAX  CLBR_EAX
-#define CLBR_RCX  CLBR_ECX
-#define CLBR_RDX  CLBR_EDX
-#define CLBR_RDI  CLBR_EDI
-#define CLBR_RSI  (1 << 4)
-#define CLBR_R8   (1 << 5)
-#define CLBR_R9   (1 << 6)
-#define CLBR_R10  (1 << 7)
-#define CLBR_R11  (1 << 8)
-
-#define CLBR_ANY  ((1 << 9) - 1)
-
-#define CLBR_ARG_REGS	(CLBR_RDI | CLBR_RSI | CLBR_RDX | \
-			 CLBR_RCX | CLBR_R8 | CLBR_R9)
-#define CLBR_RET_REG	(CLBR_RAX)
-
-#endif /* X86_64 */
-
 #ifndef __ASSEMBLY__
 
 #include <asm/desc_defs.h>
@@ -297,27 +266,23 @@ extern struct paravirt_patch_template pv_ops;
 #define paravirt_type(op)				\
 	[paravirt_typenum] "i" (PARAVIRT_PATCH(op)),	\
 	[paravirt_opptr] "m" (pv_ops.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)	\
+#define _paravirt_alt(insn_string, type)		\
 	"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"			\
 	_ASM_ALIGN "\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]")
+	_paravirt_alt(insn_string, "%c[paravirt_typenum]")
 
 /* Simple instruction patching code. */
 #define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
@@ -469,20 +434,19 @@ int paravirt_disable_iospace(void);
 	})
 
 
-#define ____PVOP_CALL(ret, op, clbr, call_clbr, extra_clbr, ...)	\
+#define ____PVOP_CALL(ret, op, call_clbr, extra_clbr, ...)	\
 	({								\
 		PVOP_CALL_ARGS;						\
 		PVOP_TEST_NULL(op);					\
 		asm volatile(paravirt_alt(PARAVIRT_CALL)		\
 			     : call_clbr, ASM_CALL_CONSTRAINT		\
 			     : paravirt_type(op),			\
-			       paravirt_clobber(clbr),			\
 			       ##__VA_ARGS__				\
 			     : "memory", "cc" extra_clbr);		\
 		ret;							\
 	})
 
-#define ____PVOP_ALT_CALL(ret, op, alt, cond, clbr, call_clbr,		\
+#define ____PVOP_ALT_CALL(ret, op, alt, cond, call_clbr,		\
 			  extra_clbr, ...)				\
 	({								\
 		PVOP_CALL_ARGS;						\
@@ -491,45 +455,44 @@ int paravirt_disable_iospace(void);
 					 alt, cond)			\
 			     : call_clbr, ASM_CALL_CONSTRAINT		\
 			     : paravirt_type(op),			\
-			       paravirt_clobber(clbr),			\
 			       ##__VA_ARGS__				\
 			     : "memory", "cc" extra_clbr);		\
 		ret;							\
 	})
 
 #define __PVOP_CALL(rettype, op, ...)					\
-	____PVOP_CALL(PVOP_RETVAL(rettype), op, CLBR_ANY,		\
+	____PVOP_CALL(PVOP_RETVAL(rettype), op,				\
 		      PVOP_CALL_CLOBBERS, EXTRA_CLOBBERS, ##__VA_ARGS__)
 
 #define __PVOP_ALT_CALL(rettype, op, alt, cond, ...)			\
-	____PVOP_ALT_CALL(PVOP_RETVAL(rettype), op, alt, cond, CLBR_ANY,\
+	____PVOP_ALT_CALL(PVOP_RETVAL(rettype), op, alt, cond,		\
 			  PVOP_CALL_CLOBBERS, EXTRA_CLOBBERS,		\
 			  ##__VA_ARGS__)
 
 #define __PVOP_CALLEESAVE(rettype, op, ...)				\
-	____PVOP_CALL(PVOP_RETVAL(rettype), op.func, CLBR_RET_REG,	\
+	____PVOP_CALL(PVOP_RETVAL(rettype), op.func,			\
 		      PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
 
 #define __PVOP_ALT_CALLEESAVE(rettype, op, alt, cond, ...)		\
 	____PVOP_ALT_CALL(PVOP_RETVAL(rettype), op.func, alt, cond,	\
-			  CLBR_RET_REG, PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
+			  PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
 
 
 #define __PVOP_VCALL(op, ...)						\
-	(void)____PVOP_CALL(, op, CLBR_ANY, PVOP_VCALL_CLOBBERS,	\
+	(void)____PVOP_CALL(, op, PVOP_VCALL_CLOBBERS,			\
 		       VEXTRA_CLOBBERS, ##__VA_ARGS__)
 
 #define __PVOP_ALT_VCALL(op, alt, cond, ...)				\
-	(void)____PVOP_ALT_CALL(, op, alt, cond, CLBR_ANY,		\
+	(void)____PVOP_ALT_CALL(, op, alt, cond,			\
 				PVOP_VCALL_CLOBBERS, VEXTRA_CLOBBERS,	\
 				##__VA_ARGS__)
 
 #define __PVOP_VCALLEESAVE(op, ...)					\
-	(void)____PVOP_CALL(, op.func, CLBR_RET_REG,			\
+	(void)____PVOP_CALL(, op.func,					\
 			    PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
 
 #define __PVOP_ALT_VCALLEESAVE(op, alt, cond, ...)			\
-	(void)____PVOP_ALT_CALL(, op.func, alt, cond, CLBR_RET_REG,	\
+	(void)____PVOP_ALT_CALL(, op.func, alt, cond,			\
 				PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)