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From: Nadav Amit <namit@vmware.com>
To: <linux-kernel@vger.kernel.org>, <x86@kernel.org>
Cc: Nadav Amit <namit@vmware.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH v2 7/9] x86: extable: use macros instead of inline assembly
Date: Mon, 4 Jun 2018 04:21:29 -0700	[thread overview]
Message-ID: <20180604112131.59100-8-namit@vmware.com> (raw)
In-Reply-To: <20180604112131.59100-1-namit@vmware.com>

Use assembly macros for exception-tables and call them from inline
assembly.  This not only makes the code more readable and allows to
avoid the duplicate implementation, but also improves compilation
decision, specifically inline decisions which GCC base on the number of
new lines in inline assembly.

   text	   data	    bss	    dec	    hex	filename
18162555 10226288 2957312 31346155 1de4deb ./vmlinux before
18162879 10226256 2957312 31346447 1de4f0f ./vmlinux after (+292)

This allows to inline functions such as nested_vmx_exit_reflected(),
set_segment_reg(), __copy_xstate_to_user().

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Josh Poimboeuf <jpoimboe@redhat.com>

Signed-off-by: Nadav Amit <namit@vmware.com>
---
 arch/x86/include/asm/asm.h | 61 +++++++++++++++++---------------------
 arch/x86/kernel/macros.S   |  1 +
 2 files changed, 28 insertions(+), 34 deletions(-)

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 219faaec51df..30bc1b0058ef 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -58,28 +58,44 @@
 # define CC_OUT(c) [_cc_ ## c] "=qm"
 #endif
 
-/* Exception table entry */
 #ifdef __ASSEMBLY__
 # define _ASM_EXTABLE_HANDLE(from, to, handler)			\
-	.pushsection "__ex_table","a" ;				\
-	.balign 4 ;						\
-	.long (from) - . ;					\
-	.long (to) - . ;					\
-	.long (handler) - . ;					\
-	.popsection
+	ASM_EXTABLE_HANDLE from to handler
+
+#else /* __ASSEMBLY__ */
+
+# define _ASM_EXTABLE_HANDLE(from, to, handler)			\
+	"ASM_EXTABLE_HANDLE from=" #from " to=" #to		\
+	" handler=\"" #handler "\"\n\t"
+
+/* For C file, we already have NOKPROBE_SYMBOL macro */
+
+#endif /* __ASSEMBLY__ */
 
-# define _ASM_EXTABLE(from, to)					\
+#define _ASM_EXTABLE(from, to)					\
 	_ASM_EXTABLE_HANDLE(from, to, ex_handler_default)
 
-# define _ASM_EXTABLE_FAULT(from, to)				\
+#define _ASM_EXTABLE_FAULT(from, to)				\
 	_ASM_EXTABLE_HANDLE(from, to, ex_handler_fault)
 
-# define _ASM_EXTABLE_EX(from, to)				\
+#define _ASM_EXTABLE_EX(from, to)				\
 	_ASM_EXTABLE_HANDLE(from, to, ex_handler_ext)
 
-# define _ASM_EXTABLE_REFCOUNT(from, to)			\
+#define _ASM_EXTABLE_REFCOUNT(from, to)				\
 	_ASM_EXTABLE_HANDLE(from, to, ex_handler_refcount)
 
+/* Exception table entry */
+#ifdef __ASSEMBLY__
+
+.macro ASM_EXTABLE_HANDLE from:req to:req handler:req
+	.pushsection "__ex_table","a"
+	.balign 4
+	.long (\from) - .
+	.long (\to) - .
+	.long (\handler) - .
+	.popsection
+.endm
+
 # define _ASM_NOKPROBE(entry)					\
 	.pushsection "_kprobe_blacklist","aw" ;			\
 	_ASM_ALIGN ;						\
@@ -110,29 +126,6 @@
 	_ASM_EXTABLE(101b,103b)
 	.endm
 
-#else
-# define _EXPAND_EXTABLE_HANDLE(x) #x
-# define _ASM_EXTABLE_HANDLE(from, to, handler)			\
-	" .pushsection \"__ex_table\",\"a\"\n"			\
-	" .balign 4\n"						\
-	" .long (" #from ") - .\n"				\
-	" .long (" #to ") - .\n"				\
-	" .long (" _EXPAND_EXTABLE_HANDLE(handler) ") - .\n"	\
-	" .popsection\n"
-
-# define _ASM_EXTABLE(from, to)					\
-	_ASM_EXTABLE_HANDLE(from, to, ex_handler_default)
-
-# define _ASM_EXTABLE_FAULT(from, to)				\
-	_ASM_EXTABLE_HANDLE(from, to, ex_handler_fault)
-
-# define _ASM_EXTABLE_EX(from, to)				\
-	_ASM_EXTABLE_HANDLE(from, to, ex_handler_ext)
-
-# define _ASM_EXTABLE_REFCOUNT(from, to)			\
-	_ASM_EXTABLE_HANDLE(from, to, ex_handler_refcount)
-
-/* For C file, we already have NOKPROBE_SYMBOL macro */
 #endif
 
 #ifndef __ASSEMBLY__
diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S
index 71d8b716b111..7baa40d5bf16 100644
--- a/arch/x86/kernel/macros.S
+++ b/arch/x86/kernel/macros.S
@@ -11,3 +11,4 @@
 #include <asm/alternative-asm.h>
 #include <asm/bug.h>
 #include <asm/paravirt.h>
+#include <asm/asm.h>
-- 
2.17.0

  parent reply	other threads:[~2018-06-04 18:38 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-04 11:21 [PATCH v2 0/9] x86: macrofying inline asm for better compilation Nadav Amit
2018-06-04 11:21 ` [PATCH v2 1/9] Makefile: Prepare for using macros for inline asm Nadav Amit
2018-06-04 11:21 ` [PATCH v2 2/9] x86: objtool: use asm macro for better compiler decisions Nadav Amit
2018-06-04 19:04   ` Josh Poimboeuf
2018-06-05  5:41   ` kbuild test robot
2018-06-04 11:21 ` [PATCH v2 3/9] x86: refcount: prevent gcc distortions Nadav Amit
2018-06-04 22:06   ` Kees Cook
2018-06-04 22:20     ` Nadav Amit
2018-06-05  8:26   ` kbuild test robot
2018-06-04 11:21 ` [PATCH v2 4/9] x86: alternatives: macrofy locks for better inlining Nadav Amit
2018-06-05  5:36   ` kbuild test robot
2018-06-05 14:07   ` kbuild test robot
2018-06-07  3:05   ` [lkp-robot] [x86] 1a39381d70: WARNING:at_kernel/locking/mutex.c:#__mutex_unlock_slowpath kernel test robot
2018-06-04 11:21 ` [PATCH v2 5/9] x86: bug: prevent gcc distortions Nadav Amit
2018-06-05  7:34   ` kbuild test robot
2018-06-04 11:21 ` [PATCH v2 6/9] x86: prevent inline distortion by paravirt ops Nadav Amit
2018-06-04 11:21 ` Nadav Amit [this message]
2018-06-04 11:21 ` [PATCH v2 8/9] x86: cpufeature: use macros instead of inline assembly Nadav Amit
2018-06-04 11:21 ` [PATCH v2 9/9] x86: jump-labels: " Nadav Amit
2018-06-04 19:05 ` [PATCH v2 0/9] x86: macrofying inline asm for better compilation Josh Poimboeuf
2018-06-04 19:56   ` Nadav Amit

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