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From: Nadav Amit <namit@vmware.com>
To: Ingo Molnar <mingo@redhat.com>
Cc: <linux-kernel@vger.kernel.org>, <x86@kernel.org>,
	Nadav Amit <namit@vmware.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH v8 08/10] x86: extable: use macros instead of inline assembly
Date: Tue, 18 Sep 2018 14:28:45 -0700	[thread overview]
Message-ID: <20180918212847.199085-9-namit@vmware.com> (raw)
In-Reply-To: <20180918212847.199085-1-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>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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 990770f9e76b..e47a2256c64e 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -117,28 +117,44 @@
 # 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 ;						\
@@ -169,29 +185,6 @@
 	_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>
-- 
2.17.1


  parent reply	other threads:[~2018-09-18 21:31 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-18 21:28 [PATCH v8 00/10] x86: macrofying inline asm for better compilation Nadav Amit
2018-09-18 21:28 ` [PATCH v8 01/10] xtensa: defining LINKER_SCRIPT for the linker script Nadav Amit
2018-09-18 21:28 ` [PATCH v8 02/10] Makefile: Prepare for using macros for inline asm Nadav Amit
2018-09-26  8:58   ` Rasmus Villemoes
2018-09-26 17:56     ` Nadav Amit
2018-09-27  7:52       ` Rasmus Villemoes
2018-10-01 22:01       ` Masahiro Yamada
2018-10-03 19:41         ` Nadav Amit
2018-10-02 10:59       ` Ingo Molnar
2018-10-03 19:43         ` hpa
2018-10-03 20:29           ` Nadav Amit
2018-09-18 21:28 ` [PATCH v8 03/10] x86: objtool: use asm macro for better compiler decisions Nadav Amit
2018-09-18 21:28 ` [PATCH v8 04/10] x86: refcount: prevent gcc distortions Nadav Amit
2018-09-18 21:28 ` [PATCH v8 05/10] x86: alternatives: macrofy locks for better inlining Nadav Amit
2018-09-18 21:28 ` [PATCH v8 06/10] x86: bug: prevent gcc distortions Nadav Amit
2018-09-18 21:28 ` [PATCH v8 07/10] x86: prevent inline distortion by paravirt ops Nadav Amit
2018-09-18 21:28 ` Nadav Amit [this message]
2018-09-18 21:28 ` [PATCH v8 09/10] x86: cpufeature: use macros instead of inline assembly Nadav Amit
2018-09-18 21:28 ` [PATCH v8 10/10] x86: jump-labels: " Nadav Amit
2018-09-21 18:26 ` [PATCH v8 00/10] x86: macrofying inline asm for better compilation Kees Cook

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