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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>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	Philippe Ombredanne <pombredanne@nexb.com>
Subject: [PATCH v9 10/10] x86: jump-labels: use macros instead of inline assembly
Date: Wed, 3 Oct 2018 14:31:00 -0700	[thread overview]
Message-ID: <20181003213100.189959-11-namit@vmware.com> (raw)
In-Reply-To: <20181003213100.189959-1-namit@vmware.com>

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

As a result the code size is slightly increased.

   text	   data	    bss	    dec	    hex	filename
18163528 10226300 2957312 31347140 1de51c4 ./vmlinux before
18163608 10227348 2957312 31348268 1de562c ./vmlinux after (+1128)

And functions such as intel_pstate_adjust_policy_max(),
kvm_cpu_accept_dm_intr(), kvm_register_readl() are inlined.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
---
 arch/x86/entry/calling.h          |  2 +-
 arch/x86/include/asm/jump_label.h | 77 +++++++++++--------------------
 arch/x86/kernel/macros.S          |  1 +
 3 files changed, 30 insertions(+), 50 deletions(-)

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 352e70cd33e8..708b46a54578 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -338,7 +338,7 @@ For 32-bit we have the following conventions - kernel is built with
 .macro CALL_enter_from_user_mode
 #ifdef CONFIG_CONTEXT_TRACKING
 #ifdef HAVE_JUMP_LABEL
-	STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0
+	STATIC_BRANCH_JMP l_yes=.Lafter_call_\@, key=context_tracking_enabled, branch=1
 #endif
 	call enter_from_user_mode
 .Lafter_call_\@:
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 8c0de4282659..4606a7101f97 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -2,19 +2,6 @@
 #ifndef _ASM_X86_JUMP_LABEL_H
 #define _ASM_X86_JUMP_LABEL_H
 
-#ifndef HAVE_JUMP_LABEL
-/*
- * For better or for worse, if jump labels (the gcc extension) are missing,
- * then the entire static branch patching infrastructure is compiled out.
- * If that happens, the code in here will malfunction.  Raise a compiler
- * error instead.
- *
- * In theory, jump labels and the static branch patching infrastructure
- * could be decoupled to fix this.
- */
-#error asm/jump_label.h included on a non-jump-label kernel
-#endif
-
 #define JUMP_LABEL_NOP_SIZE 5
 
 #ifdef CONFIG_X86_64
@@ -28,18 +15,27 @@
 
 #ifndef __ASSEMBLY__
 
+#ifndef HAVE_JUMP_LABEL
+/*
+ * For better or for worse, if jump labels (the gcc extension) are missing,
+ * then the entire static branch patching infrastructure is compiled out.
+ * If that happens, the code in here will malfunction.  Raise a compiler
+ * error instead.
+ *
+ * In theory, jump labels and the static branch patching infrastructure
+ * could be decoupled to fix this.
+ */
+#error asm/jump_label.h included on a non-jump-label kernel
+#endif
+
 #include <linux/stringify.h>
 #include <linux/types.h>
 
 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-	asm_volatile_goto("1:"
-		".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
-		".pushsection __jump_table,  \"aw\" \n\t"
-		_ASM_ALIGN "\n\t"
-		_ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
-		".popsection \n\t"
-		: :  "i" (key), "i" (branch) : : l_yes);
+	asm_volatile_goto("STATIC_BRANCH_NOP l_yes=\"%l[l_yes]\" key=\"%c0\" "
+			  "branch=\"%c1\""
+			: :  "i" (key), "i" (branch) : : l_yes);
 
 	return false;
 l_yes:
@@ -48,13 +44,8 @@ static __always_inline bool arch_static_branch(struct static_key *key, bool bran
 
 static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
 {
-	asm_volatile_goto("1:"
-		".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t"
-		"2:\n\t"
-		".pushsection __jump_table,  \"aw\" \n\t"
-		_ASM_ALIGN "\n\t"
-		_ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
-		".popsection \n\t"
+	asm_volatile_goto("STATIC_BRANCH_JMP l_yes=\"%l[l_yes]\" key=\"%c0\" "
+			  "branch=\"%c1\""
 		: :  "i" (key), "i" (branch) : : l_yes);
 
 	return false;
@@ -76,35 +67,23 @@ struct jump_entry {
 
 #else	/* __ASSEMBLY__ */
 
-.macro STATIC_JUMP_IF_TRUE target, key, def
-.Lstatic_jump_\@:
-	.if \def
-	/* Equivalent to "jmp.d32 \target" */
-	.byte		0xe9
-	.long		\target - .Lstatic_jump_after_\@
-.Lstatic_jump_after_\@:
-	.else
-	.byte		STATIC_KEY_INIT_NOP
-	.endif
+.macro STATIC_BRANCH_NOP l_yes:req key:req branch:req
+1:
+	.byte STATIC_KEY_INIT_NOP
 	.pushsection __jump_table, "aw"
 	_ASM_ALIGN
-	_ASM_PTR	.Lstatic_jump_\@, \target, \key
+	_ASM_PTR 1b, \l_yes, \key + \branch
 	.popsection
 .endm
 
-.macro STATIC_JUMP_IF_FALSE target, key, def
-.Lstatic_jump_\@:
-	.if \def
-	.byte		STATIC_KEY_INIT_NOP
-	.else
-	/* Equivalent to "jmp.d32 \target" */
-	.byte		0xe9
-	.long		\target - .Lstatic_jump_after_\@
-.Lstatic_jump_after_\@:
-	.endif
+.macro STATIC_BRANCH_JMP l_yes:req key:req branch:req
+1:
+	.byte 0xe9
+	.long \l_yes - 2f
+2:
 	.pushsection __jump_table, "aw"
 	_ASM_ALIGN
-	_ASM_PTR	.Lstatic_jump_\@, \target, \key + 1
+	_ASM_PTR 1b, \l_yes, \key + \branch
 	.popsection
 .endm
 
diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S
index bf8b9c93e255..161c95059044 100644
--- a/arch/x86/kernel/macros.S
+++ b/arch/x86/kernel/macros.S
@@ -13,3 +13,4 @@
 #include <asm/paravirt.h>
 #include <asm/asm.h>
 #include <asm/cpufeature.h>
+#include <asm/jump_label.h>
-- 
2.17.1


  parent reply	other threads:[~2018-10-03 21:32 UTC|newest]

Thread overview: 116+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-03 21:30 [PATCH v9 00/10] x86: macrofying inline asm Nadav Amit
2018-10-03 21:30 ` [PATCH v9 01/10] xtensa: defining LINKER_SCRIPT for the linker script Nadav Amit
2018-10-04 10:00   ` [tip:x86/build] kbuild/arch/xtensa: Define " tip-bot for Nadav Amit
2018-10-03 21:30 ` [PATCH v9 02/10] Makefile: Prepare for using macros for inline asm Nadav Amit
2018-10-04 10:01   ` [tip:x86/build] kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs tip-bot for Nadav Amit
2018-11-06 18:57   ` [PATCH v9 02/10] Makefile: Prepare for using macros for inline asm Logan Gunthorpe
2018-11-06 19:18     ` Nadav Amit
2018-11-06 20:01       ` Logan Gunthorpe
2018-11-07 18:01         ` Nadav Amit
2018-11-07 18:53           ` Logan Gunthorpe
2018-11-07 18:56             ` Nadav Amit
2018-11-07 21:43               ` Logan Gunthorpe
2018-11-07 21:50                 ` hpa
2018-11-08  6:18                   ` Nadav Amit
2018-11-08 17:14                     ` Logan Gunthorpe
2018-11-08 19:54                       ` Nadav Amit
2018-11-08 20:00                         ` Logan Gunthorpe
2018-11-08 20:18                           ` Nadav Amit
2018-11-10 22:04                             ` Nadav Amit
2018-11-13  4:56                               ` Logan Gunthorpe
2018-10-03 21:30 ` [PATCH v9 03/10] x86: objtool: use asm macro for better compiler decisions Nadav Amit
2018-10-04 10:02   ` [tip:x86/build] x86/objtool: Use asm macros to work around GCC inlining bugs tip-bot for Nadav Amit
2018-10-03 21:30 ` [PATCH v9 04/10] x86: refcount: prevent gcc distortions Nadav Amit
2018-10-04  7:57   ` Ingo Molnar
2018-10-04  8:33     ` Ingo Molnar
2018-10-04  8:40       ` hpa
2018-10-04  8:56         ` Ingo Molnar
2018-10-04  8:56         ` Nadav Amit
2018-10-04  9:02           ` hpa
2018-10-04  9:16             ` Ingo Molnar
2018-10-04 19:33               ` H. Peter Anvin
2018-10-04 20:05                 ` Nadav Amit
2018-10-04 20:08                   ` H. Peter Anvin
2018-10-04 20:29                 ` Andy Lutomirski
2018-10-04 23:11                   ` H. Peter Anvin
2018-10-06  1:40                 ` Rasmus Villemoes
2018-10-04  9:12           ` Ingo Molnar
2018-10-04  9:17             ` hpa
2018-10-04  9:30             ` Nadav Amit
2018-10-04  9:45               ` Ingo Molnar
2018-10-04 10:23                 ` Nadav Amit
2018-10-05  9:31                   ` Ingo Molnar
2018-10-05 11:20                     ` Borislav Petkov
2018-10-05 12:52                       ` Ingo Molnar
2018-10-05 20:27                     ` [PATCH 0/3] Macrofying inline asm rebased Nadav Amit
2018-10-05 20:27                       ` [PATCH 1/3] x86/extable: Macrofy inline assembly code to work around GCC inlining bugs Nadav Amit
2018-10-06 14:42                         ` [tip:x86/build] " tip-bot for Nadav Amit
2018-10-05 20:27                       ` [PATCH 2/3] x86/cpufeature: " Nadav Amit
2018-10-06 14:43                         ` [tip:x86/build] " tip-bot for Nadav Amit
2018-10-05 20:27                       ` [PATCH 3/3] x86/jump-labels: " Nadav Amit
2018-10-06 14:44                         ` [tip:x86/build] " tip-bot for Nadav Amit
2018-10-08  2:17                     ` [PATCH v9 04/10] x86: refcount: prevent gcc distortions Nadav Amit
2018-10-04  8:40     ` Nadav Amit
2018-10-04  9:01       ` Ingo Molnar
2018-10-04 10:02   ` [tip:x86/build] x86/refcount: Work around GCC inlining bug tip-bot for Nadav Amit
2018-10-03 21:30 ` [PATCH v9 05/10] x86: alternatives: macrofy locks for better inlining Nadav Amit
2018-10-04 10:03   ` [tip:x86/build] x86/alternatives: Macrofy lock prefixes to work around GCC inlining bugs tip-bot for Nadav Amit
2018-10-03 21:30 ` [PATCH v9 06/10] x86: bug: prevent gcc distortions Nadav Amit
2018-10-04 10:03   ` [tip:x86/build] x86/bug: Macrofy the BUG table section handling, to work around GCC inlining bugs tip-bot for Nadav Amit
2018-10-03 21:30 ` [PATCH v9 07/10] x86: prevent inline distortion by paravirt ops Nadav Amit
2018-10-04 10:04   ` [tip:x86/build] x86/paravirt: Work around GCC inlining bugs when compiling " tip-bot for Nadav Amit
2018-10-03 21:30 ` [PATCH v9 08/10] x86: extable: use macros instead of inline assembly Nadav Amit
2018-10-03 21:30 ` [PATCH v9 09/10] x86: cpufeature: " Nadav Amit
2018-10-03 21:31 ` Nadav Amit [this message]
2018-10-07  9:18 ` PROPOSAL: Extend inline asm syntax with size spec Borislav Petkov
     [not found]   ` <20181007132228.GJ29268@gate.crashing.org>
2018-10-07 14:13     ` Borislav Petkov
2018-10-07 15:14       ` Segher Boessenkool
2018-10-08  5:58         ` Ingo Molnar
2018-10-08  7:53           ` Segher Boessenkool
2018-10-07 15:53     ` Michael Matz
2018-10-08  6:13       ` Ingo Molnar
2018-10-08  8:18         ` Segher Boessenkool
2018-10-08  7:31       ` Segher Boessenkool
2018-10-08  9:07         ` Richard Biener
2018-10-08 10:02           ` Segher Boessenkool
2018-10-09 14:53           ` Segher Boessenkool
2018-10-10  6:35             ` Ingo Molnar
2018-10-10  7:12             ` Richard Biener
2018-10-10  7:22               ` Ingo Molnar
2018-10-10  8:03                 ` Segher Boessenkool
2018-10-10  8:19                   ` Borislav Petkov
2018-10-10  8:35                     ` Richard Biener
2018-10-10 18:54                     ` Segher Boessenkool
2018-10-10 19:14                       ` Borislav Petkov
2018-10-13 19:33                         ` Borislav Petkov
2018-10-13 21:14                           ` Alexander Monakov
2018-10-13 21:30                             ` Borislav Petkov
2018-10-25 10:24                           ` Borislav Petkov
2018-10-31 12:55                           ` Peter Zijlstra
2018-10-31 13:11                             ` Peter Zijlstra
2018-10-31 16:31                             ` Segher Boessenkool
2018-11-01  5:20                             ` Joe Perches
2018-11-01  9:01                               ` Peter Zijlstra
2018-11-01  9:20                                 ` Joe Perches
2018-11-01 11:15                                   ` Peter Zijlstra
2018-12-27  4:47                             ` Masahiro Yamada
2018-10-10 10:29                   ` Richard Biener
2018-10-10  7:53               ` Segher Boessenkool
2018-10-10 16:31             ` Nadav Amit
2018-10-10 19:21               ` Segher Boessenkool
2018-10-11  7:04               ` Richard Biener
2018-11-29 11:46             ` Masahiro Yamada
2018-11-29 12:25               ` Segher Boessenkool
2018-11-30  9:06                 ` Boris Petkov
2018-11-30 13:16                   ` Segher Boessenkool
2018-12-10  8:16                     ` Masahiro Yamada
2018-11-29 13:07               ` Borislav Petkov
2018-11-29 13:09                 ` Richard Biener
2018-11-29 13:16                   ` Borislav Petkov
2018-11-29 13:24                     ` Richard Biener
2018-10-08 16:24       ` David Laight
2018-10-07 16:09   ` Nadav Amit
2018-10-07 16:46     ` Richard Biener
2018-10-07 19:06       ` Nadav Amit
2018-10-07 19:52         ` Jeff Law
2018-10-08  7:46         ` Richard Biener

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