linux-kernel - [GIT PULL] x86/asm changes for v4.18

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Message-ID: <20180604122132.GA3337@gmail.com>
Date:   Mon, 4 Jun 2018 14:21:32 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/asm changes for v4.18

Linus,

Please pull the latest x86-asm-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-asm-for-linus

   # HEAD: 6469a0ee0a06b2ea1f5afbb1d5a3feed017d4c7a x86/io: Define readq()/writeq() to use 64-bit type

Two smaller changes:

 - better support (non-atomic) 64-bit readq()/writeq() variants (Andy Shevchenko)

 - __clear_user() micro-optimization (Alexey Dobriyan)

 Thanks,

	Ingo

------------------>
Alexey Dobriyan (1):
      x86/asm/64: Micro-optimize __clear_user() - Use immediate constants

Andy Shevchenko (1):
      x86/io: Define readq()/writeq() to use 64-bit type


 arch/x86/include/asm/io.h  | 8 ++++----
 arch/x86/lib/usercopy_64.c | 9 ++++-----
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index f6e5b9375d8c..6de64840dd22 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -94,10 +94,10 @@ build_mmio_write(__writel, "l", unsigned int, "r", )
 
 #ifdef CONFIG_X86_64
 
-build_mmio_read(readq, "q", unsigned long, "=r", :"memory")
-build_mmio_read(__readq, "q", unsigned long, "=r", )
-build_mmio_write(writeq, "q", unsigned long, "r", :"memory")
-build_mmio_write(__writeq, "q", unsigned long, "r", )
+build_mmio_read(readq, "q", u64, "=r", :"memory")
+build_mmio_read(__readq, "q", u64, "=r", )
+build_mmio_write(writeq, "q", u64, "r", :"memory")
+build_mmio_write(__writeq, "q", u64, "r", )
 
 #define readq_relaxed(a)	__readq(a)
 #define writeq_relaxed(v, a)	__writeq(v, a)
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index 75d3776123cc..a624dcc4de10 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -23,13 +23,13 @@ unsigned long __clear_user(void __user *addr, unsigned long size)
 	asm volatile(
 		"	testq  %[size8],%[size8]\n"
 		"	jz     4f\n"
-		"0:	movq %[zero],(%[dst])\n"
-		"	addq   %[eight],%[dst]\n"
+		"0:	movq $0,(%[dst])\n"
+		"	addq   $8,%[dst]\n"
 		"	decl %%ecx ; jnz   0b\n"
 		"4:	movq  %[size1],%%rcx\n"
 		"	testl %%ecx,%%ecx\n"
 		"	jz     2f\n"
-		"1:	movb   %b[zero],(%[dst])\n"
+		"1:	movb   $0,(%[dst])\n"
 		"	incq   %[dst]\n"
 		"	decl %%ecx ; jnz  1b\n"
 		"2:\n"
@@ -40,8 +40,7 @@ unsigned long __clear_user(void __user *addr, unsigned long size)
 		_ASM_EXTABLE(0b,3b)
 		_ASM_EXTABLE(1b,2b)
 		: [size8] "=&c"(size), [dst] "=&D" (__d0)
-		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
-		  [zero] "r" (0UL), [eight] "r" (8UL));
+		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr));
 	clac();
 	return size;
 }