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From: tip-bot for Denys Vlasenko <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
	rostedt@goodmis.org, ast@plumgrid.com, keescook@chromium.org,
	wad@chromium.org, oleg@redhat.com, hpa@zytor.com,
	mingo@kernel.org, luto@amacapital.net,
	torvalds@linux-foundation.org, fweisbec@gmail.com,
	dvlasenk@redhat.com, bp@alien8.de
Subject: [tip:x86/asm] x86/asm: Replace "MOVQ $imm, %reg" with MOVL
Date: Thu, 2 Apr 2015 05:26:28 -0700	[thread overview]
Message-ID: <tip-a734b4a23e4b5a5bba577d11b6e2ff21f6ca4fce@git.kernel.org> (raw)
In-Reply-To: <1427821211-25099-8-git-send-email-dvlasenk@redhat.com>

Commit-ID:  a734b4a23e4b5a5bba577d11b6e2ff21f6ca4fce
Gitweb:     http://git.kernel.org/tip/a734b4a23e4b5a5bba577d11b6e2ff21f6ca4fce
Author:     Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Tue, 31 Mar 2015 19:00:10 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 1 Apr 2015 13:17:39 +0200

x86/asm: Replace "MOVQ $imm, %reg" with MOVL

There is no reason to use MOVQ to load a non-negative immediate
constant value into a 64-bit register. MOVL does the same, since
the upper 32 bits are zero-extended by the CPU.

This makes the code a bit smaller, while leaving functionality
unchanged.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1427821211-25099-8-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 2 +-
 arch/x86/crypto/twofish-x86_64-asm_64.S   | 4 ++--
 arch/x86/kernel/relocate_kernel_64.S      | 8 ++++----
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
index 26d49eb..225be06 100644
--- a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
+++ b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
@@ -178,7 +178,7 @@ continue_block:
 	## 2a) PROCESS FULL BLOCKS:
 	################################################################
 full_block:
-	movq    $128,%rax
+	movl    $128,%eax
 	lea     128*8*2(block_0), block_1
 	lea     128*8*3(block_0), block_2
 	add     $128*8*1, block_0
diff --git a/arch/x86/crypto/twofish-x86_64-asm_64.S b/arch/x86/crypto/twofish-x86_64-asm_64.S
index a039d21..a350c99 100644
--- a/arch/x86/crypto/twofish-x86_64-asm_64.S
+++ b/arch/x86/crypto/twofish-x86_64-asm_64.S
@@ -264,7 +264,7 @@ ENTRY(twofish_enc_blk)
 	movq	R1,	8(%rsi)
 
 	popq	R1
-	movq	$1,%rax
+	movl	$1,%eax
 	ret
 ENDPROC(twofish_enc_blk)
 
@@ -316,6 +316,6 @@ ENTRY(twofish_dec_blk)
 	movq	R1,	8(%rsi)
 
 	popq	R1
-	movq	$1,%rax
+	movl	$1,%eax
 	ret
 ENDPROC(twofish_dec_blk)
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 04cb179..98111b3 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -123,7 +123,7 @@ identity_mapped:
 	 * Set cr4 to a known state:
 	 *  - physical address extension enabled
 	 */
-	movq	$X86_CR4_PAE, %rax
+	movl	$X86_CR4_PAE, %eax
 	movq	%rax, %cr4
 
 	jmp 1f
@@ -246,17 +246,17 @@ swap_pages:
 	movq	%rsi, %rax
 
 	movq	%r10, %rdi
-	movq	$512,   %rcx
+	movl	$512, %ecx
 	rep ; movsq
 
 	movq	%rax, %rdi
 	movq	%rdx, %rsi
-	movq	$512,   %rcx
+	movl	$512, %ecx
 	rep ; movsq
 
 	movq	%rdx, %rdi
 	movq	%r10, %rsi
-	movq	$512,   %rcx
+	movl	$512, %ecx
 	rep ; movsq
 
 	lea	PAGE_SIZE(%rax), %rsi

  reply	other threads:[~2015-04-02 12:27 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-31 17:00 [PATCH 1/9] x86/asm/entry/64: do not TRACE_IRQS fast SYSRET64 path Denys Vlasenko
2015-03-31 17:00 ` [PATCH 2/9] x86/asm/entry/32: Use PUSH instructions to build pt_regs on stack Denys Vlasenko
2015-04-01  8:51   ` Ingo Molnar
2015-04-01 13:12     ` Denys Vlasenko
2015-04-01 13:21       ` Ingo Molnar
2015-04-01 13:53       ` Borislav Petkov
2015-04-02 12:25   ` [tip:x86/asm] x86/asm/entry/32: Use smaller PUSH instructions instead of MOV, to build 'pt_regs' " tip-bot for Denys Vlasenko
2015-03-31 17:00 ` [PATCH 3/9] x86/asm/entry/64: simplify retint_kernel label usage, make retint_restore_args label local Denys Vlasenko
2015-04-02 12:25   ` [tip:x86/asm] x86/asm/entry/64: Simplify " tip-bot for Denys Vlasenko
2015-03-31 17:00 ` [PATCH 4/9] x86/asm/entry/64: remove redundant DISABLE_INTERRUPTS Denys Vlasenko
2015-04-02 12:25   ` [tip:x86/asm] x86/asm/entry/64: Remove redundant DISABLE_INTERRUPTS() tip-bot for Denys Vlasenko
2015-03-31 17:00 ` [PATCH 5/9] x86/asm/entry/64: simplify looping around preempt_schedule_irq Denys Vlasenko
2015-04-02 12:26   ` [tip:x86/asm] x86/asm/entry/64: Simplify looping around preempt_schedule_irq() tip-bot for Denys Vlasenko
2015-03-31 17:00 ` [PATCH 6/9] x86/asm/entry/64: tidy up some instructions Denys Vlasenko
2015-03-31 17:00 ` [PATCH 7/9] x86/asm/entry/32: " Denys Vlasenko
2015-03-31 22:21   ` Brian Gerst
2015-03-31 23:09     ` Linus Torvalds
2015-04-01 11:10     ` Denys Vlasenko
2015-04-01 15:50       ` Linus Torvalds
2015-04-01 20:52         ` Denys Vlasenko
2015-04-01 20:57           ` H. Peter Anvin
2015-04-01 22:14           ` Linus Torvalds
2015-04-02  0:32             ` Brian Gerst
2015-04-01  8:29   ` Ingo Molnar
2015-03-31 17:00 ` [PATCH 8/9] x86/asm: replace MOVQ $imm,%reg with MOVL Denys Vlasenko
2015-04-02 12:26   ` tip-bot for Denys Vlasenko [this message]
2015-03-31 17:00 ` [PATCH 9/9] x86/asm/entry/64: use local label to skip around sycall dispatch Denys Vlasenko
2015-04-02 12:26   ` [tip:x86/asm] x86/asm/entry/64: Use " tip-bot for Denys Vlasenko
2015-04-02 12:25 ` [tip:x86/asm] x86/asm/entry/64: Do not TRACE_IRQS fast SYSRET64 path tip-bot for Denys Vlasenko

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