* [PATCH 2/2] x86/asm/entry/64: Clean up usage of TEST insns
2015-04-27 13:21 [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs Denys Vlasenko
@ 2015-04-27 13:21 ` Denys Vlasenko
2015-05-08 9:25 ` [tip:x86/asm] " tip-bot for Denys Vlasenko
2015-04-27 21:13 ` [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs Andy Lutomirski
` (2 subsequent siblings)
3 siblings, 1 reply; 7+ messages in thread
From: Denys Vlasenko @ 2015-04-27 13:21 UTC (permalink / raw)
To: Ingo Molnar
Cc: Denys Vlasenko, Linus Torvalds, Steven Rostedt, Borislav Petkov,
H. Peter Anvin, Andy Lutomirski, Oleg Nesterov,
Frederic Weisbecker, Alexei Starovoitov, Will Drewry, Kees Cook,
x86, linux-kernel
By the nature of TEST operation, it is often possible
to test a narrower part of the operand:
"testl $3, mem" -> "testb $3, mem"
This results in shorter insns, because TEST insn has no
sign-entending byte-immediate forms unlike other ALU ops.
text data bss dec hex filename
11674 0 0 11674 2d9a entry_64.o.before
11658 0 0 11658 2d8a entry_64.o
Changes in object code:
- f7 84 24 88 00 00 00 03 00 00 00 testl $0x3,0x88(%rsp)
+ f6 84 24 88 00 00 00 03 testb $0x3,0x88(%rsp)
- f7 44 24 68 03 00 00 00 testl $0x3,0x68(%rsp)
+ f6 44 24 68 03 testb $0x3,0x68(%rsp)
- f7 84 24 90 00 00 00 03 00 00 00 testl $0x3,0x90(%rsp)
+ f6 84 24 90 00 00 00 03 testb $0x3,0x90(%rsp)
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: Will Drewry <wad@chromium.org>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
arch/x86/kernel/entry_64.S | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 8f8b22a..60705b03 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -601,7 +601,7 @@ ENTRY(ret_from_fork)
RESTORE_EXTRA_REGS
- testl $3,CS(%rsp) # from kernel_thread?
+ testb $3, CS(%rsp) # from kernel_thread?
/*
* By the time we get here, we have no idea whether our pt_regs,
@@ -665,7 +665,7 @@ END(irq_entries_start)
leaq -RBP(%rsp),%rdi /* arg1 for \func (pointer to pt_regs) */
- testl $3, CS-RBP(%rsp)
+ testb $3, CS-RBP(%rsp)
jz 1f
SWAPGS
1:
@@ -720,7 +720,7 @@ ret_from_intr:
CFI_DEF_CFA_REGISTER rsp
CFI_ADJUST_CFA_OFFSET RBP
- testl $3,CS(%rsp)
+ testb $3, CS(%rsp)
jz retint_kernel
/* Interrupt came from user space */
@@ -968,7 +968,7 @@ ENTRY(\sym)
.if \paranoid
.if \paranoid == 1
CFI_REMEMBER_STATE
- testl $3, CS(%rsp) /* If coming from userspace, switch */
+ testb $3, CS(%rsp) /* If coming from userspace, switch */
jnz 1f /* stacks. */
.endif
call paranoid_entry
@@ -1309,7 +1309,7 @@ ENTRY(error_entry)
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
xorl %ebx,%ebx
- testl $3,CS+8(%rsp)
+ testb $3, CS+8(%rsp)
jz error_kernelspace
error_swapgs:
SWAPGS
@@ -1606,7 +1606,6 @@ end_repeat_nmi:
je 1f
movq %r12, %cr2
1:
-
testl %ebx,%ebx /* swapgs needed? */
jnz nmi_restore
nmi_swapgs:
--
1.8.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread* [tip:x86/asm] x86/asm/entry/64: Clean up usage of TEST insns
2015-04-27 13:21 ` [PATCH 2/2] x86/asm/entry/64: Clean up usage of TEST insns Denys Vlasenko
@ 2015-05-08 9:25 ` tip-bot for Denys Vlasenko
0 siblings, 0 replies; 7+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-05-08 9:25 UTC (permalink / raw)
To: linux-tip-commits
Cc: bp, luto, rostedt, oleg, linux-kernel, wad, dvlasenk, keescook,
torvalds, fweisbec, hpa, brgerst, mingo, ast, tglx
Commit-ID: 03335e95e27fc1f2b17b05b27342ad76986b3cf0
Gitweb: http://git.kernel.org/tip/03335e95e27fc1f2b17b05b27342ad76986b3cf0
Author: Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Mon, 27 Apr 2015 15:21:52 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 May 2015 11:07:32 +0200
x86/asm/entry/64: Clean up usage of TEST insns
By the nature of TEST operation, it is often possible
to test a narrower part of the operand:
"testl $3, mem" -> "testb $3, mem"
This results in shorter insns, because TEST insn has no
sign-entending byte-immediate forms unlike other ALU ops.
text data bss dec hex filename
11674 0 0 11674 2d9a entry_64.o.before
11658 0 0 11658 2d8a entry_64.o
Changes in object code:
- f7 84 24 88 00 00 00 03 00 00 00 testl $0x3,0x88(%rsp)
+ f6 84 24 88 00 00 00 03 testb $0x3,0x88(%rsp)
- f7 44 24 68 03 00 00 00 testl $0x3,0x68(%rsp)
+ f6 44 24 68 03 testb $0x3,0x68(%rsp)
- f7 84 24 90 00 00 00 03 00 00 00 testl $0x3,0x90(%rsp)
+ f6 84 24 90 00 00 00 03 testb $0x3,0x90(%rsp)
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1430140912-7960-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/entry_64.S | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 8f8b22a..60705b03 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -601,7 +601,7 @@ ENTRY(ret_from_fork)
RESTORE_EXTRA_REGS
- testl $3,CS(%rsp) # from kernel_thread?
+ testb $3, CS(%rsp) # from kernel_thread?
/*
* By the time we get here, we have no idea whether our pt_regs,
@@ -665,7 +665,7 @@ END(irq_entries_start)
leaq -RBP(%rsp),%rdi /* arg1 for \func (pointer to pt_regs) */
- testl $3, CS-RBP(%rsp)
+ testb $3, CS-RBP(%rsp)
jz 1f
SWAPGS
1:
@@ -720,7 +720,7 @@ ret_from_intr:
CFI_DEF_CFA_REGISTER rsp
CFI_ADJUST_CFA_OFFSET RBP
- testl $3,CS(%rsp)
+ testb $3, CS(%rsp)
jz retint_kernel
/* Interrupt came from user space */
@@ -968,7 +968,7 @@ ENTRY(\sym)
.if \paranoid
.if \paranoid == 1
CFI_REMEMBER_STATE
- testl $3, CS(%rsp) /* If coming from userspace, switch */
+ testb $3, CS(%rsp) /* If coming from userspace, switch */
jnz 1f /* stacks. */
.endif
call paranoid_entry
@@ -1309,7 +1309,7 @@ ENTRY(error_entry)
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
xorl %ebx,%ebx
- testl $3,CS+8(%rsp)
+ testb $3, CS+8(%rsp)
jz error_kernelspace
error_swapgs:
SWAPGS
@@ -1606,7 +1606,6 @@ end_repeat_nmi:
je 1f
movq %r12, %cr2
1:
-
testl %ebx,%ebx /* swapgs needed? */
jnz nmi_restore
nmi_swapgs:
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs
2015-04-27 13:21 [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs Denys Vlasenko
2015-04-27 13:21 ` [PATCH 2/2] x86/asm/entry/64: Clean up usage of TEST insns Denys Vlasenko
@ 2015-04-27 21:13 ` Andy Lutomirski
2015-04-27 22:16 ` H. Peter Anvin
2015-05-08 9:25 ` [tip:x86/asm] " tip-bot for Denys Vlasenko
3 siblings, 0 replies; 7+ messages in thread
From: Andy Lutomirski @ 2015-04-27 21:13 UTC (permalink / raw)
To: Denys Vlasenko
Cc: Ingo Molnar, Linus Torvalds, Steven Rostedt, Borislav Petkov,
H. Peter Anvin, Oleg Nesterov, Frederic Weisbecker,
Alexei Starovoitov, Will Drewry, Kees Cook, X86 ML,
linux-kernel@vger.kernel.org
On Mon, Apr 27, 2015 at 6:21 AM, Denys Vlasenko <dvlasenk@redhat.com> wrote:
> After TESTs, use logically correct JZ/JNZ mnemonics instead of JE/JNE.
> This doesn't change code.
>
Acked-by: Andy Lutomirski <luto@kernel.org>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs
2015-04-27 13:21 [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs Denys Vlasenko
2015-04-27 13:21 ` [PATCH 2/2] x86/asm/entry/64: Clean up usage of TEST insns Denys Vlasenko
2015-04-27 21:13 ` [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs Andy Lutomirski
@ 2015-04-27 22:16 ` H. Peter Anvin
2015-04-28 10:05 ` Denys Vlasenko
2015-05-08 9:25 ` [tip:x86/asm] " tip-bot for Denys Vlasenko
3 siblings, 1 reply; 7+ messages in thread
From: H. Peter Anvin @ 2015-04-27 22:16 UTC (permalink / raw)
To: Denys Vlasenko, Ingo Molnar
Cc: Linus Torvalds, Steven Rostedt, Borislav Petkov, Andy Lutomirski,
Oleg Nesterov, Frederic Weisbecker, Alexei Starovoitov,
Will Drewry, Kees Cook, x86, linux-kernel
On 04/27/2015 06:21 AM, Denys Vlasenko wrote:
>
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index e952f6b..8f8b22a 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -666,7 +666,7 @@ END(irq_entries_start)
> leaq -RBP(%rsp),%rdi /* arg1 for \func (pointer to pt_regs) */
>
> testl $3, CS-RBP(%rsp)
> - je 1f
> + jz 1f
> SWAPGS
> 1:
Please don't insert tabs between opcode and operand unless that is the
style of the surrounding code.
Otherwise this patchset looks good.
-hpa
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs
2015-04-27 22:16 ` H. Peter Anvin
@ 2015-04-28 10:05 ` Denys Vlasenko
0 siblings, 0 replies; 7+ messages in thread
From: Denys Vlasenko @ 2015-04-28 10:05 UTC (permalink / raw)
To: H. Peter Anvin, Ingo Molnar
Cc: Linus Torvalds, Steven Rostedt, Borislav Petkov, Andy Lutomirski,
Oleg Nesterov, Frederic Weisbecker, Alexei Starovoitov,
Will Drewry, Kees Cook, x86, linux-kernel
On 04/28/2015 12:16 AM, H. Peter Anvin wrote:
> On 04/27/2015 06:21 AM, Denys Vlasenko wrote:
>>
>> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
>> index e952f6b..8f8b22a 100644
>> --- a/arch/x86/kernel/entry_64.S
>> +++ b/arch/x86/kernel/entry_64.S
>> @@ -666,7 +666,7 @@ END(irq_entries_start)
>> leaq -RBP(%rsp),%rdi /* arg1 for \func (pointer to pt_regs) */
>>
>> testl $3, CS-RBP(%rsp)
>> - je 1f
>> + jz 1f
>> SWAPGS
>> 1:
>
> Please don't insert tabs between opcode and operand unless that is the
> style of the surrounding code.
The next patch inserts tab in the preceding TEST insn too,
converting entire mini-block of code to "tab" style.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [tip:x86/asm] x86/asm/entry/64: Tidy up JZ insns after TESTs
2015-04-27 13:21 [PATCH 1/2] x86/asm/entry/64: Tidy up JZ insns after TESTs Denys Vlasenko
` (2 preceding siblings ...)
2015-04-27 22:16 ` H. Peter Anvin
@ 2015-05-08 9:25 ` tip-bot for Denys Vlasenko
3 siblings, 0 replies; 7+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-05-08 9:25 UTC (permalink / raw)
To: linux-tip-commits
Cc: bp, linux-kernel, wad, oleg, keescook, dvlasenk, rostedt, tglx,
mingo, brgerst, fweisbec, torvalds, luto, ast, hpa
Commit-ID: dde74f2e4a4447ef838c57e407f7139de3df68cb
Gitweb: http://git.kernel.org/tip/dde74f2e4a4447ef838c57e407f7139de3df68cb
Author: Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Mon, 27 Apr 2015 15:21:51 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 May 2015 11:07:31 +0200
x86/asm/entry/64: Tidy up JZ insns after TESTs
After TESTs, use logically correct JZ/JNZ mnemonics instead of
JE/JNE. This doesn't change code.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1430140912-7960-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/entry_64.S | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index e952f6b..8f8b22a 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -666,7 +666,7 @@ END(irq_entries_start)
leaq -RBP(%rsp),%rdi /* arg1 for \func (pointer to pt_regs) */
testl $3, CS-RBP(%rsp)
- je 1f
+ jz 1f
SWAPGS
1:
/*
@@ -721,7 +721,7 @@ ret_from_intr:
CFI_ADJUST_CFA_OFFSET RBP
testl $3,CS(%rsp)
- je retint_kernel
+ jz retint_kernel
/* Interrupt came from user space */
GET_THREAD_INFO(%rcx)
@@ -1310,7 +1310,7 @@ ENTRY(error_entry)
SAVE_EXTRA_REGS 8
xorl %ebx,%ebx
testl $3,CS+8(%rsp)
- je error_kernelspace
+ jz error_kernelspace
error_swapgs:
SWAPGS
error_sti:
@@ -1361,7 +1361,7 @@ ENTRY(error_exit)
TRACE_IRQS_OFF
GET_THREAD_INFO(%rcx)
testl %eax,%eax
- jne retint_kernel
+ jnz retint_kernel
LOCKDEP_SYS_EXIT_IRQ
movl TI_flags(%rcx),%edx
movl $_TIF_WORK_MASK,%edi
^ permalink raw reply related [flat|nested] 7+ messages in thread