From: Denys Vlasenko <dvlasenk@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@amacapital.net>,
Oleg Nesterov <oleg@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Alexei Starovoitov <ast@plumgrid.com>,
Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 3/9] x86/asm/entry/64: simplify retint_kernel label usage, make retint_restore_args label local
Date: Tue, 31 Mar 2015 19:00:05 +0200 [thread overview]
Message-ID: <1427821211-25099-3-git-send-email-dvlasenk@redhat.com> (raw)
In-Reply-To: <1427821211-25099-1-git-send-email-dvlasenk@redhat.com>
Get rid of #define obfuscation of retint_kernel in CONFIG_PREEMPT case
by defining retint_kernel label always, not only for CONFIG_PREEMPT.
Strip retint_kernel of .global-ness (ENTRY macro) - it has no users
outside of this file.
This looks like cosmetics, but it is not:
"je LABEL" can be optimized to short jump by assember
only if LABEL is not global, for global labels jump is always
a near one with relocation.
Convert retint_restore_args to a local numeric label, making it clearer
that it is not used elsewhere in the file.
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 | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index f6e37de..1879c55 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -57,10 +57,6 @@
.section .entry.text, "ax"
-#ifndef CONFIG_PREEMPT
-#define retint_kernel retint_restore_args
-#endif
-
#ifdef CONFIG_PARAVIRT
ENTRY(native_usergs_sysret64)
swapgs
@@ -741,18 +737,18 @@ opportunistic_sysret_failed:
jmp restore_args
/* Returning to kernel space */
+retint_kernel:
#ifdef CONFIG_PREEMPT
/* Interrupts are off */
/* Check if we need preemption */
-ENTRY(retint_kernel)
cmpl $0,PER_CPU_VAR(__preempt_count)
- jnz retint_restore_args
+ jnz 1f
bt $9,EFLAGS(%rsp) /* interrupts were off? */
- jnc retint_restore_args
+ jnc 1f
call preempt_schedule_irq
jmp exit_intr
+1:
#endif
-retint_restore_args:
DISABLE_INTERRUPTS(CLBR_ANY)
/*
* The iretq could re-enable interrupts:
--
1.8.1.4
next prev parent reply other threads:[~2015-03-31 17:01 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 ` Denys Vlasenko [this message]
2015-04-02 12:25 ` [tip:x86/asm] x86/asm/entry/64: Simplify retint_kernel label usage, make retint_restore_args label local 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:x86/asm] x86/asm: Replace "MOVQ $imm, %reg" " tip-bot for Denys Vlasenko
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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