From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Nicolai Stange <nstange@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Shuah Khan <shuah@kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Mimi Zohar <zohar@linux.ibm.com>, Juergen Gross <jgross@suse.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Nayna Jain <nayna@linux.ibm.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Joerg Roedel <jroedel@suse.de>,
linux-kselftest@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH 1/4] x86/entry/32: Clean up return from interrupt preemption path
Date: Wed, 08 May 2019 09:49:02 +0200 [thread overview]
Message-ID: <20190508080612.665396175@infradead.org> (raw)
In-Reply-To: 20190508074901.982470324@infradead.org
The code flow around the return from interrupt preemption point seems
needlesly complicated.
There is only one site jumping to resume_kernel, and none (outside of
resume_kernel) jumping to restore_all_kernel. Inline resume_kernel
in restore_all_kernel and avoid the CONFIG_PREEMPT dependent label.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/entry/entry_32.S | 24 ++++++++++--------------
1 file changed, 10 insertions(+), 14 deletions(-)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -67,7 +67,6 @@
# define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
#else
# define preempt_stop(clobbers)
-# define resume_kernel restore_all_kernel
#endif
.macro TRACE_IRQS_IRET
@@ -755,7 +754,7 @@ END(ret_from_fork)
andl $SEGMENT_RPL_MASK, %eax
#endif
cmpl $USER_RPL, %eax
- jb resume_kernel # not returning to v8086 or userspace
+ jb restore_all_kernel # not returning to v8086 or userspace
ENTRY(resume_userspace)
DISABLE_INTERRUPTS(CLBR_ANY)
@@ -765,18 +764,6 @@ ENTRY(resume_userspace)
jmp restore_all
END(ret_from_exception)
-#ifdef CONFIG_PREEMPT
-ENTRY(resume_kernel)
- DISABLE_INTERRUPTS(CLBR_ANY)
- cmpl $0, PER_CPU_VAR(__preempt_count)
- jnz restore_all_kernel
- testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
- jz restore_all_kernel
- call preempt_schedule_irq
- jmp restore_all_kernel
-END(resume_kernel)
-#endif
-
GLOBAL(__begin_SYSENTER_singlestep_region)
/*
* All code from here through __end_SYSENTER_singlestep_region is subject
@@ -1027,6 +1014,15 @@ ENTRY(entry_INT80_32)
INTERRUPT_RETURN
restore_all_kernel:
+#ifdef CONFIG_PREEMPT
+ DISABLE_INTERRUPTS(CLBR_ANY)
+ cmpl $0, PER_CPU_VAR(__preempt_count)
+ jnz .Lno_preempt
+ testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
+ jz .Lno_preempt
+ call preempt_schedule_irq
+.Lno_preempt:
+#endif
TRACE_IRQS_IRET
PARANOID_EXIT_TO_KERNEL_MODE
BUG_IF_WRONG_CR3
next prev parent reply other threads:[~2019-05-08 8:12 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-08 7:49 [PATCH 0/4] x86: int3 fallout Peter Zijlstra
2019-05-08 7:49 ` Peter Zijlstra [this message]
2019-05-08 7:49 ` [PATCH 2/4] x86/kprobes: Fix frame pointer annotations Peter Zijlstra
2019-05-08 11:54 ` Josh Poimboeuf
2019-05-08 12:04 ` Peter Zijlstra
2019-05-08 12:40 ` Peter Zijlstra
2019-05-08 12:42 ` Josh Poimboeuf
2019-05-08 15:39 ` Peter Zijlstra
2019-05-08 18:48 ` Josh Poimboeuf
2019-05-09 1:20 ` Masami Hiramatsu
2019-05-09 8:14 ` Peter Zijlstra
2019-05-09 9:27 ` Peter Zijlstra
2019-05-09 14:00 ` Josh Poimboeuf
2019-05-09 14:01 ` Masami Hiramatsu
2019-05-09 17:14 ` Peter Zijlstra
2019-05-10 4:58 ` Masami Hiramatsu
2019-05-10 12:31 ` Peter Zijlstra
2019-05-11 0:52 ` Masami Hiramatsu
2019-05-10 12:40 ` Peter Zijlstra
2019-05-11 0:56 ` Masami Hiramatsu
2019-05-13 8:15 ` Peter Zijlstra
2019-05-09 16:20 ` Andy Lutomirski
2019-05-09 17:18 ` Peter Zijlstra
2019-05-09 17:43 ` Steven Rostedt
2019-05-10 3:21 ` Masami Hiramatsu
2019-05-10 12:14 ` Peter Zijlstra
2019-05-10 12:17 ` Peter Zijlstra
2019-05-10 14:54 ` Steven Rostedt
2019-05-09 17:37 ` Steven Rostedt
2019-05-09 18:26 ` Peter Zijlstra
2019-05-09 18:36 ` Steven Rostedt
2019-05-08 7:49 ` [PATCH 3/4] x86/ftrace: Add pt_regs frame annotations Peter Zijlstra
2019-05-08 7:49 ` [RFC][PATCH 4/4] x86_32: Provide consistent pt_regs Peter Zijlstra
2019-05-08 11:57 ` Josh Poimboeuf
2019-05-08 12:46 ` Ingo Molnar
2019-05-08 20:58 ` Linus Torvalds
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