From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Steven Rostedt <rostedt@goodmis.org>,
Brian Gerst <brgerst@gmail.com>, Juergen Gross <jgross@suse.com>,
Frederic Weisbecker <frederic@kernel.org>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [patch part-III V2 02/23] x86/entry/64: Avoid pointless code when CONTEXT_TRACKING=n
Date: Mon, 09 Mar 2020 00:14:12 +0100 [thread overview]
Message-ID: <20200308231718.634477991@linutronix.de> (raw)
In-Reply-To: 20200308231410.905396057@linutronix.de
From: Thomas Gleixner <tglx@linutronix.de>
GAS cannot optimize out the test and conditional jump when context tracking
is disabled and CALL_enter_from_user_mode is an empty macro.
Wrap it in #ifdeffery. Will go away once all this is moved to C.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/entry_64.S | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -884,12 +884,14 @@ apicinterrupt IRQ_WORK_VECTOR irq_work
TRACE_IRQS_OFF
.endif
+#ifdef CONFIG_CONTEXT_TRACKING
.if \paranoid == 0
testb $3, CS(%rsp)
jz .Lfrom_kernel_no_context_tracking_\@
CALL_enter_from_user_mode
.Lfrom_kernel_no_context_tracking_\@:
.endif
+#endif
movq %rsp, %rdi /* pt_regs pointer */
next prev parent reply other threads:[~2020-03-08 23:24 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-08 23:14 [patch part-III V2 00/23] x86/entry: Consolidation - Part III (simple exceptions) Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 01/23] x86/traps: Split trap numbers out in a seperate header Thomas Gleixner
2020-03-08 23:14 ` Thomas Gleixner [this message]
2020-03-08 23:14 ` [patch part-III V2 03/23] x86/entry/64: Reorder idtentries Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 04/23] x86/entry: Distangle idtentry Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 05/23] x86/entry/32: Provide macro to emit IDT entry stubs Thomas Gleixner
2020-03-09 5:08 ` Brian Gerst
2020-03-09 7:01 ` Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 06/23] x86/idtentry: Provide macros to define/declare IDT entry points Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 07/23] x86/traps: Prepare for using DEFINE_IDTENTRY Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 08/23] x86/entry: Convert Divide Error to IDTENTRY Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 09/23] x86/entry: Convert Overflow exception " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 10/23] x86/entry: Convert Bounds " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 11/23] x86/entry: Convert Invalid Opcode " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 12/23] x86/entry: Convert Device not available " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 13/23] x86/entry: Convert Coprocessor segment overrun " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 14/23] x86/entry: Provide IDTENTRY_ERRORCODE Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 15/23] x86/entry: Convert Invalid TSS exception to IDTENTRY Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 16/23] x86/entry: Convert Segment not present " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 17/23] x86/entry: Convert Stack segment " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 18/23] x86/entry: Convert General protection " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 19/23] x86/entry: Convert Spurious interrupt bug " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 20/23] x86/entry: Convert Coprocessor error " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 21/23] x86/entry: Convert Alignment check " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 22/23] x86/entry: Convert SIMD coprocessor error " Thomas Gleixner
2020-03-08 23:14 ` [patch part-III V2 23/23] x86/entry/32: Convert IRET exception to IDTENTRY_SW Thomas Gleixner
2020-03-09 9:32 ` [patch part-III V2 00/23] x86/entry: Consolidation - Part III (simple exceptions) Jürgen Groß
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