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From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: "Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Rik van Riel" <riel@redhat.com>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Denys Vlasenko" <vda.linux@googlemail.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Kees Cook" <keescook@chromium.org>,
	"Brian Gerst" <brgerst@gmail.com>,
	"Andy Lutomirski" <luto@kernel.org>
Subject: [RFC/INCOMPLETE 11/13] x86/asm/entry/64: Simplify irq stack pt_regs handling
Date: Tue, 16 Jun 2015 13:16:57 -0700	[thread overview]
Message-ID: <c75155bc8136d91b13aa6181d1870571eb08a982.1434485184.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1434485184.git.luto@kernel.org>
In-Reply-To: <cover.1434485184.git.luto@kernel.org>

There's no need for both rsi and rdi to point to the original stack.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/entry/entry_64.S | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 43bf5762443c..ab8cbf602d19 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -505,8 +505,6 @@ END(irq_entries_start)
 	SAVE_C_REGS
 	SAVE_EXTRA_REGS
 
-	movq	%rsp,%rdi	/* arg1 for \func (pointer to pt_regs) */
-
 	testb	$3, CS(%rsp)
 	jz	1f
 	SWAPGS
@@ -518,14 +516,14 @@ END(irq_entries_start)
 	 * a little cheaper to use a separate counter in the PDA (short of
 	 * moving irq_enter into assembly, which would be too much work)
 	 */
-	movq	%rsp, %rsi
+	movq	%rsp, %rdi
 	incl	PER_CPU_VAR(irq_count)
 	cmovzq	PER_CPU_VAR(irq_stack_ptr), %rsp
-	pushq	%rsi
+	pushq	%rdi
 	/* We entered an interrupt context - irqs are off: */
 	TRACE_IRQS_OFF
 
-	call	\func
+	call	\func	/* rdi points to pt_regs */
 	.endm
 
 	/*
-- 
2.4.3


  parent reply	other threads:[~2015-06-16 20:19 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-16 20:16 [RFC/INCOMPLETE 00/13] x86: Rewrite exit-to-userspace code Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 01/13] context_tracking: Add context_tracking_assert_state Andy Lutomirski
2015-06-17  9:41   ` Ingo Molnar
2015-06-17 14:15     ` Andy Lutomirski
2015-06-18  9:57       ` Ingo Molnar
2015-06-18 11:07         ` Andy Lutomirski
2015-06-18 15:52           ` Andy Lutomirski
2015-06-18 16:17             ` Ingo Molnar
2015-06-18 16:26               ` Frederic Weisbecker
2015-06-18 19:26                 ` Andy Lutomirski
2015-06-17 15:27     ` Paul E. McKenney
2015-06-18  9:59       ` Ingo Molnar
2015-06-18 22:54         ` Paul E. McKenney
2015-06-19  2:19           ` Paul E. McKenney
2015-06-30 11:04           ` Ingo Molnar
2015-06-30 16:16             ` Paul E. McKenney
2015-06-16 20:16 ` [RFC/INCOMPLETE 02/13] notifiers: Assert that RCU is watching in notify_die Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 03/13] x86: Move C entry and exit code to arch/x86/entry/common.c Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 04/13] x86/traps: Assert that we're in CONTEXT_KERNEL in exception entries Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 05/13] x86/entry: Add enter_from_user_mode and use it in syscalls Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 06/13] x86/entry: Add new, comprehensible entry and exit hooks Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 07/13] x86/entry/64: Really create an error-entry-from-usermode code path Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 08/13] x86/entry/64: Migrate 64-bit syscalls to new exit hooks Andy Lutomirski
2015-06-17 10:00   ` Ingo Molnar
2015-06-17 10:02     ` Ingo Molnar
2015-06-17 14:12       ` Andy Lutomirski
2015-06-18 10:17         ` Ingo Molnar
2015-06-18 10:19           ` Ingo Molnar
2015-06-16 20:16 ` [RFC/INCOMPLETE 09/13] x86/entry/compat: Migrate compat " Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 10/13] x86/asm/entry/64: Save all regs on interrupt entry Andy Lutomirski
2015-06-16 20:16 ` Andy Lutomirski [this message]
2015-06-16 20:16 ` [RFC/INCOMPLETE 12/13] x86/asm/entry/64: Migrate error and interrupt exit work to C Andy Lutomirski
2015-06-16 20:16 ` [RFC/INCOMPLETE 13/13] x86/entry: Remove SCHEDULE_USER and asm/context-tracking.h Andy Lutomirski
2015-06-17  9:48 ` [RFC/INCOMPLETE 00/13] x86: Rewrite exit-to-userspace code Ingo Molnar
2015-06-17 10:13   ` Richard Weinberger
2015-06-17 11:04     ` Ingo Molnar
2015-06-17 14:19     ` Andy Lutomirski
2015-06-17 15:16   ` Andy Lutomirski
2015-06-18 10:14     ` Ingo Molnar
2015-06-17 10:32 ` Ingo Molnar
2015-06-17 11:14   ` Ingo Molnar
2015-06-17 14:23   ` Andy Lutomirski
2015-06-18 10:11     ` Ingo Molnar
2015-06-18 11:06       ` Andy Lutomirski
2015-06-18 16:24         ` Ingo Molnar

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