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From: tip-bot for Andy Lutomirski <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: dvlasenk@redhat.com, peterz@infradead.org,
	torvalds@linux-foundation.org, tglx@linutronix.de,
	riel@redhat.com, fweisbec@gmail.com, luto@kernel.org,
	bp@alien8.de, brgerst@gmail.com, vda.linux@googlemail.com,
	keescook@chromium.org, oleg@redhat.com, mingo@kernel.org,
	luto@amacapital.net, linux-kernel@vger.kernel.org, hpa@zytor.com
Subject: [tip:x86/asm] x86/asm/entry/64: Save all regs on interrupt entry
Date: Tue, 7 Jul 2015 03:52:50 -0700
Message-ID: <tip-ff467594f2a4be01a0fa5e9ffc223fa930d232dd@git.kernel.org> (raw)
In-Reply-To: <d8a766a7f558b30e6e01352854628a2d9943460c.1435952415.git.luto@kernel.org>

Commit-ID:  ff467594f2a4be01a0fa5e9ffc223fa930d232dd
Gitweb:     http://git.kernel.org/tip/ff467594f2a4be01a0fa5e9ffc223fa930d232dd
Author:     Andy Lutomirski <luto@kernel.org>
AuthorDate: Fri, 3 Jul 2015 12:44:29 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Jul 2015 10:59:07 +0200

x86/asm/entry/64: Save all regs on interrupt entry

To prepare for the big rewrite of the error and interrupt exit
paths, we will need pt_regs completely filled in.

It's already completely filled in when error_exit runs, so rearrange
interrupt handling to match it.  This will slow down interrupt
handling very slightly (eight instructions), but the
simplification it enables will be more than worth it.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.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: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/d8a766a7f558b30e6e01352854628a2d9943460c.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/entry/calling.h  |  3 ---
 arch/x86/entry/entry_64.S | 29 +++++++++--------------------
 2 files changed, 9 insertions(+), 23 deletions(-)

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 519207f..3c71dd9 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -135,9 +135,6 @@ For 32-bit we have the following conventions - kernel is built with
 	movq %rbp, 4*8+\offset(%rsp)
 	movq %rbx, 5*8+\offset(%rsp)
 	.endm
-	.macro SAVE_EXTRA_REGS_RBP offset=0
-	movq %rbp, 4*8+\offset(%rsp)
-	.endm
 
 	.macro RESTORE_EXTRA_REGS offset=0
 	movq 0*8+\offset(%rsp), %r15
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 4ca5b78..65029f4 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -502,21 +502,13 @@ END(irq_entries_start)
 /* 0(%rsp): ~(interrupt number) */
 	.macro interrupt func
 	cld
-	/*
-	 * Since nothing in interrupt handling code touches r12...r15 members
-	 * of "struct pt_regs", and since interrupts can nest, we can save
-	 * four stack slots and simultaneously provide
-	 * an unwind-friendly stack layout by saving "truncated" pt_regs
-	 * exactly up to rbp slot, without these members.
-	 */
-	ALLOC_PT_GPREGS_ON_STACK -RBP
-	SAVE_C_REGS -RBP
-	/* this goes to 0(%rsp) for unwinder, not for saving the value: */
-	SAVE_EXTRA_REGS_RBP -RBP
+	ALLOC_PT_GPREGS_ON_STACK
+	SAVE_C_REGS
+	SAVE_EXTRA_REGS
 
-	leaq	-RBP(%rsp), %rdi		/* arg1 for \func (pointer to pt_regs) */
+	movq	%rsp,%rdi	/* arg1 for \func (pointer to pt_regs) */
 
-	testb	$3, CS-RBP(%rsp)
+	testb	$3, CS(%rsp)
 	jz	1f
 	SWAPGS
 1:
@@ -553,9 +545,7 @@ ret_from_intr:
 	decl	PER_CPU_VAR(irq_count)
 
 	/* Restore saved previous stack */
-	popq	%rsi
-	/* return code expects complete pt_regs - adjust rsp accordingly: */
-	leaq	-RBP(%rsi), %rsp
+	popq	%rsp
 
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
@@ -580,7 +570,7 @@ retint_swapgs:					/* return to user-space */
 	TRACE_IRQS_IRETQ
 
 	SWAPGS
-	jmp	restore_c_regs_and_iret
+	jmp	restore_regs_and_iret
 
 /* Returning to kernel space */
 retint_kernel:
@@ -604,6 +594,8 @@ retint_kernel:
  * At this label, code paths which return to kernel and to user,
  * which come from interrupts/exception and from syscalls, merge.
  */
+restore_regs_and_iret:
+	RESTORE_EXTRA_REGS
 restore_c_regs_and_iret:
 	RESTORE_C_REGS
 	REMOVE_PT_GPREGS_FROM_STACK 8
@@ -674,12 +666,10 @@ retint_signal:
 	jz	retint_swapgs
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
-	SAVE_EXTRA_REGS
 	movq	$-1, ORIG_RAX(%rsp)
 	xorl	%esi, %esi			/* oldset */
 	movq	%rsp, %rdi			/* &pt_regs */
 	call	do_notify_resume
-	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 	GET_THREAD_INFO(%rcx)
@@ -1160,7 +1150,6 @@ END(error_entry)
  */
 ENTRY(error_exit)
 	movl	%ebx, %eax
-	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 	testl	%eax, %eax

  reply index

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-03 19:44 [PATCH v5 00/17] x86: Rewrite exit-to-userspace code Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 01/17] selftests/x86: Add a test for 32-bit fast syscall arg faults Andy Lutomirski
2015-07-07 10:49   ` [tip:x86/asm] x86/entry, " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 02/17] x86/entry/64/compat: Fix bad fast syscall arg failure path Andy Lutomirski
2015-07-07 10:49   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 03/17] uml: Fix do_signal() prototype Andy Lutomirski
2015-07-07 10:49   ` [tip:x86/asm] um: " tip-bot for Ingo Molnar
2015-07-03 19:44 ` [PATCH v5 04/17] context_tracking: Add ct_state and CT_WARN_ON Andy Lutomirski
2015-07-07 10:50   ` [tip:x86/asm] context_tracking: Add ct_state() and CT_WARN_ON() tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 05/17] notifiers: Assert that RCU is watching in notify_die Andy Lutomirski
2015-07-07 10:50   ` [tip:x86/asm] notifiers, RCU: Assert that RCU is watching in notify_die() tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 06/17] x86: Move C entry and exit code to arch/x86/entry/common.c Andy Lutomirski
2015-07-07 10:50   ` [tip:x86/asm] x86/entry: Move C entry and exit code to arch/x86/ entry/common.c tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 07/17] x86/traps: Assert that we're in CONTEXT_KERNEL in exception entries Andy Lutomirski
2015-07-07 10:51   ` [tip:x86/asm] x86/traps, context_tracking: Assert that we' re " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 08/17] x86/entry: Add enter_from_user_mode and use it in syscalls Andy Lutomirski
2015-07-07 10:51   ` [tip:x86/asm] x86/entry: Add enter_from_user_mode() " tip-bot for Andy Lutomirski
2015-07-14 23:00     ` Frederic Weisbecker
2015-07-14 23:04       ` Andy Lutomirski
2015-07-14 23:28         ` Frederic Weisbecker
2015-12-21 20:50   ` [PATCH v5 08/17] x86/entry: Add enter_from_user_mode " Sasha Levin
2015-12-21 22:44     ` Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 09/17] x86/entry: Add new, comprehensible entry and exit hooks Andy Lutomirski
2015-07-07 10:51   ` [tip:x86/asm] x86/entry: Add new, comprehensible entry and exit handlers written in C tip-bot for Andy Lutomirski
2015-07-14 23:07     ` Frederic Weisbecker
2015-07-15 19:56       ` Linus Torvalds
2015-07-15 20:46         ` Andy Lutomirski
2015-07-15 21:25           ` [PATCH] x86/entry: Fix _TIF_USER_RETURN_NOTIFY check in prepare_exit_to_usermode Andy Lutomirski
2015-07-18  3:25             ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 10/17] x86/entry/64: Really create an error-entry-from-usermode code path Andy Lutomirski
2015-07-07 10:52   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 11/17] x86/entry/64: Migrate 64-bit and compat syscalls to new exit hooks Andy Lutomirski
2015-07-07 10:52   ` [tip:x86/asm] x86/entry/64: Migrate 64-bit and compat syscalls to the new exit handlers and remove old assembly code tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 12/17] x86/asm/entry/64: Save all regs on interrupt entry Andy Lutomirski
2015-07-07 10:52   ` tip-bot for Andy Lutomirski [this message]
2015-07-03 19:44 ` [PATCH v5 13/17] x86/asm/entry/64: Simplify irq stack pt_regs handling Andy Lutomirski
2015-07-07 10:53   ` [tip:x86/asm] x86/asm/entry/64: Simplify IRQ " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 14/17] x86/asm/entry/64: Migrate error and interrupt exit work to C Andy Lutomirski
2015-07-07 10:53   ` [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code tip-bot for Andy Lutomirski
2015-08-11 22:18     ` Frederic Weisbecker
2015-08-11 22:25       ` Andy Lutomirski
2015-08-11 22:49         ` Frederic Weisbecker
2015-08-11 22:59           ` Andy Lutomirski
2015-08-12  1:02             ` Paul E. McKenney
2015-08-12 13:13             ` Frederic Weisbecker
2015-08-11 22:38     ` Frederic Weisbecker
2015-08-11 22:51       ` Andy Lutomirski
2015-08-11 23:22         ` Frederic Weisbecker
2015-08-11 23:33           ` Andy Lutomirski
2015-08-12 13:32             ` Frederic Weisbecker
2015-08-12 14:59               ` Andy Lutomirski
2015-08-18 22:34                 ` Frederic Weisbecker
2015-08-18 22:40                   ` Andy Lutomirski
2015-08-19 17:18                     ` Frederic Weisbecker
2015-08-19 18:02                       ` Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 15/17] x86/entry: Remove exception_enter from most trap handlers Andy Lutomirski
2015-07-07 10:53   ` [tip:x86/asm] x86/entry: Remove exception_enter() " tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 16/17] x86/entry: Remove SCHEDULE_USER and asm/context-tracking.h Andy Lutomirski
2015-07-07 10:54   ` [tip:x86/asm] x86/entry: Remove SCHEDULE_USER and asm/ context-tracking.h tip-bot for Andy Lutomirski
2015-07-03 19:44 ` [PATCH v5 17/17] x86/irq: Document how IRQ context tracking works and add an assertion Andy Lutomirski
2015-07-07 10:54   ` [tip:x86/asm] x86/irq, context_tracking: Document how IRQ context tracking works and add an RCU assertion tip-bot for Andy Lutomirski
2015-07-14 23:26     ` Frederic Weisbecker
2015-07-14 23:33       ` Andy Lutomirski
2015-07-18 13:23         ` Frederic Weisbecker
2015-07-18 14:10           ` Paul E. McKenney
2015-07-07 11:12 ` [PATCH v5 00/17] x86: Rewrite exit-to-userspace code Ingo Molnar
2015-07-07 16:03   ` Andy Lutomirski
2015-07-07 17:55     ` [PATCH] x86/entry/64: Fix warning on compat syscalls with CONFIG_AUDITSYSCALL=n Andy Lutomirski
2015-07-08  9:57       ` [tip:x86/asm] x86/entry/64: Fix IRQ state confusion and related warning on compat syscalls with CONFIG_AUDITSYSCALL =n tip-bot for Andy Lutomirski
2015-07-08 19:12       ` tip-bot for Andy Lutomirski

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