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Message-ID: <tip-90a6acc4e7ebafa8672a7a1a5b23fbad3dd04130@git.kernel.org>
Date: Wed, 21 Feb 2018 08:59:41 -0800
From: tip-bot for Dominik Brodowski <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: hpa@...or.com, linux-kernel@...r.kernel.org,
torvalds@...ux-foundation.org, mingo@...nel.org,
dwmw2@...radead.org, brgerst@...il.com, tglx@...utronix.de,
luto@...nel.org, jpoimboe@...hat.com, linux@...inikbrodowski.net,
peterz@...radead.org, dvlasenk@...hat.com, bp@...en8.de
Subject: [tip:x86/pti] x86/entry/64: Move the switch_to_thread_stack() call
to interrupt_entry()
Commit-ID: 90a6acc4e7ebafa8672a7a1a5b23fbad3dd04130
Gitweb: https://git.kernel.org/tip/90a6acc4e7ebafa8672a7a1a5b23fbad3dd04130
Author: Dominik Brodowski <linux@...inikbrodowski.net>
AuthorDate: Tue, 20 Feb 2018 22:01:10 +0100
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 21 Feb 2018 16:54:04 +0100
x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry()
We can also move the CLD, SWAPGS, and the switch_to_thread_stack() call
to the interrupt_entry() helper function. As we do not want call depths
of two, convert switch_to_thread_stack() to a macro.
However, switch_to_thread_stack() has another user in entry_64_compat.S,
which currently expects it to be a function. To keep the code changes
in this patch minimal, create a wrapper function.
The switch to a macro means that there is some binary code duplication
if CONFIG_IA32_EMULATION=y is enabled. Therefore, the size reduction
differs whether CONFIG_IA32_EMULATION is enabled or not:
CONFIG_IA32_EMULATION=y (-0.13k):
text data bss dec hex filename
17158 0 0 17158 4306 entry_64.o-orig
17028 0 0 17028 4284 entry_64.o
CONFIG_IA32_EMULATION=n (-0.27k):
text data bss dec hex filename
17158 0 0 17158 4306 entry_64.o-orig
16882 0 0 16882 41f2 entry_64.o
Signed-off-by: Dominik Brodowski <linux@...inikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: David Woodhouse <dwmw2@...radead.org>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: dan.j.williams@...el.com
Link: http://lkml.kernel.org/r/20180220210113.6725-4-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
arch/x86/entry/entry_64.S | 66 ++++++++++++++++++++++++++---------------------
1 file changed, 37 insertions(+), 29 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 7a6ae19..b45d766 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -538,14 +538,47 @@ END(irq_entries_start)
.endm
/*
+ * Switch to the thread stack. This is called with the IRET frame and
+ * orig_ax on the stack. (That is, RDI..R12 are not on the stack and
+ * space has not been allocated for them.)
+ */
+.macro DO_SWITCH_TO_THREAD_STACK
+ pushq %rdi
+ /* Need to switch before accessing the thread stack. */
+ SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
+ movq %rsp, %rdi
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+ UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
+
+ pushq 7*8(%rdi) /* regs->ss */
+ pushq 6*8(%rdi) /* regs->rsp */
+ pushq 5*8(%rdi) /* regs->eflags */
+ pushq 4*8(%rdi) /* regs->cs */
+ pushq 3*8(%rdi) /* regs->ip */
+ pushq 2*8(%rdi) /* regs->orig_ax */
+ pushq 8(%rdi) /* return address */
+ UNWIND_HINT_FUNC
+
+ movq (%rdi), %rdi
+.endm
+
+/*
* Interrupt entry/exit.
*
* Interrupt entry points save only callee clobbered registers in fast path.
*
* Entry runs with interrupts off.
*/
+/* 8(%rsp): ~(interrupt number) */
ENTRY(interrupt_entry)
UNWIND_HINT_FUNC
+ cld
+
+ testb $3, CS-ORIG_RAX+8(%rsp)
+ jz 1f
+ SWAPGS
+ DO_SWITCH_TO_THREAD_STACK
+1:
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
@@ -577,14 +610,6 @@ END(interrupt_entry)
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
- cld
-
- testb $3, CS-ORIG_RAX(%rsp)
- jz 1f
- SWAPGS
- call switch_to_thread_stack
-1:
-
call interrupt_entry
UNWIND_HINT_REGS indirect=1
@@ -858,33 +883,16 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
*/
#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
-/*
- * Switch to the thread stack. This is called with the IRET frame and
- * orig_ax on the stack. (That is, RDI..R12 are not on the stack and
- * space has not been allocated for them.)
- */
+#if defined(CONFIG_IA32_EMULATION)
+/* entry_64_compat.S::entry_INT80_compat expects this to be an ASM function */
ENTRY(switch_to_thread_stack)
UNWIND_HINT_FUNC
- pushq %rdi
- /* Need to switch before accessing the thread stack. */
- SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
- movq %rsp, %rdi
- movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
-
- pushq 7*8(%rdi) /* regs->ss */
- pushq 6*8(%rdi) /* regs->rsp */
- pushq 5*8(%rdi) /* regs->eflags */
- pushq 4*8(%rdi) /* regs->cs */
- pushq 3*8(%rdi) /* regs->ip */
- pushq 2*8(%rdi) /* regs->orig_ax */
- pushq 8(%rdi) /* return address */
- UNWIND_HINT_FUNC
+ DO_SWITCH_TO_THREAD_STACK
- movq (%rdi), %rdi
ret
END(switch_to_thread_stack)
+#endif
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)
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