From: Dominik Brodowski <linux@dominikbrodowski.net>
To: linux-kernel@vger.kernel.org, mingo@kernel.org, x86@kernel.org,
brgerst@gmail.com, luto@kernel.org, jpoimboe@redhat.com
Cc: torvalds@linux-foundation.org, ak@linux.intel.com,
tglx@linutronix.de, dan.j.williams@intel.com
Subject: [RFC PATCH v3 3/6] x86/entry/64: move switch_to_thread_stack to interrupt_entry
Date: Tue, 20 Feb 2018 22:01:10 +0100 [thread overview]
Message-ID: <20180220210113.6725-4-linux@dominikbrodowski.net> (raw)
In-Reply-To: <20180220210113.6725-1-linux@dominikbrodowski.net>
We can also move the CLD, SWAPGS, and the switch_to_thread_stack 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 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@dominikbrodowski.net>
---
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 7a6ae19962ec..b45d76649eff 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -537,6 +537,31 @@ END(irq_entries_start)
decl PER_CPU_VAR(irq_count)
.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.
*
@@ -544,8 +569,16 @@ END(irq_entries_start)
*
* 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)
--
2.16.2
next prev parent reply other threads:[~2018-02-20 21:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-20 21:01 [RFC PATCH v3 0/6] x86/entry/64: interrupt entry size reduction Dominik Brodowski
2018-02-20 21:01 ` [RFC PATCH v3 1/6] x86/entry/64: move PUSH_AND_CLEAR_REGS from interrupt macro to helper function Dominik Brodowski
2018-02-20 22:25 ` Linus Torvalds
2018-02-21 2:42 ` [PATCH] x86/entry/64: Simplify ENCODE_FRAME_POINTER Josh Poimboeuf
2018-02-21 10:50 ` [tip:x86/pti] " tip-bot for Josh Poimboeuf
2018-02-21 17:03 ` tip-bot for Josh Poimboeuf
2018-02-21 10:45 ` [tip:x86/pti] x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper function tip-bot for Dominik Brodowski
2018-02-21 16:58 ` tip-bot for Dominik Brodowski
2018-02-20 21:01 ` [RFC PATCH v3 2/6] x86/entry/64: move ENTER_IRQ_STACK from interrupt macro to interrupt_entry Dominik Brodowski
2018-02-21 10:46 ` [tip:x86/pti] x86/entry/64: Move " tip-bot for Dominik Brodowski
2018-02-21 16:59 ` tip-bot for Dominik Brodowski
2018-02-20 21:01 ` Dominik Brodowski [this message]
2018-02-21 10:46 ` [tip:x86/pti] x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry() tip-bot for Dominik Brodowski
2018-02-21 16:59 ` tip-bot for Dominik Brodowski
2018-02-20 21:01 ` [RFC PATCH v3 4/6] x86/entry/64: remove interrupt macro Dominik Brodowski
2018-02-21 10:47 ` [tip:x86/pti] x86/entry/64: Remove 'interrupt' macro tip-bot for Dominik Brodowski
2018-02-21 17:00 ` tip-bot for Dominik Brodowski
2018-02-20 21:01 ` [RFC PATCH v3 5/6] x86/entry/64: move ASM_CLAC to interrupt_entry Dominik Brodowski
2018-02-21 10:47 ` [tip:x86/pti] x86/entry/64: Move ASM_CLAC to interrupt_entry() tip-bot for Dominik Brodowski
2018-02-21 17:00 ` tip-bot for Dominik Brodowski
2018-02-20 21:01 ` [RFC PATCH v3 6/6] x86/entry/64: open-code switch_to_thread_stack Dominik Brodowski
2018-02-21 10:48 ` [tip:x86/pti] x86/entry/64: Open-code switch_to_thread_stack() tip-bot for Dominik Brodowski
2018-02-21 17:01 ` tip-bot for Dominik Brodowski
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