From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161891AbeBNSWh (ORCPT ); Wed, 14 Feb 2018 13:22:37 -0500 Received: from isilmar-4.linta.de ([136.243.71.142]:48090 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161764AbeBNSWe (ORCPT ); Wed, 14 Feb 2018 13:22:34 -0500 From: Dominik Brodowski To: linux-kernel@vger.kernel.org, mingo@kernel.org, x86@kernel.org Cc: torvalds@linux-foundation.org, luto@kernel.org, ak@linux.intel.com, tglx@linutronix.de, dan.j.williams@intel.com Subject: [RFC PATCH 3/4] x86/entry/64: move switch_to_thread_stack to interrupt helper function Date: Wed, 14 Feb 2018 19:21:12 +0100 Message-Id: <20180214182113.27247-4-linux@dominikbrodowski.net> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180214182113.27247-1-linux@dominikbrodowski.net> References: <20180214182113.27247-1-linux@dominikbrodowski.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We can also move the SWAPGS and the switch_to_thread_stack to the interrupt helper function. As we do not want call depths of two, convert switch_to_thread_stack to a macro. However, as entry_64_compat.S expects switch_to_thread_stack to be a function, provide a wrapper for that, which leads to some code duplication if CONFIG_IA32_EMULATION is enabled. Therefore, the size reduction differs slightly: With CONFIG_IA32_EMULATION enabled (-0.13k): text data bss dec hex filename 16897 0 0 16897 4201 entry_64.o-orig 16767 0 0 16767 417f entry_64.o With CONFIG_IA32_EMULATION disabled (-0.27k): text data bss dec hex filename 16897 0 0 16897 4201 entry_64.o-orig 16622 0 0 16622 40ee entry_64.o Signed-off-by: Dominik Brodowski --- arch/x86/entry/entry_64.S | 65 ++++++++++++++++++++++++++--------------------- 1 file changed, 36 insertions(+), 29 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3046b12a1acb..b60a3b692ca9 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -536,6 +536,31 @@ 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. * @@ -543,10 +568,17 @@ END(irq_entries_start) * * Entry runs with interrupts off. */ +/* 8(%rsp): ~(interrupt number) */ ENTRY(interrupt_helper) 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 @@ -579,12 +611,6 @@ END(interrupt_helper) .macro interrupt func cld - testb $3, CS-ORIG_RAX(%rsp) - jz 1f - SWAPGS - call switch_to_thread_stack -1: - call interrupt_helper call \func /* rdi points to pt_regs */ @@ -853,33 +879,14 @@ 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 - - movq (%rdi), %rdi + DO_SWITCH_TO_THREAD_STACK ret END(switch_to_thread_stack) +#endif .macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ENTRY(\sym) -- 2.16.1