Messages in this thread Patch in this message |  | | From | Dominik Brodowski <> | Subject | [RFC PATCH v2 5/5] x86/entry/64: open-code switch_to_thread_stack | Date | Sun, 18 Feb 2018 13:31:16 +0100 |
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Open-code the two instances which used switch_to_thread_stack. This allows us to remove the wrapper around DO_SWITCH_TO_THREAD_STACK.
While at it, update the UNWIND hint to reflect where the IRET frame is.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> --- arch/x86/entry/entry_64.S | 59 ++++++++++++++++------------------------ arch/x86/entry/entry_64_compat.S | 19 ++++++++++++- 2 files changed, 42 insertions(+), 36 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 0ac2b4865d58..fa61be457082 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -539,17 +539,36 @@ 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.) + * Interrupt entry/exit. + * + * Interrupt entry points save only callee clobbered registers in fast path. + * + * Entry runs with interrupts off. */ -.macro DO_SWITCH_TO_THREAD_STACK +/* 8(%rsp): ~(interrupt number) */ +ENTRY(interrupt_helper) + UNWIND_HINT_FUNC + cld + + testb $3, CS-ORIG_RAX+8(%rsp) + jz 1f + SWAPGS + + /* + * Switch to the thread stack. The IRET frame and orig_ax are + * on the stack, as well as the return address. RDI..R12 are + * not (yet) on the stack and space has not (yet) been + * allocated for them. + */ 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 + /* We have RDI, return address, and orig_ax on the stack on + * top of the IRET frame. That means offset=24 */ + UNWIND_HINT_IRET_REGS base=%rdi offset=24 pushq 7*8(%rdi) /* regs->ss */ pushq 6*8(%rdi) /* regs->rsp */ @@ -561,24 +580,6 @@ END(irq_entries_start) 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_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 @@ -880,18 +881,6 @@ 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) -#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 - cld - - 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) UNWIND_HINT_IRET_REGS offset=\has_error_code*8 diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 364ea4a207be..5b9503c7148d 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -350,7 +350,24 @@ ENTRY(entry_INT80_compat) pushq %rax /* pt_regs->orig_ax */ /* switch to thread stack expects orig_ax to be pushed */ - call 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 + /* We have RDI and orig_ax on the stack on top of the IRET frame. + * That means offset=16 */ + UNWIND_HINT_IRET_REGS base=%rdi offset=16 + + pushq 6*8(%rdi) /* regs->ss */ + pushq 5*8(%rdi) /* regs->rsp */ + pushq 4*8(%rdi) /* regs->eflags */ + pushq 3*8(%rdi) /* regs->cs */ + pushq 2*8(%rdi) /* regs->ip */ + pushq 1*8(%rdi) /* regs->orig_ax */ + + movq (%rdi), %rdi /* restore %rdi */ pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ -- 2.16.1
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