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Message-ID: <20081121154318.GA13014@mailshack.com> Date: Fri, 21 Nov 2008 16:43:18 +0100 From: Alexander van Heukelum <heukelum@...lshack.com> To: Ingo Molnar <mingo@...e.hu> Cc: LKML <linux-kernel@...r.kernel.org>, Andi Kleen <andi@...stfloor.org>, "H. Peter Anvin" <hpa@...or.com>, Jan Beulich <jbeulich@...ell.com>, Glauber Costa <gcosta@...hat.com>, Matt Mackall <mpm@...enic.com>, Thomas Gleixner <tglx@...utronix.de>, Nick Piggin <nickpiggin@...oo.com.au>, Cyrill Gorcunov <gorcunov@...il.com> Subject: [PATCH] x86: entry_64.S: Factor out save_paranoid and paranoid_exit. Also expand the paranoid_exit0 macro into nmi_exit inside the nmi stub in the case of enabled irq-tracing. This gives a few hundred bytes code size reduction. Signed-off-by: Alexander van Heukelum <heukelum@...tmail.fm> --- arch/x86/kernel/entry_64.S | 151 +++++++++++++++++++++++++++++-------------- 1 files changed, 102 insertions(+), 49 deletions(-) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index ef95c45..fad777b 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -353,6 +353,36 @@ ENTRY(save_rest) CFI_ENDPROC END(save_rest) +/* save complete stack frame */ +ENTRY(save_paranoid) + XCPT_FRAME 1 RDI+8 + cld + movq_cfi rdi, RDI+8 + movq_cfi rsi, RSI+8 + movq_cfi rdx, RDX+8 + movq_cfi rcx, RCX+8 + movq_cfi rax, RAX+8 + movq_cfi r8, R8+8 + movq_cfi r9, R9+8 + movq_cfi r10, R10+8 + movq_cfi r11, R11+8 + movq_cfi rbx, RBX+8 + movq_cfi rbp, RBP+8 + movq_cfi r12, R12+8 + movq_cfi r13, R13+8 + movq_cfi r14, R14+8 + movq_cfi r15, R15+8 + movl $1,%ebx + movl $MSR_GS_BASE,%ecx + rdmsr + testl %edx,%edx + js 1f /* negative -> in kernel */ + SWAPGS + xorl %ebx,%ebx +1: ret + CFI_ENDPROC +END(save_paranoid) + /* * A newly forked process directly context switches into this. */ @@ -1012,24 +1042,15 @@ END(spurious_interrupt) .endm /* error code is on the stack already */ - /* handle NMI like exceptions that can happen everywhere */ - .macro paranoidentry sym, ist=0, irqtrace=1 - SAVE_ALL - cld - movl $1,%ebx - movl $MSR_GS_BASE,%ecx - rdmsr - testl %edx,%edx - js 1f - SWAPGS - xorl %ebx,%ebx -1: + .macro paranoidentry sym ist=0 + subq $15*8, %rsp + CFI_ADJUST_CFA_OFFSET 15*8 + call save_paranoid + DEFAULT_FRAME 0 .if \ist movq %gs:pda_data_offset, %rbp .endif - .if \irqtrace TRACE_IRQS_OFF - .endif movq %rsp,%rdi movq ORIG_RAX(%rsp),%rsi movq $-1,ORIG_RAX(%rsp) @@ -1041,9 +1062,7 @@ END(spurious_interrupt) addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) .endif DISABLE_INTERRUPTS(CLBR_NONE) - .if \irqtrace TRACE_IRQS_OFF - .endif .endm /* @@ -1058,57 +1077,48 @@ END(spurious_interrupt) * is fundamentally NMI-unsafe. (we cannot change the soft and * hard flags at once, atomically) */ - .macro paranoidexit trace=1 + /* ebx: no swapgs flag */ -paranoid_exit\trace: +KPROBE_ENTRY(paranoid_exit) + INTR_FRAME testl %ebx,%ebx /* swapgs needed? */ - jnz paranoid_restore\trace + jnz paranoid_restore testl $3,CS(%rsp) - jnz paranoid_userspace\trace -paranoid_swapgs\trace: - .if \trace + jnz paranoid_userspace +paranoid_swapgs: TRACE_IRQS_IRETQ 0 - .endif SWAPGS_UNSAFE_STACK -paranoid_restore\trace: +paranoid_restore: RESTORE_ALL 8 jmp irq_return -paranoid_userspace\trace: +paranoid_userspace: GET_THREAD_INFO(%rcx) movl TI_flags(%rcx),%ebx andl $_TIF_WORK_MASK,%ebx - jz paranoid_swapgs\trace + jz paranoid_swapgs movq %rsp,%rdi /* &pt_regs */ call sync_regs movq %rax,%rsp /* switch stack for scheduling */ testl $_TIF_NEED_RESCHED,%ebx - jnz paranoid_schedule\trace + jnz paranoid_schedule movl %ebx,%edx /* arg3: thread flags */ - .if \trace TRACE_IRQS_ON - .endif ENABLE_INTERRUPTS(CLBR_NONE) xorl %esi,%esi /* arg2: oldset */ movq %rsp,%rdi /* arg1: &pt_regs */ call do_notify_resume DISABLE_INTERRUPTS(CLBR_NONE) - .if \trace TRACE_IRQS_OFF - .endif - jmp paranoid_userspace\trace -paranoid_schedule\trace: - .if \trace + jmp paranoid_userspace +paranoid_schedule: TRACE_IRQS_ON - .endif ENABLE_INTERRUPTS(CLBR_ANY) call schedule DISABLE_INTERRUPTS(CLBR_ANY) - .if \trace TRACE_IRQS_OFF - .endif - jmp paranoid_userspace\trace + jmp paranoid_userspace CFI_ENDPROC - .endm +END(paranoid_exit) /* * Exception entry point. This expects an error code/orig_rax on the stack. @@ -1326,20 +1336,63 @@ KPROBE_ENTRY(debug) pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_debug, DEBUG_STACK - paranoidexit + jmp paranoid_exit + CFI_ENDPROC KPROBE_END(debug) /* runs on exception stack */ KPROBE_ENTRY(nmi) INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME - pushq $-1 - CFI_ADJUST_CFA_OFFSET 8 - paranoidentry do_nmi, 0, 0 + pushq_cfi $-1 + subq $15*8, %rsp + CFI_ADJUST_CFA_OFFSET 15*8 + call save_paranoid + DEFAULT_FRAME 0 + /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ + movq %rsp,%rdi + movq ORIG_RAX(%rsp),%rsi + movq $-1,ORIG_RAX(%rsp) + call do_nmi + DISABLE_INTERRUPTS(CLBR_NONE) #ifdef CONFIG_TRACE_IRQFLAGS - paranoidexit 0 + /* paranoidexit; without TRACE_IRQS_OFF */ + /* ebx: no swapgs flag */ +nmi_exit: + testl %ebx,%ebx /* swapgs needed? */ + jnz nmi_restore + testl $3,CS(%rsp) + jnz nmi_userspace +nmi_swapgs: + SWAPGS_UNSAFE_STACK +nmi_restore: + RESTORE_ALL 8 + jmp irq_return +nmi_userspace: + GET_THREAD_INFO(%rcx) + movl TI_flags(%rcx),%ebx + andl $_TIF_WORK_MASK,%ebx + jz nmi_swapgs + movq %rsp,%rdi /* &pt_regs */ + call sync_regs + movq %rax,%rsp /* switch stack for scheduling */ + testl $_TIF_NEED_RESCHED,%ebx + jnz nmi_schedule + movl %ebx,%edx /* arg3: thread flags */ + ENABLE_INTERRUPTS(CLBR_NONE) + xorl %esi,%esi /* arg2: oldset */ + movq %rsp,%rdi /* arg1: &pt_regs */ + call do_notify_resume + DISABLE_INTERRUPTS(CLBR_NONE) + jmp nmi_userspace +nmi_schedule: + ENABLE_INTERRUPTS(CLBR_ANY) + call schedule + DISABLE_INTERRUPTS(CLBR_ANY) + jmp nmi_userspace + CFI_ENDPROC #else - jmp paranoid_exit1 + jmp paranoid_exit CFI_ENDPROC #endif KPROBE_END(nmi) @@ -1350,7 +1403,7 @@ KPROBE_ENTRY(int3) pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_int3, DEBUG_STACK - jmp paranoid_exit1 + jmp paranoid_exit CFI_ENDPROC KPROBE_END(int3) @@ -1375,7 +1428,7 @@ ENTRY(double_fault) XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME paranoidentry do_double_fault - jmp paranoid_exit1 + jmp paranoid_exit CFI_ENDPROC END(double_fault) @@ -1392,7 +1445,7 @@ ENTRY(stack_segment) XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME paranoidentry do_stack_segment - jmp paranoid_exit1 + jmp paranoid_exit CFI_ENDPROC END(stack_segment) @@ -1420,7 +1473,7 @@ ENTRY(machine_check) pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_machine_check - jmp paranoid_exit1 + jmp paranoid_exit CFI_ENDPROC END(machine_check) #endif -- 1.5.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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