diff options
Diffstat (limited to 'arch/x86_64/kernel/entry.S')
| -rw-r--r-- | arch/x86_64/kernel/entry.S | 188 |
1 files changed, 136 insertions, 52 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S index ed92c298360..d464dded68c 100644 --- a/arch/x86_64/kernel/entry.S +++ b/arch/x86_64/kernel/entry.S @@ -41,13 +41,24 @@ #include <asm/thread_info.h> #include <asm/hw_irq.h> #include <asm/page.h> +#include <asm/irqflags.h> .code64 #ifndef CONFIG_PREEMPT #define retint_kernel retint_restore_args #endif - + + +.macro TRACE_IRQS_IRETQ offset=ARGOFFSET +#ifdef CONFIG_TRACE_IRQFLAGS + bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */ + jnc 1f + TRACE_IRQS_ON +1: +#endif +.endm + /* * C code is not supposed to know about undefined top of stack. Every time * a C function with an pt_regs argument is called from the SYSCALL based @@ -194,6 +205,10 @@ ENTRY(system_call) swapgs movq %rsp,%gs:pda_oldrsp movq %gs:pda_kernelstack,%rsp + /* + * No need to follow this irqs off/on section - it's straight + * and short: + */ sti SAVE_ARGS 8,1 movq %rax,ORIG_RAX-ARGOFFSET(%rsp) @@ -219,10 +234,15 @@ ret_from_sys_call: sysret_check: GET_THREAD_INFO(%rcx) cli + TRACE_IRQS_OFF movl threadinfo_flags(%rcx),%edx andl %edi,%edx CFI_REMEMBER_STATE jnz sysret_careful + /* + * sysretq will re-enable interrupts: + */ + TRACE_IRQS_ON movq RIP-ARGOFFSET(%rsp),%rcx CFI_REGISTER rip,rcx RESTORE_ARGS 0,-ARG_SKIP,1 @@ -237,6 +257,7 @@ sysret_careful: CFI_RESTORE_STATE bt $TIF_NEED_RESCHED,%edx jnc sysret_signal + TRACE_IRQS_ON sti pushq %rdi CFI_ADJUST_CFA_OFFSET 8 @@ -247,6 +268,7 @@ sysret_careful: /* Handle a signal */ sysret_signal: + TRACE_IRQS_ON sti testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx jz 1f @@ -261,6 +283,7 @@ sysret_signal: /* Use IRET because user could have changed frame. This works because ptregscall_common has called FIXUP_TOP_OF_STACK. */ cli + TRACE_IRQS_OFF jmp int_with_check badsys: @@ -309,6 +332,7 @@ ENTRY(int_ret_from_sys_call) CFI_REL_OFFSET r10,R10-ARGOFFSET CFI_REL_OFFSET r11,R11-ARGOFFSET cli + TRACE_IRQS_OFF testl $3,CS-ARGOFFSET(%rsp) je retint_restore_args movl $_TIF_ALLWORK_MASK,%edi @@ -327,6 +351,7 @@ int_with_check: int_careful: bt $TIF_NEED_RESCHED,%edx jnc int_very_careful + TRACE_IRQS_ON sti pushq %rdi CFI_ADJUST_CFA_OFFSET 8 @@ -334,10 +359,12 @@ int_careful: popq %rdi CFI_ADJUST_CFA_OFFSET -8 cli + TRACE_IRQS_OFF jmp int_with_check /* handle signals and tracing -- both require a full stack frame */ int_very_careful: + TRACE_IRQS_ON sti SAVE_REST /* Check for syscall exit trace */ @@ -351,6 +378,7 @@ int_very_careful: CFI_ADJUST_CFA_OFFSET -8 andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi cli + TRACE_IRQS_OFF jmp int_restore_rest int_signal: @@ -363,6 +391,7 @@ int_signal: int_restore_rest: RESTORE_REST cli + TRACE_IRQS_OFF jmp int_with_check CFI_ENDPROC END(int_ret_from_sys_call) @@ -484,6 +513,10 @@ END(stub_rt_sigreturn) swapgs 1: incl %gs:pda_irqcount # RED-PEN should check preempt count cmoveq %gs:pda_irqstackptr,%rsp + /* + * We entered an interrupt context - irqs are off: + */ + TRACE_IRQS_OFF call \func .endm @@ -493,6 +526,7 @@ ENTRY(common_interrupt) /* 0(%rsp): oldrsp-ARGOFFSET */ ret_from_intr: cli + TRACE_IRQS_OFF decl %gs:pda_irqcount leaveq CFI_DEF_CFA_REGISTER rsp @@ -515,9 +549,21 @@ retint_check: CFI_REMEMBER_STATE jnz retint_careful retint_swapgs: + /* + * The iretq could re-enable interrupts: + */ + cli + TRACE_IRQS_IRETQ swapgs + jmp restore_args + retint_restore_args: cli + /* + * The iretq could re-enable interrupts: + */ + TRACE_IRQS_IRETQ +restore_args: RESTORE_ARGS 0,8,0 iret_label: iretq @@ -530,6 +576,7 @@ iret_label: /* running with kernel gs */ bad_iret: movq $11,%rdi /* SIGSEGV */ + TRACE_IRQS_ON sti jmp do_exit .previous @@ -539,6 +586,7 @@ retint_careful: CFI_RESTORE_STATE bt $TIF_NEED_RESCHED,%edx jnc retint_signal + TRACE_IRQS_ON sti pushq %rdi CFI_ADJUST_CFA_OFFSET 8 @@ -547,11 +595,13 @@ retint_careful: CFI_ADJUST_CFA_OFFSET -8 GET_THREAD_INFO(%rcx) cli + TRACE_IRQS_OFF jmp retint_check retint_signal: testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx jz retint_swapgs + TRACE_IRQS_ON sti SAVE_REST movq $-1,ORIG_RAX(%rsp) @@ -560,6 +610,7 @@ retint_signal: call do_notify_resume RESTORE_REST cli + TRACE_IRQS_OFF movl $_TIF_NEED_RESCHED,%edi GET_THREAD_INFO(%rcx) jmp retint_check @@ -666,7 +717,7 @@ END(spurious_interrupt) /* error code is on the stack already */ /* handle NMI like exceptions that can happen everywhere */ - .macro paranoidentry sym, ist=0 + .macro paranoidentry sym, ist=0, irqtrace=1 SAVE_ALL cld movl $1,%ebx @@ -691,8 +742,73 @@ END(spurious_interrupt) addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) .endif cli + .if \irqtrace + TRACE_IRQS_OFF + .endif .endm - + + /* + * "Paranoid" exit path from exception stack. + * Paranoid because this is used by NMIs and cannot take + * any kernel state for granted. + * We don't do kernel preemption checks here, because only + * NMI should be common and it does not enable IRQs and + * cannot get reschedule ticks. + * + * "trace" is 0 for the NMI handler only, because irq-tracing + * 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: + testl %ebx,%ebx /* swapgs needed? */ + jnz paranoid_restore\trace + testl $3,CS(%rsp) + jnz paranoid_userspace\trace +paranoid_swapgs\trace: + TRACE_IRQS_IRETQ 0 + swapgs +paranoid_restore\trace: + RESTORE_ALL 8 + iretq +paranoid_userspace\trace: + GET_THREAD_INFO(%rcx) + movl threadinfo_flags(%rcx),%ebx + andl $_TIF_WORK_MASK,%ebx + jz paranoid_swapgs\trace + movq %rsp,%rdi /* &pt_regs */ + call sync_regs + movq %rax,%rsp /* switch stack for scheduling */ + testl $_TIF_NEED_RESCHED,%ebx + jnz paranoid_schedule\trace + movl %ebx,%edx /* arg3: thread flags */ + .if \trace + TRACE_IRQS_ON + .endif + sti + xorl %esi,%esi /* arg2: oldset */ + movq %rsp,%rdi /* arg1: &pt_regs */ + call do_notify_resume + cli + .if \trace + TRACE_IRQS_OFF + .endif + jmp paranoid_userspace\trace +paranoid_schedule\trace: + .if \trace + TRACE_IRQS_ON + .endif + sti + call schedule + cli + .if \trace + TRACE_IRQS_OFF + .endif + jmp paranoid_userspace\trace + CFI_ENDPROC + .endm + /* * Exception entry point. This expects an error code/orig_rax on the stack * and the exception handler in %rax. @@ -748,6 +864,7 @@ error_exit: movl %ebx,%eax RESTORE_REST cli + TRACE_IRQS_OFF GET_THREAD_INFO(%rcx) testl %eax,%eax jne retint_kernel @@ -755,6 +872,10 @@ error_exit: movl $_TIF_WORK_MASK,%edi andl %edi,%edx jnz retint_careful + /* + * The iret might restore flags: + */ + TRACE_IRQS_IRETQ swapgs RESTORE_ARGS 0,8,0 jmp iret_label @@ -916,8 +1037,7 @@ KPROBE_ENTRY(debug) pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_debug, DEBUG_STACK - jmp paranoid_exit - CFI_ENDPROC + paranoidexit END(debug) .previous .text @@ -926,49 +1046,13 @@ KPROBE_ENTRY(nmi) INTR_FRAME pushq $-1 CFI_ADJUST_CFA_OFFSET 8 - paranoidentry do_nmi - /* - * "Paranoid" exit path from exception stack. - * Paranoid because this is used by NMIs and cannot take - * any kernel state for granted. - * We don't do kernel preemption checks here, because only - * NMI should be common and it does not enable IRQs and - * cannot get reschedule ticks. - */ - /* ebx: no swapgs flag */ -paranoid_exit: - testl %ebx,%ebx /* swapgs needed? */ - jnz paranoid_restore - testl $3,CS(%rsp) - jnz paranoid_userspace -paranoid_swapgs: - swapgs -paranoid_restore: - RESTORE_ALL 8 - iretq -paranoid_userspace: - GET_THREAD_INFO(%rcx) - movl threadinfo_flags(%rcx),%ebx - andl $_TIF_WORK_MASK,%ebx - 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 - movl %ebx,%edx /* arg3: thread flags */ - sti - xorl %esi,%esi /* arg2: oldset */ - movq %rsp,%rdi /* arg1: &pt_regs */ - call do_notify_resume - cli - jmp paranoid_userspace -paranoid_schedule: - sti - call schedule - cli - jmp paranoid_userspace - CFI_ENDPROC + paranoidentry do_nmi, 0, 0 +#ifdef CONFIG_TRACE_IRQFLAGS + paranoidexit 0 +#else + jmp paranoid_exit1 + CFI_ENDPROC +#endif END(nmi) .previous .text @@ -977,7 +1061,7 @@ KPROBE_ENTRY(int3) pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_int3, DEBUG_STACK - jmp paranoid_exit + jmp paranoid_exit1 CFI_ENDPROC END(int3) .previous .text @@ -1006,7 +1090,7 @@ END(reserved) ENTRY(double_fault) XCPT_FRAME paranoidentry do_double_fault - jmp paranoid_exit + jmp paranoid_exit1 CFI_ENDPROC END(double_fault) @@ -1022,7 +1106,7 @@ END(segment_not_present) ENTRY(stack_segment) XCPT_FRAME paranoidentry do_stack_segment - jmp paranoid_exit + jmp paranoid_exit1 CFI_ENDPROC END(stack_segment) @@ -1050,7 +1134,7 @@ ENTRY(machine_check) pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_machine_check - jmp paranoid_exit + jmp paranoid_exit1 CFI_ENDPROC END(machine_check) #endif |