diff options
Diffstat (limited to 'arch/x86/kernel/entry_64.S')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 264 |
1 files changed, 156 insertions, 108 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 1e96c3628bf2..96987987c5de 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -36,7 +36,7 @@ * - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack * frame that is otherwise undefined after a SYSCALL * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging. - * - errorentry/paranoidentry/zeroentry - Define exception entry points. + * - idtentry - Define exception entry points. */ #include <linux/linkage.h> @@ -58,6 +58,7 @@ #include <asm/asm.h> #include <asm/context_tracking.h> #include <asm/smap.h> +#include <asm/pgtable_types.h> #include <linux/err.h> /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ @@ -1040,8 +1041,18 @@ restore_args: RESTORE_ARGS 1,8,1 irq_return: + /* + * Are we returning to a stack segment from the LDT? Note: in + * 64-bit mode SS:RSP on the exception stack is always valid. + */ +#ifdef CONFIG_X86_ESPFIX64 + testb $4,(SS-RIP)(%rsp) + jnz irq_return_ldt +#endif + +irq_return_iret: INTERRUPT_RETURN - _ASM_EXTABLE(irq_return, bad_iret) + _ASM_EXTABLE(irq_return_iret, bad_iret) #ifdef CONFIG_PARAVIRT ENTRY(native_iret) @@ -1049,6 +1060,32 @@ ENTRY(native_iret) _ASM_EXTABLE(native_iret, bad_iret) #endif +#ifdef CONFIG_X86_ESPFIX64 +irq_return_ldt: + pushq_cfi %rax + pushq_cfi %rdi + SWAPGS + movq PER_CPU_VAR(espfix_waddr),%rdi + movq %rax,(0*8)(%rdi) /* RAX */ + movq (2*8)(%rsp),%rax /* RIP */ + movq %rax,(1*8)(%rdi) + movq (3*8)(%rsp),%rax /* CS */ + movq %rax,(2*8)(%rdi) + movq (4*8)(%rsp),%rax /* RFLAGS */ + movq %rax,(3*8)(%rdi) + movq (6*8)(%rsp),%rax /* SS */ + movq %rax,(5*8)(%rdi) + movq (5*8)(%rsp),%rax /* RSP */ + movq %rax,(4*8)(%rdi) + andl $0xffff0000,%eax + popq_cfi %rdi + orq PER_CPU_VAR(espfix_stack),%rax + SWAPGS + movq %rax,%rsp + popq_cfi %rax + jmp irq_return_iret +#endif + .section .fixup,"ax" bad_iret: /* @@ -1110,9 +1147,45 @@ ENTRY(retint_kernel) call preempt_schedule_irq jmp exit_intr #endif - CFI_ENDPROC END(common_interrupt) + + /* + * If IRET takes a fault on the espfix stack, then we + * end up promoting it to a doublefault. In that case, + * modify the stack to make it look like we just entered + * the #GP handler from user space, similar to bad_iret. + */ +#ifdef CONFIG_X86_ESPFIX64 + ALIGN +__do_double_fault: + XCPT_FRAME 1 RDI+8 + movq RSP(%rdi),%rax /* Trap on the espfix stack? */ + sarq $PGDIR_SHIFT,%rax + cmpl $ESPFIX_PGD_ENTRY,%eax + jne do_double_fault /* No, just deliver the fault */ + cmpl $__KERNEL_CS,CS(%rdi) + jne do_double_fault + movq RIP(%rdi),%rax + cmpq $irq_return_iret,%rax +#ifdef CONFIG_PARAVIRT + je 1f + cmpq $native_iret,%rax +#endif + jne do_double_fault /* This shouldn't happen... */ +1: + movq PER_CPU_VAR(kernel_stack),%rax + subq $(6*8-KERNEL_STACK_OFFSET),%rax /* Reset to original stack */ + movq %rax,RSP(%rdi) + movq $0,(%rax) /* Missing (lost) #GP error code */ + movq $general_protection,RIP(%rdi) + retq + CFI_ENDPROC +END(__do_double_fault) +#else +# define __do_double_fault do_double_fault +#endif + /* * End of kprobes section */ @@ -1203,125 +1276,100 @@ apicinterrupt IRQ_WORK_VECTOR \ /* * Exception entry points. */ -.macro zeroentry sym do_sym -ENTRY(\sym) - INTR_FRAME - ASM_CLAC - PARAVIRT_ADJUST_EXCEPTION_FRAME - pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ - subq $ORIG_RAX-R15, %rsp - CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 - call error_entry - DEFAULT_FRAME 0 - movq %rsp,%rdi /* pt_regs pointer */ - xorl %esi,%esi /* no error code */ - call \do_sym - jmp error_exit /* %ebx: no swapgs flag */ - CFI_ENDPROC -END(\sym) -.endm +#define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8) -.macro paranoidzeroentry sym do_sym +.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ENTRY(\sym) - INTR_FRAME - ASM_CLAC - PARAVIRT_ADJUST_EXCEPTION_FRAME - pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ - subq $ORIG_RAX-R15, %rsp - CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 - call save_paranoid - TRACE_IRQS_OFF - movq %rsp,%rdi /* pt_regs pointer */ - xorl %esi,%esi /* no error code */ - call \do_sym - jmp paranoid_exit /* %ebx: no swapgs flag */ - CFI_ENDPROC -END(\sym) -.endm + /* Sanity check */ + .if \shift_ist != -1 && \paranoid == 0 + .error "using shift_ist requires paranoid=1" + .endif -#define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8) -.macro paranoidzeroentry_ist sym do_sym ist -ENTRY(\sym) + .if \has_error_code + XCPT_FRAME + .else INTR_FRAME - ASM_CLAC - PARAVIRT_ADJUST_EXCEPTION_FRAME - pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ - subq $ORIG_RAX-R15, %rsp - CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 - call save_paranoid - TRACE_IRQS_OFF_DEBUG - movq %rsp,%rdi /* pt_regs pointer */ - xorl %esi,%esi /* no error code */ - subq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist) - call \do_sym - addq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist) - jmp paranoid_exit /* %ebx: no swapgs flag */ - CFI_ENDPROC -END(\sym) -.endm + .endif -.macro errorentry sym do_sym -ENTRY(\sym) - XCPT_FRAME ASM_CLAC PARAVIRT_ADJUST_EXCEPTION_FRAME + + .ifeq \has_error_code + pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ + .endif + subq $ORIG_RAX-R15, %rsp CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 + + .if \paranoid + call save_paranoid + .else call error_entry + .endif + DEFAULT_FRAME 0 + + .if \paranoid + .if \shift_ist != -1 + TRACE_IRQS_OFF_DEBUG /* reload IDT in case of recursion */ + .else + TRACE_IRQS_OFF + .endif + .endif + movq %rsp,%rdi /* pt_regs pointer */ + + .if \has_error_code movq ORIG_RAX(%rsp),%rsi /* get error code */ movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */ + .else + xorl %esi,%esi /* no error code */ + .endif + + .if \shift_ist != -1 + subq $EXCEPTION_STKSZ, INIT_TSS_IST(\shift_ist) + .endif + call \do_sym + + .if \shift_ist != -1 + addq $EXCEPTION_STKSZ, INIT_TSS_IST(\shift_ist) + .endif + + .if \paranoid + jmp paranoid_exit /* %ebx: no swapgs flag */ + .else jmp error_exit /* %ebx: no swapgs flag */ + .endif + CFI_ENDPROC END(\sym) .endm #ifdef CONFIG_TRACING -.macro trace_errorentry sym do_sym -errorentry trace(\sym) trace(\do_sym) -errorentry \sym \do_sym +.macro trace_idtentry sym do_sym has_error_code:req +idtentry trace(\sym) trace(\do_sym) has_error_code=\has_error_code +idtentry \sym \do_sym has_error_code=\has_error_code .endm #else -.macro trace_errorentry sym do_sym -errorentry \sym \do_sym +.macro trace_idtentry sym do_sym has_error_code:req +idtentry \sym \do_sym has_error_code=\has_error_code .endm #endif - /* error code is on the stack already */ -.macro paranoiderrorentry sym do_sym -ENTRY(\sym) - XCPT_FRAME - ASM_CLAC - PARAVIRT_ADJUST_EXCEPTION_FRAME - subq $ORIG_RAX-R15, %rsp - CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 - call save_paranoid - DEFAULT_FRAME 0 - TRACE_IRQS_OFF - movq %rsp,%rdi /* pt_regs pointer */ - movq ORIG_RAX(%rsp),%rsi /* get error code */ - movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */ - call \do_sym - jmp paranoid_exit /* %ebx: no swapgs flag */ - CFI_ENDPROC -END(\sym) -.endm - -zeroentry divide_error do_divide_error -zeroentry overflow do_overflow -zeroentry bounds do_bounds -zeroentry invalid_op do_invalid_op -zeroentry device_not_available do_device_not_available -paranoiderrorentry double_fault do_double_fault -zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun -errorentry invalid_TSS do_invalid_TSS -errorentry segment_not_present do_segment_not_present -zeroentry spurious_interrupt_bug do_spurious_interrupt_bug -zeroentry coprocessor_error do_coprocessor_error -errorentry alignment_check do_alignment_check -zeroentry simd_coprocessor_error do_simd_coprocessor_error +idtentry divide_error do_divide_error has_error_code=0 +idtentry overflow do_overflow has_error_code=0 +idtentry bounds do_bounds has_error_code=0 +idtentry invalid_op do_invalid_op has_error_code=0 +idtentry device_not_available do_device_not_available has_error_code=0 +idtentry double_fault __do_double_fault has_error_code=1 paranoid=1 +idtentry coprocessor_segment_overrun do_coprocessor_segment_overrun has_error_code=0 +idtentry invalid_TSS do_invalid_TSS has_error_code=1 +idtentry segment_not_present do_segment_not_present has_error_code=1 +idtentry spurious_interrupt_bug do_spurious_interrupt_bug has_error_code=0 +idtentry coprocessor_error do_coprocessor_error has_error_code=0 +idtentry alignment_check do_alignment_check has_error_code=1 +idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0 /* Reload gs selector with exception handling */ @@ -1371,7 +1419,7 @@ ENTRY(do_softirq_own_stack) END(do_softirq_own_stack) #ifdef CONFIG_XEN -zeroentry xen_hypervisor_callback xen_do_hypervisor_callback +idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0 /* * A note on the "critical region" in our callback handler. @@ -1482,21 +1530,21 @@ apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ */ .pushsection .kprobes.text, "ax" -paranoidzeroentry_ist debug do_debug DEBUG_STACK -paranoidzeroentry_ist int3 do_int3 DEBUG_STACK -paranoiderrorentry stack_segment do_stack_segment +idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK +idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK +idtentry stack_segment do_stack_segment has_error_code=1 paranoid=1 #ifdef CONFIG_XEN -zeroentry xen_debug do_debug -zeroentry xen_int3 do_int3 -errorentry xen_stack_segment do_stack_segment +idtentry xen_debug do_debug has_error_code=0 +idtentry xen_int3 do_int3 has_error_code=0 +idtentry xen_stack_segment do_stack_segment has_error_code=1 #endif -errorentry general_protection do_general_protection -trace_errorentry page_fault do_page_fault +idtentry general_protection do_general_protection has_error_code=1 +trace_idtentry page_fault do_page_fault has_error_code=1 #ifdef CONFIG_KVM_GUEST -errorentry async_page_fault do_async_page_fault +idtentry async_page_fault do_async_page_fault has_error_code=1 #endif #ifdef CONFIG_X86_MCE -paranoidzeroentry machine_check *machine_check_vector(%rip) +idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip) #endif /* @@ -1601,7 +1649,7 @@ error_sti: */ error_kernelspace: incl %ebx - leaq irq_return(%rip),%rcx + leaq irq_return_iret(%rip),%rcx cmpq %rcx,RIP+8(%rsp) je error_swapgs movl %ecx,%eax /* zero extend */ |