diff options
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 170 |
1 files changed, 93 insertions, 77 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 69808aaa6851..b83feb7d9464 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -249,7 +249,6 @@ GLOBAL(entry_SYSCALL_64_after_hwframe) */ syscall_return_via_sysret: /* rcx and r11 are already restored (see code above) */ - UNWIND_HINT_EMPTY POP_REGS pop_rdi=0 skip_r11rcx=1 /* @@ -258,6 +257,7 @@ syscall_return_via_sysret: */ movq %rsp, %rdi movq PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %rsp + UNWIND_HINT_EMPTY pushq RSP-RDI(%rdi) /* RSP */ pushq (%rdi) /* RDI */ @@ -512,7 +512,7 @@ END(spurious_entries_start) * +----------------------------------------------------+ */ ENTRY(interrupt_entry) - UNWIND_HINT_FUNC + UNWIND_HINT_IRET_REGS offset=16 ASM_CLAC cld @@ -544,9 +544,9 @@ ENTRY(interrupt_entry) pushq 5*8(%rdi) /* regs->eflags */ pushq 4*8(%rdi) /* regs->cs */ pushq 3*8(%rdi) /* regs->ip */ + UNWIND_HINT_IRET_REGS pushq 2*8(%rdi) /* regs->orig_ax */ pushq 8(%rdi) /* return address */ - UNWIND_HINT_FUNC movq (%rdi), %rdi jmp 2f @@ -637,6 +637,7 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode) */ movq %rsp, %rdi movq PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %rsp + UNWIND_HINT_EMPTY /* Copy the IRET frame to the trampoline stack. */ pushq 6*8(%rdi) /* SS */ @@ -866,18 +867,84 @@ 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) * 8) +.macro idtentry_part do_sym, has_error_code:req, read_cr2:req, paranoid:req, shift_ist=-1, ist_offset=0 + + .if \paranoid + call paranoid_entry + /* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */ + .else + call error_entry + .endif + UNWIND_HINT_REGS + + .if \read_cr2 + /* + * Store CR2 early so subsequent faults cannot clobber it. Use R12 as + * intermediate storage as RDX can be clobbered in enter_from_user_mode(). + * GET_CR2_INTO can clobber RAX. + */ + GET_CR2_INTO(%r12); + .endif + + .if \shift_ist != -1 + TRACE_IRQS_OFF_DEBUG /* reload IDT in case of recursion */ + .else + TRACE_IRQS_OFF + .endif + + .if \paranoid == 0 + testb $3, CS(%rsp) + jz .Lfrom_kernel_no_context_tracking_\@ + CALL_enter_from_user_mode +.Lfrom_kernel_no_context_tracking_\@: + .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 $\ist_offset, CPU_TSS_IST(\shift_ist) + .endif + + .if \read_cr2 + movq %r12, %rdx /* Move CR2 into 3rd argument */ + .endif + + call \do_sym + + .if \shift_ist != -1 + addq $\ist_offset, CPU_TSS_IST(\shift_ist) + .endif + + .if \paranoid + /* this procedure expect "no swapgs" flag in ebx */ + jmp paranoid_exit + .else + jmp error_exit + .endif + +.endm + /** * idtentry - Generate an IDT entry stub * @sym: Name of the generated entry point - * @do_sym: C function to be called - * @has_error_code: True if this IDT vector has an error code on the stack - * @paranoid: non-zero means that this vector may be invoked from + * @do_sym: C function to be called + * @has_error_code: True if this IDT vector has an error code on the stack + * @paranoid: non-zero means that this vector may be invoked from * kernel mode with user GSBASE and/or user CR3. * 2 is special -- see below. * @shift_ist: Set to an IST index if entries from kernel mode should - * decrement the IST stack so that nested entries get a + * decrement the IST stack so that nested entries get a * fresh stack. (This is for #DB, which has a nasty habit - * of recursing.) + * of recursing.) + * @create_gap: create a 6-word stack gap when coming from kernel mode. + * @read_cr2: load CR2 into the 3rd argument; done before calling any C code * * idtentry generates an IDT stub that sets up a usable kernel context, * creates struct pt_regs, and calls @do_sym. The stub has the following @@ -902,15 +969,19 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt * @paranoid == 2 is special: the stub will never switch stacks. This is for * #DF: if the thread stack is somehow unusable, we'll still get a useful OOPS. */ -.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 create_gap=0 +.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 create_gap=0 read_cr2=0 ENTRY(\sym) UNWIND_HINT_IRET_REGS offset=\has_error_code*8 /* Sanity check */ - .if \shift_ist != -1 && \paranoid == 0 + .if \shift_ist != -1 && \paranoid != 1 .error "using shift_ist requires paranoid=1" .endif + .if \create_gap && \paranoid + .error "using create_gap requires paranoid=0" + .endif + ASM_CLAC .if \has_error_code == 0 @@ -936,47 +1007,7 @@ ENTRY(\sym) .Lfrom_usermode_no_gap_\@: .endif - .if \paranoid - call paranoid_entry - .else - call error_entry - .endif - UNWIND_HINT_REGS - /* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */ - - .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 $\ist_offset, CPU_TSS_IST(\shift_ist) - .endif - - call \do_sym - - .if \shift_ist != -1 - addq $\ist_offset, CPU_TSS_IST(\shift_ist) - .endif - - /* these procedures expect "no swapgs" flag in ebx */ - .if \paranoid - jmp paranoid_exit - .else - jmp error_exit - .endif + idtentry_part \do_sym, \has_error_code, \read_cr2, \paranoid, \shift_ist, \ist_offset .if \paranoid == 1 /* @@ -985,21 +1016,9 @@ ENTRY(\sym) * run in real process context if user_mode(regs). */ .Lfrom_usermode_switch_stack_\@: - call error_entry - - 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 */ + idtentry_part \do_sym, \has_error_code, \read_cr2, paranoid=0 .endif - call \do_sym - - jmp error_exit - .endif _ASM_NOKPROBE(\sym) END(\sym) .endm @@ -1009,7 +1028,7 @@ 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=2 +idtentry double_fault do_double_fault has_error_code=1 paranoid=2 read_cr2=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 @@ -1176,10 +1195,10 @@ idtentry xendebug do_debug has_error_code=0 #endif idtentry general_protection do_general_protection has_error_code=1 -idtentry page_fault do_page_fault has_error_code=1 +idtentry page_fault do_page_fault has_error_code=1 read_cr2=1 #ifdef CONFIG_KVM_GUEST -idtentry async_page_fault do_async_page_fault has_error_code=1 +idtentry async_page_fault do_async_page_fault has_error_code=1 read_cr2=1 #endif #ifdef CONFIG_X86_MCE @@ -1286,20 +1305,11 @@ ENTRY(error_entry) movq %rax, %rsp /* switch stack */ ENCODE_FRAME_POINTER pushq %r12 - - /* - * We need to tell lockdep that IRQs are off. We can't do this until - * we fix gsbase, and we should do it before enter_from_user_mode - * (which can take locks). - */ - TRACE_IRQS_OFF - CALL_enter_from_user_mode ret .Lerror_entry_done_lfence: FENCE_SWAPGS_KERNEL_ENTRY .Lerror_entry_done: - TRACE_IRQS_OFF ret /* @@ -1706,11 +1716,17 @@ nmi_restore: iretq END(nmi) +#ifndef CONFIG_IA32_EMULATION +/* + * This handles SYSCALL from 32-bit code. There is no way to program + * MSRs to fully disable 32-bit SYSCALL. + */ ENTRY(ignore_sysret) UNWIND_HINT_EMPTY mov $-ENOSYS, %eax sysret END(ignore_sysret) +#endif ENTRY(rewind_stack_do_exit) UNWIND_HINT_FUNC @@ -1719,7 +1735,7 @@ ENTRY(rewind_stack_do_exit) movq PER_CPU_VAR(cpu_current_top_of_stack), %rax leaq -PTREGS_SIZE(%rax), %rsp - UNWIND_HINT_FUNC sp_offset=PTREGS_SIZE + UNWIND_HINT_REGS call do_exit END(rewind_stack_do_exit) |