diff options
Diffstat (limited to 'arch/x86/kernel/entry_64.S')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 126 |
1 files changed, 91 insertions, 35 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 3fe8239fd8fb..cdc79b5cfcd9 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -320,7 +320,7 @@ ENDPROC(native_usergs_sysret64) movq %rsp, %rsi leaq -RBP(%rsp),%rdi /* arg1 for handler */ - testl $3, CS(%rdi) + testl $3, CS-RBP(%rsi) je 1f SWAPGS /* @@ -330,11 +330,10 @@ ENDPROC(native_usergs_sysret64) * moving irq_enter into assembly, which would be too much work) */ 1: incl PER_CPU_VAR(irq_count) - jne 2f - mov PER_CPU_VAR(irq_stack_ptr),%rsp + cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp CFI_DEF_CFA_REGISTER rsi -2: /* Store previous stack value */ + /* Store previous stack value */ pushq %rsi CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \ 0x77 /* DW_OP_breg7 */, 0, \ @@ -482,7 +481,12 @@ GLOBAL(system_call_after_swapgs) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) jnz tracesys system_call_fastpath: +#if __SYSCALL_MASK == ~0 cmpq $__NR_syscall_max,%rax +#else + andl $__SYSCALL_MASK,%eax + cmpl $__NR_syscall_max,%eax +#endif ja badsys movq %r10,%rcx call *sys_call_table(,%rax,8) # XXX: rip relative @@ -596,7 +600,12 @@ tracesys: */ LOAD_ARGS ARGOFFSET, 1 RESTORE_REST +#if __SYSCALL_MASK == ~0 cmpq $__NR_syscall_max,%rax +#else + andl $__SYSCALL_MASK,%eax + cmpl $__NR_syscall_max,%eax +#endif ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */ movq %r10,%rcx /* fixup for C */ call *sys_call_table(,%rax,8) @@ -736,6 +745,40 @@ ENTRY(stub_rt_sigreturn) CFI_ENDPROC END(stub_rt_sigreturn) +#ifdef CONFIG_X86_X32_ABI + PTREGSCALL stub_x32_sigaltstack, sys32_sigaltstack, %rdx + +ENTRY(stub_x32_rt_sigreturn) + CFI_STARTPROC + addq $8, %rsp + PARTIAL_FRAME 0 + SAVE_REST + movq %rsp,%rdi + FIXUP_TOP_OF_STACK %r11 + call sys32_x32_rt_sigreturn + movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer + RESTORE_REST + jmp int_ret_from_sys_call + CFI_ENDPROC +END(stub_x32_rt_sigreturn) + +ENTRY(stub_x32_execve) + CFI_STARTPROC + addq $8, %rsp + PARTIAL_FRAME 0 + SAVE_REST + FIXUP_TOP_OF_STACK %r11 + movq %rsp, %rcx + call sys32_execve + RESTORE_TOP_OF_STACK %r11 + movq %rax,RAX(%rsp) + RESTORE_REST + jmp int_ret_from_sys_call + CFI_ENDPROC +END(stub_x32_execve) + +#endif + /* * Build the entry stubs and pointer table with some assembler magic. * We pack 7 stubs into a single 32-byte chunk, which will fit in a @@ -813,7 +856,7 @@ ret_from_intr: /* Restore saved previous stack */ popq %rsi - CFI_DEF_CFA_REGISTER rsi + CFI_DEF_CFA rsi,SS+8-RBP /* reg/off reset after def_cfa_expr */ leaq ARGOFFSET-RBP(%rsi), %rsp CFI_DEF_CFA_REGISTER rsp CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET @@ -1530,12 +1573,20 @@ ENTRY(nmi) /* Use %rdx as out temp variable throughout */ pushq_cfi %rdx + CFI_REL_OFFSET rdx, 0 + + /* + * If %cs was not the kernel segment, then the NMI triggered in user + * space, which means it is definitely not nested. + */ + cmpl $__KERNEL_CS, 16(%rsp) + jne first_nmi /* * Check the special variable on the stack to see if NMIs are * executing. */ - cmp $1, -8(%rsp) + cmpl $1, -8(%rsp) je nested_nmi /* @@ -1547,6 +1598,7 @@ ENTRY(nmi) */ lea 6*8(%rsp), %rdx test_in_nmi rdx, 4*8(%rsp), nested_nmi, first_nmi + CFI_REMEMBER_STATE nested_nmi: /* @@ -1578,10 +1630,12 @@ nested_nmi: nested_nmi_out: popq_cfi %rdx + CFI_RESTORE rdx /* No need to check faults here */ INTERRUPT_RETURN + CFI_RESTORE_STATE first_nmi: /* * Because nested NMIs will use the pushed location that we @@ -1613,10 +1667,15 @@ first_nmi: * | pt_regs | * +-------------------------+ * - * The saved RIP is used to fix up the copied RIP that a nested - * NMI may zero out. The original stack frame and the temp storage + * The saved stack frame is used to fix up the copied stack frame + * that a nested NMI may change to make the interrupted NMI iret jump + * to the repeat_nmi. The original stack frame and the temp storage * is also used by nested NMIs and can not be trusted on exit. */ + /* Do not pop rdx, nested NMIs will corrupt that part of the stack */ + movq (%rsp), %rdx + CFI_RESTORE rdx + /* Set the NMI executing variable on the stack. */ pushq_cfi $1 @@ -1624,22 +1683,39 @@ first_nmi: .rept 5 pushq_cfi 6*8(%rsp) .endr + CFI_DEF_CFA_OFFSET SS+8-RIP + + /* Everything up to here is safe from nested NMIs */ + + /* + * If there was a nested NMI, the first NMI's iret will return + * here. But NMIs are still enabled and we can take another + * nested NMI. The nested NMI checks the interrupted RIP to see + * if it is between repeat_nmi and end_repeat_nmi, and if so + * it will just return, as we are about to repeat an NMI anyway. + * This makes it safe to copy to the stack frame that a nested + * NMI will update. + */ +repeat_nmi: + /* + * Update the stack variable to say we are still in NMI (the update + * is benign for the non-repeat case, where 1 was pushed just above + * to this very stack slot). + */ + movq $1, 5*8(%rsp) /* Make another copy, this one may be modified by nested NMIs */ .rept 5 pushq_cfi 4*8(%rsp) .endr - - /* Do not pop rdx, nested NMIs will corrupt it */ - movq 11*8(%rsp), %rdx + CFI_DEF_CFA_OFFSET SS+8-RIP +end_repeat_nmi: /* * Everything below this point can be preempted by a nested - * NMI if the first NMI took an exception. Repeated NMIs - * caused by an exception and nested NMI will start here, and - * can still be preempted by another NMI. + * NMI if the first NMI took an exception and reset our iret stack + * so that we repeat another NMI. */ -restart_nmi: pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ subq $ORIG_RAX-R15, %rsp CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 @@ -1668,26 +1744,6 @@ nmi_restore: CFI_ENDPROC END(nmi) - /* - * If an NMI hit an iret because of an exception or breakpoint, - * it can lose its NMI context, and a nested NMI may come in. - * In that case, the nested NMI will change the preempted NMI's - * stack to jump to here when it does the final iret. - */ -repeat_nmi: - INTR_FRAME - /* Update the stack variable to say we are still in NMI */ - movq $1, 5*8(%rsp) - - /* copy the saved stack back to copy stack */ - .rept 5 - pushq_cfi 4*8(%rsp) - .endr - - jmp restart_nmi - CFI_ENDPROC -end_repeat_nmi: - ENTRY(ignore_sysret) CFI_STARTPROC mov $-ENOSYS,%eax |