diff options
Diffstat (limited to 'arch/x86/entry/entry_32.S')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 233 |
1 files changed, 168 insertions, 65 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 7b23431be5cb..4f86928246e7 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -67,7 +67,6 @@ # define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF #else # define preempt_stop(clobbers) -# define resume_kernel restore_all_kernel #endif .macro TRACE_IRQS_IRET @@ -203,9 +202,104 @@ .Lend_\@: .endm -.macro SAVE_ALL pt_regs_ax=%eax switch_stacks=0 +#define CS_FROM_ENTRY_STACK (1 << 31) +#define CS_FROM_USER_CR3 (1 << 30) +#define CS_FROM_KERNEL (1 << 29) + +.macro FIXUP_FRAME + /* + * The high bits of the CS dword (__csh) are used for CS_FROM_*. + * Clear them in case hardware didn't do this for us. + */ + andl $0x0000ffff, 3*4(%esp) + +#ifdef CONFIG_VM86 + testl $X86_EFLAGS_VM, 4*4(%esp) + jnz .Lfrom_usermode_no_fixup_\@ +#endif + testl $SEGMENT_RPL_MASK, 3*4(%esp) + jnz .Lfrom_usermode_no_fixup_\@ + + orl $CS_FROM_KERNEL, 3*4(%esp) + + /* + * When we're here from kernel mode; the (exception) stack looks like: + * + * 5*4(%esp) - <previous context> + * 4*4(%esp) - flags + * 3*4(%esp) - cs + * 2*4(%esp) - ip + * 1*4(%esp) - orig_eax + * 0*4(%esp) - gs / function + * + * Lets build a 5 entry IRET frame after that, such that struct pt_regs + * is complete and in particular regs->sp is correct. This gives us + * the original 5 enties as gap: + * + * 12*4(%esp) - <previous context> + * 11*4(%esp) - gap / flags + * 10*4(%esp) - gap / cs + * 9*4(%esp) - gap / ip + * 8*4(%esp) - gap / orig_eax + * 7*4(%esp) - gap / gs / function + * 6*4(%esp) - ss + * 5*4(%esp) - sp + * 4*4(%esp) - flags + * 3*4(%esp) - cs + * 2*4(%esp) - ip + * 1*4(%esp) - orig_eax + * 0*4(%esp) - gs / function + */ + + pushl %ss # ss + pushl %esp # sp (points at ss) + addl $6*4, (%esp) # point sp back at the previous context + pushl 6*4(%esp) # flags + pushl 6*4(%esp) # cs + pushl 6*4(%esp) # ip + pushl 6*4(%esp) # orig_eax + pushl 6*4(%esp) # gs / function +.Lfrom_usermode_no_fixup_\@: +.endm + +.macro IRET_FRAME + testl $CS_FROM_KERNEL, 1*4(%esp) + jz .Lfinished_frame_\@ + + /* + * Reconstruct the 3 entry IRET frame right after the (modified) + * regs->sp without lowering %esp in between, such that an NMI in the + * middle doesn't scribble our stack. + */ + pushl %eax + pushl %ecx + movl 5*4(%esp), %eax # (modified) regs->sp + + movl 4*4(%esp), %ecx # flags + movl %ecx, -4(%eax) + + movl 3*4(%esp), %ecx # cs + andl $0x0000ffff, %ecx + movl %ecx, -8(%eax) + + movl 2*4(%esp), %ecx # ip + movl %ecx, -12(%eax) + + movl 1*4(%esp), %ecx # eax + movl %ecx, -16(%eax) + + popl %ecx + lea -16(%eax), %esp + popl %eax +.Lfinished_frame_\@: +.endm + +.macro SAVE_ALL pt_regs_ax=%eax switch_stacks=0 skip_gs=0 cld +.if \skip_gs == 0 PUSH_GS +.endif + FIXUP_FRAME pushl %fs pushl %es pushl %ds @@ -221,13 +315,13 @@ movl %edx, %es movl $(__KERNEL_PERCPU), %edx movl %edx, %fs +.if \skip_gs == 0 SET_KERNEL_GS %edx - +.endif /* Switch to kernel stack if necessary */ .if \switch_stacks > 0 SWITCH_TO_KERNEL_STACK .endif - .endm .macro SAVE_ALL_NMI cr3_reg:req @@ -247,22 +341,6 @@ .Lend_\@: .endm -/* - * This is a sneaky trick to help the unwinder find pt_regs on the stack. The - * frame pointer is replaced with an encoded pointer to pt_regs. The encoding - * is just clearing the MSB, which makes it an invalid stack address and is also - * a signal to the unwinder that it's a pt_regs pointer in disguise. - * - * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the - * original rbp. - */ -.macro ENCODE_FRAME_POINTER -#ifdef CONFIG_FRAME_POINTER - mov %esp, %ebp - andl $0x7fffffff, %ebp -#endif -.endm - .macro RESTORE_INT_REGS popl %ebx popl %ecx @@ -375,9 +453,6 @@ * switch to it before we do any copying. */ -#define CS_FROM_ENTRY_STACK (1 << 31) -#define CS_FROM_USER_CR3 (1 << 30) - .macro SWITCH_TO_KERNEL_STACK ALTERNATIVE "", "jmp .Lend_\@", X86_FEATURE_XENPV @@ -391,13 +466,6 @@ * that register for the time this macro runs */ - /* - * The high bits of the CS dword (__csh) are used for - * CS_FROM_ENTRY_STACK and CS_FROM_USER_CR3. Clear them in case - * hardware didn't do this for us. - */ - andl $(0x0000ffff), PT_CS(%esp) - /* Are we on the entry stack? Bail out if not! */ movl PER_CPU_VAR(cpu_entry_area), %ecx addl $CPU_ENTRY_AREA_entry_stack + SIZEOF_entry_stack, %ecx @@ -755,7 +823,7 @@ ret_from_intr: andl $SEGMENT_RPL_MASK, %eax #endif cmpl $USER_RPL, %eax - jb resume_kernel # not returning to v8086 or userspace + jb restore_all_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) DISABLE_INTERRUPTS(CLBR_ANY) @@ -765,18 +833,6 @@ ENTRY(resume_userspace) jmp restore_all END(ret_from_exception) -#ifdef CONFIG_PREEMPT -ENTRY(resume_kernel) - DISABLE_INTERRUPTS(CLBR_ANY) - cmpl $0, PER_CPU_VAR(__preempt_count) - jnz restore_all_kernel - testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ? - jz restore_all_kernel - call preempt_schedule_irq - jmp restore_all_kernel -END(resume_kernel) -#endif - GLOBAL(__begin_SYSENTER_singlestep_region) /* * All code from here through __end_SYSENTER_singlestep_region is subject @@ -1019,6 +1075,7 @@ restore_all: /* Restore user state */ RESTORE_REGS pop=4 # skip orig_eax/error_code .Lirq_return: + IRET_FRAME /* * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization * when returning from IPI handler and when returning from @@ -1027,6 +1084,15 @@ restore_all: INTERRUPT_RETURN restore_all_kernel: +#ifdef CONFIG_PREEMPT + DISABLE_INTERRUPTS(CLBR_ANY) + cmpl $0, PER_CPU_VAR(__preempt_count) + jnz .Lno_preempt + testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ? + jz .Lno_preempt + call preempt_schedule_irq +.Lno_preempt: +#endif TRACE_IRQS_IRET PARANOID_EXIT_TO_KERNEL_MODE BUG_IF_WRONG_CR3 @@ -1104,6 +1170,30 @@ ENTRY(irq_entries_start) .endr END(irq_entries_start) +#ifdef CONFIG_X86_LOCAL_APIC + .align 8 +ENTRY(spurious_entries_start) + vector=FIRST_SYSTEM_VECTOR + .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR) + pushl $(~vector+0x80) /* Note: always in signed byte range */ + vector=vector+1 + jmp common_spurious + .align 8 + .endr +END(spurious_entries_start) + +common_spurious: + ASM_CLAC + addl $-0x80, (%esp) /* Adjust vector into the [-256, -1] range */ + SAVE_ALL switch_stacks=1 + ENCODE_FRAME_POINTER + TRACE_IRQS_OFF + movl %esp, %eax + call smp_spurious_interrupt + jmp ret_from_intr +ENDPROC(common_spurious) +#endif + /* * the CPU automatically disables interrupts when executing an IRQ vector, * so IRQ-flags tracing has to follow that: @@ -1354,37 +1444,50 @@ BUILD_INTERRUPT3(hv_stimer0_callback_vector, HYPERV_STIMER0_VECTOR, ENTRY(page_fault) ASM_CLAC pushl $do_page_fault - ALIGN - jmp common_exception + jmp common_exception_read_cr2 END(page_fault) -common_exception: +common_exception_read_cr2: /* the function address is in %gs's slot on the stack */ - pushl %fs - pushl %es - pushl %ds - pushl %eax - movl $(__USER_DS), %eax - movl %eax, %ds - movl %eax, %es - movl $(__KERNEL_PERCPU), %eax - movl %eax, %fs - pushl %ebp - pushl %edi - pushl %esi - pushl %edx - pushl %ecx - pushl %ebx - SWITCH_TO_KERNEL_STACK + SAVE_ALL switch_stacks=1 skip_gs=1 + ENCODE_FRAME_POINTER - cld UNWIND_ESPFIX_STACK + + /* fixup %gs */ GS_TO_REG %ecx - movl PT_GS(%esp), %edi # get the function address + movl PT_GS(%esp), %edi + REG_TO_PTGS %ecx + SET_KERNEL_GS %ecx + + GET_CR2_INTO(%ecx) # might clobber %eax + + /* fixup orig %eax */ movl PT_ORIG_EAX(%esp), %edx # get the error code movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart + + TRACE_IRQS_OFF + movl %esp, %eax # pt_regs pointer + CALL_NOSPEC %edi + jmp ret_from_exception +END(common_exception_read_cr2) + +common_exception: + /* the function address is in %gs's slot on the stack */ + SAVE_ALL switch_stacks=1 skip_gs=1 + ENCODE_FRAME_POINTER + UNWIND_ESPFIX_STACK + + /* fixup %gs */ + GS_TO_REG %ecx + movl PT_GS(%esp), %edi # get the function address REG_TO_PTGS %ecx SET_KERNEL_GS %ecx + + /* fixup orig %eax */ + movl PT_ORIG_EAX(%esp), %edx # get the error code + movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart + TRACE_IRQS_OFF movl %esp, %eax # pt_regs pointer CALL_NOSPEC %edi @@ -1497,7 +1600,7 @@ END(general_protection) ENTRY(async_page_fault) ASM_CLAC pushl $do_async_page_fault - jmp common_exception + jmp common_exception_read_cr2 END(async_page_fault) #endif |