diff options
Diffstat (limited to 'arch/x86/entry/entry_32.S')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 485 |
1 files changed, 118 insertions, 367 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index a5eed844e948..024d7d276cd4 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -44,40 +44,13 @@ #include <asm/asm.h> #include <asm/smap.h> #include <asm/frame.h> +#include <asm/trapnr.h> #include <asm/nospec-branch.h> #include "calling.h" .section .entry.text, "ax" -/* - * We use macros for low-level operations which need to be overridden - * for paravirtualization. The following will never clobber any registers: - * INTERRUPT_RETURN (aka. "iret") - * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax") - * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit"). - * - * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must - * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY). - * Allowing a register to be clobbered can shrink the paravirt replacement - * enough to patch inline, increasing performance. - */ - -#ifdef CONFIG_PREEMPTION -# define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF -#else -# define preempt_stop(clobbers) -#endif - -.macro TRACE_IRQS_IRET -#ifdef CONFIG_TRACE_IRQFLAGS - testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off? - jz 1f - TRACE_IRQS_ON -1: -#endif -.endm - #define PTI_SWITCH_MASK (1 << PAGE_SHIFT) /* @@ -726,10 +699,68 @@ .Lend_\@: .endm + +/** + * idtentry - Macro to generate entry stubs for simple IDT entries + * @vector: Vector number + * @asmsym: ASM symbol for the entry point + * @cfunc: C function to be called + * @has_error_code: Hardware pushed error code on stack + */ +.macro idtentry vector asmsym cfunc has_error_code:req +SYM_CODE_START(\asmsym) + ASM_CLAC + cld + + .if \has_error_code == 0 + pushl $0 /* Clear the error code */ + .endif + + /* Push the C-function address into the GS slot */ + pushl $\cfunc + /* Invoke the common exception entry */ + jmp handle_exception +SYM_CODE_END(\asmsym) +.endm + +.macro idtentry_irq vector cfunc + .p2align CONFIG_X86_L1_CACHE_SHIFT +SYM_CODE_START_LOCAL(asm_\cfunc) + ASM_CLAC + SAVE_ALL switch_stacks=1 + ENCODE_FRAME_POINTER + movl %esp, %eax + movl PT_ORIG_EAX(%esp), %edx /* get the vector from stack */ + movl $-1, PT_ORIG_EAX(%esp) /* no syscall to restart */ + call \cfunc + jmp handle_exception_return +SYM_CODE_END(asm_\cfunc) +.endm + +.macro idtentry_sysvec vector cfunc + idtentry \vector asm_\cfunc \cfunc has_error_code=0 +.endm + +/* + * Include the defines which emit the idt entries which are shared + * shared between 32 and 64 bit and emit the __irqentry_text_* markers + * so the stacktrace boundary checks work. + */ + .align 16 + .globl __irqentry_text_start +__irqentry_text_start: + +#include <asm/idtentry.h> + + .align 16 + .globl __irqentry_text_end +__irqentry_text_end: + /* * %eax: prev task * %edx: next task */ +.pushsection .text, "ax" SYM_CODE_START(__switch_to_asm) /* * Save callee-saved registers @@ -776,6 +807,7 @@ SYM_CODE_START(__switch_to_asm) jmp __switch_to SYM_CODE_END(__switch_to_asm) +.popsection /* * The unwinder expects the last frame on the stack to always be at the same @@ -784,6 +816,7 @@ SYM_CODE_END(__switch_to_asm) * asmlinkage function so its argument has to be pushed on the stack. This * wrapper creates a proper "end of stack" frame header before the call. */ +.pushsection .text, "ax" SYM_FUNC_START(schedule_tail_wrapper) FRAME_BEGIN @@ -794,6 +827,8 @@ SYM_FUNC_START(schedule_tail_wrapper) FRAME_END ret SYM_FUNC_END(schedule_tail_wrapper) +.popsection + /* * A newly forked process directly context switches into this address. * @@ -801,6 +836,7 @@ SYM_FUNC_END(schedule_tail_wrapper) * ebx: kernel thread func (NULL for user thread) * edi: kernel thread arg */ +.pushsection .text, "ax" SYM_CODE_START(ret_from_fork) call schedule_tail_wrapper @@ -811,8 +847,7 @@ SYM_CODE_START(ret_from_fork) /* When we fork, we trace the syscall return in the child, too. */ movl %esp, %eax call syscall_return_slowpath - STACKLEAK_ERASE - jmp restore_all + jmp .Lsyscall_32_done /* kernel thread */ 1: movl %edi, %eax @@ -825,38 +860,7 @@ SYM_CODE_START(ret_from_fork) movl $0, PT_EAX(%esp) jmp 2b SYM_CODE_END(ret_from_fork) - -/* - * Return to user mode is not as complex as all this looks, - * but we want the default path for a system call return to - * go as quickly as possible which is why some of this is - * less clear than it otherwise should be. - */ - - # userspace resumption stub bypassing syscall exit tracing -SYM_CODE_START_LOCAL(ret_from_exception) - preempt_stop(CLBR_ANY) -ret_from_intr: -#ifdef CONFIG_VM86 - movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS - movb PT_CS(%esp), %al - andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax -#else - /* - * We can be coming here from child spawned by kernel_thread(). - */ - movl PT_CS(%esp), %eax - andl $SEGMENT_RPL_MASK, %eax -#endif - cmpl $USER_RPL, %eax - jb restore_all_kernel # not returning to v8086 or userspace - - DISABLE_INTERRUPTS(CLBR_ANY) - TRACE_IRQS_OFF - movl %esp, %eax - call prepare_exit_to_usermode - jmp restore_all -SYM_CODE_END(ret_from_exception) +.popsection SYM_ENTRY(__begin_SYSENTER_singlestep_region, SYM_L_GLOBAL, SYM_A_NONE) /* @@ -960,12 +964,6 @@ SYM_FUNC_START(entry_SYSENTER_32) jnz .Lsysenter_fix_flags .Lsysenter_flags_fixed: - /* - * User mode is traced as though IRQs are on, and SYSENTER - * turned them off. - */ - TRACE_IRQS_OFF - movl %esp, %eax call do_fast_syscall_32 /* XEN PV guests always use IRET path */ @@ -974,8 +972,7 @@ SYM_FUNC_START(entry_SYSENTER_32) STACKLEAK_ERASE -/* Opportunistic SYSEXIT */ - TRACE_IRQS_ON /* User mode traces as IRQs on. */ + /* Opportunistic SYSEXIT */ /* * Setup entry stack - we keep the pointer in %eax and do the @@ -1075,20 +1072,12 @@ SYM_FUNC_START(entry_INT80_32) SAVE_ALL pt_regs_ax=$-ENOSYS switch_stacks=1 /* save rest */ - /* - * User mode is traced as though IRQs are on, and the interrupt gate - * turned them off. - */ - TRACE_IRQS_OFF - movl %esp, %eax call do_int80_syscall_32 .Lsyscall_32_done: - STACKLEAK_ERASE -restore_all: - TRACE_IRQS_ON +restore_all_switch_stack: SWITCH_TO_ENTRY_STACK CHECK_AND_APPLY_ESPFIX @@ -1107,26 +1096,10 @@ restore_all: */ INTERRUPT_RETURN -restore_all_kernel: -#ifdef CONFIG_PREEMPTION - 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 - RESTORE_REGS 4 - jmp .Lirq_return - .section .fixup, "ax" -SYM_CODE_START(iret_exc) +SYM_CODE_START(asm_iret_error) pushl $0 # no error code - pushl $do_iret_error + pushl $iret_error #ifdef CONFIG_DEBUG_ENTRY /* @@ -1140,10 +1113,10 @@ SYM_CODE_START(iret_exc) popl %eax #endif - jmp common_exception -SYM_CODE_END(iret_exc) + jmp handle_exception +SYM_CODE_END(asm_iret_error) .previous - _ASM_EXTABLE(.Lirq_return, iret_exc) + _ASM_EXTABLE(.Lirq_return, asm_iret_error) SYM_FUNC_END(entry_INT80_32) .macro FIXUP_ESPFIX_STACK @@ -1193,192 +1166,21 @@ SYM_FUNC_END(entry_INT80_32) #endif .endm -/* - * Build the entry stubs with some assembler magic. - * We pack 1 stub into every 8-byte block. - */ - .align 8 -SYM_CODE_START(irq_entries_start) - vector=FIRST_EXTERNAL_VECTOR - .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) - pushl $(~vector+0x80) /* Note: always in signed byte range */ - vector=vector+1 - jmp common_interrupt - .align 8 - .endr -SYM_CODE_END(irq_entries_start) - -#ifdef CONFIG_X86_LOCAL_APIC - .align 8 -SYM_CODE_START(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 -SYM_CODE_END(spurious_entries_start) - -SYM_CODE_START_LOCAL(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 -SYM_CODE_END(common_spurious) -#endif - -/* - * the CPU automatically disables interrupts when executing an IRQ vector, - * so IRQ-flags tracing has to follow that: - */ - .p2align CONFIG_X86_L1_CACHE_SHIFT -SYM_CODE_START_LOCAL(common_interrupt) - 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 do_IRQ - jmp ret_from_intr -SYM_CODE_END(common_interrupt) - -#define BUILD_INTERRUPT3(name, nr, fn) \ -SYM_FUNC_START(name) \ - ASM_CLAC; \ - pushl $~(nr); \ - SAVE_ALL switch_stacks=1; \ - ENCODE_FRAME_POINTER; \ - TRACE_IRQS_OFF \ - movl %esp, %eax; \ - call fn; \ - jmp ret_from_intr; \ -SYM_FUNC_END(name) - -#define BUILD_INTERRUPT(name, nr) \ - BUILD_INTERRUPT3(name, nr, smp_##name); \ - -/* The include is where all of the SMP etc. interrupts come from */ -#include <asm/entry_arch.h> - -SYM_CODE_START(coprocessor_error) - ASM_CLAC - pushl $0 - pushl $do_coprocessor_error - jmp common_exception -SYM_CODE_END(coprocessor_error) - -SYM_CODE_START(simd_coprocessor_error) - ASM_CLAC - pushl $0 -#ifdef CONFIG_X86_INVD_BUG - /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */ - ALTERNATIVE "pushl $do_general_protection", \ - "pushl $do_simd_coprocessor_error", \ - X86_FEATURE_XMM -#else - pushl $do_simd_coprocessor_error -#endif - jmp common_exception -SYM_CODE_END(simd_coprocessor_error) - -SYM_CODE_START(device_not_available) - ASM_CLAC - pushl $0 - pushl $do_device_not_available - jmp common_exception -SYM_CODE_END(device_not_available) - #ifdef CONFIG_PARAVIRT SYM_CODE_START(native_iret) iret - _ASM_EXTABLE(native_iret, iret_exc) + _ASM_EXTABLE(native_iret, asm_iret_error) SYM_CODE_END(native_iret) #endif -SYM_CODE_START(overflow) - ASM_CLAC - pushl $0 - pushl $do_overflow - jmp common_exception -SYM_CODE_END(overflow) - -SYM_CODE_START(bounds) - ASM_CLAC - pushl $0 - pushl $do_bounds - jmp common_exception -SYM_CODE_END(bounds) - -SYM_CODE_START(invalid_op) - ASM_CLAC - pushl $0 - pushl $do_invalid_op - jmp common_exception -SYM_CODE_END(invalid_op) - -SYM_CODE_START(coprocessor_segment_overrun) - ASM_CLAC - pushl $0 - pushl $do_coprocessor_segment_overrun - jmp common_exception -SYM_CODE_END(coprocessor_segment_overrun) - -SYM_CODE_START(invalid_TSS) - ASM_CLAC - pushl $do_invalid_TSS - jmp common_exception -SYM_CODE_END(invalid_TSS) - -SYM_CODE_START(segment_not_present) - ASM_CLAC - pushl $do_segment_not_present - jmp common_exception -SYM_CODE_END(segment_not_present) - -SYM_CODE_START(stack_segment) - ASM_CLAC - pushl $do_stack_segment - jmp common_exception -SYM_CODE_END(stack_segment) - -SYM_CODE_START(alignment_check) - ASM_CLAC - pushl $do_alignment_check - jmp common_exception -SYM_CODE_END(alignment_check) - -SYM_CODE_START(divide_error) - ASM_CLAC - pushl $0 # no error code - pushl $do_divide_error - jmp common_exception -SYM_CODE_END(divide_error) - -#ifdef CONFIG_X86_MCE -SYM_CODE_START(machine_check) - ASM_CLAC - pushl $0 - pushl $do_mce - jmp common_exception -SYM_CODE_END(machine_check) -#endif - -SYM_CODE_START(spurious_interrupt_bug) - ASM_CLAC - pushl $0 - pushl $do_spurious_interrupt_bug - jmp common_exception -SYM_CODE_END(spurious_interrupt_bug) - #ifdef CONFIG_XEN_PV -SYM_FUNC_START(xen_hypervisor_callback) +/* + * See comment in entry_64.S for further explanation + * + * Note: This is not an actual IDT entry point. It's a XEN specific entry + * point and therefore named to match the 64-bit trampoline counterpart. + */ +SYM_FUNC_START(xen_asm_exc_xen_hypervisor_callback) /* * Check to see if we got the event in the critical * region in xen_iret_direct, after we've reenabled @@ -1395,14 +1197,11 @@ SYM_FUNC_START(xen_hypervisor_callback) pushl $-1 /* orig_ax = -1 => not a system call */ SAVE_ALL ENCODE_FRAME_POINTER - TRACE_IRQS_OFF + mov %esp, %eax - call xen_evtchn_do_upcall -#ifndef CONFIG_PREEMPTION - call xen_maybe_preempt_hcall -#endif - jmp ret_from_intr -SYM_FUNC_END(xen_hypervisor_callback) + call xen_pv_evtchn_do_upcall + jmp handle_exception_return +SYM_FUNC_END(xen_asm_exc_xen_hypervisor_callback) /* * Hypervisor uses this for application faults while it executes. @@ -1429,11 +1228,11 @@ SYM_FUNC_START(xen_failsafe_callback) popl %eax lea 16(%esp), %esp jz 5f - jmp iret_exc + jmp asm_iret_error 5: pushl $-1 /* orig_ax = -1 => not a system call */ SAVE_ALL ENCODE_FRAME_POINTER - jmp ret_from_exception + jmp handle_exception_return .section .fixup, "ax" 6: xorl %eax, %eax @@ -1456,56 +1255,7 @@ SYM_FUNC_START(xen_failsafe_callback) SYM_FUNC_END(xen_failsafe_callback) #endif /* CONFIG_XEN_PV */ -#ifdef CONFIG_XEN_PVHVM -BUILD_INTERRUPT3(xen_hvm_callback_vector, HYPERVISOR_CALLBACK_VECTOR, - xen_evtchn_do_upcall) -#endif - - -#if IS_ENABLED(CONFIG_HYPERV) - -BUILD_INTERRUPT3(hyperv_callback_vector, HYPERVISOR_CALLBACK_VECTOR, - hyperv_vector_handler) - -BUILD_INTERRUPT3(hyperv_reenlightenment_vector, HYPERV_REENLIGHTENMENT_VECTOR, - hyperv_reenlightenment_intr) - -BUILD_INTERRUPT3(hv_stimer0_callback_vector, HYPERV_STIMER0_VECTOR, - hv_stimer0_vector_handler) - -#endif /* CONFIG_HYPERV */ - -SYM_CODE_START(page_fault) - ASM_CLAC - pushl $do_page_fault - jmp common_exception_read_cr2 -SYM_CODE_END(page_fault) - -SYM_CODE_START_LOCAL_NOALIGN(common_exception_read_cr2) - /* the function address is in %gs's slot on the stack */ - SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1 - - ENCODE_FRAME_POINTER - - /* fixup %gs */ - GS_TO_REG %ecx - 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 -SYM_CODE_END(common_exception_read_cr2) - -SYM_CODE_START_LOCAL_NOALIGN(common_exception) +SYM_CODE_START_LOCAL_NOALIGN(handle_exception) /* the function address is in %gs's slot on the stack */ SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1 ENCODE_FRAME_POINTER @@ -1520,23 +1270,35 @@ SYM_CODE_START_LOCAL_NOALIGN(common_exception) 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 -SYM_CODE_END(common_exception) -SYM_CODE_START(debug) +handle_exception_return: +#ifdef CONFIG_VM86 + movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS + movb PT_CS(%esp), %al + andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax +#else /* - * Entry from sysenter is now handled in common_exception + * We can be coming here from child spawned by kernel_thread(). */ - ASM_CLAC - pushl $0 - pushl $do_debug - jmp common_exception -SYM_CODE_END(debug) + movl PT_CS(%esp), %eax + andl $SEGMENT_RPL_MASK, %eax +#endif + cmpl $USER_RPL, %eax # returning to v8086 or userspace ? + jnb ret_to_user -SYM_CODE_START(double_fault) + PARANOID_EXIT_TO_KERNEL_MODE + BUG_IF_WRONG_CR3 + RESTORE_REGS 4 + jmp .Lirq_return + +ret_to_user: + movl %esp, %eax + jmp restore_all_switch_stack +SYM_CODE_END(handle_exception) + +SYM_CODE_START(asm_exc_double_fault) 1: /* * This is a task gate handler, not an interrupt gate handler. @@ -1574,7 +1336,7 @@ SYM_CODE_START(double_fault) 1: hlt jmp 1b -SYM_CODE_END(double_fault) +SYM_CODE_END(asm_exc_double_fault) /* * NMI is doubly nasty. It can happen on the first instruction of @@ -1583,7 +1345,7 @@ SYM_CODE_END(double_fault) * switched stacks. We handle both conditions by simply checking whether we * interrupted kernel code running on the SYSENTER stack. */ -SYM_CODE_START(nmi) +SYM_CODE_START(asm_exc_nmi) ASM_CLAC #ifdef CONFIG_X86_ESPFIX32 @@ -1612,7 +1374,7 @@ SYM_CODE_START(nmi) jb .Lnmi_from_sysenter_stack /* Not on SYSENTER stack. */ - call do_nmi + call exc_nmi jmp .Lnmi_return .Lnmi_from_sysenter_stack: @@ -1622,7 +1384,7 @@ SYM_CODE_START(nmi) */ movl %esp, %ebx movl PER_CPU_VAR(cpu_current_top_of_stack), %esp - call do_nmi + call exc_nmi movl %ebx, %esp .Lnmi_return: @@ -1676,21 +1438,9 @@ SYM_CODE_START(nmi) lss (1+5+6)*4(%esp), %esp # back to espfix stack jmp .Lirq_return #endif -SYM_CODE_END(nmi) - -SYM_CODE_START(int3) - ASM_CLAC - pushl $0 - pushl $do_int3 - jmp common_exception -SYM_CODE_END(int3) - -SYM_CODE_START(general_protection) - ASM_CLAC - pushl $do_general_protection - jmp common_exception -SYM_CODE_END(general_protection) +SYM_CODE_END(asm_exc_nmi) +.pushsection .text, "ax" SYM_CODE_START(rewind_stack_do_exit) /* Prevent any naive code from trying to unwind to our caller. */ xorl %ebp, %ebp @@ -1701,3 +1451,4 @@ SYM_CODE_START(rewind_stack_do_exit) call do_exit 1: jmp 1b SYM_CODE_END(rewind_stack_do_exit) +.popsection |