diff options
Diffstat (limited to 'arch/x86/kernel/entry_32.S')
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 1401 |
1 files changed, 0 insertions, 1401 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S deleted file mode 100644 index 1c309763e321..000000000000 --- a/arch/x86/kernel/entry_32.S +++ /dev/null @@ -1,1401 +0,0 @@ -/* - * - * Copyright (C) 1991, 1992 Linus Torvalds - */ - -/* - * entry.S contains the system-call and fault low-level handling routines. - * This also contains the timer-interrupt handler, as well as all interrupts - * and faults that can result in a task-switch. - * - * NOTE: This code handles signal-recognition, which happens every time - * after a timer-interrupt and after each system call. - * - * I changed all the .align's to 4 (16 byte alignment), as that's faster - * on a 486. - * - * Stack layout in 'syscall_exit': - * ptrace needs to have all regs on the stack. - * if the order here is changed, it needs to be - * updated in fork.c:copy_process, signal.c:do_signal, - * ptrace.c and ptrace.h - * - * 0(%esp) - %ebx - * 4(%esp) - %ecx - * 8(%esp) - %edx - * C(%esp) - %esi - * 10(%esp) - %edi - * 14(%esp) - %ebp - * 18(%esp) - %eax - * 1C(%esp) - %ds - * 20(%esp) - %es - * 24(%esp) - %fs - * 28(%esp) - %gs saved iff !CONFIG_X86_32_LAZY_GS - * 2C(%esp) - orig_eax - * 30(%esp) - %eip - * 34(%esp) - %cs - * 38(%esp) - %eflags - * 3C(%esp) - %oldesp - * 40(%esp) - %oldss - * - * "current" is in register %ebx during any slow entries. - */ - -#include <linux/linkage.h> -#include <linux/err.h> -#include <asm/thread_info.h> -#include <asm/irqflags.h> -#include <asm/errno.h> -#include <asm/segment.h> -#include <asm/smp.h> -#include <asm/page_types.h> -#include <asm/percpu.h> -#include <asm/dwarf2.h> -#include <asm/processor-flags.h> -#include <asm/ftrace.h> -#include <asm/irq_vectors.h> -#include <asm/cpufeature.h> -#include <asm/alternative-asm.h> -#include <asm/asm.h> -#include <asm/smap.h> - -/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ -#include <linux/elf-em.h> -#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE) -#define __AUDIT_ARCH_LE 0x40000000 - -#ifndef CONFIG_AUDITSYSCALL -#define sysenter_audit syscall_trace_entry -#define sysexit_audit syscall_exit_work -#endif - - .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_PREEMPT -#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF -#else -#define preempt_stop(clobbers) -#define resume_kernel restore_all -#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 - -/* - * User gs save/restore - * - * %gs is used for userland TLS and kernel only uses it for stack - * canary which is required to be at %gs:20 by gcc. Read the comment - * at the top of stackprotector.h for more info. - * - * Local labels 98 and 99 are used. - */ -#ifdef CONFIG_X86_32_LAZY_GS - - /* unfortunately push/pop can't be no-op */ -.macro PUSH_GS - pushl_cfi $0 -.endm -.macro POP_GS pop=0 - addl $(4 + \pop), %esp - CFI_ADJUST_CFA_OFFSET -(4 + \pop) -.endm -.macro POP_GS_EX -.endm - - /* all the rest are no-op */ -.macro PTGS_TO_GS -.endm -.macro PTGS_TO_GS_EX -.endm -.macro GS_TO_REG reg -.endm -.macro REG_TO_PTGS reg -.endm -.macro SET_KERNEL_GS reg -.endm - -#else /* CONFIG_X86_32_LAZY_GS */ - -.macro PUSH_GS - pushl_cfi %gs - /*CFI_REL_OFFSET gs, 0*/ -.endm - -.macro POP_GS pop=0 -98: popl_cfi %gs - /*CFI_RESTORE gs*/ - .if \pop <> 0 - add $\pop, %esp - CFI_ADJUST_CFA_OFFSET -\pop - .endif -.endm -.macro POP_GS_EX -.pushsection .fixup, "ax" -99: movl $0, (%esp) - jmp 98b -.popsection - _ASM_EXTABLE(98b,99b) -.endm - -.macro PTGS_TO_GS -98: mov PT_GS(%esp), %gs -.endm -.macro PTGS_TO_GS_EX -.pushsection .fixup, "ax" -99: movl $0, PT_GS(%esp) - jmp 98b -.popsection - _ASM_EXTABLE(98b,99b) -.endm - -.macro GS_TO_REG reg - movl %gs, \reg - /*CFI_REGISTER gs, \reg*/ -.endm -.macro REG_TO_PTGS reg - movl \reg, PT_GS(%esp) - /*CFI_REL_OFFSET gs, PT_GS*/ -.endm -.macro SET_KERNEL_GS reg - movl $(__KERNEL_STACK_CANARY), \reg - movl \reg, %gs -.endm - -#endif /* CONFIG_X86_32_LAZY_GS */ - -.macro SAVE_ALL - cld - PUSH_GS - pushl_cfi %fs - /*CFI_REL_OFFSET fs, 0;*/ - pushl_cfi %es - /*CFI_REL_OFFSET es, 0;*/ - pushl_cfi %ds - /*CFI_REL_OFFSET ds, 0;*/ - pushl_cfi %eax - CFI_REL_OFFSET eax, 0 - pushl_cfi %ebp - CFI_REL_OFFSET ebp, 0 - pushl_cfi %edi - CFI_REL_OFFSET edi, 0 - pushl_cfi %esi - CFI_REL_OFFSET esi, 0 - pushl_cfi %edx - CFI_REL_OFFSET edx, 0 - pushl_cfi %ecx - CFI_REL_OFFSET ecx, 0 - pushl_cfi %ebx - CFI_REL_OFFSET ebx, 0 - movl $(__USER_DS), %edx - movl %edx, %ds - movl %edx, %es - movl $(__KERNEL_PERCPU), %edx - movl %edx, %fs - SET_KERNEL_GS %edx -.endm - -.macro RESTORE_INT_REGS - popl_cfi %ebx - CFI_RESTORE ebx - popl_cfi %ecx - CFI_RESTORE ecx - popl_cfi %edx - CFI_RESTORE edx - popl_cfi %esi - CFI_RESTORE esi - popl_cfi %edi - CFI_RESTORE edi - popl_cfi %ebp - CFI_RESTORE ebp - popl_cfi %eax - CFI_RESTORE eax -.endm - -.macro RESTORE_REGS pop=0 - RESTORE_INT_REGS -1: popl_cfi %ds - /*CFI_RESTORE ds;*/ -2: popl_cfi %es - /*CFI_RESTORE es;*/ -3: popl_cfi %fs - /*CFI_RESTORE fs;*/ - POP_GS \pop -.pushsection .fixup, "ax" -4: movl $0, (%esp) - jmp 1b -5: movl $0, (%esp) - jmp 2b -6: movl $0, (%esp) - jmp 3b -.popsection - _ASM_EXTABLE(1b,4b) - _ASM_EXTABLE(2b,5b) - _ASM_EXTABLE(3b,6b) - POP_GS_EX -.endm - -.macro RING0_INT_FRAME - CFI_STARTPROC simple - CFI_SIGNAL_FRAME - CFI_DEF_CFA esp, 3*4 - /*CFI_OFFSET cs, -2*4;*/ - CFI_OFFSET eip, -3*4 -.endm - -.macro RING0_EC_FRAME - CFI_STARTPROC simple - CFI_SIGNAL_FRAME - CFI_DEF_CFA esp, 4*4 - /*CFI_OFFSET cs, -2*4;*/ - CFI_OFFSET eip, -3*4 -.endm - -.macro RING0_PTREGS_FRAME - CFI_STARTPROC simple - CFI_SIGNAL_FRAME - CFI_DEF_CFA esp, PT_OLDESP-PT_EBX - /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/ - CFI_OFFSET eip, PT_EIP-PT_OLDESP - /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/ - /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/ - CFI_OFFSET eax, PT_EAX-PT_OLDESP - CFI_OFFSET ebp, PT_EBP-PT_OLDESP - CFI_OFFSET edi, PT_EDI-PT_OLDESP - CFI_OFFSET esi, PT_ESI-PT_OLDESP - CFI_OFFSET edx, PT_EDX-PT_OLDESP - CFI_OFFSET ecx, PT_ECX-PT_OLDESP - CFI_OFFSET ebx, PT_EBX-PT_OLDESP -.endm - -ENTRY(ret_from_fork) - CFI_STARTPROC - pushl_cfi %eax - call schedule_tail - GET_THREAD_INFO(%ebp) - popl_cfi %eax - pushl_cfi $0x0202 # Reset kernel eflags - popfl_cfi - jmp syscall_exit - CFI_ENDPROC -END(ret_from_fork) - -ENTRY(ret_from_kernel_thread) - CFI_STARTPROC - pushl_cfi %eax - call schedule_tail - GET_THREAD_INFO(%ebp) - popl_cfi %eax - pushl_cfi $0x0202 # Reset kernel eflags - popfl_cfi - movl PT_EBP(%esp),%eax - call *PT_EBX(%esp) - movl $0,PT_EAX(%esp) - jmp syscall_exit - CFI_ENDPROC -ENDPROC(ret_from_kernel_thread) - -/* - * 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 - ALIGN - RING0_PTREGS_FRAME -ret_from_exception: - preempt_stop(CLBR_ANY) -ret_from_intr: - GET_THREAD_INFO(%ebp) -#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 resume_kernel # not returning to v8086 or userspace - -ENTRY(resume_userspace) - LOCKDEP_SYS_EXIT - DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt - # setting need_resched or sigpending - # between sampling and the iret - TRACE_IRQS_OFF - movl TI_flags(%ebp), %ecx - andl $_TIF_WORK_MASK, %ecx # is there any work to be done on - # int/exception return? - jne work_pending - jmp restore_all -END(ret_from_exception) - -#ifdef CONFIG_PREEMPT -ENTRY(resume_kernel) - DISABLE_INTERRUPTS(CLBR_ANY) -need_resched: - cmpl $0,PER_CPU_VAR(__preempt_count) - jnz restore_all - testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ? - jz restore_all - call preempt_schedule_irq - jmp need_resched -END(resume_kernel) -#endif - CFI_ENDPROC - -/* SYSENTER_RETURN points to after the "sysenter" instruction in - the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */ - - # sysenter call handler stub -ENTRY(ia32_sysenter_target) - CFI_STARTPROC simple - CFI_SIGNAL_FRAME - CFI_DEF_CFA esp, 0 - CFI_REGISTER esp, ebp - movl TSS_sysenter_sp0(%esp),%esp -sysenter_past_esp: - /* - * Interrupts are disabled here, but we can't trace it until - * enough kernel state to call TRACE_IRQS_OFF can be called - but - * we immediately enable interrupts at that point anyway. - */ - pushl_cfi $__USER_DS - /*CFI_REL_OFFSET ss, 0*/ - pushl_cfi %ebp - CFI_REL_OFFSET esp, 0 - pushfl_cfi - orl $X86_EFLAGS_IF, (%esp) - pushl_cfi $__USER_CS - /*CFI_REL_OFFSET cs, 0*/ - /* - * Push current_thread_info()->sysenter_return to the stack. - * A tiny bit of offset fixup is necessary: TI_sysenter_return - * is relative to thread_info, which is at the bottom of the - * kernel stack page. 4*4 means the 4 words pushed above; - * TOP_OF_KERNEL_STACK_PADDING takes us to the top of the stack; - * and THREAD_SIZE takes us to the bottom. - */ - pushl_cfi ((TI_sysenter_return) - THREAD_SIZE + TOP_OF_KERNEL_STACK_PADDING + 4*4)(%esp) - CFI_REL_OFFSET eip, 0 - - pushl_cfi %eax - SAVE_ALL - ENABLE_INTERRUPTS(CLBR_NONE) - -/* - * Load the potential sixth argument from user stack. - * Careful about security. - */ - cmpl $__PAGE_OFFSET-3,%ebp - jae syscall_fault - ASM_STAC -1: movl (%ebp),%ebp - ASM_CLAC - movl %ebp,PT_EBP(%esp) - _ASM_EXTABLE(1b,syscall_fault) - - GET_THREAD_INFO(%ebp) - - testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp) - jnz sysenter_audit -sysenter_do_call: - cmpl $(NR_syscalls), %eax - jae sysenter_badsys - call *sys_call_table(,%eax,4) -sysenter_after_call: - movl %eax,PT_EAX(%esp) - LOCKDEP_SYS_EXIT - DISABLE_INTERRUPTS(CLBR_ANY) - TRACE_IRQS_OFF - movl TI_flags(%ebp), %ecx - testl $_TIF_ALLWORK_MASK, %ecx - jnz sysexit_audit -sysenter_exit: -/* if something modifies registers it must also disable sysexit */ - movl PT_EIP(%esp), %edx - movl PT_OLDESP(%esp), %ecx - xorl %ebp,%ebp - TRACE_IRQS_ON -1: mov PT_FS(%esp), %fs - PTGS_TO_GS - ENABLE_INTERRUPTS_SYSEXIT - -#ifdef CONFIG_AUDITSYSCALL -sysenter_audit: - testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp) - jnz syscall_trace_entry - /* movl PT_EAX(%esp), %eax already set, syscall number: 1st arg to audit */ - movl PT_EBX(%esp), %edx /* ebx/a0: 2nd arg to audit */ - /* movl PT_ECX(%esp), %ecx already set, a1: 3nd arg to audit */ - pushl_cfi PT_ESI(%esp) /* a3: 5th arg */ - pushl_cfi PT_EDX+4(%esp) /* a2: 4th arg */ - call __audit_syscall_entry - popl_cfi %ecx /* get that remapped edx off the stack */ - popl_cfi %ecx /* get that remapped esi off the stack */ - movl PT_EAX(%esp),%eax /* reload syscall number */ - jmp sysenter_do_call - -sysexit_audit: - testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx - jnz syscall_exit_work - TRACE_IRQS_ON - ENABLE_INTERRUPTS(CLBR_ANY) - movl %eax,%edx /* second arg, syscall return value */ - cmpl $-MAX_ERRNO,%eax /* is it an error ? */ - setbe %al /* 1 if so, 0 if not */ - movzbl %al,%eax /* zero-extend that */ - call __audit_syscall_exit - DISABLE_INTERRUPTS(CLBR_ANY) - TRACE_IRQS_OFF - movl TI_flags(%ebp), %ecx - testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx - jnz syscall_exit_work - movl PT_EAX(%esp),%eax /* reload syscall return value */ - jmp sysenter_exit -#endif - - CFI_ENDPROC -.pushsection .fixup,"ax" -2: movl $0,PT_FS(%esp) - jmp 1b -.popsection - _ASM_EXTABLE(1b,2b) - PTGS_TO_GS_EX -ENDPROC(ia32_sysenter_target) - - # system call handler stub -ENTRY(system_call) - RING0_INT_FRAME # can't unwind into user space anyway - ASM_CLAC - pushl_cfi %eax # save orig_eax - SAVE_ALL - GET_THREAD_INFO(%ebp) - # system call tracing in operation / emulation - testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp) - jnz syscall_trace_entry - cmpl $(NR_syscalls), %eax - jae syscall_badsys -syscall_call: - call *sys_call_table(,%eax,4) -syscall_after_call: - movl %eax,PT_EAX(%esp) # store the return value -syscall_exit: - LOCKDEP_SYS_EXIT - DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt - # setting need_resched or sigpending - # between sampling and the iret - TRACE_IRQS_OFF - movl TI_flags(%ebp), %ecx - testl $_TIF_ALLWORK_MASK, %ecx # current->work - jnz syscall_exit_work - -restore_all: - TRACE_IRQS_IRET -restore_all_notrace: -#ifdef CONFIG_X86_ESPFIX32 - movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS - # Warning: PT_OLDSS(%esp) contains the wrong/random values if we - # are returning to the kernel. - # See comments in process.c:copy_thread() for details. - movb PT_OLDSS(%esp), %ah - movb PT_CS(%esp), %al - andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax - cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax - CFI_REMEMBER_STATE - je ldt_ss # returning to user-space with LDT SS -#endif -restore_nocheck: - RESTORE_REGS 4 # skip orig_eax/error_code -irq_return: - INTERRUPT_RETURN -.section .fixup,"ax" -ENTRY(iret_exc) - pushl $0 # no error code - pushl $do_iret_error - jmp error_code -.previous - _ASM_EXTABLE(irq_return,iret_exc) - -#ifdef CONFIG_X86_ESPFIX32 - CFI_RESTORE_STATE -ldt_ss: -#ifdef CONFIG_PARAVIRT - /* - * The kernel can't run on a non-flat stack if paravirt mode - * is active. Rather than try to fixup the high bits of - * ESP, bypass this code entirely. This may break DOSemu - * and/or Wine support in a paravirt VM, although the option - * is still available to implement the setting of the high - * 16-bits in the INTERRUPT_RETURN paravirt-op. - */ - cmpl $0, pv_info+PARAVIRT_enabled - jne restore_nocheck -#endif - -/* - * Setup and switch to ESPFIX stack - * - * We're returning to userspace with a 16 bit stack. The CPU will not - * restore the high word of ESP for us on executing iret... This is an - * "official" bug of all the x86-compatible CPUs, which we can work - * around to make dosemu and wine happy. We do this by preloading the - * high word of ESP with the high word of the userspace ESP while - * compensating for the offset by changing to the ESPFIX segment with - * a base address that matches for the difference. - */ -#define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page) + (GDT_ENTRY_ESPFIX_SS * 8) - mov %esp, %edx /* load kernel esp */ - mov PT_OLDESP(%esp), %eax /* load userspace esp */ - mov %dx, %ax /* eax: new kernel esp */ - sub %eax, %edx /* offset (low word is 0) */ - shr $16, %edx - mov %dl, GDT_ESPFIX_SS + 4 /* bits 16..23 */ - mov %dh, GDT_ESPFIX_SS + 7 /* bits 24..31 */ - pushl_cfi $__ESPFIX_SS - pushl_cfi %eax /* new kernel esp */ - /* Disable interrupts, but do not irqtrace this section: we - * will soon execute iret and the tracer was already set to - * the irqstate after the iret */ - DISABLE_INTERRUPTS(CLBR_EAX) - lss (%esp), %esp /* switch to espfix segment */ - CFI_ADJUST_CFA_OFFSET -8 - jmp restore_nocheck -#endif - CFI_ENDPROC -ENDPROC(system_call) - - # perform work that needs to be done immediately before resumption - ALIGN - RING0_PTREGS_FRAME # can't unwind into user space anyway -work_pending: - testb $_TIF_NEED_RESCHED, %cl - jz work_notifysig -work_resched: - call schedule - LOCKDEP_SYS_EXIT - DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt - # setting need_resched or sigpending - # between sampling and the iret - TRACE_IRQS_OFF - movl TI_flags(%ebp), %ecx - andl $_TIF_WORK_MASK, %ecx # is there any work to be done other - # than syscall tracing? - jz restore_all - testb $_TIF_NEED_RESCHED, %cl - jnz work_resched - -work_notifysig: # deal with pending signals and - # notify-resume requests -#ifdef CONFIG_VM86 - testl $X86_EFLAGS_VM, PT_EFLAGS(%esp) - movl %esp, %eax - jnz work_notifysig_v86 # returning to kernel-space or - # vm86-space -1: -#else - movl %esp, %eax -#endif - TRACE_IRQS_ON - ENABLE_INTERRUPTS(CLBR_NONE) - movb PT_CS(%esp), %bl - andb $SEGMENT_RPL_MASK, %bl - cmpb $USER_RPL, %bl - jb resume_kernel - xorl %edx, %edx - call do_notify_resume - jmp resume_userspace - -#ifdef CONFIG_VM86 - ALIGN -work_notifysig_v86: - pushl_cfi %ecx # save ti_flags for do_notify_resume - call save_v86_state # %eax contains pt_regs pointer - popl_cfi %ecx - movl %eax, %esp - jmp 1b -#endif -END(work_pending) - - # perform syscall exit tracing - ALIGN -syscall_trace_entry: - movl $-ENOSYS,PT_EAX(%esp) - movl %esp, %eax - call syscall_trace_enter - /* What it returned is what we'll actually use. */ - cmpl $(NR_syscalls), %eax - jnae syscall_call - jmp syscall_exit -END(syscall_trace_entry) - - # perform syscall exit tracing - ALIGN -syscall_exit_work: - testl $_TIF_WORK_SYSCALL_EXIT, %ecx - jz work_pending - TRACE_IRQS_ON - ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call - # schedule() instead - movl %esp, %eax - call syscall_trace_leave - jmp resume_userspace -END(syscall_exit_work) - CFI_ENDPROC - - RING0_INT_FRAME # can't unwind into user space anyway -syscall_fault: - ASM_CLAC - GET_THREAD_INFO(%ebp) - movl $-EFAULT,PT_EAX(%esp) - jmp resume_userspace -END(syscall_fault) - -syscall_badsys: - movl $-ENOSYS,%eax - jmp syscall_after_call -END(syscall_badsys) - -sysenter_badsys: - movl $-ENOSYS,%eax - jmp sysenter_after_call -END(sysenter_badsys) - CFI_ENDPROC - -.macro FIXUP_ESPFIX_STACK -/* - * Switch back for ESPFIX stack to the normal zerobased stack - * - * We can't call C functions using the ESPFIX stack. This code reads - * the high word of the segment base from the GDT and swiches to the - * normal stack and adjusts ESP with the matching offset. - */ -#ifdef CONFIG_X86_ESPFIX32 - /* fixup the stack */ - mov GDT_ESPFIX_SS + 4, %al /* bits 16..23 */ - mov GDT_ESPFIX_SS + 7, %ah /* bits 24..31 */ - shl $16, %eax - addl %esp, %eax /* the adjusted stack pointer */ - pushl_cfi $__KERNEL_DS - pushl_cfi %eax - lss (%esp), %esp /* switch to the normal stack segment */ - CFI_ADJUST_CFA_OFFSET -8 -#endif -.endm -.macro UNWIND_ESPFIX_STACK -#ifdef CONFIG_X86_ESPFIX32 - movl %ss, %eax - /* see if on espfix stack */ - cmpw $__ESPFIX_SS, %ax - jne 27f - movl $__KERNEL_DS, %eax - movl %eax, %ds - movl %eax, %es - /* switch to normal stack */ - FIXUP_ESPFIX_STACK -27: -#endif -.endm - -/* - * Build the entry stubs with some assembler magic. - * We pack 1 stub into every 8-byte block. - */ - .align 8 -ENTRY(irq_entries_start) - RING0_INT_FRAME - vector=FIRST_EXTERNAL_VECTOR - .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) - pushl_cfi $(~vector+0x80) /* Note: always in signed byte range */ - vector=vector+1 - jmp common_interrupt - CFI_ADJUST_CFA_OFFSET -4 - .align 8 - .endr -END(irq_entries_start) - -/* - * the CPU automatically disables interrupts when executing an IRQ vector, - * so IRQ-flags tracing has to follow that: - */ - .p2align CONFIG_X86_L1_CACHE_SHIFT -common_interrupt: - ASM_CLAC - addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */ - SAVE_ALL - TRACE_IRQS_OFF - movl %esp,%eax - call do_IRQ - jmp ret_from_intr -ENDPROC(common_interrupt) - CFI_ENDPROC - -#define BUILD_INTERRUPT3(name, nr, fn) \ -ENTRY(name) \ - RING0_INT_FRAME; \ - ASM_CLAC; \ - pushl_cfi $~(nr); \ - SAVE_ALL; \ - TRACE_IRQS_OFF \ - movl %esp,%eax; \ - call fn; \ - jmp ret_from_intr; \ - CFI_ENDPROC; \ -ENDPROC(name) - - -#ifdef CONFIG_TRACING -#define TRACE_BUILD_INTERRUPT(name, nr) \ - BUILD_INTERRUPT3(trace_##name, nr, smp_trace_##name) -#else -#define TRACE_BUILD_INTERRUPT(name, nr) -#endif - -#define BUILD_INTERRUPT(name, nr) \ - BUILD_INTERRUPT3(name, nr, smp_##name); \ - TRACE_BUILD_INTERRUPT(name, nr) - -/* The include is where all of the SMP etc. interrupts come from */ -#include <asm/entry_arch.h> - -ENTRY(coprocessor_error) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi $do_coprocessor_error - jmp error_code - CFI_ENDPROC -END(coprocessor_error) - -ENTRY(simd_coprocessor_error) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 -#ifdef CONFIG_X86_INVD_BUG - /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */ - ALTERNATIVE "pushl_cfi $do_general_protection", \ - "pushl $do_simd_coprocessor_error", \ - X86_FEATURE_XMM -#else - pushl_cfi $do_simd_coprocessor_error -#endif - jmp error_code - CFI_ENDPROC -END(simd_coprocessor_error) - -ENTRY(device_not_available) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $-1 # mark this as an int - pushl_cfi $do_device_not_available - jmp error_code - CFI_ENDPROC -END(device_not_available) - -#ifdef CONFIG_PARAVIRT -ENTRY(native_iret) - iret - _ASM_EXTABLE(native_iret, iret_exc) -END(native_iret) - -ENTRY(native_irq_enable_sysexit) - sti - sysexit -END(native_irq_enable_sysexit) -#endif - -ENTRY(overflow) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi $do_overflow - jmp error_code - CFI_ENDPROC -END(overflow) - -ENTRY(bounds) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi $do_bounds - jmp error_code - CFI_ENDPROC -END(bounds) - -ENTRY(invalid_op) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi $do_invalid_op - jmp error_code - CFI_ENDPROC -END(invalid_op) - -ENTRY(coprocessor_segment_overrun) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi $do_coprocessor_segment_overrun - jmp error_code - CFI_ENDPROC -END(coprocessor_segment_overrun) - -ENTRY(invalid_TSS) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $do_invalid_TSS - jmp error_code - CFI_ENDPROC -END(invalid_TSS) - -ENTRY(segment_not_present) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $do_segment_not_present - jmp error_code - CFI_ENDPROC -END(segment_not_present) - -ENTRY(stack_segment) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $do_stack_segment - jmp error_code - CFI_ENDPROC -END(stack_segment) - -ENTRY(alignment_check) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $do_alignment_check - jmp error_code - CFI_ENDPROC -END(alignment_check) - -ENTRY(divide_error) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 # no error code - pushl_cfi $do_divide_error - jmp error_code - CFI_ENDPROC -END(divide_error) - -#ifdef CONFIG_X86_MCE -ENTRY(machine_check) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi machine_check_vector - jmp error_code - CFI_ENDPROC -END(machine_check) -#endif - -ENTRY(spurious_interrupt_bug) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $0 - pushl_cfi $do_spurious_interrupt_bug - jmp error_code - CFI_ENDPROC -END(spurious_interrupt_bug) - -#ifdef CONFIG_XEN -/* Xen doesn't set %esp to be precisely what the normal sysenter - entrypoint expects, so fix it up before using the normal path. */ -ENTRY(xen_sysenter_target) - RING0_INT_FRAME - addl $5*4, %esp /* remove xen-provided frame */ - CFI_ADJUST_CFA_OFFSET -5*4 - jmp sysenter_past_esp - CFI_ENDPROC - -ENTRY(xen_hypervisor_callback) - CFI_STARTPROC - pushl_cfi $-1 /* orig_ax = -1 => not a system call */ - SAVE_ALL - TRACE_IRQS_OFF - - /* Check to see if we got the event in the critical - region in xen_iret_direct, after we've reenabled - events and checked for pending events. This simulates - iret instruction's behaviour where it delivers a - pending interrupt when enabling interrupts. */ - movl PT_EIP(%esp),%eax - cmpl $xen_iret_start_crit,%eax - jb 1f - cmpl $xen_iret_end_crit,%eax - jae 1f - - jmp xen_iret_crit_fixup - -ENTRY(xen_do_upcall) -1: mov %esp, %eax - call xen_evtchn_do_upcall -#ifndef CONFIG_PREEMPT - call xen_maybe_preempt_hcall -#endif - jmp ret_from_intr - CFI_ENDPROC -ENDPROC(xen_hypervisor_callback) - -# Hypervisor uses this for application faults while it executes. -# We get here for two reasons: -# 1. Fault while reloading DS, ES, FS or GS -# 2. Fault while executing IRET -# Category 1 we fix up by reattempting the load, and zeroing the segment -# register if the load fails. -# Category 2 we fix up by jumping to do_iret_error. We cannot use the -# normal Linux return path in this case because if we use the IRET hypercall -# to pop the stack frame we end up in an infinite loop of failsafe callbacks. -# We distinguish between categories by maintaining a status value in EAX. -ENTRY(xen_failsafe_callback) - CFI_STARTPROC - pushl_cfi %eax - movl $1,%eax -1: mov 4(%esp),%ds -2: mov 8(%esp),%es -3: mov 12(%esp),%fs -4: mov 16(%esp),%gs - /* EAX == 0 => Category 1 (Bad segment) - EAX != 0 => Category 2 (Bad IRET) */ - testl %eax,%eax - popl_cfi %eax - lea 16(%esp),%esp - CFI_ADJUST_CFA_OFFSET -16 - jz 5f - jmp iret_exc -5: pushl_cfi $-1 /* orig_ax = -1 => not a system call */ - SAVE_ALL - jmp ret_from_exception - CFI_ENDPROC - -.section .fixup,"ax" -6: xorl %eax,%eax - movl %eax,4(%esp) - jmp 1b -7: xorl %eax,%eax - movl %eax,8(%esp) - jmp 2b -8: xorl %eax,%eax - movl %eax,12(%esp) - jmp 3b -9: xorl %eax,%eax - movl %eax,16(%esp) - jmp 4b -.previous - _ASM_EXTABLE(1b,6b) - _ASM_EXTABLE(2b,7b) - _ASM_EXTABLE(3b,8b) - _ASM_EXTABLE(4b,9b) -ENDPROC(xen_failsafe_callback) - -BUILD_INTERRUPT3(xen_hvm_callback_vector, HYPERVISOR_CALLBACK_VECTOR, - xen_evtchn_do_upcall) - -#endif /* CONFIG_XEN */ - -#if IS_ENABLED(CONFIG_HYPERV) - -BUILD_INTERRUPT3(hyperv_callback_vector, HYPERVISOR_CALLBACK_VECTOR, - hyperv_vector_handler) - -#endif /* CONFIG_HYPERV */ - -#ifdef CONFIG_FUNCTION_TRACER -#ifdef CONFIG_DYNAMIC_FTRACE - -ENTRY(mcount) - ret -END(mcount) - -ENTRY(ftrace_caller) - pushl %eax - pushl %ecx - pushl %edx - pushl $0 /* Pass NULL as regs pointer */ - movl 4*4(%esp), %eax - movl 0x4(%ebp), %edx - movl function_trace_op, %ecx - subl $MCOUNT_INSN_SIZE, %eax - -.globl ftrace_call -ftrace_call: - call ftrace_stub - - addl $4,%esp /* skip NULL pointer */ - popl %edx - popl %ecx - popl %eax -ftrace_ret: -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -.globl ftrace_graph_call -ftrace_graph_call: - jmp ftrace_stub -#endif - -.globl ftrace_stub -ftrace_stub: - ret -END(ftrace_caller) - -ENTRY(ftrace_regs_caller) - pushf /* push flags before compare (in cs location) */ - - /* - * i386 does not save SS and ESP when coming from kernel. - * Instead, to get sp, ®s->sp is used (see ptrace.h). - * Unfortunately, that means eflags must be at the same location - * as the current return ip is. We move the return ip into the - * ip location, and move flags into the return ip location. - */ - pushl 4(%esp) /* save return ip into ip slot */ - - pushl $0 /* Load 0 into orig_ax */ - pushl %gs - pushl %fs - pushl %es - pushl %ds - pushl %eax - pushl %ebp - pushl %edi - pushl %esi - pushl %edx - pushl %ecx - pushl %ebx - - movl 13*4(%esp), %eax /* Get the saved flags */ - movl %eax, 14*4(%esp) /* Move saved flags into regs->flags location */ - /* clobbering return ip */ - movl $__KERNEL_CS,13*4(%esp) - - movl 12*4(%esp), %eax /* Load ip (1st parameter) */ - subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */ - movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */ - movl function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */ - pushl %esp /* Save pt_regs as 4th parameter */ - -GLOBAL(ftrace_regs_call) - call ftrace_stub - - addl $4, %esp /* Skip pt_regs */ - movl 14*4(%esp), %eax /* Move flags back into cs */ - movl %eax, 13*4(%esp) /* Needed to keep addl from modifying flags */ - movl 12*4(%esp), %eax /* Get return ip from regs->ip */ - movl %eax, 14*4(%esp) /* Put return ip back for ret */ - - popl %ebx - popl %ecx - popl %edx - popl %esi - popl %edi - popl %ebp - popl %eax - popl %ds - popl %es - popl %fs - popl %gs - addl $8, %esp /* Skip orig_ax and ip */ - popf /* Pop flags at end (no addl to corrupt flags) */ - jmp ftrace_ret - - popf - jmp ftrace_stub -#else /* ! CONFIG_DYNAMIC_FTRACE */ - -ENTRY(mcount) - cmpl $__PAGE_OFFSET, %esp - jb ftrace_stub /* Paging not enabled yet? */ - - cmpl $ftrace_stub, ftrace_trace_function - jnz trace -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - cmpl $ftrace_stub, ftrace_graph_return - jnz ftrace_graph_caller - - cmpl $ftrace_graph_entry_stub, ftrace_graph_entry - jnz ftrace_graph_caller -#endif -.globl ftrace_stub -ftrace_stub: - ret - - /* taken from glibc */ -trace: - pushl %eax - pushl %ecx - pushl %edx - movl 0xc(%esp), %eax - movl 0x4(%ebp), %edx - subl $MCOUNT_INSN_SIZE, %eax - - call *ftrace_trace_function - - popl %edx - popl %ecx - popl %eax - jmp ftrace_stub -END(mcount) -#endif /* CONFIG_DYNAMIC_FTRACE */ -#endif /* CONFIG_FUNCTION_TRACER */ - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller) - pushl %eax - pushl %ecx - pushl %edx - movl 0xc(%esp), %eax - lea 0x4(%ebp), %edx - movl (%ebp), %ecx - subl $MCOUNT_INSN_SIZE, %eax - call prepare_ftrace_return - popl %edx - popl %ecx - popl %eax - ret -END(ftrace_graph_caller) - -.globl return_to_handler -return_to_handler: - pushl %eax - pushl %edx - movl %ebp, %eax - call ftrace_return_to_handler - movl %eax, %ecx - popl %edx - popl %eax - jmp *%ecx -#endif - -#ifdef CONFIG_TRACING -ENTRY(trace_page_fault) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $trace_do_page_fault - jmp error_code - CFI_ENDPROC -END(trace_page_fault) -#endif - -ENTRY(page_fault) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $do_page_fault - ALIGN -error_code: - /* the function address is in %gs's slot on the stack */ - pushl_cfi %fs - /*CFI_REL_OFFSET fs, 0*/ - pushl_cfi %es - /*CFI_REL_OFFSET es, 0*/ - pushl_cfi %ds - /*CFI_REL_OFFSET ds, 0*/ - pushl_cfi_reg eax - pushl_cfi_reg ebp - pushl_cfi_reg edi - pushl_cfi_reg esi - pushl_cfi_reg edx - pushl_cfi_reg ecx - pushl_cfi_reg ebx - cld - movl $(__KERNEL_PERCPU), %ecx - movl %ecx, %fs - UNWIND_ESPFIX_STACK - GS_TO_REG %ecx - movl PT_GS(%esp), %edi # get the function address - movl PT_ORIG_EAX(%esp), %edx # get the error code - movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart - REG_TO_PTGS %ecx - SET_KERNEL_GS %ecx - movl $(__USER_DS), %ecx - movl %ecx, %ds - movl %ecx, %es - TRACE_IRQS_OFF - movl %esp,%eax # pt_regs pointer - call *%edi - jmp ret_from_exception - CFI_ENDPROC -END(page_fault) - -/* - * Debug traps and NMI can happen at the one SYSENTER instruction - * that sets up the real kernel stack. Check here, since we can't - * allow the wrong stack to be used. - * - * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have - * already pushed 3 words if it hits on the sysenter instruction: - * eflags, cs and eip. - * - * We just load the right stack, and push the three (known) values - * by hand onto the new stack - while updating the return eip past - * the instruction that would have done it for sysenter. - */ -.macro FIX_STACK offset ok label - cmpw $__KERNEL_CS, 4(%esp) - jne \ok -\label: - movl TSS_sysenter_sp0 + \offset(%esp), %esp - CFI_DEF_CFA esp, 0 - CFI_UNDEFINED eip - pushfl_cfi - pushl_cfi $__KERNEL_CS - pushl_cfi $sysenter_past_esp - CFI_REL_OFFSET eip, 0 -.endm - -ENTRY(debug) - RING0_INT_FRAME - ASM_CLAC - cmpl $ia32_sysenter_target,(%esp) - jne debug_stack_correct - FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn -debug_stack_correct: - pushl_cfi $-1 # mark this as an int - SAVE_ALL - TRACE_IRQS_OFF - xorl %edx,%edx # error code 0 - movl %esp,%eax # pt_regs pointer - call do_debug - jmp ret_from_exception - CFI_ENDPROC -END(debug) - -/* - * NMI is doubly nasty. It can happen _while_ we're handling - * a debug fault, and the debug fault hasn't yet been able to - * clear up the stack. So we first check whether we got an - * NMI on the sysenter entry path, but after that we need to - * check whether we got an NMI on the debug path where the debug - * fault happened on the sysenter path. - */ -ENTRY(nmi) - RING0_INT_FRAME - ASM_CLAC -#ifdef CONFIG_X86_ESPFIX32 - pushl_cfi %eax - movl %ss, %eax - cmpw $__ESPFIX_SS, %ax - popl_cfi %eax - je nmi_espfix_stack -#endif - cmpl $ia32_sysenter_target,(%esp) - je nmi_stack_fixup - pushl_cfi %eax - movl %esp,%eax - /* Do not access memory above the end of our stack page, - * it might not exist. - */ - andl $(THREAD_SIZE-1),%eax - cmpl $(THREAD_SIZE-20),%eax - popl_cfi %eax - jae nmi_stack_correct - cmpl $ia32_sysenter_target,12(%esp) - je nmi_debug_stack_check -nmi_stack_correct: - /* We have a RING0_INT_FRAME here */ - pushl_cfi %eax - SAVE_ALL - xorl %edx,%edx # zero error code - movl %esp,%eax # pt_regs pointer - call do_nmi - jmp restore_all_notrace - CFI_ENDPROC - -nmi_stack_fixup: - RING0_INT_FRAME - FIX_STACK 12, nmi_stack_correct, 1 - jmp nmi_stack_correct - -nmi_debug_stack_check: - /* We have a RING0_INT_FRAME here */ - cmpw $__KERNEL_CS,16(%esp) - jne nmi_stack_correct - cmpl $debug,(%esp) - jb nmi_stack_correct - cmpl $debug_esp_fix_insn,(%esp) - ja nmi_stack_correct - FIX_STACK 24, nmi_stack_correct, 1 - jmp nmi_stack_correct - -#ifdef CONFIG_X86_ESPFIX32 -nmi_espfix_stack: - /* We have a RING0_INT_FRAME here. - * - * create the pointer to lss back - */ - pushl_cfi %ss - pushl_cfi %esp - addl $4, (%esp) - /* copy the iret frame of 12 bytes */ - .rept 3 - pushl_cfi 16(%esp) - .endr - pushl_cfi %eax - SAVE_ALL - FIXUP_ESPFIX_STACK # %eax == %esp - xorl %edx,%edx # zero error code - call do_nmi - RESTORE_REGS - lss 12+4(%esp), %esp # back to espfix stack - CFI_ADJUST_CFA_OFFSET -24 - jmp irq_return -#endif - CFI_ENDPROC -END(nmi) - -ENTRY(int3) - RING0_INT_FRAME - ASM_CLAC - pushl_cfi $-1 # mark this as an int - SAVE_ALL - TRACE_IRQS_OFF - xorl %edx,%edx # zero error code - movl %esp,%eax # pt_regs pointer - call do_int3 - jmp ret_from_exception - CFI_ENDPROC -END(int3) - -ENTRY(general_protection) - RING0_EC_FRAME - pushl_cfi $do_general_protection - jmp error_code - CFI_ENDPROC -END(general_protection) - -#ifdef CONFIG_KVM_GUEST -ENTRY(async_page_fault) - RING0_EC_FRAME - ASM_CLAC - pushl_cfi $do_async_page_fault - jmp error_code - CFI_ENDPROC -END(async_page_fault) -#endif - |