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-rw-r--r--arch/x86/entry/entry_32.S1249
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diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
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+/*
+ *
+ * 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/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 $0
+.endm
+.macro POP_GS pop=0
+ addl $(4 + \pop), %esp
+.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 %gs
+.endm
+
+.macro POP_GS pop=0
+98: popl %gs
+ .if \pop <> 0
+ add $\pop, %esp
+ .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
+.endm
+.macro REG_TO_PTGS reg
+ movl \reg, PT_GS(%esp)
+.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 %fs
+ pushl %es
+ pushl %ds
+ pushl %eax
+ pushl %ebp
+ pushl %edi
+ pushl %esi
+ pushl %edx
+ pushl %ecx
+ pushl %ebx
+ 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 %ebx
+ popl %ecx
+ popl %edx
+ popl %esi
+ popl %edi
+ popl %ebp
+ popl %eax
+.endm
+
+.macro RESTORE_REGS pop=0
+ RESTORE_INT_REGS
+1: popl %ds
+2: popl %es
+3: popl %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
+
+ENTRY(ret_from_fork)
+ pushl %eax
+ call schedule_tail
+ GET_THREAD_INFO(%ebp)
+ popl %eax
+ pushl $0x0202 # Reset kernel eflags
+ popfl
+ jmp syscall_exit
+END(ret_from_fork)
+
+ENTRY(ret_from_kernel_thread)
+ pushl %eax
+ call schedule_tail
+ GET_THREAD_INFO(%ebp)
+ popl %eax
+ pushl $0x0202 # Reset kernel eflags
+ popfl
+ movl PT_EBP(%esp),%eax
+ call *PT_EBX(%esp)
+ movl $0,PT_EAX(%esp)
+ jmp syscall_exit
+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
+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
+
+/* 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)
+ 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 $__USER_DS
+ pushl %ebp
+ pushfl
+ orl $X86_EFLAGS_IF, (%esp)
+ pushl $__USER_CS
+ /*
+ * 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 ((TI_sysenter_return) - THREAD_SIZE + TOP_OF_KERNEL_STACK_PADDING + 4*4)(%esp)
+
+ pushl %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 PT_ESI(%esp) /* a3: 5th arg */
+ pushl PT_EDX+4(%esp) /* a2: 4th arg */
+ call __audit_syscall_entry
+ popl %ecx /* get that remapped edx off the stack */
+ popl %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
+
+.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)
+ ASM_CLAC
+ pushl %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
+ 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
+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 $__ESPFIX_SS
+ pushl %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 */
+ jmp restore_nocheck
+#endif
+ENDPROC(system_call)
+
+ # perform work that needs to be done immediately before resumption
+ ALIGN
+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 %ecx # save ti_flags for do_notify_resume
+ call save_v86_state # %eax contains pt_regs pointer
+ popl %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)
+
+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)
+
+.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 $__KERNEL_DS
+ pushl %eax
+ lss (%esp), %esp /* switch to the normal stack segment */
+#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)
+ 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
+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)
+
+#define BUILD_INTERRUPT3(name, nr, fn) \
+ENTRY(name) \
+ ASM_CLAC; \
+ pushl $~(nr); \
+ SAVE_ALL; \
+ TRACE_IRQS_OFF \
+ movl %esp,%eax; \
+ call fn; \
+ jmp ret_from_intr; \
+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)
+ ASM_CLAC
+ pushl $0
+ pushl $do_coprocessor_error
+ jmp error_code
+END(coprocessor_error)
+
+ENTRY(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 error_code
+END(simd_coprocessor_error)
+
+ENTRY(device_not_available)
+ ASM_CLAC
+ pushl $-1 # mark this as an int
+ pushl $do_device_not_available
+ jmp error_code
+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)
+ ASM_CLAC
+ pushl $0
+ pushl $do_overflow
+ jmp error_code
+END(overflow)
+
+ENTRY(bounds)
+ ASM_CLAC
+ pushl $0
+ pushl $do_bounds
+ jmp error_code
+END(bounds)
+
+ENTRY(invalid_op)
+ ASM_CLAC
+ pushl $0
+ pushl $do_invalid_op
+ jmp error_code
+END(invalid_op)
+
+ENTRY(coprocessor_segment_overrun)
+ ASM_CLAC
+ pushl $0
+ pushl $do_coprocessor_segment_overrun
+ jmp error_code
+END(coprocessor_segment_overrun)
+
+ENTRY(invalid_TSS)
+ ASM_CLAC
+ pushl $do_invalid_TSS
+ jmp error_code
+END(invalid_TSS)
+
+ENTRY(segment_not_present)
+ ASM_CLAC
+ pushl $do_segment_not_present
+ jmp error_code
+END(segment_not_present)
+
+ENTRY(stack_segment)
+ ASM_CLAC
+ pushl $do_stack_segment
+ jmp error_code
+END(stack_segment)
+
+ENTRY(alignment_check)
+ ASM_CLAC
+ pushl $do_alignment_check
+ jmp error_code
+END(alignment_check)
+
+ENTRY(divide_error)
+ ASM_CLAC
+ pushl $0 # no error code
+ pushl $do_divide_error
+ jmp error_code
+END(divide_error)
+
+#ifdef CONFIG_X86_MCE
+ENTRY(machine_check)
+ ASM_CLAC
+ pushl $0
+ pushl machine_check_vector
+ jmp error_code
+END(machine_check)
+#endif
+
+ENTRY(spurious_interrupt_bug)
+ ASM_CLAC
+ pushl $0
+ pushl $do_spurious_interrupt_bug
+ jmp error_code
+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)
+ addl $5*4, %esp /* remove xen-provided frame */
+ jmp sysenter_past_esp
+
+ENTRY(xen_hypervisor_callback)
+ pushl $-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
+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)
+ pushl %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 %eax
+ lea 16(%esp),%esp
+ jz 5f
+ jmp iret_exc
+5: pushl $-1 /* orig_ax = -1 => not a system call */
+ SAVE_ALL
+ jmp ret_from_exception
+
+.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, &regs->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)
+ ASM_CLAC
+ pushl $trace_do_page_fault
+ jmp error_code
+END(trace_page_fault)
+#endif
+
+ENTRY(page_fault)
+ ASM_CLAC
+ pushl $do_page_fault
+ ALIGN
+error_code:
+ /* the function address is in %gs's slot on the stack */
+ pushl %fs
+ pushl %es
+ pushl %ds
+ pushl %eax
+ pushl %ebp
+ pushl %edi
+ pushl %esi
+ pushl %edx
+ pushl %ecx
+ pushl %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
+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
+ pushfl
+ pushl $__KERNEL_CS
+ pushl $sysenter_past_esp
+.endm
+
+ENTRY(debug)
+ 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 $-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
+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)
+ ASM_CLAC
+#ifdef CONFIG_X86_ESPFIX32
+ pushl %eax
+ movl %ss, %eax
+ cmpw $__ESPFIX_SS, %ax
+ popl %eax
+ je nmi_espfix_stack
+#endif
+ cmpl $ia32_sysenter_target,(%esp)
+ je nmi_stack_fixup
+ pushl %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 %eax
+ jae nmi_stack_correct
+ cmpl $ia32_sysenter_target,12(%esp)
+ je nmi_debug_stack_check
+nmi_stack_correct:
+ pushl %eax
+ SAVE_ALL
+ xorl %edx,%edx # zero error code
+ movl %esp,%eax # pt_regs pointer
+ call do_nmi
+ jmp restore_all_notrace
+
+nmi_stack_fixup:
+ FIX_STACK 12, nmi_stack_correct, 1
+ jmp nmi_stack_correct
+
+nmi_debug_stack_check:
+ 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:
+ /*
+ * create the pointer to lss back
+ */
+ pushl %ss
+ pushl %esp
+ addl $4, (%esp)
+ /* copy the iret frame of 12 bytes */
+ .rept 3
+ pushl 16(%esp)
+ .endr
+ pushl %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
+ jmp irq_return
+#endif
+END(nmi)
+
+ENTRY(int3)
+ ASM_CLAC
+ pushl $-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
+END(int3)
+
+ENTRY(general_protection)
+ pushl $do_general_protection
+ jmp error_code
+END(general_protection)
+
+#ifdef CONFIG_KVM_GUEST
+ENTRY(async_page_fault)
+ ASM_CLAC
+ pushl $do_async_page_fault
+ jmp error_code
+END(async_page_fault)
+#endif
+