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kernel-fxtec-pro1x/arch/x86_64/kernel/entry.S
Andi Kleen c33d4568ac [PATCH] x86-64: Fix up handling of non canonical user RIPs 
EM64T CPUs have somewhat weird error reporting for non canonical RIPs in
SYSRET.

We can't handle any exceptions there because the exception handler would
end up running on the user stack which is unsafe.

To avoid problems any code that might end up with a user touched pt_regs
should return using int_ret_from_syscall.  int_ret_from_syscall ends up
using IRET, which allows safe exceptions.

Cc: Ernie Petrides <petrides@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-12 22:56:29 -08:00

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/*
* linux/arch/x86_64/entry.S
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
* Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
*
* $Id$
*/
/*
* entry.S contains the system-call and fault low-level handling routines.
*
* NOTE: This code handles signal-recognition, which happens every time
* after an interrupt and after each system call.
*
* Normal syscalls and interrupts don't save a full stack frame, this is
* only done for syscall tracing, signals or fork/exec et.al.
*
* A note on terminology:
* - top of stack: Architecture defined interrupt frame from SS to RIP
* at the top of the kernel process stack.
* - partial stack frame: partially saved registers upto R11.
* - full stack frame: Like partial stack frame, but all register saved.
*
* TODO:
* - schedule it carefully for the final hardware.
*/
#define ASSEMBLY 1
#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/smp.h>
#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/dwarf2.h>
#include <asm/calling.h>
#include <asm/asm-offsets.h>
#include <asm/msr.h>
#include <asm/unistd.h>
#include <asm/thread_info.h>
#include <asm/hw_irq.h>
#include <asm/page.h>
.code64
#ifndef CONFIG_PREEMPT
#define retint_kernel retint_restore_args
#endif
/*
* C code is not supposed to know about undefined top of stack. Every time
* a C function with an pt_regs argument is called from the SYSCALL based
* fast path FIXUP_TOP_OF_STACK is needed.
* RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
* manipulation.
*/
/* %rsp:at FRAMEEND */
.macro FIXUP_TOP_OF_STACK tmp
movq %gs:pda_oldrsp,\tmp
movq \tmp,RSP(%rsp)
movq $__USER_DS,SS(%rsp)
movq $__USER_CS,CS(%rsp)
movq $-1,RCX(%rsp)
movq R11(%rsp),\tmp /* get eflags */
movq \tmp,EFLAGS(%rsp)
.endm
.macro RESTORE_TOP_OF_STACK tmp,offset=0
movq RSP-\offset(%rsp),\tmp
movq \tmp,%gs:pda_oldrsp
movq EFLAGS-\offset(%rsp),\tmp
movq \tmp,R11-\offset(%rsp)
.endm
.macro FAKE_STACK_FRAME child_rip
/* push in order ss, rsp, eflags, cs, rip */
xorl %eax, %eax
pushq %rax /* ss */
CFI_ADJUST_CFA_OFFSET 8
/*CFI_REL_OFFSET ss,0*/
pushq %rax /* rsp */
CFI_ADJUST_CFA_OFFSET 8
CFI_REL_OFFSET rsp,0
pushq $(1<<9) /* eflags - interrupts on */
CFI_ADJUST_CFA_OFFSET 8
/*CFI_REL_OFFSET rflags,0*/
pushq $__KERNEL_CS /* cs */
CFI_ADJUST_CFA_OFFSET 8
/*CFI_REL_OFFSET cs,0*/
pushq \child_rip /* rip */
CFI_ADJUST_CFA_OFFSET 8
CFI_REL_OFFSET rip,0
pushq %rax /* orig rax */
CFI_ADJUST_CFA_OFFSET 8
.endm
.macro UNFAKE_STACK_FRAME
addq $8*6, %rsp
CFI_ADJUST_CFA_OFFSET -(6*8)
.endm
.macro CFI_DEFAULT_STACK start=1
.if \start
CFI_STARTPROC simple
CFI_DEF_CFA rsp,SS+8
.else
CFI_DEF_CFA_OFFSET SS+8
.endif
CFI_REL_OFFSET r15,R15
CFI_REL_OFFSET r14,R14
CFI_REL_OFFSET r13,R13
CFI_REL_OFFSET r12,R12
CFI_REL_OFFSET rbp,RBP
CFI_REL_OFFSET rbx,RBX
CFI_REL_OFFSET r11,R11
CFI_REL_OFFSET r10,R10
CFI_REL_OFFSET r9,R9
CFI_REL_OFFSET r8,R8
CFI_REL_OFFSET rax,RAX
CFI_REL_OFFSET rcx,RCX
CFI_REL_OFFSET rdx,RDX
CFI_REL_OFFSET rsi,RSI
CFI_REL_OFFSET rdi,RDI
CFI_REL_OFFSET rip,RIP
/*CFI_REL_OFFSET cs,CS*/
/*CFI_REL_OFFSET rflags,EFLAGS*/
CFI_REL_OFFSET rsp,RSP
/*CFI_REL_OFFSET ss,SS*/
.endm
/*
* A newly forked process directly context switches into this.
*/
/* rdi: prev */
ENTRY(ret_from_fork)
CFI_DEFAULT_STACK
call schedule_tail
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx)
jnz rff_trace
rff_action:
RESTORE_REST
testl $3,CS-ARGOFFSET(%rsp) # from kernel_thread?
je int_ret_from_sys_call
testl $_TIF_IA32,threadinfo_flags(%rcx)
jnz int_ret_from_sys_call
RESTORE_TOP_OF_STACK %rdi,ARGOFFSET
jmp ret_from_sys_call
rff_trace:
movq %rsp,%rdi
call syscall_trace_leave
GET_THREAD_INFO(%rcx)
jmp rff_action
CFI_ENDPROC
/*
* System call entry. Upto 6 arguments in registers are supported.
*
* SYSCALL does not save anything on the stack and does not change the
* stack pointer.
*/
/*
* Register setup:
* rax system call number
* rdi arg0
* rcx return address for syscall/sysret, C arg3
* rsi arg1
* rdx arg2
* r10 arg3 (--> moved to rcx for C)
* r8 arg4
* r9 arg5
* r11 eflags for syscall/sysret, temporary for C
* r12-r15,rbp,rbx saved by C code, not touched.
*
* Interrupts are off on entry.
* Only called from user space.
*
* EM64T CPUs have somewhat weird error reporting for non canonical RIPs in SYSRET.
* We can't handle any exceptions there because the exception handler would
* end up running on the user stack which is unsafe. To avoid problems
* any code that might end up with a user touched pt_regs should return
* using int_ret_from_syscall.
*
* XXX if we had a free scratch register we could save the RSP into the stack frame
* and report it properly in ps. Unfortunately we haven't.
*/
ENTRY(system_call)
CFI_STARTPROC simple
CFI_DEF_CFA rsp,0
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
swapgs
movq %rsp,%gs:pda_oldrsp
movq %gs:pda_kernelstack,%rsp
sti
SAVE_ARGS 8,1
movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
movq %rcx,RIP-ARGOFFSET(%rsp)
CFI_REL_OFFSET rip,RIP-ARGOFFSET
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%rcx)
CFI_REMEMBER_STATE
jnz tracesys
cmpq $__NR_syscall_max,%rax
ja badsys
movq %r10,%rcx
call *sys_call_table(,%rax,8) # XXX: rip relative
movq %rax,RAX-ARGOFFSET(%rsp)
/*
* Syscall return path ending with SYSRET (fast path)
* Has incomplete stack frame and undefined top of stack.
*/
.globl ret_from_sys_call
ret_from_sys_call:
movl $_TIF_ALLWORK_MASK,%edi
/* edi: flagmask */
sysret_check:
GET_THREAD_INFO(%rcx)
cli
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
CFI_REMEMBER_STATE
jnz sysret_careful
movq RIP-ARGOFFSET(%rsp),%rcx
CFI_REGISTER rip,rcx
RESTORE_ARGS 0,-ARG_SKIP,1
/*CFI_REGISTER rflags,r11*/
movq %gs:pda_oldrsp,%rsp
swapgs
sysretq
/* Handle reschedules */
/* edx: work, edi: workmask */
sysret_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc sysret_signal
sti
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call schedule
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
jmp sysret_check
/* Handle a signal */
sysret_signal:
sti
testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
jz 1f
/* Really a signal */
/* edx: work flags (arg3) */
leaq do_notify_resume(%rip),%rax
leaq -ARGOFFSET(%rsp),%rdi # &pt_regs -> arg1
xorl %esi,%esi # oldset -> arg2
call ptregscall_common
1: movl $_TIF_NEED_RESCHED,%edi
/* Stack frame might have been changed. The IRET path does
some additional checks to handle this */
jmp int_with_check
badsys:
movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
jmp ret_from_sys_call
/* Do syscall tracing */
tracesys:
CFI_RESTORE_STATE
SAVE_REST
movq $-ENOSYS,RAX(%rsp)
FIXUP_TOP_OF_STACK %rdi
movq %rsp,%rdi
call syscall_trace_enter
LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */
RESTORE_REST
cmpq $__NR_syscall_max,%rax
ja 1f
movq %r10,%rcx /* fixup for C */
call *sys_call_table(,%rax,8)
movq %rax,RAX-ARGOFFSET(%rsp)
1: SAVE_REST
movq %rsp,%rdi
call syscall_trace_leave
RESTORE_TOP_OF_STACK %rbx
RESTORE_REST
/* Stack frame might have been changed. Use the more careful IRET path */
jmp int_ret_from_sys_call
CFI_ENDPROC
/*
* Syscall return path ending with IRET.
* Has correct top of stack, but partial stack frame.
*/
ENTRY(int_ret_from_sys_call)
CFI_STARTPROC simple
CFI_DEF_CFA rsp,SS+8-ARGOFFSET
/*CFI_REL_OFFSET ss,SS-ARGOFFSET*/
CFI_REL_OFFSET rsp,RSP-ARGOFFSET
/*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/
/*CFI_REL_OFFSET cs,CS-ARGOFFSET*/
CFI_REL_OFFSET rip,RIP-ARGOFFSET
CFI_REL_OFFSET rdx,RDX-ARGOFFSET
CFI_REL_OFFSET rcx,RCX-ARGOFFSET
CFI_REL_OFFSET rax,RAX-ARGOFFSET
CFI_REL_OFFSET rdi,RDI-ARGOFFSET
CFI_REL_OFFSET rsi,RSI-ARGOFFSET
CFI_REL_OFFSET r8,R8-ARGOFFSET
CFI_REL_OFFSET r9,R9-ARGOFFSET
CFI_REL_OFFSET r10,R10-ARGOFFSET
CFI_REL_OFFSET r11,R11-ARGOFFSET
cli
testl $3,CS-ARGOFFSET(%rsp)
je retint_restore_args
movl $_TIF_ALLWORK_MASK,%edi
/* edi: mask to check */
int_with_check:
GET_THREAD_INFO(%rcx)
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
jnz int_careful
andl $~TS_COMPAT,threadinfo_status(%rcx)
jmp retint_swapgs
/* Either reschedule or signal or syscall exit tracking needed. */
/* First do a reschedule test. */
/* edx: work, edi: workmask */
int_careful:
bt $TIF_NEED_RESCHED,%edx
jnc int_very_careful
sti
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call schedule
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
cli
jmp int_with_check
/* handle signals and tracing -- both require a full stack frame */
int_very_careful:
sti
SAVE_REST
/* Check for syscall exit trace */
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edx
jz int_signal
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
leaq 8(%rsp),%rdi # &ptregs -> arg1
call syscall_trace_leave
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi
cli
jmp int_restore_rest
int_signal:
testl $(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_SINGLESTEP),%edx
jz 1f
movq %rsp,%rdi # &ptregs -> arg1
xorl %esi,%esi # oldset -> arg2
call do_notify_resume
1: movl $_TIF_NEED_RESCHED,%edi
int_restore_rest:
RESTORE_REST
cli
jmp int_with_check
CFI_ENDPROC
/*
* Certain special system calls that need to save a complete full stack frame.
*/
.macro PTREGSCALL label,func,arg
.globl \label
\label:
leaq \func(%rip),%rax
leaq -ARGOFFSET+8(%rsp),\arg /* 8 for return address */
jmp ptregscall_common
.endm
CFI_STARTPROC
PTREGSCALL stub_clone, sys_clone, %r8
PTREGSCALL stub_fork, sys_fork, %rdi
PTREGSCALL stub_vfork, sys_vfork, %rdi
PTREGSCALL stub_rt_sigsuspend, sys_rt_sigsuspend, %rdx
PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
PTREGSCALL stub_iopl, sys_iopl, %rsi
ENTRY(ptregscall_common)
popq %r11
CFI_ADJUST_CFA_OFFSET -8
CFI_REGISTER rip, r11
SAVE_REST
movq %r11, %r15
CFI_REGISTER rip, r15
FIXUP_TOP_OF_STACK %r11
call *%rax
RESTORE_TOP_OF_STACK %r11
movq %r15, %r11
CFI_REGISTER rip, r11
RESTORE_REST
pushq %r11
CFI_ADJUST_CFA_OFFSET 8
CFI_REL_OFFSET rip, 0
ret
CFI_ENDPROC
ENTRY(stub_execve)
CFI_STARTPROC
popq %r11
CFI_ADJUST_CFA_OFFSET -8
CFI_REGISTER rip, r11
SAVE_REST
FIXUP_TOP_OF_STACK %r11
call sys_execve
RESTORE_TOP_OF_STACK %r11
movq %rax,RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
CFI_ENDPROC
/*
* sigreturn is special because it needs to restore all registers on return.
* This cannot be done with SYSRET, so use the IRET return path instead.
*/
ENTRY(stub_rt_sigreturn)
CFI_STARTPROC
addq $8, %rsp
CFI_ADJUST_CFA_OFFSET -8
SAVE_REST
movq %rsp,%rdi
FIXUP_TOP_OF_STACK %r11
call sys_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
/*
* initial frame state for interrupts and exceptions
*/
.macro _frame ref
CFI_STARTPROC simple
CFI_DEF_CFA rsp,SS+8-\ref
/*CFI_REL_OFFSET ss,SS-\ref*/
CFI_REL_OFFSET rsp,RSP-\ref
/*CFI_REL_OFFSET rflags,EFLAGS-\ref*/
/*CFI_REL_OFFSET cs,CS-\ref*/
CFI_REL_OFFSET rip,RIP-\ref
.endm
/* initial frame state for interrupts (and exceptions without error code) */
#define INTR_FRAME _frame RIP
/* initial frame state for exceptions with error code (and interrupts with
vector already pushed) */
#define XCPT_FRAME _frame ORIG_RAX
/*
* Interrupt entry/exit.
*
* Interrupt entry points save only callee clobbered registers in fast path.
*
* Entry runs with interrupts off.
*/
/* 0(%rsp): interrupt number */
.macro interrupt func
cld
#ifdef CONFIG_DEBUG_INFO
SAVE_ALL
movq %rsp,%rdi
/*
* Setup a stack frame pointer. This allows gdb to trace
* back to the original stack.
*/
movq %rsp,%rbp
CFI_DEF_CFA_REGISTER rbp
#else
SAVE_ARGS
leaq -ARGOFFSET(%rsp),%rdi # arg1 for handler
#endif
testl $3,CS(%rdi)
je 1f
swapgs
1: incl %gs:pda_irqcount # RED-PEN should check preempt count
movq %gs:pda_irqstackptr,%rax
cmoveq %rax,%rsp /*todo This needs CFI annotation! */
pushq %rdi # save old stack
#ifndef CONFIG_DEBUG_INFO
CFI_ADJUST_CFA_OFFSET 8
#endif
call \func
.endm
ENTRY(common_interrupt)
XCPT_FRAME
interrupt do_IRQ
/* 0(%rsp): oldrsp-ARGOFFSET */
ret_from_intr:
popq %rdi
#ifndef CONFIG_DEBUG_INFO
CFI_ADJUST_CFA_OFFSET -8
#endif
cli
decl %gs:pda_irqcount
#ifdef CONFIG_DEBUG_INFO
movq RBP(%rdi),%rbp
CFI_DEF_CFA_REGISTER rsp
#endif
leaq ARGOFFSET(%rdi),%rsp /*todo This needs CFI annotation! */
exit_intr:
GET_THREAD_INFO(%rcx)
testl $3,CS-ARGOFFSET(%rsp)
je retint_kernel
/* Interrupt came from user space */
/*
* Has a correct top of stack, but a partial stack frame
* %rcx: thread info. Interrupts off.
*/
retint_with_reschedule:
movl $_TIF_WORK_MASK,%edi
retint_check:
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
CFI_REMEMBER_STATE
jnz retint_careful
retint_swapgs:
swapgs
retint_restore_args:
cli
RESTORE_ARGS 0,8,0
iret_label:
iretq
.section __ex_table,"a"
.quad iret_label,bad_iret
.previous
.section .fixup,"ax"
/* force a signal here? this matches i386 behaviour */
/* running with kernel gs */
bad_iret:
movq $-9999,%rdi /* better code? */
sti
jmp do_exit
.previous
/* edi: workmask, edx: work */
retint_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc retint_signal
sti
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
call schedule
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
GET_THREAD_INFO(%rcx)
cli
jmp retint_check
retint_signal:
testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
jz retint_swapgs
sti
SAVE_REST
movq $-1,ORIG_RAX(%rsp)
xorl %esi,%esi # oldset
movq %rsp,%rdi # &pt_regs
call do_notify_resume
RESTORE_REST
cli
movl $_TIF_NEED_RESCHED,%edi
GET_THREAD_INFO(%rcx)
jmp retint_check
#ifdef CONFIG_PREEMPT
/* Returning to kernel space. Check if we need preemption */
/* rcx: threadinfo. interrupts off. */
.p2align
retint_kernel:
cmpl $0,threadinfo_preempt_count(%rcx)
jnz retint_restore_args
bt $TIF_NEED_RESCHED,threadinfo_flags(%rcx)
jnc retint_restore_args
bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
jnc retint_restore_args
call preempt_schedule_irq
jmp exit_intr
#endif
CFI_ENDPROC
/*
* APIC interrupts.
*/
.macro apicinterrupt num,func
INTR_FRAME
pushq $\num-256
CFI_ADJUST_CFA_OFFSET 8
interrupt \func
jmp ret_from_intr
CFI_ENDPROC
.endm
ENTRY(thermal_interrupt)
apicinterrupt THERMAL_APIC_VECTOR,smp_thermal_interrupt
ENTRY(threshold_interrupt)
apicinterrupt THRESHOLD_APIC_VECTOR,mce_threshold_interrupt
#ifdef CONFIG_SMP
ENTRY(reschedule_interrupt)
apicinterrupt RESCHEDULE_VECTOR,smp_reschedule_interrupt
.macro INVALIDATE_ENTRY num
ENTRY(invalidate_interrupt\num)
apicinterrupt INVALIDATE_TLB_VECTOR_START+\num,smp_invalidate_interrupt
.endm
INVALIDATE_ENTRY 0
INVALIDATE_ENTRY 1
INVALIDATE_ENTRY 2
INVALIDATE_ENTRY 3
INVALIDATE_ENTRY 4
INVALIDATE_ENTRY 5
INVALIDATE_ENTRY 6
INVALIDATE_ENTRY 7
ENTRY(call_function_interrupt)
apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt
#endif
#ifdef CONFIG_X86_LOCAL_APIC
ENTRY(apic_timer_interrupt)
apicinterrupt LOCAL_TIMER_VECTOR,smp_apic_timer_interrupt
ENTRY(error_interrupt)
apicinterrupt ERROR_APIC_VECTOR,smp_error_interrupt
ENTRY(spurious_interrupt)
apicinterrupt SPURIOUS_APIC_VECTOR,smp_spurious_interrupt
#endif
/*
* Exception entry points.
*/
.macro zeroentry sym
INTR_FRAME
pushq $0 /* push error code/oldrax */
CFI_ADJUST_CFA_OFFSET 8
pushq %rax /* push real oldrax to the rdi slot */
CFI_ADJUST_CFA_OFFSET 8
leaq \sym(%rip),%rax
jmp error_entry
CFI_ENDPROC
.endm
.macro errorentry sym
XCPT_FRAME
pushq %rax
CFI_ADJUST_CFA_OFFSET 8
leaq \sym(%rip),%rax
jmp error_entry
CFI_ENDPROC
.endm
/* error code is on the stack already */
/* handle NMI like exceptions that can happen everywhere */
.macro paranoidentry sym, ist=0
SAVE_ALL
cld
movl $1,%ebx
movl $MSR_GS_BASE,%ecx
rdmsr
testl %edx,%edx
js 1f
swapgs
xorl %ebx,%ebx
1:
.if \ist
movq %gs:pda_data_offset, %rbp
.endif
movq %rsp,%rdi
movq ORIG_RAX(%rsp),%rsi
movq $-1,ORIG_RAX(%rsp)
.if \ist
subq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
.endif
call \sym
.if \ist
addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
.endif
cli
.endm
/*
* Exception entry point. This expects an error code/orig_rax on the stack
* and the exception handler in %rax.
*/
ENTRY(error_entry)
_frame RDI
/* rdi slot contains rax, oldrax contains error code */
cld
subq $14*8,%rsp
CFI_ADJUST_CFA_OFFSET (14*8)
movq %rsi,13*8(%rsp)
CFI_REL_OFFSET rsi,RSI
movq 14*8(%rsp),%rsi /* load rax from rdi slot */
movq %rdx,12*8(%rsp)
CFI_REL_OFFSET rdx,RDX
movq %rcx,11*8(%rsp)
CFI_REL_OFFSET rcx,RCX
movq %rsi,10*8(%rsp) /* store rax */
CFI_REL_OFFSET rax,RAX
movq %r8, 9*8(%rsp)
CFI_REL_OFFSET r8,R8
movq %r9, 8*8(%rsp)
CFI_REL_OFFSET r9,R9
movq %r10,7*8(%rsp)
CFI_REL_OFFSET r10,R10
movq %r11,6*8(%rsp)
CFI_REL_OFFSET r11,R11
movq %rbx,5*8(%rsp)
CFI_REL_OFFSET rbx,RBX
movq %rbp,4*8(%rsp)
CFI_REL_OFFSET rbp,RBP
movq %r12,3*8(%rsp)
CFI_REL_OFFSET r12,R12
movq %r13,2*8(%rsp)
CFI_REL_OFFSET r13,R13
movq %r14,1*8(%rsp)
CFI_REL_OFFSET r14,R14
movq %r15,(%rsp)
CFI_REL_OFFSET r15,R15
xorl %ebx,%ebx
testl $3,CS(%rsp)
je error_kernelspace
error_swapgs:
swapgs
error_sti:
movq %rdi,RDI(%rsp)
movq %rsp,%rdi
movq ORIG_RAX(%rsp),%rsi /* get error code */
movq $-1,ORIG_RAX(%rsp)
call *%rax
/* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
error_exit:
movl %ebx,%eax
RESTORE_REST
cli
GET_THREAD_INFO(%rcx)
testl %eax,%eax
jne retint_kernel
movl threadinfo_flags(%rcx),%edx
movl $_TIF_WORK_MASK,%edi
andl %edi,%edx
jnz retint_careful
swapgs
RESTORE_ARGS 0,8,0
jmp iret_label
CFI_ENDPROC
error_kernelspace:
incl %ebx
/* There are two places in the kernel that can potentially fault with
usergs. Handle them here. The exception handlers after
iret run with kernel gs again, so don't set the user space flag.
B stepping K8s sometimes report an truncated RIP for IRET
exceptions returning to compat mode. Check for these here too. */
leaq iret_label(%rip),%rbp
cmpq %rbp,RIP(%rsp)
je error_swapgs
movl %ebp,%ebp /* zero extend */
cmpq %rbp,RIP(%rsp)
je error_swapgs
cmpq $gs_change,RIP(%rsp)
je error_swapgs
jmp error_sti
/* Reload gs selector with exception handling */
/* edi: new selector */
ENTRY(load_gs_index)
CFI_STARTPROC
pushf
CFI_ADJUST_CFA_OFFSET 8
cli
swapgs
gs_change:
movl %edi,%gs
2: mfence /* workaround */
swapgs
popf
CFI_ADJUST_CFA_OFFSET -8
ret
CFI_ENDPROC
.section __ex_table,"a"
.align 8
.quad gs_change,bad_gs
.previous
.section .fixup,"ax"
/* running with kernelgs */
bad_gs:
swapgs /* switch back to user gs */
xorl %eax,%eax
movl %eax,%gs
jmp 2b
.previous
/*
* Create a kernel thread.
*
* C extern interface:
* extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
*
* asm input arguments:
* rdi: fn, rsi: arg, rdx: flags
*/
ENTRY(kernel_thread)
CFI_STARTPROC
FAKE_STACK_FRAME $child_rip
SAVE_ALL
# rdi: flags, rsi: usp, rdx: will be &pt_regs
movq %rdx,%rdi
orq kernel_thread_flags(%rip),%rdi
movq $-1, %rsi
movq %rsp, %rdx
xorl %r8d,%r8d
xorl %r9d,%r9d
# clone now
call do_fork
movq %rax,RAX(%rsp)
xorl %edi,%edi
/*
* It isn't worth to check for reschedule here,
* so internally to the x86_64 port you can rely on kernel_thread()
* not to reschedule the child before returning, this avoids the need
* of hacks for example to fork off the per-CPU idle tasks.
* [Hopefully no generic code relies on the reschedule -AK]
*/
RESTORE_ALL
UNFAKE_STACK_FRAME
ret
CFI_ENDPROC
child_rip:
/*
* Here we are in the child and the registers are set as they were
* at kernel_thread() invocation in the parent.
*/
movq %rdi, %rax
movq %rsi, %rdi
call *%rax
# exit
xorl %edi, %edi
call do_exit
/*
* execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
*
* C extern interface:
* extern long execve(char *name, char **argv, char **envp)
*
* asm input arguments:
* rdi: name, rsi: argv, rdx: envp
*
* We want to fallback into:
* extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs regs)
*
* do_sys_execve asm fallback arguments:
* rdi: name, rsi: argv, rdx: envp, fake frame on the stack
*/
ENTRY(execve)
CFI_STARTPROC
FAKE_STACK_FRAME $0
SAVE_ALL
call sys_execve
movq %rax, RAX(%rsp)
RESTORE_REST
testq %rax,%rax
je int_ret_from_sys_call
RESTORE_ARGS
UNFAKE_STACK_FRAME
ret
CFI_ENDPROC
KPROBE_ENTRY(page_fault)
errorentry do_page_fault
.previous .text
ENTRY(coprocessor_error)
zeroentry do_coprocessor_error
ENTRY(simd_coprocessor_error)
zeroentry do_simd_coprocessor_error
ENTRY(device_not_available)
zeroentry math_state_restore
/* runs on exception stack */
KPROBE_ENTRY(debug)
INTR_FRAME
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_debug, DEBUG_STACK
jmp paranoid_exit
CFI_ENDPROC
.previous .text
/* runs on exception stack */
KPROBE_ENTRY(nmi)
INTR_FRAME
pushq $-1
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_nmi
/*
* "Paranoid" exit path from exception stack.
* Paranoid because this is used by NMIs and cannot take
* any kernel state for granted.
* We don't do kernel preemption checks here, because only
* NMI should be common and it does not enable IRQs and
* cannot get reschedule ticks.
*/
/* ebx: no swapgs flag */
paranoid_exit:
testl %ebx,%ebx /* swapgs needed? */
jnz paranoid_restore
testl $3,CS(%rsp)
jnz paranoid_userspace
paranoid_swapgs:
swapgs
paranoid_restore:
RESTORE_ALL 8
iretq
paranoid_userspace:
GET_THREAD_INFO(%rcx)
movl threadinfo_flags(%rcx),%ebx
andl $_TIF_WORK_MASK,%ebx
jz paranoid_swapgs
movq %rsp,%rdi /* &pt_regs */
call sync_regs
movq %rax,%rsp /* switch stack for scheduling */
testl $_TIF_NEED_RESCHED,%ebx
jnz paranoid_schedule
movl %ebx,%edx /* arg3: thread flags */
sti
xorl %esi,%esi /* arg2: oldset */
movq %rsp,%rdi /* arg1: &pt_regs */
call do_notify_resume
cli
jmp paranoid_userspace
paranoid_schedule:
sti
call schedule
cli
jmp paranoid_userspace
CFI_ENDPROC
.previous .text
KPROBE_ENTRY(int3)
INTR_FRAME
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_int3, DEBUG_STACK
jmp paranoid_exit
CFI_ENDPROC
.previous .text
ENTRY(overflow)
zeroentry do_overflow
ENTRY(bounds)
zeroentry do_bounds
ENTRY(invalid_op)
zeroentry do_invalid_op
ENTRY(coprocessor_segment_overrun)
zeroentry do_coprocessor_segment_overrun
ENTRY(reserved)
zeroentry do_reserved
/* runs on exception stack */
ENTRY(double_fault)
XCPT_FRAME
paranoidentry do_double_fault
jmp paranoid_exit
CFI_ENDPROC
ENTRY(invalid_TSS)
errorentry do_invalid_TSS
ENTRY(segment_not_present)
errorentry do_segment_not_present
/* runs on exception stack */
ENTRY(stack_segment)
XCPT_FRAME
paranoidentry do_stack_segment
jmp paranoid_exit
CFI_ENDPROC
KPROBE_ENTRY(general_protection)
errorentry do_general_protection
.previous .text
ENTRY(alignment_check)
errorentry do_alignment_check
ENTRY(divide_error)
zeroentry do_divide_error
ENTRY(spurious_interrupt_bug)
zeroentry do_spurious_interrupt_bug
#ifdef CONFIG_X86_MCE
/* runs on exception stack */
ENTRY(machine_check)
INTR_FRAME
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_machine_check
jmp paranoid_exit
CFI_ENDPROC
#endif
ENTRY(call_softirq)
CFI_STARTPROC
movq %gs:pda_irqstackptr,%rax
movq %rsp,%rdx
CFI_DEF_CFA_REGISTER rdx
incl %gs:pda_irqcount
cmove %rax,%rsp
pushq %rdx
/*todo CFI_DEF_CFA_EXPRESSION ...*/
call __do_softirq
popq %rsp
CFI_DEF_CFA_REGISTER rsp
decl %gs:pda_irqcount
ret
CFI_ENDPROC
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