mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-26 06:04:14 +08:00
61f01dd941
AMD CPUs don't reinitialize the SS descriptor on SYSRET, so SYSRET with
SS == 0 results in an invalid usermode state in which SS is apparently
equal to __USER_DS but causes #SS if used.
Work around the issue by setting SS to __KERNEL_DS __switch_to, thus
ensuring that SYSRET never happens with SS set to NULL.
This was exposed by a recent vDSO cleanup.
Fixes: e7d6eefaaa
x86/vdso32/syscall.S: Do not load __USER32_DS to %ss
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
612 lines
17 KiB
ArmAsm
612 lines
17 KiB
ArmAsm
/*
|
|
* Compatibility mode system call entry point for x86-64.
|
|
*
|
|
* Copyright 2000-2002 Andi Kleen, SuSE Labs.
|
|
*/
|
|
|
|
#include <asm/dwarf2.h>
|
|
#include <asm/calling.h>
|
|
#include <asm/asm-offsets.h>
|
|
#include <asm/current.h>
|
|
#include <asm/errno.h>
|
|
#include <asm/ia32_unistd.h>
|
|
#include <asm/thread_info.h>
|
|
#include <asm/segment.h>
|
|
#include <asm/irqflags.h>
|
|
#include <asm/asm.h>
|
|
#include <asm/smap.h>
|
|
#include <linux/linkage.h>
|
|
#include <linux/err.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 sysexit_audit ia32_ret_from_sys_call
|
|
#define sysretl_audit ia32_ret_from_sys_call
|
|
#endif
|
|
|
|
.section .entry.text, "ax"
|
|
|
|
/* clobbers %rax */
|
|
.macro CLEAR_RREGS _r9=rax
|
|
xorl %eax,%eax
|
|
movq %rax,R11(%rsp)
|
|
movq %rax,R10(%rsp)
|
|
movq %\_r9,R9(%rsp)
|
|
movq %rax,R8(%rsp)
|
|
.endm
|
|
|
|
/*
|
|
* Reload arg registers from stack in case ptrace changed them.
|
|
* We don't reload %eax because syscall_trace_enter() returned
|
|
* the %rax value we should see. Instead, we just truncate that
|
|
* value to 32 bits again as we did on entry from user mode.
|
|
* If it's a new value set by user_regset during entry tracing,
|
|
* this matches the normal truncation of the user-mode value.
|
|
* If it's -1 to make us punt the syscall, then (u32)-1 is still
|
|
* an appropriately invalid value.
|
|
*/
|
|
.macro LOAD_ARGS32 _r9=0
|
|
.if \_r9
|
|
movl R9(%rsp),%r9d
|
|
.endif
|
|
movl RCX(%rsp),%ecx
|
|
movl RDX(%rsp),%edx
|
|
movl RSI(%rsp),%esi
|
|
movl RDI(%rsp),%edi
|
|
movl %eax,%eax /* zero extension */
|
|
.endm
|
|
|
|
.macro CFI_STARTPROC32 simple
|
|
CFI_STARTPROC \simple
|
|
CFI_UNDEFINED r8
|
|
CFI_UNDEFINED r9
|
|
CFI_UNDEFINED r10
|
|
CFI_UNDEFINED r11
|
|
CFI_UNDEFINED r12
|
|
CFI_UNDEFINED r13
|
|
CFI_UNDEFINED r14
|
|
CFI_UNDEFINED r15
|
|
.endm
|
|
|
|
#ifdef CONFIG_PARAVIRT
|
|
ENTRY(native_usergs_sysret32)
|
|
swapgs
|
|
sysretl
|
|
ENDPROC(native_usergs_sysret32)
|
|
|
|
ENTRY(native_irq_enable_sysexit)
|
|
swapgs
|
|
sti
|
|
sysexit
|
|
ENDPROC(native_irq_enable_sysexit)
|
|
#endif
|
|
|
|
/*
|
|
* 32bit SYSENTER instruction entry.
|
|
*
|
|
* SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs.
|
|
* IF and VM in rflags are cleared (IOW: interrupts are off).
|
|
* SYSENTER does not save anything on the stack,
|
|
* and does not save old rip (!!!) and rflags.
|
|
*
|
|
* Arguments:
|
|
* eax system call number
|
|
* ebx arg1
|
|
* ecx arg2
|
|
* edx arg3
|
|
* esi arg4
|
|
* edi arg5
|
|
* ebp user stack
|
|
* 0(%ebp) arg6
|
|
*
|
|
* This is purely a fast path. For anything complicated we use the int 0x80
|
|
* path below. We set up a complete hardware stack frame to share code
|
|
* with the int 0x80 path.
|
|
*/
|
|
ENTRY(ia32_sysenter_target)
|
|
CFI_STARTPROC32 simple
|
|
CFI_SIGNAL_FRAME
|
|
CFI_DEF_CFA rsp,0
|
|
CFI_REGISTER rsp,rbp
|
|
|
|
/*
|
|
* Interrupts are off on entry.
|
|
* We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
|
|
* it is too small to ever cause noticeable irq latency.
|
|
*/
|
|
SWAPGS_UNSAFE_STACK
|
|
movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
|
|
/* Zero-extending 32-bit regs, do not remove */
|
|
movl %ebp, %ebp
|
|
movl %eax, %eax
|
|
|
|
movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d
|
|
CFI_REGISTER rip,r10
|
|
|
|
/* Construct struct pt_regs on stack */
|
|
pushq_cfi $__USER32_DS /* pt_regs->ss */
|
|
pushq_cfi %rbp /* pt_regs->sp */
|
|
CFI_REL_OFFSET rsp,0
|
|
pushfq_cfi /* pt_regs->flags */
|
|
pushq_cfi $__USER32_CS /* pt_regs->cs */
|
|
pushq_cfi %r10 /* pt_regs->ip = thread_info->sysenter_return */
|
|
CFI_REL_OFFSET rip,0
|
|
pushq_cfi_reg rax /* pt_regs->orig_ax */
|
|
pushq_cfi_reg rdi /* pt_regs->di */
|
|
pushq_cfi_reg rsi /* pt_regs->si */
|
|
pushq_cfi_reg rdx /* pt_regs->dx */
|
|
pushq_cfi_reg rcx /* pt_regs->cx */
|
|
pushq_cfi_reg rax /* pt_regs->ax */
|
|
cld
|
|
sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
|
|
CFI_ADJUST_CFA_OFFSET 10*8
|
|
|
|
/*
|
|
* no need to do an access_ok check here because rbp has been
|
|
* 32bit zero extended
|
|
*/
|
|
ASM_STAC
|
|
1: movl (%rbp),%ebp
|
|
_ASM_EXTABLE(1b,ia32_badarg)
|
|
ASM_CLAC
|
|
|
|
/*
|
|
* Sysenter doesn't filter flags, so we need to clear NT
|
|
* ourselves. To save a few cycles, we can check whether
|
|
* NT was set instead of doing an unconditional popfq.
|
|
*/
|
|
testl $X86_EFLAGS_NT,EFLAGS(%rsp)
|
|
jnz sysenter_fix_flags
|
|
sysenter_flags_fixed:
|
|
|
|
orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
|
|
testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
CFI_REMEMBER_STATE
|
|
jnz sysenter_tracesys
|
|
cmpq $(IA32_NR_syscalls-1),%rax
|
|
ja ia32_badsys
|
|
sysenter_do_call:
|
|
/* 32bit syscall -> 64bit C ABI argument conversion */
|
|
movl %edi,%r8d /* arg5 */
|
|
movl %ebp,%r9d /* arg6 */
|
|
xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */
|
|
movl %ebx,%edi /* arg1 */
|
|
movl %edx,%edx /* arg3 (zero extension) */
|
|
sysenter_dispatch:
|
|
call *ia32_sys_call_table(,%rax,8)
|
|
movq %rax,RAX(%rsp)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jnz sysexit_audit
|
|
sysexit_from_sys_call:
|
|
/*
|
|
* NB: SYSEXIT is not obviously safe for 64-bit kernels -- an
|
|
* NMI between STI and SYSEXIT has poorly specified behavior,
|
|
* and and NMI followed by an IRQ with usergs is fatal. So
|
|
* we just pretend we're using SYSEXIT but we really use
|
|
* SYSRETL instead.
|
|
*
|
|
* This code path is still called 'sysexit' because it pairs
|
|
* with 'sysenter' and it uses the SYSENTER calling convention.
|
|
*/
|
|
andl $~TS_COMPAT,ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
|
|
movl RIP(%rsp),%ecx /* User %eip */
|
|
CFI_REGISTER rip,rcx
|
|
RESTORE_RSI_RDI
|
|
xorl %edx,%edx /* avoid info leaks */
|
|
xorq %r8,%r8
|
|
xorq %r9,%r9
|
|
xorq %r10,%r10
|
|
movl EFLAGS(%rsp),%r11d /* User eflags */
|
|
/*CFI_RESTORE rflags*/
|
|
TRACE_IRQS_ON
|
|
|
|
/*
|
|
* SYSRETL works even on Intel CPUs. Use it in preference to SYSEXIT,
|
|
* since it avoids a dicey window with interrupts enabled.
|
|
*/
|
|
movl RSP(%rsp),%esp
|
|
|
|
/*
|
|
* USERGS_SYSRET32 does:
|
|
* gsbase = user's gs base
|
|
* eip = ecx
|
|
* rflags = r11
|
|
* cs = __USER32_CS
|
|
* ss = __USER_DS
|
|
*
|
|
* The prologue set RIP(%rsp) to VDSO32_SYSENTER_RETURN, which does:
|
|
*
|
|
* pop %ebp
|
|
* pop %edx
|
|
* pop %ecx
|
|
*
|
|
* Therefore, we invoke SYSRETL with EDX and R8-R10 zeroed to
|
|
* avoid info leaks. R11 ends up with VDSO32_SYSENTER_RETURN's
|
|
* address (already known to user code), and R12-R15 are
|
|
* callee-saved and therefore don't contain any interesting
|
|
* kernel data.
|
|
*/
|
|
USERGS_SYSRET32
|
|
|
|
CFI_RESTORE_STATE
|
|
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
.macro auditsys_entry_common
|
|
movl %esi,%r8d /* 5th arg: 4th syscall arg */
|
|
movl %ecx,%r9d /*swap with edx*/
|
|
movl %edx,%ecx /* 4th arg: 3rd syscall arg */
|
|
movl %r9d,%edx /* 3rd arg: 2nd syscall arg */
|
|
movl %ebx,%esi /* 2nd arg: 1st syscall arg */
|
|
movl %eax,%edi /* 1st arg: syscall number */
|
|
call __audit_syscall_entry
|
|
movl RAX(%rsp),%eax /* reload syscall number */
|
|
cmpq $(IA32_NR_syscalls-1),%rax
|
|
ja ia32_badsys
|
|
movl %ebx,%edi /* reload 1st syscall arg */
|
|
movl RCX(%rsp),%esi /* reload 2nd syscall arg */
|
|
movl RDX(%rsp),%edx /* reload 3rd syscall arg */
|
|
movl RSI(%rsp),%ecx /* reload 4th syscall arg */
|
|
movl RDI(%rsp),%r8d /* reload 5th syscall arg */
|
|
.endm
|
|
|
|
.macro auditsys_exit exit
|
|
testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jnz ia32_ret_from_sys_call
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
movl %eax,%esi /* second arg, syscall return value */
|
|
cmpl $-MAX_ERRNO,%eax /* is it an error ? */
|
|
jbe 1f
|
|
movslq %eax, %rsi /* if error sign extend to 64 bits */
|
|
1: setbe %al /* 1 if error, 0 if not */
|
|
movzbl %al,%edi /* zero-extend that into %edi */
|
|
call __audit_syscall_exit
|
|
movq RAX(%rsp),%rax /* reload syscall return value */
|
|
movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jz \exit
|
|
CLEAR_RREGS
|
|
jmp int_with_check
|
|
.endm
|
|
|
|
sysenter_auditsys:
|
|
auditsys_entry_common
|
|
movl %ebp,%r9d /* reload 6th syscall arg */
|
|
jmp sysenter_dispatch
|
|
|
|
sysexit_audit:
|
|
auditsys_exit sysexit_from_sys_call
|
|
#endif
|
|
|
|
sysenter_fix_flags:
|
|
pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
|
|
popfq_cfi
|
|
jmp sysenter_flags_fixed
|
|
|
|
sysenter_tracesys:
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jz sysenter_auditsys
|
|
#endif
|
|
SAVE_EXTRA_REGS
|
|
CLEAR_RREGS
|
|
movq $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */
|
|
movq %rsp,%rdi /* &pt_regs -> arg1 */
|
|
call syscall_trace_enter
|
|
LOAD_ARGS32 /* reload args from stack in case ptrace changed it */
|
|
RESTORE_EXTRA_REGS
|
|
cmpq $(IA32_NR_syscalls-1),%rax
|
|
ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
|
|
jmp sysenter_do_call
|
|
CFI_ENDPROC
|
|
ENDPROC(ia32_sysenter_target)
|
|
|
|
/*
|
|
* 32bit SYSCALL instruction entry.
|
|
*
|
|
* 32bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
|
|
* then loads new ss, cs, and rip from previously programmed MSRs.
|
|
* rflags gets masked by a value from another MSR (so CLD and CLAC
|
|
* are not needed). SYSCALL does not save anything on the stack
|
|
* and does not change rsp.
|
|
*
|
|
* Note: rflags saving+masking-with-MSR happens only in Long mode
|
|
* (in legacy 32bit mode, IF, RF and VM bits are cleared and that's it).
|
|
* Don't get confused: rflags saving+masking depends on Long Mode Active bit
|
|
* (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes
|
|
* or target CS descriptor's L bit (SYSCALL does not read segment descriptors).
|
|
*
|
|
* Arguments:
|
|
* eax system call number
|
|
* ecx return address
|
|
* ebx arg1
|
|
* ebp arg2 (note: not saved in the stack frame, should not be touched)
|
|
* edx arg3
|
|
* esi arg4
|
|
* edi arg5
|
|
* esp user stack
|
|
* 0(%esp) arg6
|
|
*
|
|
* This is purely a fast path. For anything complicated we use the int 0x80
|
|
* path below. We set up a complete hardware stack frame to share code
|
|
* with the int 0x80 path.
|
|
*/
|
|
ENTRY(ia32_cstar_target)
|
|
CFI_STARTPROC32 simple
|
|
CFI_SIGNAL_FRAME
|
|
CFI_DEF_CFA rsp,0
|
|
CFI_REGISTER rip,rcx
|
|
/*CFI_REGISTER rflags,r11*/
|
|
|
|
/*
|
|
* Interrupts are off on entry.
|
|
* We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
|
|
* it is too small to ever cause noticeable irq latency.
|
|
*/
|
|
SWAPGS_UNSAFE_STACK
|
|
movl %esp,%r8d
|
|
CFI_REGISTER rsp,r8
|
|
movq PER_CPU_VAR(kernel_stack),%rsp
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
|
|
/* Zero-extending 32-bit regs, do not remove */
|
|
movl %eax,%eax
|
|
|
|
/* Construct struct pt_regs on stack */
|
|
pushq_cfi $__USER32_DS /* pt_regs->ss */
|
|
pushq_cfi %r8 /* pt_regs->sp */
|
|
CFI_REL_OFFSET rsp,0
|
|
pushq_cfi %r11 /* pt_regs->flags */
|
|
pushq_cfi $__USER32_CS /* pt_regs->cs */
|
|
pushq_cfi %rcx /* pt_regs->ip */
|
|
CFI_REL_OFFSET rip,0
|
|
pushq_cfi_reg rax /* pt_regs->orig_ax */
|
|
pushq_cfi_reg rdi /* pt_regs->di */
|
|
pushq_cfi_reg rsi /* pt_regs->si */
|
|
pushq_cfi_reg rdx /* pt_regs->dx */
|
|
pushq_cfi_reg rbp /* pt_regs->cx */
|
|
movl %ebp,%ecx
|
|
pushq_cfi_reg rax /* pt_regs->ax */
|
|
sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
|
|
CFI_ADJUST_CFA_OFFSET 10*8
|
|
|
|
/*
|
|
* no need to do an access_ok check here because r8 has been
|
|
* 32bit zero extended
|
|
*/
|
|
ASM_STAC
|
|
1: movl (%r8),%r9d
|
|
_ASM_EXTABLE(1b,ia32_badarg)
|
|
ASM_CLAC
|
|
orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
|
|
testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
CFI_REMEMBER_STATE
|
|
jnz cstar_tracesys
|
|
cmpq $IA32_NR_syscalls-1,%rax
|
|
ja ia32_badsys
|
|
cstar_do_call:
|
|
/* 32bit syscall -> 64bit C ABI argument conversion */
|
|
movl %edi,%r8d /* arg5 */
|
|
/* r9 already loaded */ /* arg6 */
|
|
xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */
|
|
movl %ebx,%edi /* arg1 */
|
|
movl %edx,%edx /* arg3 (zero extension) */
|
|
cstar_dispatch:
|
|
call *ia32_sys_call_table(,%rax,8)
|
|
movq %rax,RAX(%rsp)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jnz sysretl_audit
|
|
sysretl_from_sys_call:
|
|
andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
|
|
RESTORE_RSI_RDI_RDX
|
|
movl RIP(%rsp),%ecx
|
|
CFI_REGISTER rip,rcx
|
|
movl EFLAGS(%rsp),%r11d
|
|
/*CFI_REGISTER rflags,r11*/
|
|
xorq %r10,%r10
|
|
xorq %r9,%r9
|
|
xorq %r8,%r8
|
|
TRACE_IRQS_ON
|
|
movl RSP(%rsp),%esp
|
|
CFI_RESTORE rsp
|
|
/*
|
|
* 64bit->32bit SYSRET restores eip from ecx,
|
|
* eflags from r11 (but RF and VM bits are forced to 0),
|
|
* cs and ss are loaded from MSRs.
|
|
* (Note: 32bit->32bit SYSRET is different: since r11
|
|
* does not exist, it merely sets eflags.IF=1).
|
|
*
|
|
* NB: On AMD CPUs with the X86_BUG_SYSRET_SS_ATTRS bug, the ss
|
|
* descriptor is not reinitialized. This means that we must
|
|
* avoid SYSRET with SS == NULL, which could happen if we schedule,
|
|
* exit the kernel, and re-enter using an interrupt vector. (All
|
|
* interrupt entries on x86_64 set SS to NULL.) We prevent that
|
|
* from happening by reloading SS in __switch_to.
|
|
*/
|
|
USERGS_SYSRET32
|
|
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
cstar_auditsys:
|
|
CFI_RESTORE_STATE
|
|
movl %r9d,R9(%rsp) /* register to be clobbered by call */
|
|
auditsys_entry_common
|
|
movl R9(%rsp),%r9d /* reload 6th syscall arg */
|
|
jmp cstar_dispatch
|
|
|
|
sysretl_audit:
|
|
auditsys_exit sysretl_from_sys_call
|
|
#endif
|
|
|
|
cstar_tracesys:
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jz cstar_auditsys
|
|
#endif
|
|
xchgl %r9d,%ebp
|
|
SAVE_EXTRA_REGS
|
|
CLEAR_RREGS r9
|
|
movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
|
|
movq %rsp,%rdi /* &pt_regs -> arg1 */
|
|
call syscall_trace_enter
|
|
LOAD_ARGS32 1 /* reload args from stack in case ptrace changed it */
|
|
RESTORE_EXTRA_REGS
|
|
xchgl %ebp,%r9d
|
|
cmpq $(IA32_NR_syscalls-1),%rax
|
|
ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
|
|
jmp cstar_do_call
|
|
END(ia32_cstar_target)
|
|
|
|
ia32_badarg:
|
|
ASM_CLAC
|
|
movq $-EFAULT,%rax
|
|
jmp ia32_sysret
|
|
CFI_ENDPROC
|
|
|
|
/*
|
|
* Emulated IA32 system calls via int 0x80.
|
|
*
|
|
* Arguments:
|
|
* eax system call number
|
|
* ebx arg1
|
|
* ecx arg2
|
|
* edx arg3
|
|
* esi arg4
|
|
* edi arg5
|
|
* ebp arg6 (note: not saved in the stack frame, should not be touched)
|
|
*
|
|
* Notes:
|
|
* Uses the same stack frame as the x86-64 version.
|
|
* All registers except eax must be saved (but ptrace may violate that).
|
|
* Arguments are zero extended. For system calls that want sign extension and
|
|
* take long arguments a wrapper is needed. Most calls can just be called
|
|
* directly.
|
|
* Assumes it is only called from user space and entered with interrupts off.
|
|
*/
|
|
|
|
ENTRY(ia32_syscall)
|
|
CFI_STARTPROC32 simple
|
|
CFI_SIGNAL_FRAME
|
|
CFI_DEF_CFA rsp,5*8
|
|
/*CFI_REL_OFFSET ss,4*8 */
|
|
CFI_REL_OFFSET rsp,3*8
|
|
/*CFI_REL_OFFSET rflags,2*8 */
|
|
/*CFI_REL_OFFSET cs,1*8 */
|
|
CFI_REL_OFFSET rip,0*8
|
|
|
|
/*
|
|
* Interrupts are off on entry.
|
|
* We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
|
|
* it is too small to ever cause noticeable irq latency.
|
|
*/
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
SWAPGS
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
|
|
/* Zero-extending 32-bit regs, do not remove */
|
|
movl %eax,%eax
|
|
|
|
/* Construct struct pt_regs on stack (iret frame is already on stack) */
|
|
pushq_cfi_reg rax /* pt_regs->orig_ax */
|
|
pushq_cfi_reg rdi /* pt_regs->di */
|
|
pushq_cfi_reg rsi /* pt_regs->si */
|
|
pushq_cfi_reg rdx /* pt_regs->dx */
|
|
pushq_cfi_reg rcx /* pt_regs->cx */
|
|
pushq_cfi_reg rax /* pt_regs->ax */
|
|
cld
|
|
sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
|
|
CFI_ADJUST_CFA_OFFSET 10*8
|
|
|
|
orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
|
|
testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
|
|
jnz ia32_tracesys
|
|
cmpq $(IA32_NR_syscalls-1),%rax
|
|
ja ia32_badsys
|
|
ia32_do_call:
|
|
/* 32bit syscall -> 64bit C ABI argument conversion */
|
|
movl %edi,%r8d /* arg5 */
|
|
movl %ebp,%r9d /* arg6 */
|
|
xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */
|
|
movl %ebx,%edi /* arg1 */
|
|
movl %edx,%edx /* arg3 (zero extension) */
|
|
call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
|
|
ia32_sysret:
|
|
movq %rax,RAX(%rsp)
|
|
ia32_ret_from_sys_call:
|
|
CLEAR_RREGS
|
|
jmp int_ret_from_sys_call
|
|
|
|
ia32_tracesys:
|
|
SAVE_EXTRA_REGS
|
|
CLEAR_RREGS
|
|
movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
|
|
movq %rsp,%rdi /* &pt_regs -> arg1 */
|
|
call syscall_trace_enter
|
|
LOAD_ARGS32 /* reload args from stack in case ptrace changed it */
|
|
RESTORE_EXTRA_REGS
|
|
cmpq $(IA32_NR_syscalls-1),%rax
|
|
ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */
|
|
jmp ia32_do_call
|
|
END(ia32_syscall)
|
|
|
|
ia32_badsys:
|
|
movq $0,ORIG_RAX(%rsp)
|
|
movq $-ENOSYS,%rax
|
|
jmp ia32_sysret
|
|
|
|
CFI_ENDPROC
|
|
|
|
.macro PTREGSCALL label, func
|
|
ALIGN
|
|
GLOBAL(\label)
|
|
leaq \func(%rip),%rax
|
|
jmp ia32_ptregs_common
|
|
.endm
|
|
|
|
CFI_STARTPROC32
|
|
|
|
PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
|
|
PTREGSCALL stub32_sigreturn, sys32_sigreturn
|
|
PTREGSCALL stub32_fork, sys_fork
|
|
PTREGSCALL stub32_vfork, sys_vfork
|
|
|
|
ALIGN
|
|
GLOBAL(stub32_clone)
|
|
leaq sys_clone(%rip),%rax
|
|
mov %r8, %rcx
|
|
jmp ia32_ptregs_common
|
|
|
|
ALIGN
|
|
ia32_ptregs_common:
|
|
CFI_ENDPROC
|
|
CFI_STARTPROC32 simple
|
|
CFI_SIGNAL_FRAME
|
|
CFI_DEF_CFA rsp,SIZEOF_PTREGS
|
|
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*/
|
|
SAVE_EXTRA_REGS 8
|
|
call *%rax
|
|
RESTORE_EXTRA_REGS 8
|
|
ret
|
|
CFI_ENDPROC
|
|
END(ia32_ptregs_common)
|