diff options
Diffstat (limited to 'arch/x86/ia32/ia32entry.S')
| -rw-r--r-- | arch/x86/ia32/ia32entry.S | 485 |
1 files changed, 287 insertions, 198 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 156ebcab4ada..a821b1cd4fa7 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -30,24 +30,13 @@ .section .entry.text, "ax" - .macro IA32_ARG_FIXUP noebp=0 - movl %edi,%r8d - .if \noebp - .else - movl %ebp,%r9d - .endif - xchg %ecx,%esi - movl %ebx,%edi - movl %edx,%edx /* zero extension */ - .endm - - /* clobbers %eax */ - .macro CLEAR_RREGS offset=0, _r9=rax + /* clobbers %rax */ + .macro CLEAR_RREGS _r9=rax xorl %eax,%eax - movq %rax,\offset+R11(%rsp) - movq %rax,\offset+R10(%rsp) - movq %\_r9,\offset+R9(%rsp) - movq %rax,\offset+R8(%rsp) + movq %rax,R11(%rsp) + movq %rax,R10(%rsp) + movq %\_r9,R9(%rsp) + movq %rax,R8(%rsp) .endm /* @@ -60,14 +49,14 @@ * If it's -1 to make us punt the syscall, then (u32)-1 is still * an appropriately invalid value. */ - .macro LOAD_ARGS32 offset, _r9=0 + .macro LOAD_ARGS32 _r9=0 .if \_r9 - movl \offset+16(%rsp),%r9d + movl R9(%rsp),%r9d .endif - movl \offset+40(%rsp),%ecx - movl \offset+48(%rsp),%edx - movl \offset+56(%rsp),%esi - movl \offset+64(%rsp),%edi + movl RCX(%rsp),%ecx + movl RDX(%rsp),%edx + movl RSI(%rsp),%esi + movl RDI(%rsp),%edi movl %eax,%eax /* zero extension */ .endm @@ -99,54 +88,69 @@ ENDPROC(native_irq_enable_sysexit) /* * 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 - * - * Interrupts off. - * + * 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. Set up a complete hardware stack frame to share code + * 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 - SWAPGS_UNSAFE_STACK - movq PER_CPU_VAR(kernel_stack), %rsp - addq $(KERNEL_STACK_OFFSET),%rsp + /* - * No need to follow this irqs on/off section: the syscall - * disabled irqs, here we enable it straight after entry: + * 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) - movl %ebp,%ebp /* zero extension */ - pushq_cfi $__USER32_DS - /*CFI_REL_OFFSET ss,0*/ - pushq_cfi %rbp - CFI_REL_OFFSET rsp,0 - pushfq_cfi - /*CFI_REL_OFFSET rflags,0*/ - movl TI_sysenter_return+THREAD_INFO(%rsp,3*8-KERNEL_STACK_OFFSET),%r10d - CFI_REGISTER rip,r10 - pushq_cfi $__USER32_CS - /*CFI_REL_OFFSET cs,0*/ + + /* Zero-extending 32-bit regs, do not remove */ + movl %ebp, %ebp movl %eax, %eax - pushq_cfi %r10 - CFI_REL_OFFSET rip,0 - pushq_cfi %rax + + 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 - SAVE_ARGS 0,1,0 - /* no need to do an access_ok check here because rbp has been - 32bit zero extended */ + 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) @@ -157,42 +161,80 @@ ENTRY(ia32_sysenter_target) * ourselves. To save a few cycles, we can check whether * NT was set instead of doing an unconditional popfq. */ - testl $X86_EFLAGS_NT,EFLAGS-ARGOFFSET(%rsp) + testl $X86_EFLAGS_NT,EFLAGS(%rsp) jnz sysenter_fix_flags sysenter_flags_fixed: - orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) - testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + 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: - IA32_ARG_FIXUP + /* 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-ARGOFFSET(%rsp) + movq %rax,RAX(%rsp) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF - testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jnz sysexit_audit sysexit_from_sys_call: - andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) - /* clear IF, that popfq doesn't enable interrupts early */ - andl $~0x200,EFLAGS-ARGOFFSET(%rsp) - movl RIP-ARGOFFSET(%rsp),%edx /* User %eip */ - CFI_REGISTER rip,rdx - RESTORE_ARGS 0,24,0,0,0,0 + /* + * 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 - xorq %r11,%r11 - popfq_cfi + movl EFLAGS(%rsp),%r11d /* User eflags */ /*CFI_RESTORE rflags*/ - popq_cfi %rcx /* User %esp */ - CFI_REGISTER rsp,rcx TRACE_IRQS_ON - ENABLE_INTERRUPTS_SYSEXIT32 + + /* + * 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 @@ -205,18 +247,18 @@ sysexit_from_sys_call: movl %ebx,%esi /* 2nd arg: 1st syscall arg */ movl %eax,%edi /* 1st arg: syscall number */ call __audit_syscall_entry - movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall number */ + 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-ARGOFFSET(%rsp),%esi /* reload 2nd syscall arg */ - movl RDX-ARGOFFSET(%rsp),%edx /* reload 3rd syscall arg */ - movl RSI-ARGOFFSET(%rsp),%ecx /* reload 4th syscall arg */ - movl RDI-ARGOFFSET(%rsp),%r8d /* reload 5th 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),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + 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) @@ -227,13 +269,13 @@ sysexit_from_sys_call: 1: setbe %al /* 1 if error, 0 if not */ movzbl %al,%edi /* zero-extend that into %edi */ call __audit_syscall_exit - movq RAX-ARGOFFSET(%rsp),%rax /* reload syscall return value */ + 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,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jz \exit - CLEAR_RREGS -ARGOFFSET + CLEAR_RREGS jmp int_with_check .endm @@ -253,16 +295,16 @@ sysenter_fix_flags: sysenter_tracesys: #ifdef CONFIG_AUDITSYSCALL - testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jz sysenter_auditsys #endif - SAVE_REST + 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 ARGOFFSET /* reload args from stack in case ptrace changed it */ - RESTORE_REST + 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 @@ -272,94 +314,128 @@ 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. - * %ebx Arg1 - * %ecx return EIP - * %edx Arg3 - * %esi Arg4 - * %edi Arg5 - * %ebp Arg2 [note: not saved in the stack frame, should not be touched] - * %esp user stack - * 0(%esp) Arg6 - * - * Interrupts off. - * + * 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. Set up a complete hardware stack frame to share code - * with the int 0x80 path. - */ + * 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,KERNEL_STACK_OFFSET + 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 - /* - * No need to follow this irqs on/off section: the syscall - * disabled irqs and here we enable it straight after entry: - */ ENABLE_INTERRUPTS(CLBR_NONE) - SAVE_ARGS 8,0,0 - movl %eax,%eax /* zero extension */ - movq %rax,ORIG_RAX-ARGOFFSET(%rsp) - movq %rcx,RIP-ARGOFFSET(%rsp) - CFI_REL_OFFSET rip,RIP-ARGOFFSET - movq %rbp,RCX-ARGOFFSET(%rsp) /* this lies slightly to ptrace */ + + /* 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 - movq $__USER32_CS,CS-ARGOFFSET(%rsp) - movq $__USER32_DS,SS-ARGOFFSET(%rsp) - movq %r11,EFLAGS-ARGOFFSET(%rsp) - /*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/ - movq %r8,RSP-ARGOFFSET(%rsp) - CFI_REL_OFFSET rsp,RSP-ARGOFFSET - /* no need to do an access_ok check here because r8 has been - 32bit zero extended */ - /* hardware stack frame is complete now */ + 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,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) - testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + 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: - IA32_ARG_FIXUP 1 + /* 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-ARGOFFSET(%rsp) + movq %rax,RAX(%rsp) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF - testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jnz sysretl_audit sysretl_from_sys_call: - andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) - RESTORE_ARGS 0,-ARG_SKIP,0,0,0 - movl RIP-ARGOFFSET(%rsp),%ecx + 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-ARGOFFSET(%rsp),%r11d + movl EFLAGS(%rsp),%r11d /*CFI_REGISTER rflags,r11*/ xorq %r10,%r10 xorq %r9,%r9 xorq %r8,%r8 TRACE_IRQS_ON - movl RSP-ARGOFFSET(%rsp),%esp + 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). + */ USERGS_SYSRET32 - + #ifdef CONFIG_AUDITSYSCALL cstar_auditsys: CFI_RESTORE_STATE - movl %r9d,R9-ARGOFFSET(%rsp) /* register to be clobbered by call */ + movl %r9d,R9(%rsp) /* register to be clobbered by call */ auditsys_entry_common - movl R9-ARGOFFSET(%rsp),%r9d /* reload 6th syscall arg */ + movl R9(%rsp),%r9d /* reload 6th syscall arg */ jmp cstar_dispatch sysretl_audit: @@ -368,17 +444,17 @@ sysretl_audit: cstar_tracesys: #ifdef CONFIG_AUDITSYSCALL - testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jz cstar_auditsys #endif xchgl %r9d,%ebp - SAVE_REST - CLEAR_RREGS 0, r9 + 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 ARGOFFSET, 1 /* reload args from stack in case ptrace changed it */ - RESTORE_REST + 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) */ @@ -391,78 +467,94 @@ ia32_badarg: jmp ia32_sysret CFI_ENDPROC -/* - * Emulated IA32 system calls via int 0x80. +/* + * 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] + * 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) + * 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. - */ + * 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,SS+8-RIP - /*CFI_REL_OFFSET ss,SS-RIP*/ - CFI_REL_OFFSET rsp,RSP-RIP - /*CFI_REL_OFFSET rflags,EFLAGS-RIP*/ - /*CFI_REL_OFFSET cs,CS-RIP*/ - CFI_REL_OFFSET rip,RIP-RIP - PARAVIRT_ADJUST_EXCEPTION_FRAME - SWAPGS + 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 + /* - * No need to follow this irqs on/off section: the syscall - * disabled irqs and here we enable it straight after entry: + * 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) - movl %eax,%eax - pushq_cfi %rax + + /* 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 - /* note the registers are not zero extended to the sf. - this could be a problem. */ - SAVE_ARGS 0,1,0 - orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) - testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) + 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: - IA32_ARG_FIXUP + /* 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-ARGOFFSET(%rsp) + movq %rax,RAX(%rsp) ia32_ret_from_sys_call: - CLEAR_RREGS -ARGOFFSET - jmp int_ret_from_sys_call + CLEAR_RREGS + jmp int_ret_from_sys_call -ia32_tracesys: - SAVE_REST +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 ARGOFFSET /* reload args from stack in case ptrace changed it */ - RESTORE_REST + 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-ARGOFFSET(%rsp) + movq $0,ORIG_RAX(%rsp) movq $-ENOSYS,%rax jmp ia32_sysret @@ -479,8 +571,6 @@ GLOBAL(\label) PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn PTREGSCALL stub32_sigreturn, sys32_sigreturn - PTREGSCALL stub32_execve, compat_sys_execve - PTREGSCALL stub32_execveat, compat_sys_execveat PTREGSCALL stub32_fork, sys_fork PTREGSCALL stub32_vfork, sys_vfork @@ -492,24 +582,23 @@ GLOBAL(stub32_clone) ALIGN ia32_ptregs_common: - popq %r11 CFI_ENDPROC CFI_STARTPROC32 simple CFI_SIGNAL_FRAME - CFI_DEF_CFA rsp,SS+8-ARGOFFSET - CFI_REL_OFFSET rax,RAX-ARGOFFSET - CFI_REL_OFFSET rcx,RCX-ARGOFFSET - CFI_REL_OFFSET rdx,RDX-ARGOFFSET - CFI_REL_OFFSET rsi,RSI-ARGOFFSET - CFI_REL_OFFSET rdi,RDI-ARGOFFSET - CFI_REL_OFFSET rip,RIP-ARGOFFSET -/* CFI_REL_OFFSET cs,CS-ARGOFFSET*/ -/* CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/ - CFI_REL_OFFSET rsp,RSP-ARGOFFSET -/* CFI_REL_OFFSET ss,SS-ARGOFFSET*/ - SAVE_REST + 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_REST - jmp ia32_sysret /* misbalances the return cache */ + RESTORE_EXTRA_REGS 8 + ret CFI_ENDPROC END(ia32_ptregs_common) |