From: Ingo Molnar Date: Fri, 5 Jun 2015 11:02:28 +0000 (+0200) Subject: x86/asm/entry/32: Improve code readability X-Git-Tag: v4.2-rc1~166^2^2~8^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=54ad726c51b7f7dffcc1dc379bedadee19f742f7;p=platform%2Fkernel%2Flinux-exynos.git x86/asm/entry/32: Improve code readability Make the 64-bit compat 32-bit syscall entry code a bit more readable: - eliminate whitespace noise - use consistent vertical spacing - use consistent assembly coding style similar to entry_64.S - fix various comments No code changed: arch/x86/entry/ia32entry.o: text data bss dec hex filename 1391 0 0 1391 56f ia32entry.o.before 1391 0 0 1391 56f ia32entry.o.after md5: f28501dcc366e68b557313942c6496d6 ia32entry.o.before.asm f28501dcc366e68b557313942c6496d6 ia32entry.o.after.asm Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/entry/ia32entry.S b/arch/x86/entry/ia32entry.S index 6321915..4bb9f7b 100644 --- a/arch/x86/entry/ia32entry.S +++ b/arch/x86/entry/ia32entry.S @@ -1,15 +1,14 @@ /* - * Compatibility mode system call entry point for x86-64. - * + * Compatibility mode system call entry point for x86-64. + * * Copyright 2000-2002 Andi Kleen, SuSE Labs. - */ - + */ #include "calling.h" #include #include #include -#include -#include +#include +#include #include #include #include @@ -20,11 +19,11 @@ /* Avoid __ASSEMBLER__'ifying just for this. */ #include #define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE) -#define __AUDIT_ARCH_LE 0x40000000 +#define __AUDIT_ARCH_LE 0x40000000 #ifndef CONFIG_AUDITSYSCALL -#define sysexit_audit ia32_ret_from_sys_call -#define sysretl_audit ia32_ret_from_sys_call +# define sysexit_audit ia32_ret_from_sys_call +# define sysretl_audit ia32_ret_from_sys_call #endif .section .entry.text, "ax" @@ -37,7 +36,7 @@ ENDPROC(native_usergs_sysret32) #endif /* - * 32bit SYSENTER instruction entry. + * 32-bit 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). @@ -79,7 +78,7 @@ ENTRY(ia32_sysenter_target) pushq %rbp /* pt_regs->sp */ pushfq /* pt_regs->flags */ pushq $__USER32_CS /* pt_regs->cs */ - pushq %r10 /* pt_regs->ip = thread_info->sysenter_return */ + pushq %r10 /* pt_regs->ip = thread_info->sysenter_return */ pushq %rax /* pt_regs->orig_ax */ pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ @@ -87,15 +86,15 @@ ENTRY(ia32_sysenter_target) pushq %rcx /* pt_regs->cx */ pushq $-ENOSYS /* pt_regs->ax */ cld - sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */ + sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */ /* * no need to do an access_ok check here because rbp has been - * 32bit zero extended + * 32-bit zero extended */ ASM_STAC -1: movl (%rbp),%ebp - _ASM_EXTABLE(1b,ia32_badarg) +1: movl (%rbp), %ebp + _ASM_EXTABLE(1b, ia32_badarg) ASM_CLAC /* @@ -103,26 +102,26 @@ 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(%rsp) - jnz sysenter_fix_flags + 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) - jnz sysenter_tracesys + jnz sysenter_tracesys 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) */ + /* 32-bit syscall -> 64-bit 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: - cmpq $(IA32_NR_syscalls-1),%rax + cmpq $(IA32_NR_syscalls-1), %rax ja 1f - call *ia32_sys_call_table(,%rax,8) - movq %rax,RAX(%rsp) + call *ia32_sys_call_table(, %rax, 8) + movq %rax, RAX(%rsp) 1: DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF @@ -139,21 +138,21 @@ sysexit_from_sys_call: * 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 */ + andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) + movl RIP(%rsp), %ecx /* User %eip */ RESTORE_RSI_RDI - xorl %edx,%edx /* avoid info leaks */ - xorq %r8,%r8 - xorq %r9,%r9 - xorq %r10,%r10 - movl EFLAGS(%rsp),%r11d /* User eflags */ + xorl %edx, %edx /* Do not leak kernel information */ + xorq %r8, %r8 + xorq %r9, %r9 + xorq %r10, %r10 + movl EFLAGS(%rsp), %r11d /* User eflags */ 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 + movl RSP(%rsp), %esp /* * USERGS_SYSRET32 does: @@ -179,51 +178,51 @@ sysexit_from_sys_call: #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 ORIG_RAX(%rsp),%eax /* reload syscall number */ - 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 */ + 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 ORIG_RAX(%rsp), %eax /* reload syscall number */ + 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 + 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 + 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 - xorl %eax, %eax /* do not leak kernel information */ + testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) + jz \exit + xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) movq %rax, R10(%rsp) movq %rax, R9(%rsp) movq %rax, R8(%rsp) - jmp int_with_check + jmp int_with_check .endm sysenter_auditsys: auditsys_entry_common - movl %ebp,%r9d /* reload 6th syscall arg */ - jmp sysenter_dispatch + movl %ebp, %r9d /* reload 6th syscall arg */ + jmp sysenter_dispatch sysexit_audit: auditsys_exit sysexit_from_sys_call @@ -232,7 +231,7 @@ sysexit_audit: sysenter_fix_flags: pushq $(X86_EFLAGS_IF|X86_EFLAGS_FIXED) popfq - jmp sysenter_flags_fixed + jmp sysenter_flags_fixed sysenter_tracesys: #ifdef CONFIG_AUDITSYSCALL @@ -240,12 +239,12 @@ sysenter_tracesys: jz sysenter_auditsys #endif SAVE_EXTRA_REGS - xorl %eax, %eax /* do not leak kernel information */ + xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) movq %rax, R10(%rsp) movq %rax, R9(%rsp) movq %rax, R8(%rsp) - movq %rsp,%rdi /* &pt_regs -> arg1 */ + movq %rsp, %rdi /* &pt_regs -> arg1 */ call syscall_trace_enter /* Reload arg registers from stack. (see sysenter_tracesys) */ @@ -253,23 +252,23 @@ sysenter_tracesys: movl RDX(%rsp), %edx movl RSI(%rsp), %esi movl RDI(%rsp), %edi - movl %eax, %eax /* zero extension */ + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS jmp sysenter_do_call ENDPROC(ia32_sysenter_target) /* - * 32bit SYSCALL instruction entry. + * 32-bit SYSCALL instruction entry. * - * 32bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11, + * 32-bit 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). + * (in legacy 32-bit 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). @@ -296,12 +295,12 @@ ENTRY(ia32_cstar_target) * it is too small to ever cause noticeable irq latency. */ SWAPGS_UNSAFE_STACK - movl %esp,%r8d - movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp + movl %esp, %r8d + movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp ENABLE_INTERRUPTS(CLBR_NONE) /* Zero-extending 32-bit regs, do not remove */ - movl %eax,%eax + movl %eax, %eax /* Construct struct pt_regs on stack */ pushq $__USER32_DS /* pt_regs->ss */ @@ -314,55 +313,58 @@ ENTRY(ia32_cstar_target) pushq %rsi /* pt_regs->si */ pushq %rdx /* pt_regs->dx */ pushq %rbp /* pt_regs->cx */ - movl %ebp,%ecx + movl %ebp, %ecx pushq $-ENOSYS /* pt_regs->ax */ - sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */ + sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */ /* - * no need to do an access_ok check here because r8 has been - * 32bit zero extended + * No need to do an access_ok check here because r8 has been + * 32-bit zero extended: */ ASM_STAC -1: movl (%r8),%ebp - _ASM_EXTABLE(1b,ia32_badarg) +1: movl (%r8), %ebp + _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) jnz cstar_tracesys cstar_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) */ + /* 32-bit syscall -> 64-bit 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) */ + cstar_dispatch: - cmpq $(IA32_NR_syscalls-1),%rax + cmpq $(IA32_NR_syscalls-1), %rax ja 1f - call *ia32_sys_call_table(,%rax,8) - movq %rax,RAX(%rsp) + + call *ia32_sys_call_table(, %rax, 8) + movq %rax, RAX(%rsp) 1: DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF - testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) - jnz sysretl_audit + 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) + andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) movl RCX(%rsp), %ebp RESTORE_RSI_RDI_RDX - movl RIP(%rsp),%ecx - movl EFLAGS(%rsp),%r11d - xorq %r10,%r10 - xorq %r9,%r9 - xorq %r8,%r8 + movl RIP(%rsp), %ecx + movl EFLAGS(%rsp), %r11d + xorq %r10, %r10 + xorq %r9, %r9 + xorq %r8, %r8 TRACE_IRQS_ON - movl RSP(%rsp),%esp + movl RSP(%rsp), %esp /* - * 64bit->32bit SYSRET restores eip from ecx, + * 64-bit->32-bit 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 + * (Note: 32-bit->32-bit 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 @@ -377,8 +379,8 @@ sysretl_from_sys_call: #ifdef CONFIG_AUDITSYSCALL cstar_auditsys: auditsys_entry_common - movl %ebp, %r9d /* reload 6th syscall arg */ - jmp cstar_dispatch + movl %ebp, %r9d /* reload 6th syscall arg */ + jmp cstar_dispatch sysretl_audit: auditsys_exit sysretl_from_sys_call @@ -386,16 +388,16 @@ sysretl_audit: cstar_tracesys: #ifdef CONFIG_AUDITSYSCALL - testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) - jz cstar_auditsys + testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) + jz cstar_auditsys #endif SAVE_EXTRA_REGS - xorl %eax, %eax /* do not leak kernel information */ + xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) movq %rax, R10(%rsp) movq %rax, R9(%rsp) movq %rax, R8(%rsp) - movq %rsp, %rdi /* &pt_regs -> arg1 */ + movq %rsp, %rdi /* &pt_regs -> arg1 */ call syscall_trace_enter /* Reload arg registers from stack. (see sysenter_tracesys) */ @@ -403,24 +405,24 @@ cstar_tracesys: movl RDX(%rsp), %edx movl RSI(%rsp), %esi movl RDI(%rsp), %edi - movl %eax, %eax /* zero extension */ + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS jmp cstar_do_call END(ia32_cstar_target) - + ia32_badarg: ASM_CLAC - movq $-EFAULT,%rax - jmp ia32_sysret + movq $-EFAULT, %rax + jmp ia32_sysret ia32_ret_from_sys_call: - xorl %eax, %eax /* do not leak kernel information */ + xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) movq %rax, R10(%rsp) movq %rax, R9(%rsp) movq %rax, R8(%rsp) - jmp int_ret_from_sys_call + jmp int_ret_from_sys_call /* * Emulated IA32 system calls via int 0x80. @@ -454,7 +456,7 @@ ENTRY(ia32_syscall) ENABLE_INTERRUPTS(CLBR_NONE) /* Zero-extending 32-bit regs, do not remove */ - movl %eax,%eax + movl %eax, %eax /* Construct struct pt_regs on stack (iret frame is already on stack) */ pushq %rax /* pt_regs->orig_ax */ @@ -468,30 +470,33 @@ ENTRY(ia32_syscall) pushq $0 /* pt_regs->r10 */ pushq $0 /* pt_regs->r11 */ cld - sub $(6*8),%rsp /* pt_regs->bp,bx,r12-15 not saved */ + sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */ + + 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 - 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 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) */ - cmpq $(IA32_NR_syscalls-1),%rax + /* 32-bit syscall -> 64-bit 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) */ + cmpq $(IA32_NR_syscalls-1), %rax ja 1f - call *ia32_sys_call_table(,%rax,8) # xxx: rip relative + + call *ia32_sys_call_table(, %rax, 8) /* RIP relative */ + ia32_sysret: - movq %rax,RAX(%rsp) + movq %rax, RAX(%rsp) 1: - jmp int_ret_from_sys_call + jmp int_ret_from_sys_call ia32_tracesys: SAVE_EXTRA_REGS - movq %rsp,%rdi /* &pt_regs -> arg1 */ - call syscall_trace_enter + movq %rsp, %rdi /* &pt_regs -> arg1 */ + call syscall_trace_enter /* * Reload arg registers from stack in case ptrace changed them. * Don't reload %eax because syscall_trace_enter() returned @@ -503,33 +508,33 @@ ia32_tracesys: movl RDX(%rsp), %edx movl RSI(%rsp), %esi movl RDI(%rsp), %edi - movl %eax, %eax /* zero extension */ + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS - jmp ia32_do_call + jmp ia32_do_call END(ia32_syscall) .macro PTREGSCALL label, func ALIGN GLOBAL(\label) - leaq \func(%rip),%rax - jmp ia32_ptregs_common + leaq \func(%rip), %rax + jmp ia32_ptregs_common .endm - PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn - PTREGSCALL stub32_sigreturn, sys32_sigreturn - PTREGSCALL stub32_fork, sys_fork - PTREGSCALL stub32_vfork, sys_vfork + 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 + leaq sys_clone(%rip), %rax mov %r8, %rcx - jmp ia32_ptregs_common + jmp ia32_ptregs_common ALIGN ia32_ptregs_common: SAVE_EXTRA_REGS 8 - call *%rax + call *%rax RESTORE_EXTRA_REGS 8 ret END(ia32_ptregs_common)