From 7076aada1040de4ed79a5977dbabdb5e5ea5e249 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 10 Sep 2012 16:44:54 -0400 Subject: x86: split ret_from_fork Signed-off-by: Al Viro --- arch/x86/Kconfig | 1 + arch/x86/include/asm/processor.h | 5 ----- arch/x86/kernel/entry_32.S | 15 ++++++++++----- arch/x86/kernel/entry_64.S | 27 +++++++++++---------------- arch/x86/kernel/process.c | 38 -------------------------------------- arch/x86/kernel/process_32.c | 31 ++++++++++++++++++++++++------- arch/x86/kernel/process_64.c | 35 +++++++++++++++++++++-------------- 7 files changed, 67 insertions(+), 85 deletions(-) (limited to 'arch') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 8ec3a1a..d93eb9d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -97,6 +97,7 @@ config X86 select KTIME_SCALAR if X86_32 select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER + select GENERIC_KERNEL_THREAD config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS || UPROBES) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index d048cad..078f3fd 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -589,11 +589,6 @@ typedef struct { } mm_segment_t; -/* - * create a kernel thread without removing it from tasklists - */ -extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); - /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 623f288..ac11073 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -994,15 +994,20 @@ END(spurious_interrupt_bug) */ .popsection -ENTRY(kernel_thread_helper) - pushl $0 # fake return address for unwinder +ENTRY(ret_from_kernel_thread) CFI_STARTPROC - movl %edi,%eax - call *%esi + pushl_cfi %eax + call schedule_tail + GET_THREAD_INFO(%ebp) + popl_cfi %eax + pushl_cfi $0x0202 # Reset kernel eflags + popfl_cfi + movl PT_EBP(%esp),%eax + call *PT_EBX(%esp) call do_exit ud2 # padding for call trace CFI_ENDPROC -ENDPROC(kernel_thread_helper) +ENDPROC(ret_from_kernel_thread) #ifdef CONFIG_XEN /* Xen doesn't set %esp to be precisely what the normal sysenter diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 69babd8..5526d17 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -450,7 +450,7 @@ ENTRY(ret_from_fork) RESTORE_REST testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread? - jz retint_restore_args + jz 1f testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET jnz int_ret_from_sys_call @@ -458,6 +458,16 @@ ENTRY(ret_from_fork) RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET jmp ret_from_sys_call # go to the SYSRET fastpath +1: + subq $REST_SKIP, %rsp # move the stack pointer back + CFI_ADJUST_CFA_OFFSET REST_SKIP + movq %rbp, %rdi + call *%rbx + # exit + mov %eax, %edi + call do_exit + ud2 # padding for call trace + CFI_ENDPROC END(ret_from_fork) @@ -1206,21 +1216,6 @@ bad_gs: jmp 2b .previous -ENTRY(kernel_thread_helper) - pushq $0 # fake return address - CFI_STARTPROC - /* - * Here we are in the child and the registers are set as they were - * at kernel_thread() invocation in the parent. - */ - call *%rsi - # exit - mov %eax, %edi - call do_exit - ud2 # padding for call trace - CFI_ENDPROC -END(kernel_thread_helper) - /* * execve(). This function needs to use IRET, not SYSRET, to set up all state properly. * diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 7162e9c..6947ec9 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -299,44 +299,6 @@ sys_clone(unsigned long clone_flags, unsigned long newsp, } /* - * This gets run with %si containing the - * function to call, and %di containing - * the "args". - */ -extern void kernel_thread_helper(void); - -/* - * Create a kernel thread - */ -int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) -{ - struct pt_regs regs; - - memset(®s, 0, sizeof(regs)); - - regs.si = (unsigned long) fn; - regs.di = (unsigned long) arg; - -#ifdef CONFIG_X86_32 - regs.ds = __USER_DS; - regs.es = __USER_DS; - regs.fs = __KERNEL_PERCPU; - regs.gs = __KERNEL_STACK_CANARY; -#else - regs.ss = __KERNEL_DS; -#endif - - regs.orig_ax = -1; - regs.ip = (unsigned long) kernel_thread_helper; - regs.cs = __KERNEL_CS | get_kernel_rpl(); - regs.flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1; - - /* Ok, create the new process.. */ - return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); -} -EXPORT_SYMBOL(kernel_thread); - -/* * sys_execve() executes a new program. */ long sys_execve(const char __user *name, diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 75fcad1..c993987 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -57,6 +57,7 @@ #include asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); +asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread"); /* * Return saved PC of a blocked thread. @@ -127,23 +128,39 @@ void release_thread(struct task_struct *dead_task) } int copy_thread(unsigned long clone_flags, unsigned long sp, - unsigned long unused, + unsigned long arg, struct task_struct *p, struct pt_regs *regs) { - struct pt_regs *childregs; + struct pt_regs *childregs = task_pt_regs(p); struct task_struct *tsk; int err; - childregs = task_pt_regs(p); + p->thread.sp = (unsigned long) childregs; + p->thread.sp0 = (unsigned long) (childregs+1); + + if (unlikely(!regs)) { + /* kernel thread */ + memset(childregs, 0, sizeof(struct pt_regs)); + p->thread.ip = (unsigned long) ret_from_kernel_thread; + task_user_gs(p) = __KERNEL_STACK_CANARY; + childregs->ds = __USER_DS; + childregs->es = __USER_DS; + childregs->fs = __KERNEL_PERCPU; + childregs->bx = sp; /* function */ + childregs->bp = arg; + childregs->orig_ax = -1; + childregs->cs = __KERNEL_CS | get_kernel_rpl(); + childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1; + p->fpu_counter = 0; + p->thread.io_bitmap_ptr = NULL; + memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); + return 0; + } *childregs = *regs; childregs->ax = 0; childregs->sp = sp; - p->thread.sp = (unsigned long) childregs; - p->thread.sp0 = (unsigned long) (childregs+1); - p->thread.ip = (unsigned long) ret_from_fork; - task_user_gs(p) = get_user_gs(regs); p->fpu_counter = 0; diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 0a980c9..937f2af 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -146,29 +146,18 @@ static inline u32 read_32bit_tls(struct task_struct *t, int tls) } int copy_thread(unsigned long clone_flags, unsigned long sp, - unsigned long unused, + unsigned long arg, struct task_struct *p, struct pt_regs *regs) { int err; struct pt_regs *childregs; struct task_struct *me = current; - childregs = ((struct pt_regs *) - (THREAD_SIZE + task_stack_page(p))) - 1; - *childregs = *regs; - - childregs->ax = 0; - if (user_mode(regs)) - childregs->sp = sp; - else - childregs->sp = (unsigned long)childregs; - + p->thread.sp0 = (unsigned long)task_stack_page(p) + THREAD_SIZE; + childregs = task_pt_regs(p); p->thread.sp = (unsigned long) childregs; - p->thread.sp0 = (unsigned long) (childregs+1); p->thread.usersp = me->thread.usersp; - set_tsk_thread_flag(p, TIF_FORK); - p->fpu_counter = 0; p->thread.io_bitmap_ptr = NULL; @@ -178,6 +167,24 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs; savesegment(es, p->thread.es); savesegment(ds, p->thread.ds); + memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); + + if (unlikely(!regs)) { + /* kernel thread */ + memset(childregs, 0, sizeof(struct pt_regs)); + childregs->sp = (unsigned long)childregs; + childregs->ss = __KERNEL_DS; + childregs->bx = sp; /* function */ + childregs->bp = arg; + childregs->orig_ax = -1; + childregs->cs = __KERNEL_CS | get_kernel_rpl(); + childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1; + return 0; + } + *childregs = *regs; + + childregs->ax = 0; + childregs->sp = sp; err = -ENOMEM; memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); -- cgit v1.1