From 616d24835eeafa8ef3466479db028abfdfc77531 Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Sat, 13 Aug 2016 12:38:20 -0400 Subject: sched/x86: Pass kernel thread parameters in 'struct fork_frame' Instead of setting up a fake pt_regs context, put the kernel thread function pointer and arg into the unused callee-restored registers of 'struct fork_frame'. Signed-off-by: Brian Gerst Reviewed-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1471106302-10159-6-git-send-email-brgerst@gmail.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/process_32.c | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) (limited to 'arch/x86/kernel/process_32.c') diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 4bedbc08e53c..18714a191b2d 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -55,9 +55,6 @@ #include #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. */ @@ -139,6 +136,7 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, int err; frame->bp = 0; + frame->ret_addr = (unsigned long) ret_from_fork; p->thread.sp = (unsigned long) fork_frame; p->thread.sp0 = (unsigned long) (childregs+1); memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); @@ -146,25 +144,17 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, if (unlikely(p->flags & PF_KTHREAD)) { /* kernel thread */ memset(childregs, 0, sizeof(struct pt_regs)); - frame->ret_addr = (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_FIXED; + frame->bx = sp; /* function */ + frame->di = arg; p->thread.io_bitmap_ptr = NULL; return 0; } + frame->bx = 0; *childregs = *current_pt_regs(); childregs->ax = 0; if (sp) childregs->sp = sp; - frame->ret_addr = (unsigned long) ret_from_fork; task_user_gs(p) = get_user_gs(current_pt_regs()); p->thread.io_bitmap_ptr = NULL; -- cgit v1.2.3