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authorBrian Gerst <brgerst@gmail.com>2016-08-13 12:38:20 -0400
committerIngo Molnar <mingo@kernel.org>2016-08-24 12:31:50 +0200
commit616d24835eeafa8ef3466479db028abfdfc77531 (patch)
tree855895f0566a9c7b7b1996cbee1a384995b5a068 /arch/x86/kernel/process_64.c
parent0100301bfdf56a2a370c7157b5ab0fbf9313e1cd (diff)
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 <brgerst@gmail.com> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1471106302-10159-6-git-send-email-brgerst@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r--arch/x86/kernel/process_64.c12
1 files changed, 3 insertions, 9 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 827eeed03e16..b812cd0d7889 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -50,8 +50,6 @@
#include <asm/switch_to.h>
#include <asm/xen/hypervisor.h>
-asmlinkage extern void ret_from_fork(void);
-
__visible DEFINE_PER_CPU(unsigned long, rsp_scratch);
/* Prints also some state that isn't saved in the pt_regs */
@@ -165,15 +163,11 @@ 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));
- 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_FIXED;
+ frame->bx = sp; /* function */
+ frame->r12 = arg;
return 0;
}
+ frame->bx = 0;
*childregs = *current_pt_regs();
childregs->ax = 0;