From 263042e4630a85e856b4a8cd72f28dab33ef4741 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Mon, 9 Mar 2015 19:39:23 +0100 Subject: x86/asm/entry/64: Save user RSP in pt_regs->sp on SYSCALL64 fastpath Prepare for the removal of 'usersp', by simplifying PER_CPU(old_rsp) usage: - use it only as temp storage - store the userspace stack pointer immediately in pt_regs->sp on syscall entry, instead of using it later, on syscall exit. - change C code to use pt_regs->sp only, instead of PER_CPU(old_rsp) and task->thread.usersp. FIXUP/RESTORE_TOP_OF_STACK are simplified as well. Signed-off-by: Denys Vlasenko Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Steven Rostedt Cc: Will Drewry Link: http://lkml.kernel.org/r/1425926364-9526-4-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/compat.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/include/asm/compat.h') diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h index 59c6c401f79f..acdee09228b3 100644 --- a/arch/x86/include/asm/compat.h +++ b/arch/x86/include/asm/compat.h @@ -301,7 +301,7 @@ static inline void __user *arch_compat_alloc_user_space(long len) sp = task_pt_regs(current)->sp; } else { /* -128 for the x32 ABI redzone */ - sp = this_cpu_read(old_rsp) - 128; + sp = task_pt_regs(current)->sp - 128; } return (void __user *)round_down(sp - len, 16); -- cgit v1.2.3