Commit-ID: 75182b1632a89f12540baa1806a7c5c180db620c Gitweb: http://git.kernel.org/tip/75182b1632a89f12540baa1806a7c5c180db620c Author: Andy Lutomirski <[email protected]> AuthorDate: Thu, 5 Mar 2015 19:19:03 -0800 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 6 Mar 2015 08:32:57 +0100
x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0() This will make modifying the semantics of kernel_stack easier. The change to ist_begin_non_atomic() is necessary because sp0 no longer points to the same THREAD_SIZE-aligned region as RSP; it's one byte too high for that. At Denys' suggestion, rather than offsetting it, just check explicitly that we're in the correct range ending at sp0. This has the added benefit that we no longer assume that the thread stack is aligned to THREAD_SIZE. Suggested-by: Denys Vlasenko <[email protected]> Signed-off-by: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/ef8254ad414cbb8034c9a56396eeb24f5dd5b0de.1425611534.git.l...@amacapital.net Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/thread_info.h | 3 +-- arch/x86/kernel/traps.c | 4 ++-- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 1d4e4f2..a2fa189 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -159,8 +159,7 @@ DECLARE_PER_CPU(unsigned long, kernel_stack); static inline struct thread_info *current_thread_info(void) { struct thread_info *ti; - ti = (void *)(this_cpu_read_stable(kernel_stack) + - KERNEL_STACK_OFFSET - THREAD_SIZE); + ti = (void *)(this_cpu_sp0() - THREAD_SIZE); return ti; } diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 9965bd1..fa29058 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -174,8 +174,8 @@ void ist_begin_non_atomic(struct pt_regs *regs) * will catch asm bugs and any attempt to use ist_preempt_enable * from double_fault. */ - BUG_ON(((current_stack_pointer() ^ this_cpu_read_stable(kernel_stack)) - & ~(THREAD_SIZE - 1)) != 0); + BUG_ON((unsigned long)(this_cpu_sp0() - current_stack_pointer()) >= + THREAD_SIZE); preempt_count_sub(HARDIRQ_OFFSET); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
