Commit-ID:  a3675b32aac81c2c4733568844f8276527a37423
Gitweb:     http://git.kernel.org/tip/a3675b32aac81c2c4733568844f8276527a37423
Author:     Denys Vlasenko <[email protected]>
AuthorDate: Mon, 30 Mar 2015 20:09:34 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Tue, 31 Mar 2015 09:31:11 +0200

x86/asm/entry/64: Do not GET_THREAD_INFO() too early

At exit_intr, we GET_THREAD_INFO(%rcx) and then jump to
retint_kernel if saved CS was from kernel. But the code at
retint_kernel doesn't need %rcx.

Move GET_THREAD_INFO(%rcx) down, after CS check and branch.

While at it, remove "has a correct top of stack" comment.
After recent changes which eliminated FIXUP_TOP_OF_STACK,
we always have a correct pt_regs layout.

Signed-off-by: Denys Vlasenko <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Will Drewry <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/kernel/entry_64.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 34d60c3..6f251a5 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -658,13 +658,12 @@ ret_from_intr:
        CFI_ADJUST_CFA_OFFSET   RBP
 
 exit_intr:
-       GET_THREAD_INFO(%rcx)
        testl $3,CS(%rsp)
        je retint_kernel
-
        /* Interrupt came from user space */
+
+       GET_THREAD_INFO(%rcx)
        /*
-        * Has a correct top of stack.
         * %rcx: thread info. Interrupts off.
         */
 retint_with_reschedule:
--
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/

Reply via email to