x86: no robust/pi futex for real i386 CPUs

[Linux Kernel Mailing List]

Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f18edc95a37a901ffcbe91f5e05105f916a04fae
Commit:     f18edc95a37a901ffcbe91f5e05105f916a04fae
Parent:     12c247a6719987aad65f83158d2bb3e73c75c1f5
Author:     Thomas Gleixner <[EMAIL PROTECTED]>
AuthorDate: Sat Feb 16 14:05:01 2008 +0100
Committer:  Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Tue Feb 26 12:56:06 2008 +0100

    x86: no robust/pi futex for real i386 CPUs
    
    Real i386 CPUs do not have cmpxchg instructions. Catch it before
    crashing on an invalid opcode.
    
    Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
---
 include/asm-x86/futex.h |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/include/asm-x86/futex.h b/include/asm-x86/futex.h
index cd9f894..c9952ea 100644
--- a/include/asm-x86/futex.h
+++ b/include/asm-x86/futex.h
@@ -102,6 +102,13 @@ futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
 static inline int
 futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 {
+
+#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
+       /* Real i386 machines have no cmpxchg instruction */
+       if (boot_cpu_data.x86 == 3)
+               return -ENOSYS;
+#endif
+
        if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
                return -EFAULT;
 
-
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html