[PATCH] x86-64: Prevent gcc from optimizing away venosys_1()

[Dave Anderson]

One of the changes in commit a4928cffe6435caf427ae673131a633c1329dbf3 
made the venosys_1() system call static, which causes it to be 
optimized out of the kernel:

  Author: Ingo Molnar <mingo@xxxxxxx>
  Date:   Wed Apr 23 13:20:56 2008 +0200

  "make namespacecheck" fixes

  Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

Commit 2e8ad43ec07545780ce7992cb18e2d82c7abd24c had originally
changed all vsyscalls from being static for the same reason:

  Author: Andi Kleen <ak@xxxxxxx>
  Date:   Mon Sep 12 18:49:24 2005 +0200

  [PATCH] x86-64: Prevent gcc 4 from optimizing away vsyscalls
    
  They were previously static.
    
  Signed-off-by: Andi Kleen <ak@xxxxxxx>
  Signed-off-by: Linus Torvalds <torvalds@xxxxxxxx>

Reported-by: Jan Stancek <jstancek@xxxxxxxxxx>
Signed-off-by: Dave Anderson <anderson@xxxxxxxxxx>

---

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 3e68218..60a34af 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -222,7 +222,7 @@ vgetcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
 	return 0;
 }
 
-static long __vsyscall(3) venosys_1(void)
+long __vsyscall(3) venosys_1(void)
 {
 	return -ENOSYS;
 }
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