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From: Greg KH on 30 Mar 2010 19:30
2.6.33-stable review patch. If anyone has any objections, please let us know.

------------------

From: David S. Miller <davem(a)davemloft.net>

[ Upstream commit 9e8307ecaf9f8c8b5b3b22145021204c4e73114a ]

For 32-bit processes, we save the full 64-bits of the regs in pt_regs.

But unlike when the userspace actually does load and store
instructions, the top 32-bits don't get automatically truncated by the
cpu in kernel mode (because the kernel doesn't execute with PSTATE_AM
address masking enabled).

So we have to do it by hand.

Reported-by: Frederic Weisbecker <fweisbec(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

---
arch/sparc/kernel/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1337,7 +1337,7 @@ static void perf_callchain_user_32(struc
callchain_store(entry, PERF_CONTEXT_USER);
callchain_store(entry, regs->tpc);

- ufp = regs->u_regs[UREG_I6];
+ ufp = regs->u_regs[UREG_I6] & 0xffffffffUL;
do {
struct sparc_stackf32 *usf, sf;
unsigned long pc;


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