[ 25/54] sparc64: Do not clobber %g2 in xcall_fetch_glob_regs().

From: Greg KH
Date: Fri May 18 2012 - 19:03:54 EST


3.0-stable review patch. If anyone has any objections, please let me know.

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

From: "David S. Miller" <davem@xxxxxxxxxxxxx>

[ Upstream commit a5a737e090e25981e99d69f01400e3a80356581c ]

%g2 is meant to hold the CPUID number throughout this routine, since
at the very beginning, and at the very end, we use %g2 to calculate
indexes into per-cpu arrays.

However we erroneously clobber it in order to hold the %cwp register
value mid-stream.

Fix this code to use %g3 for the %cwp read and related calulcations
instead.

Reported-by: Meelis Roos <mroos@xxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/kernel/central.c | 2 +-
arch/sparc/mm/ultra.S | 6 +++---
2 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/sparc/kernel/central.c
+++ b/arch/sparc/kernel/central.c
@@ -268,4 +268,4 @@ static int __init sunfire_init(void)
return 0;
}

-subsys_initcall(sunfire_init);
+fs_initcall(sunfire_init);
--- a/arch/sparc/mm/ultra.S
+++ b/arch/sparc/mm/ultra.S
@@ -495,11 +495,11 @@ xcall_fetch_glob_regs:
stx %o7, [%g1 + GR_SNAP_O7]
stx %i7, [%g1 + GR_SNAP_I7]
/* Don't try this at home kids... */
- rdpr %cwp, %g2
- sub %g2, 1, %g7
+ rdpr %cwp, %g3
+ sub %g3, 1, %g7
wrpr %g7, %cwp
mov %i7, %g7
- wrpr %g2, %cwp
+ wrpr %g3, %cwp
stx %g7, [%g1 + GR_SNAP_RPC]
sethi %hi(trap_block), %g7
or %g7, %lo(trap_block), %g7


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