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sparc64: Do not clobber %g2 in xcall_fetch_glob_regs().

%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

Reported-by: Meelis Roos <>
Signed-off-by: David S. Miller <>
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davem330 committed May 10, 2012
1 parent bc46f93 commit a5a737e090e25981e99d69f01400e3a80356581c
Showing with 4 additions and 4 deletions.
  1. +1 −1 arch/sparc/kernel/central.c
  2. +3 −3 arch/sparc/mm/ultra.S
@@ -269,4 +269,4 @@ static int __init sunfire_init(void)
return 0;
@@ -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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