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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-03-02 11:33:52 +1100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-03-09 10:55:20 +1100 |
| commit | d9ada91ae2969ae6b6dc3574fd08a6ebda5df766 (patch) | |
| tree | a4509657892acb0b853760d6d26729a913a5fc2b /arch/powerpc/kernel/exceptions-64s.S | |
| parent | 9424fabf8617c15e18a5ffd29bc3bcfa36620473 (diff) | |
| download | linux-d9ada91ae2969ae6b6dc3574fd08a6ebda5df766.tar.bz2 | |
powerpc: Replace mfmsr instructions with load from PACA kernel_msr field
On 64-bit, the mfmsr instruction can be quite slow, slower
than loading a field from the cache-hot PACA, which happens
to already contain the value we want in most cases.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64s.S')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 0fb42ae21694..02448ea58ad3 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -848,9 +848,8 @@ fast_exception_return: REST_GPR(0, r1) REST_8GPRS(2, r1) - mfmsr r10 - rldicl r10,r10,48,1 /* clear EE */ - rldicr r10,r10,16,61 /* clear RI (LE is 0 already) */ + ld r10,PACAKMSR(r13) + clrrdi r10,r10,2 /* clear RI */ mtmsrd r10,1 mtspr SPRN_SRR1,r12 |