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powerpc: Partial revert of "Context switch more PMU related SPRs" 

In commit 59affcd I added context switching of more PMU SPRs, because
they are potentially exposed to userspace on Power8. However despite me
being a smart arse in the commit message it's actually not correct. In
particular it interacts badly with a global perf record.

We will have to do something more complicated, but that will have to
wait for 3.11.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Ellerman 2013-06-05 18:03:36 +00:00 committed by Benjamin Herrenschmidt
parent 6772faa1ba
commit b11ae95100
1 changed files with 0 additions and 28 deletions
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28
arch/powerpc/kernel/entry_64.S
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@ -465,20 +465,6 @@ BEGIN_FTR_SECTION
std r0, THREAD_EBBHR(r3)
mfspr r0, SPRN_EBBRR
std r0, THREAD_EBBRR(r3)
/* PMU registers made user read/(write) by EBB */
mfspr r0, SPRN_SIAR
std r0, THREAD_SIAR(r3)
mfspr r0, SPRN_SDAR
std r0, THREAD_SDAR(r3)
mfspr r0, SPRN_SIER
std r0, THREAD_SIER(r3)
mfspr r0, SPRN_MMCR0
std r0, THREAD_MMCR0(r3)
mfspr r0, SPRN_MMCR2
std r0, THREAD_MMCR2(r3)
mfspr r0, SPRN_MMCRA
std r0, THREAD_MMCRA(r3)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
#endif
@ -581,20 +567,6 @@ BEGIN_FTR_SECTION
ld r0, THREAD_EBBRR(r4)
mtspr SPRN_EBBRR, r0
/* PMU registers made user read/(write) by EBB */
ld r0, THREAD_SIAR(r4)
mtspr SPRN_SIAR, r0
ld r0, THREAD_SDAR(r4)
mtspr SPRN_SDAR, r0
ld r0, THREAD_SIER(r4)
mtspr SPRN_SIER, r0
ld r0, THREAD_MMCR0(r4)
mtspr SPRN_MMCR0, r0
ld r0, THREAD_MMCR2(r4)
mtspr SPRN_MMCR2, r0
ld r0, THREAD_MMCRA(r4)
mtspr SPRN_MMCRA, r0
ld r0,THREAD_TAR(r4)
mtspr SPRN_TAR,r0
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)