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| author | Sam bobroff <sam.bobroff@au1.ibm.com> | 2014-05-21 16:32:38 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-05-28 13:35:40 +1000 |
| commit | 1739ea9e13e636590dd56c2f4ca85e783da512e7 (patch) | |
| tree | fcdebf258849e18544f05cdabcf176837c0b3778 /arch/powerpc/kernel/tm.S | |
| parent | 39a360ef7234942333436709fd6cf641d5c51b7b (diff) | |
| download | lwn-1739ea9e13e636590dd56c2f4ca85e783da512e7.tar.gz lwn-1739ea9e13e636590dd56c2f4ca85e783da512e7.zip | |
powerpc: Fix regression of per-CPU DSCR setting
Since commit "efcac65 powerpc: Per process DSCR + some fixes (try#4)"
it is no longer possible to set the DSCR on a per-CPU basis.
The old behaviour was to minipulate the DSCR SPR directly but this is no
longer sufficient: the value is quickly overwritten by context switching.
This patch stores the per-CPU DSCR value in a kernel variable rather than
directly in the SPR and it is used whenever a process has not set the DSCR
itself. The sysfs interface (/sys/devices/system/cpu/cpuN/dscr) is unchanged.
Writes to the old global default (/sys/devices/system/cpu/dscr_default)
now set all of the per-CPU values and reads return the last written value.
The new per-CPU default is added to the paca_struct and is used everywhere
outside of sysfs.c instead of the old global default.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/tm.S')
| -rw-r--r-- | arch/powerpc/kernel/tm.S | 16 |
1 files changed, 4 insertions, 12 deletions
diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S index ee061c3715de..2a324f4cb1b9 100644 --- a/arch/powerpc/kernel/tm.S +++ b/arch/powerpc/kernel/tm.S @@ -78,12 +78,6 @@ _GLOBAL(tm_abort) TABORT(R3) blr - .section ".toc","aw" -DSCR_DEFAULT: - .tc dscr_default[TC],dscr_default - - .section ".text" - /* void tm_reclaim(struct thread_struct *thread, * unsigned long orig_msr, * uint8_t cause) @@ -298,9 +292,8 @@ dont_backup_fp: mtlr r0 ld r2, STK_GOT(r1) - /* Load system default DSCR */ - ld r4, DSCR_DEFAULT@toc(r2) - ld r0, 0(r4) + /* Load CPU's default DSCR */ + ld r0, PACA_DSCR(r13) mtspr SPRN_DSCR, r0 blr @@ -479,9 +472,8 @@ restore_gprs: mtlr r0 ld r2, STK_GOT(r1) - /* Load system default DSCR */ - ld r4, DSCR_DEFAULT@toc(r2) - ld r0, 0(r4) + /* Load CPU's default DSCR */ + ld r0, PACA_DSCR(r13) mtspr SPRN_DSCR, r0 blr |