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powerpc/8xx: Always pin kernel instruction TLB

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Various kernel asm modifies SRR0/SRR1 just before executing
a rfi. If such code crosses a page boundary you risk a TLB miss
which will clobber SRR0/SRR1. Avoid this by always pinning
kernel instruction TLB space.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Joakim Tjernlund 2009-12-29 05:10:58 +00:00 • committed by Benjamin Herrenschmidt
parent 004b350632
commit 9f4f04ba2b
1 changed files with 4 additions and 4 deletions
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8
arch/powerpc/kernel/head_8xx.S
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@ -768,12 +768,12 @@ start_here:
*/ */
initial_mmu: initial_mmu:
tlbia /* Invalidate all TLB entries */ tlbia /* Invalidate all TLB entries */
#ifdef CONFIG_PIN_TLB /* Always pin the first 8 MB ITLB to prevent ITLB
misses while mucking around with SRR0/SRR1 in asm
*/
lis r8, MI_RSV4I@h lis r8, MI_RSV4I@h
ori r8, r8, 0x1c00 ori r8, r8, 0x1c00
#else
li r8, 0
#endif
mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */ mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */
#ifdef CONFIG_PIN_TLB #ifdef CONFIG_PIN_TLB