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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-06-03 11:41:39 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-16 17:09:08 +0300 |
| commit | 863771a28e27dc9eaeaa88cea300370d032f0e0f (patch) | |
| tree | a2b744fc7635c80ff653043735b35dea37c63dff /arch/powerpc/mm/book3s32 | |
| parent | 7235bb3593781ed022d0714a73c2c0d8eb8a835f (diff) | |
| download | linux-863771a28e27dc9eaeaa88cea300370d032f0e0f.tar.xz | |
powerpc/32s: Convert switch_mmu_context() to C
switch_mmu_context() does things that can easily be done in C.
For updating user segments, we have update_user_segments().
As mentionned in commit b5efec00b671 ("powerpc/32s: Move KUEP
locking/unlocking in C"), update_user_segments() has the loop
unrolled which is a significant performance gain.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/05c0875ad8220c03452c3a334946e207c6ca04d6.1622708530.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/mm/book3s32')
| -rw-r--r-- | arch/powerpc/mm/book3s32/mmu_context.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s32/mmu_context.c b/arch/powerpc/mm/book3s32/mmu_context.c index c949363f315f..e2708e387dc3 100644 --- a/arch/powerpc/mm/book3s32/mmu_context.c +++ b/arch/powerpc/mm/book3s32/mmu_context.c @@ -24,6 +24,12 @@ #include <asm/mmu_context.h> /* + * Room for two PTE pointers, usually the kernel and current user pointers + * to their respective root page table. + */ +void *abatron_pteptrs[2]; + +/* * On 32-bit PowerPC 6xx/7xx/7xxx CPUs, we use a set of 16 VSIDs * (virtual segment identifiers) for each context. Although the * hardware supports 24-bit VSIDs, and thus >1 million contexts, @@ -98,3 +104,32 @@ void __init mmu_context_init(void) context_map[0] = (1 << FIRST_CONTEXT) - 1; next_mmu_context = FIRST_CONTEXT; } + +void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) +{ + long id = next->context.id; + unsigned long val; + + if (id < 0) + panic("mm_struct %p has no context ID", next); + + isync(); + + val = CTX_TO_VSID(id, 0); + if (!kuep_is_disabled()) + val |= SR_NX; + if (!kuap_is_disabled()) + val |= SR_KS; + + update_user_segments(val); + + if (IS_ENABLED(CONFIG_BDI_SWITCH)) + abatron_pteptrs[1] = next->pgd; + + if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) + mtspr(SPRN_SDR1, rol32(__pa(next->pgd), 4) & 0xffff01ff); + + mb(); /* sync */ + isync(); +} +EXPORT_SYMBOL(switch_mmu_context); |