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| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-10-19 09:29:18 +0200 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2021-12-09 22:41:17 +1100 |
| commit | 70428da94c7ad692d306747a04117543827292a7 (patch) | |
| tree | a9c27bfdbaa5b4b79a93564f80ac31165f4ff560 /arch/powerpc/include/asm/book3s/32/mmu-hash.h | |
| parent | powerpc/32s: Do kuep_lock() and kuep_unlock() in assembly (diff) | |
| download | linux-dev-70428da94c7ad692d306747a04117543827292a7.tar.xz linux-dev-70428da94c7ad692d306747a04117543827292a7.zip | |
powerpc/32s: Save content of sr0 to avoid 'mfsr'
Calling 'mfsr' to get the content of segment registers is heavy,
in addition it requires clearing of the 'reserved' bits.
In order to avoid this operation, save it in mm context and in
thread struct.
The saved sr0 is the one used by kernel, this means that on
locking entry it can be used as is.
For unlocking, the only thing to do is to clear SR_NX.
This improves null_syscall selftest by 12 cycles, ie 4%.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b02baf2ed8f09bad910dfaeeb7353b2ae6830525.1634627931.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/include/asm/book3s/32/mmu-hash.h')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/32/mmu-hash.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h index e2f7ccc13edb..7be27862329f 100644 --- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h @@ -175,9 +175,14 @@ struct hash_pte { typedef struct { unsigned long id; + unsigned long sr0; void __user *vdso; } mm_context_t; +#ifdef CONFIG_PPC_KUEP +#define INIT_MM_CONTEXT(mm) .context.sr0 = SR_NX +#endif + void update_bats(void); static inline void cleanup_cpu_mmu_context(void) { } |