| Message ID | 848f18d213b8341939add7302dc4ef80cc7a12e3.1620307636.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | powerpc/32s: Speed up likely path of kuap_update_sr() | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (7619d98e5041d5c25aba5428704dba6121237a9a) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 15 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Thu, 6 May 2021 13:27:31 +0000 (UTC), Christophe Leroy wrote: > In most cases, kuap_update_sr() will update a single segment > register. > > We know that first update will always be done, if there is no > segment register to update at all, kuap_update_sr() is not > called. > > [...] Applied to powerpc/next. [1/1] powerpc/32s: Speed up likely path of kuap_update_sr() https://git.kernel.org/powerpc/c/8af8d72dc58e90dc945ca627b24968400e0f21b6 cheers
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 1670dfe9d4f1..c1f7c2e625a6 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -15,11 +15,13 @@ static inline void kuap_update_sr(u32 sr, u32 addr, u32 end) { addr &= 0xf0000000; /* align addr to start of segment */ barrier(); /* make sure thread.kuap is updated before playing with SRs */ - while (addr < end) { + for (;;) { mtsr(sr, addr); + addr += 0x10000000; /* address of next segment */ + if (addr >= end) + break; sr += 0x111; /* next VSID */ sr &= 0xf0ffffff; /* clear VSID overflow */ - addr += 0x10000000; /* address of next segment */ } isync(); /* Context sync required after mtsr() */ }
In most cases, kuap_update_sr() will update a single segment register. We know that first update will always be done, if there is no segment register to update at all, kuap_update_sr() is not called. Avoid recurring calculations and tests in that case. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/powerpc/include/asm/book3s/32/kup.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)