diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2024-07-02 15:51:30 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-12 15:52:18 -0700 |
| commit | 276d5affbbaea4d369d1e5b9711cb2951037f6ee (patch) | |
| tree | 15cf13dbe083b480a55a4cd011dc63270aa44845 | |
| parent | 84319905ca5f3759c42082e20ed978c81f4dead0 (diff) | |
powerpc/e500: don't pre-check write access on data TLB error
Don't pre-check write access on read-only pages on data TLB error.
Load the TLB anyway and take a DSI exception when it happens. This avoids
reading SPRN_ESR at every data TLB error exception.
Link: https://lkml.kernel.org/r/8525518e1657d6032b7e980c1888102828d66950.1719928057.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | arch/powerpc/kernel/head_85xx.S | 15 |
1 files changed, 0 insertions, 15 deletions
diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S index a305244afc9f..282e49c51deb 100644 --- a/arch/powerpc/kernel/head_85xx.S +++ b/arch/powerpc/kernel/head_85xx.S @@ -472,27 +472,12 @@ END_BTB_FLUSH_SECTION #endif 4: - /* Mask of required permission bits. Note that while we - * do copy ESR:ST to _PAGE_WRITE position as trying to write - * to an RO page is pretty common, we don't do it with - * _PAGE_DIRTY. We could do it, but it's a fairly rare - * event so I'd rather take the overhead when it happens - * rather than adding an instruction here. We should measure - * whether the whole thing is worth it in the first place - * as we could avoid loading SPRN_ESR completely in the first - * place... - * - * TODO: Is it worth doing that mfspr & rlwimi in the first - * place or can we save a couple of instructions here ? - */ - mfspr r12,SPRN_ESR #ifdef CONFIG_PTE_64BIT li r13,_PAGE_PRESENT|_PAGE_BAP_SR oris r13,r13,_PAGE_ACCESSED@h #else li r13,_PAGE_PRESENT|_PAGE_READ|_PAGE_ACCESSED #endif - rlwimi r13,r12,11,29,29 FIND_PTE andc. r13,r13,r11 /* Check permission */ |