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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2024-07-02 15:51:32 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-12 15:52:18 -0700 |
| commit | 7c44202e36097e23240025298ccd1fe4eacfd94e (patch) | |
| tree | 774e559385895c028afb259609c6fa70a2c28463 /arch/powerpc/kernel | |
| parent | dc0aa538a954c90d71d6bc1fcac487ef01512120 (diff) | |
| download | lwn-7c44202e36097e23240025298ccd1fe4eacfd94e.tar.gz lwn-7c44202e36097e23240025298ccd1fe4eacfd94e.zip | |
powerpc/e500: use contiguous PMD instead of hugepd
e500 supports many page sizes among which the following size are
implemented in the kernel at the time being: 4M, 16M, 64M, 256M, 1G.
On e500, TLB miss for hugepages is exclusively handled by SW even on e6500
which has HW assistance for 4k pages, so there are no constraints like on
the 8xx.
On e500/32, all are at PGD/PMD level and can be handled as cont-PMD.
On e500/64, smaller ones are on PMD while bigger ones are on PUD. Again,
they can easily be handled as cont-PMD and cont-PUD instead of hugepd.
On e500/32, use the pagesize bits in PTE to know if it is a PMD or a leaf
entry. This works because the pagesize bits are in the last 12 bits and
page tables are 4k aligned.
On e500/64, use highest bit which is always 1 on PxD (Because PxD contains
virtual address of a kernel memory) and always 0 on PTEs because not all
bits of RPN are used/possible.
Link: https://lkml.kernel.org/r/dd085987816ed2a0c70adb7e34966cb833fc03e1.1719928057.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>
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/head_85xx.S | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S index 226f88e77d6d..f9a73fae6464 100644 --- a/arch/powerpc/kernel/head_85xx.S +++ b/arch/powerpc/kernel/head_85xx.S @@ -311,16 +311,14 @@ set_ivor: rlwinm r12, r13, 14, 18, 28; /* Compute pgdir/pmd offset */ \ add r12, r11, r12; \ lwz r11, 4(r12); /* Get pgd/pmd entry */ \ + rlwinm. r10, r11, 32 - _PAGE_PSIZE_SHIFT, 0x1e; /* get tsize*/ \ + bne 1000f; /* Huge page (leaf entry) */ \ rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \ - blt 1000f; /* Normal non-huge page */ \ beq 2f; /* Bail if no table */ \ - oris r11, r11, PD_HUGE@h; /* Put back address bit */ \ - andi. r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */ \ - xor r12, r10, r11; /* drop size bits from pointer */ \ - b 1001f; \ -1000: rlwimi r12, r13, 23, 20, 28; /* Compute pte address */ \ + rlwimi r12, r13, 23, 20, 28; /* Compute pte address */ \ li r10, 0; /* clear r10 */ \ -1001: lwz r11, 4(r12); /* Get pte entry */ + lwz r11, 4(r12); /* Get pte entry */ \ +1000: #else #define FIND_PTE \ rlwinm r12, r13, 14, 18, 28; /* Compute pgdir/pmd offset */ \ @@ -735,17 +733,12 @@ finish_tlb_load: lwz r15, 0(r14) 100: stw r15, 0(r17) - /* - * Calc MAS1_TSIZE from r10 (which has pshift encoded) - * tlb_enc = (pshift - 10). - */ - subi r15, r10, 10 mfspr r16, SPRN_MAS1 - rlwimi r16, r15, 7, 20, 24 + rlwimi r16, r10, MAS1_TSIZE_SHIFT, MAS1_TSIZE_MASK mtspr SPRN_MAS1, r16 /* copy the pshift for use later */ - mr r14, r10 + addi r14, r10, _PAGE_PSIZE_SHIFT_OFFSET /* fall through */ |