diff options
| 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/include/asm/page.h | |
| parent | dc0aa538a954c90d71d6bc1fcac487ef01512120 (diff) | |
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/include/asm/page.h')
| -rw-r--r-- | arch/powerpc/include/asm/page.h | 15 |
1 files changed, 1 insertions, 14 deletions
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 018c3d55232c..7d3c3bc40e6a 100644 --- a/arch/powerpc/include/asm/page.h +++ b/arch/powerpc/include/asm/page.h @@ -269,20 +269,7 @@ static inline const void *pfn_to_kaddr(unsigned long pfn) #define is_kernel_addr(x) ((x) >= TASK_SIZE) #endif -#ifndef CONFIG_PPC_BOOK3S_64 -/* - * Use the top bit of the higher-level page table entries to indicate whether - * the entries we point to contain hugepages. This works because we know that - * the page tables live in kernel space. If we ever decide to support having - * page tables at arbitrary addresses, this breaks and will have to change. - */ -#ifdef CONFIG_PPC64 -#define PD_HUGE 0x8000000000000000UL -#else -#define PD_HUGE 0x80000000 -#endif - -#else /* CONFIG_PPC_BOOK3S_64 */ +#ifdef CONFIG_PPC_BOOK3S_64 /* * Book3S 64 stores real addresses in the hugepd entries to * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE. |