powerpc/8xx: Add a function to early map kernel via huge pages

Add a function to early map kernel memory using huge pages.

For 512k pages, just use standard page table and map in using 512k
pages.

For 8M pages, create a hugepd table and populate the two PGD
entries with it.

This function can only be used to create page tables at startup. Once
the regular SLAB allocation functions replace memblock functions,
this function cannot allocate new pages anymore. However it can still
update existing mappings with new protections.

hugepd_none() macro is moved into asm/hugetlb.h to be usable outside
of mm/hugetlbpage.c

early_pte_alloc_kernel() is made visible.

_PAGE_HUGE flag is now displayed by ptdump.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Change ptdump display to use "huge"]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/68325bcd3b6f93127f7810418a2352c3519066d6.1589866984.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy
2020-05-19 05:49:22 +00:00
committed by Michael Ellerman
parent c8bef10a9f
commit 34536d7806
6 changed files with 66 additions and 1 deletions

View File

@@ -107,6 +107,8 @@ unsigned long vmalloc_to_phys(void *vmalloc_addr);
void pgtable_cache_add(unsigned int shift);
pte_t *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va);
#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_PPC32)
void mark_initmem_nx(void);
#else