diff options
| author |   Michael Ellerman <mpe@ellerman.id.au> | 2019-03-14 23:54:53 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-04-20 22:02:11 +1000 |
| commit | eea86aa4171d4960f0fcdc99dab358c224d53ffe (patch) | |
| tree | 38e0d193c517da93546adf865cb3a16f9593488e /arch/powerpc/include/asm/book3s/64/hash-64k.h | |
| parent | powerpc/highmem: Change BUG_ON() to WARN_ON() (diff) | |
| download | linux-dev-eea86aa4171d4960f0fcdc99dab358c224d53ffe.tar.xz linux-dev-eea86aa4171d4960f0fcdc99dab358c224d53ffe.zip | |
powerpc/mm/64: Document the sizes of/sizes mapped by Pxx_INDEX_SIZE
Add comments describing the size in bytes of the various levels of the
page table tree, and the size of the virtual address space mapped by
each level, to make it clear what the sizes are without having to also
look up other definitions.
The code that calculates the sizes actually uses sizeof(pgd_t) etc.,
so in theory these comments could skew vs the code, but the size of
pgd_t etc. is unlikely to change very often.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/book3s/64/hash-64k.h')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/hash-64k.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h index f82ee8a3b561..81f4eb6e7da4 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h @@ -2,10 +2,11 @@ #ifndef _ASM_POWERPC_BOOK3S_64_HASH_64K_H #define _ASM_POWERPC_BOOK3S_64_HASH_64K_H -#define H_PTE_INDEX_SIZE 8 -#define H_PMD_INDEX_SIZE 10 -#define H_PUD_INDEX_SIZE 10 -#define H_PGD_INDEX_SIZE 8 +#define H_PTE_INDEX_SIZE 8 // size: 8B << 8 = 2KB, maps 2^8 x 64KB = 16MB +#define H_PMD_INDEX_SIZE 10 // size: 8B << 10 = 8KB, maps 2^10 x 16MB = 16GB +#define H_PUD_INDEX_SIZE 10 // size: 8B << 10 = 8KB, maps 2^10 x 16GB = 16TB +#define H_PGD_INDEX_SIZE 8 // size: 8B << 8 = 2KB, maps 2^8 x 16TB = 4PB + /* * Each context is 512TB size. SLB miss for first context/default context |