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| author | Vineet Gupta <vgupta@kernel.org> | 2020-09-30 18:58:50 -0700 |
|---|---|---|
| committer | Vineet Gupta <vgupta@kernel.org> | 2021-08-26 13:43:19 -0700 |
| commit | 2dde02ab6d1a725ddccc7144ff6bf5f55d37f916 (patch) | |
| tree | 09c3c150d3ddd76c634e86f358eac40ed2efe920 /arch/arc/mm/fault.c | |
| parent | 9f3c76aedcbfee61dcdf299e708888141c7132fd (diff) | |
| download | linux-2dde02ab6d1a725ddccc7144ff6bf5f55d37f916.tar.bz2 | |
ARC: mm: support 3 levels of page tables
ARCv2 MMU is software walked and Linux implements 2 levels of paging: pgd/pte.
Forthcoming hw will have multiple levels, so this change preps mm code
for same. It is also fun to try multi levels even on soft-walked code to
ensure generic mm code is robust to handle.
overview
________
2 levels {pgd, pte} : pmd is folded but pmd_* macros are valid and operate on pgd
3 levels {pgd, pmd, pte}:
- pud is folded and pud_* macros point to pgd
- pmd_* macros operate on actual pmd
code changes
____________
1. #include <asm-generic/pgtable-nopud.h>
2. Define CONFIG_PGTABLE_LEVELS 3
3a. Define PMD_SHIFT, PMD_SIZE, PMD_MASK, pmd_t
3b. Define pmd_val() which actually deals with pmd
(pmd_offset(), pmd_index() are provided by generic code)
3c. pmd_alloc_one()/pmd_free() also provided by generic code
(pmd_populate/pmd_free already exist)
4. Define pud_none(), pud_bad() macros based on generic pud_val() which
internally pertains to pgd now.
4b. define pud_populate() to just setup pgd
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Diffstat (limited to 'arch/arc/mm/fault.c')
| -rw-r--r-- | arch/arc/mm/fault.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 41f154320964..8da2f0ad8c69 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -39,6 +39,8 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address) if (!pgd_present(*pgd_k)) goto bad_area; + set_pgd(pgd, *pgd_k); + p4d = p4d_offset(pgd, address); p4d_k = p4d_offset(pgd_k, address); if (!p4d_present(*p4d_k)) @@ -49,6 +51,8 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address) if (!pud_present(*pud_k)) goto bad_area; + set_pud(pud, *pud_k); + pmd = pmd_offset(pud, address); pmd_k = pmd_offset(pud_k, address); if (!pmd_present(*pmd_k)) |