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authorVineet Gupta <vgupta@kernel.org>2020-09-30 18:58:50 -0700
committerVineet Gupta <vgupta@kernel.org>2021-08-26 13:43:19 -0700
commit2dde02ab6d1a725ddccc7144ff6bf5f55d37f916 (patch)
tree09c3c150d3ddd76c634e86f358eac40ed2efe920 /arch/arc/Kconfig
parent9f3c76aedcbfee61dcdf299e708888141c7132fd (diff)
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/Kconfig')
-rw-r--r--arch/arc/Kconfig4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 56aad105ad13..f631a7a60979 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -314,6 +314,10 @@ config ARC_HUGEPAGE_16M
endchoice
+config PGTABLE_LEVELS
+ int "Number of Page table levels"
+ default 2
+
config ARC_COMPACT_IRQ_LEVELS
depends on ISA_ARCOMPACT
bool "Setup Timer IRQ as high Priority"