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| author | Anup Patel <anup.patel@wdc.com> | 2019-01-07 20:57:01 +0530 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2019-02-21 11:26:42 +0530 |
| commit | f2c17aabc917e1092eedb16fa2b8891e9379f7e6 (patch) | |
| tree | 263b4020a36643cbc07ede2630e67f60801550bd /arch/riscv/mm/init.c | |
| parent | 6f1e9e946f0bc32cf55a7d7c36f80cb365e1877a (diff) | |
| download | lwn-f2c17aabc917e1092eedb16fa2b8891e9379f7e6.tar.gz lwn-f2c17aabc917e1092eedb16fa2b8891e9379f7e6.zip | |
RISC-V: Implement compile-time fixed mappings
This patch implements compile-time virtual to physical mappings. These
compile-time fixed mappings can be used by earlycon, ACPI, and early
ioremap for creating fixed mappings when FIX_EARLYCON_MEM=y.
To start with, we have enabled compile-time fixed mappings for earlycon.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/mm/init.c')
| -rw-r--r-- | arch/riscv/mm/init.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index ee9cf26b3855..9e7b3ee78089 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -19,6 +19,7 @@ #include <linux/sizes.h> #include <linux/of_fdt.h> +#include <asm/fixmap.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/pgtable.h> @@ -148,8 +149,28 @@ pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); #define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT) pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss; pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); +pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss; #endif +pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss; + +void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot) +{ + unsigned long addr = __fix_to_virt(idx); + pte_t *ptep; + + BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); + + ptep = &fixmap_pte[pte_index(addr)]; + + if (pgprot_val(prot)) { + set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot)); + } else { + pte_clear(&init_mm, addr, ptep); + local_flush_tlb_page(addr); + } +} + asmlinkage void __init setup_vm(void) { extern char _start; @@ -172,20 +193,33 @@ asmlinkage void __init setup_vm(void) for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) { size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i; + swapper_pg_dir[o] = pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i, __pgprot(_PAGE_TABLE)); } for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++) swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot); + + swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] = + pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pmd), + __pgprot(_PAGE_TABLE)); + fixmap_pmd[(FIXADDR_START >> PMD_SHIFT) % PTRS_PER_PMD] = + pfn_pmd(PFN_DOWN((uintptr_t)fixmap_pte), + __pgprot(_PAGE_TABLE)); #else trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] = pfn_pgd(PFN_DOWN(pa), prot); for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) { size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i; + swapper_pg_dir[o] = pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot); } + + swapper_pg_dir[(FIXADDR_START >> PGDIR_SHIFT) % PTRS_PER_PGD] = + pfn_pgd(PFN_DOWN((uintptr_t)fixmap_pte), + __pgprot(_PAGE_TABLE)); #endif } |