Unverified Commit 1074dd44 authored by Anup Patel's avatar Anup Patel Committed by Palmer Dabbelt
Browse files

RISC-V: Use non-PGD mappings for early DTB access 



Currently, we use PGD mappings for early DTB mapping in early_pgd
but this breaks Linux kernel on SiFive Unleashed because on SiFive
Unleashed PMP checks don't work correctly for PGD mappings.

To fix early DTB mappings on SiFive Unleashed, we use non-PGD
mappings (i.e. PMD) for early DTB access.

Fixes: 8f3a2b4a ("RISC-V: Move DT mapping outof fixmap")
Signed-off-by: default avatarAnup Patel <anup.patel@wdc.com>
Reviewed-by: default avatarAtish Patra <atish.patra@wdc.com>
Tested-by: default avatarAtish Patra <atish.patra@wdc.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent 635e3f3e

arch/riscv/mm/init.c

+14 −0
Original line number Diff line number Diff line
@@ -293,6 +293,7 @@ pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss; 
#define NUM_EARLY_PMDS		(1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)

#endif

pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);

pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);



static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)

{
@@ -490,6 +491,18 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) 
				   load_pa + (va - PAGE_OFFSET),

				   map_size, PAGE_KERNEL_EXEC);



#ifndef __PAGETABLE_PMD_FOLDED

	/* Setup early PMD for DTB */

	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,

			   (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);

	/* Create two consecutive PMD mappings for FDT early scan */

	pa = dtb_pa & ~(PMD_SIZE - 1);

	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,

			   pa, PMD_SIZE, PAGE_KERNEL);

	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,

			   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);

	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));

#else

	/* Create two consecutive PGD mappings for FDT early scan */

	pa = dtb_pa & ~(PGDIR_SIZE - 1);

	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
@@ -497,6 +510,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) 
	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,

			   pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);

	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));

#endif

	dtb_early_pa = dtb_pa;



	/*

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