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authorAlexandre Ghiti <alexghiti@rivosinc.com>2023-03-29 10:19:30 +0200
committerPalmer Dabbelt <palmer@rivosinc.com>2023-04-13 18:14:26 -0700
commitef69d2559fe91f23d27a3d6fd640b5641787d22e (patch)
tree9f3d47ea6a4adb1c6108d9d2094a936c1569972a /arch/riscv/mm/init.c
parent8d736482749f6d350892ef83a7a11d43cd49981e (diff)
riscv: Move early dtb mapping into the fixmap region
riscv establishes 2 virtual mappings: - early_pg_dir maps the kernel which allows to discover the system memory - swapper_pg_dir installs the final mapping (linear mapping included) We used to map the dtb in early_pg_dir using DTB_EARLY_BASE_VA, and this mapping was not carried over in swapper_pg_dir. It happens that early_init_fdt_scan_reserved_mem() must be called before swapper_pg_dir is setup otherwise we could allocate reserved memory defined in the dtb. And this function initializes reserved_mem variable with addresses that lie in the early_pg_dir dtb mapping: when those addresses are reused with swapper_pg_dir, this mapping does not exist and then we trap. The previous "fix" was incorrect as early_init_fdt_scan_reserved_mem() must be called before swapper_pg_dir is set up otherwise we could allocate in reserved memory defined in the dtb. So move the dtb mapping in the fixmap region which is established in early_pg_dir and handed over to swapper_pg_dir. Fixes: 922b0375fc93 ("riscv: Fix memblock reservation for device tree blob") Fixes: 8f3a2b4a96dc ("RISC-V: Move DT mapping outof fixmap") Fixes: 50e63dd8ed92 ("riscv: fix reserved memory setup") Reported-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/all/f8e67f82-103d-156c-deb0-d6d6e2756f5e@microchip.com/ Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230329081932.79831-2-alexghiti@rivosinc.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/mm/init.c')
-rw-r--r--arch/riscv/mm/init.c61
1 files changed, 34 insertions, 27 deletions
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 478d6763a01a..fb78d6bbabae 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -57,7 +57,6 @@ unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
EXPORT_SYMBOL(empty_zero_page);
extern char _start[];
-#define DTB_EARLY_BASE_VA PGDIR_SIZE
void *_dtb_early_va __initdata;
uintptr_t _dtb_early_pa __initdata;
@@ -236,6 +235,14 @@ static void __init setup_bootmem(void)
set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
reserve_initrd_mem();
+
+ /*
+ * No allocation should be done before reserving the memory as defined
+ * in the device tree, otherwise the allocation could end up in a
+ * reserved region.
+ */
+ early_init_fdt_scan_reserved_mem();
+
/*
* If DTB is built in, no need to reserve its memblock.
* Otherwise, do reserve it but avoid using
@@ -279,9 +286,6 @@ pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
static pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
-static p4d_t __maybe_unused early_dtb_p4d[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);
-static pud_t __maybe_unused early_dtb_pud[PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);
-static pmd_t __maybe_unused early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
#ifdef CONFIG_XIP_KERNEL
#define pt_ops (*(struct pt_alloc_ops *)XIP_FIXUP(&pt_ops))
@@ -626,9 +630,6 @@ static void __init create_p4d_mapping(p4d_t *p4dp,
#define trampoline_pgd_next (pgtable_l5_enabled ? \
(uintptr_t)trampoline_p4d : (pgtable_l4_enabled ? \
(uintptr_t)trampoline_pud : (uintptr_t)trampoline_pmd))
-#define early_dtb_pgd_next (pgtable_l5_enabled ? \
- (uintptr_t)early_dtb_p4d : (pgtable_l4_enabled ? \
- (uintptr_t)early_dtb_pud : (uintptr_t)early_dtb_pmd))
#else
#define pgd_next_t pte_t
#define alloc_pgd_next(__va) pt_ops.alloc_pte(__va)
@@ -636,7 +637,6 @@ static void __init create_p4d_mapping(p4d_t *p4dp,
#define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot) \
create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
#define fixmap_pgd_next ((uintptr_t)fixmap_pte)
-#define early_dtb_pgd_next ((uintptr_t)early_dtb_pmd)
#define create_p4d_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
#define create_pud_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
#define create_pmd_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
@@ -860,32 +860,28 @@ static void __init create_kernel_page_table(pgd_t *pgdir, bool early)
* this means 2 PMD entries whereas for 32-bit kernel, this is only 1 PGDIR
* entry.
*/
-static void __init create_fdt_early_page_table(pgd_t *pgdir, uintptr_t dtb_pa)
+static void __init create_fdt_early_page_table(pgd_t *pgdir,
+ uintptr_t fix_fdt_va,
+ uintptr_t dtb_pa)
{
-#ifndef CONFIG_BUILTIN_DTB
uintptr_t pa = dtb_pa & ~(PMD_SIZE - 1);
- create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
- IS_ENABLED(CONFIG_64BIT) ? early_dtb_pgd_next : pa,
- PGDIR_SIZE,
- IS_ENABLED(CONFIG_64BIT) ? PAGE_TABLE : PAGE_KERNEL);
-
- if (pgtable_l5_enabled)
- create_p4d_mapping(early_dtb_p4d, DTB_EARLY_BASE_VA,
- (uintptr_t)early_dtb_pud, P4D_SIZE, PAGE_TABLE);
-
- if (pgtable_l4_enabled)
- create_pud_mapping(early_dtb_pud, DTB_EARLY_BASE_VA,
- (uintptr_t)early_dtb_pmd, PUD_SIZE, PAGE_TABLE);
+#ifndef CONFIG_BUILTIN_DTB
+ /* Make sure the fdt fixmap address is always aligned on PMD size */
+ BUILD_BUG_ON(FIX_FDT % (PMD_SIZE / PAGE_SIZE));
- if (IS_ENABLED(CONFIG_64BIT)) {
- create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
+ /* In 32-bit only, the fdt lies in its own PGD */
+ if (!IS_ENABLED(CONFIG_64BIT)) {
+ create_pgd_mapping(early_pg_dir, fix_fdt_va,
+ pa, MAX_FDT_SIZE, PAGE_KERNEL);
+ } else {
+ create_pmd_mapping(fixmap_pmd, fix_fdt_va,
pa, PMD_SIZE, PAGE_KERNEL);
- create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,
+ create_pmd_mapping(fixmap_pmd, fix_fdt_va + PMD_SIZE,
pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
}
- dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
+ dtb_early_va = (void *)fix_fdt_va + (dtb_pa & (PMD_SIZE - 1));
#else
/*
* For 64-bit kernel, __va can't be used since it would return a linear
@@ -1055,7 +1051,8 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
create_kernel_page_table(early_pg_dir, true);
/* Setup early mapping for FDT early scan */
- create_fdt_early_page_table(early_pg_dir, dtb_pa);
+ create_fdt_early_page_table(early_pg_dir,
+ __fix_to_virt(FIX_FDT), dtb_pa);
/*
* Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
@@ -1097,6 +1094,16 @@ static void __init setup_vm_final(void)
u64 i;
/* Setup swapper PGD for fixmap */
+#if !defined(CONFIG_64BIT)
+ /*
+ * In 32-bit, the device tree lies in a pgd entry, so it must be copied
+ * directly in swapper_pg_dir in addition to the pgd entry that points
+ * to fixmap_pte.
+ */
+ unsigned long idx = pgd_index(__fix_to_virt(FIX_FDT));
+
+ set_pgd(&swapper_pg_dir[idx], early_pg_dir[idx]);
+#endif
create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
__pa_symbol(fixmap_pgd_next),
PGDIR_SIZE, PAGE_TABLE);