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authorLinus Torvalds <torvalds@linux-foundation.org>2022-05-06 11:30:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-05-06 11:30:59 -0700
commit497fe3bb196de7249723ba1496fb72ca63ce14e2 (patch)
treeecdaee3b0432d768d59e35b42f097556d83cc9a2 /arch
parent4df22ca85d3d73f9822b1a354bb56dd1872180cd (diff)
parentc6fe81191bd74f7e6ae9ce96a4837df9485f3ab8 (diff)
Merge tag 'riscv-for-linus-5.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fix from Palmer Dabbelt: - A fix to relocate the DTB early in boot, in cases where the bootloader doesn't put the DTB in a region that will end up mapped by the kernel. This manifests as a crash early in boot on a handful of configurations. * tag 'riscv-for-linus-5.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: RISC-V: relocate DTB if it's outside memory region
Diffstat (limited to 'arch')
-rw-r--r--arch/riscv/mm/init.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index b0793dc0c291..05ed641a1134 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -208,8 +208,25 @@ static void __init setup_bootmem(void)
* early_init_fdt_reserve_self() since __pa() does
* not work for DTB pointers that are fixmap addresses
*/
- if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
- memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
+ if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) {
+ /*
+ * In case the DTB is not located in a memory region we won't
+ * be able to locate it later on via the linear mapping and
+ * get a segfault when accessing it via __va(dtb_early_pa).
+ * To avoid this situation copy DTB to a memory region.
+ * Note that memblock_phys_alloc will also reserve DTB region.
+ */
+ if (!memblock_is_memory(dtb_early_pa)) {
+ size_t fdt_size = fdt_totalsize(dtb_early_va);
+ phys_addr_t new_dtb_early_pa = memblock_phys_alloc(fdt_size, PAGE_SIZE);
+ void *new_dtb_early_va = early_memremap(new_dtb_early_pa, fdt_size);
+
+ memcpy(new_dtb_early_va, dtb_early_va, fdt_size);
+ early_memunmap(new_dtb_early_va, fdt_size);
+ _dtb_early_pa = new_dtb_early_pa;
+ } else
+ memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
+ }
early_init_fdt_scan_reserved_mem();
dma_contiguous_reserve(dma32_phys_limit);