diff options
| author | Nick Kossifidis | 2022-03-22 15:28:39 +0200 |
|---|---|---|
| committer | Palmer Dabbelt | 2022-04-29 07:59:18 -0700 |
| commit | c6fe81191bd74f7e6ae9ce96a4837df9485f3ab8 (patch) | |
| tree | 28026403d851010d0b9b48f63127898b4c758817 /arch | |
| parent | ac0280a9ca106c5501257e79d165f968712b5899 (diff) | |
RISC-V: relocate DTB if it's outside memory region
In case the DTB provided by the bootloader/BootROM is before the kernel
image or outside /memory, we won't be able to access it through the
linear mapping, and get a segfault on setup_arch(). Currently OpenSBI
relocates DTB but that's not always the case (e.g. if FW_JUMP_FDT_ADDR
is not specified), and it's also not the most portable approach since
the default FW_JUMP_FDT_ADDR of the generic platform relocates the DTB
at a specific offset that may not be available. To avoid this situation
copy DTB so that it's visible through the linear mapping.
Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Link: https://lore.kernel.org/r/20220322132839.3653682-1-mick@ics.forth.gr
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Fixes: f105aa940e78 ("riscv: add BUILTIN_DTB support for MMU-enabled targets")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/mm/init.c | 21 |
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); |