To support the new /sys/firmware/fdt entry that gives access to the FDT blob as passed by the bootloader, call preserve_fdt() in the early arch code to make a copy of it before the unflattening code gets its hands on it. Also, make the early mapping of the FDT read only so we are certain it will not get clobbered by anything called by setup_machine_fdt(), which handles the FDT blob even earlier. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> --- arch/arm64/kernel/head.S | 3 +++ arch/arm64/kernel/setup.c | 1 + 2 files changed, 4 insertions(+) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 0a6e4f924df8..df25dffcda9f 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -79,8 +79,10 @@ #ifdef CONFIG_ARM64_64K_PAGES #define MM_MMUFLAGS PTE_ATTRINDX(MT_NORMAL) | PTE_FLAGS +#define MM_MMUFLAGS_RO PTE_ATTRINDX(MT_NORMAL) | PTE_FLAGS | PTE_RDONLY #else #define MM_MMUFLAGS PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS +#define MM_MMUFLAGS_RO PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS | PMD_SECT_RDONLY #endif /* @@ -607,6 +609,7 @@ __create_page_tables: * Map the FDT blob (maximum 2MB; must be within 512MB of * PHYS_OFFSET). */ + ldr x7, =MM_MMUFLAGS_RO mov x3, x21 // FDT phys address and x3, x3, #~((1 << 21) - 1) // 2MB aligned mov x6, #PAGE_OFFSET diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 2437196cc5d4..1b535cc42981 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -394,6 +394,7 @@ void __init setup_arch(char **cmdline_p) efi_idmap_init(); + preserve_fdt(); unflatten_device_tree(); psci_init(); -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
