On Wed, Jun 12, 2019 at 12:32:58PM +0800, Hsin-Yi Wang wrote:
> Currently in arm64, FDT is mapped to RO before it's passed to
> early_init_dt_scan(). However, there might be some codes
> (eg. commit "fdt: add support for rng-seed") that need to modify FDT
> during init. Map FDT to RO after early fixups are done.
>
> Signed-off-by: Hsin-Yi Wang <hsi...@chromium.org>
> Reviewed-by: Stephen Boyd <swb...@chromium.org>
Reviewed-by: Mike Rapoport <r...@linux.ibm.com>
> ---
> change log v5->v6:
> * no change.
> ---
> arch/arm64/include/asm/mmu.h | 2 +-
> arch/arm64/kernel/kaslr.c | 5 +----
> arch/arm64/kernel/setup.c | 9 ++++++++-
> arch/arm64/mm/mmu.c | 15 +--------------
> 4 files changed, 11 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
> index 67ef25d037ea..27f6f17aae36 100644
> --- a/arch/arm64/include/asm/mmu.h
> +++ b/arch/arm64/include/asm/mmu.h
> @@ -137,7 +137,7 @@ extern void init_mem_pgprot(void);
> extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
> unsigned long virt, phys_addr_t size,
> pgprot_t prot, bool page_mappings_only);
> -extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
> +extern void *fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot);
> extern void mark_linear_text_alias_ro(void);
>
> #define INIT_MM_CONTEXT(name) \
> diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
> index 06941c1fe418..92bb53460401 100644
> --- a/arch/arm64/kernel/kaslr.c
> +++ b/arch/arm64/kernel/kaslr.c
> @@ -65,9 +65,6 @@ static __init const u8 *kaslr_get_cmdline(void *fdt)
> return default_cmdline;
> }
>
> -extern void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size,
> - pgprot_t prot);
> -
> /*
> * This routine will be executed with the kernel mapped at its default
> virtual
> * address, and if it returns successfully, the kernel will be remapped, and
> @@ -96,7 +93,7 @@ u64 __init kaslr_early_init(u64 dt_phys)
> * attempt at mapping the FDT in setup_machine()
> */
> early_fixmap_init();
> - fdt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL);
> + fdt = fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL);
> if (!fdt)
> return 0;
>
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index 413d566405d1..6a7050319b5b 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -181,9 +181,13 @@ static void __init smp_build_mpidr_hash(void)
>
> static void __init setup_machine_fdt(phys_addr_t dt_phys)
> {
> - void *dt_virt = fixmap_remap_fdt(dt_phys);
> + int size;
> + void *dt_virt = fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL);
> const char *name;
>
> + if (dt_virt)
> + memblock_reserve(dt_phys, size);
> +
> if (!dt_virt || !early_init_dt_scan(dt_virt)) {
> pr_crit("\n"
> "Error: invalid device tree blob at physical address
> %pa (virtual address 0x%p)\n"
> @@ -195,6 +199,9 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
> cpu_relax();
> }
>
> + /* Early fixups are done, map the FDT as read-only now */
> + fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
> +
> name = of_flat_dt_get_machine_name();
> if (!name)
> return;
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 93ed0df4df79..5d01365a4333 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -887,7 +887,7 @@ void __set_fixmap(enum fixed_addresses idx,
> }
> }
>
> -void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t
> prot)
> +void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
> {
> const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
> int offset;
> @@ -940,19 +940,6 @@ void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int
> *size, pgprot_t prot)
> return dt_virt;
> }
>
> -void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
> -{
> - void *dt_virt;
> - int size;
> -
> - dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
> - if (!dt_virt)
> - return NULL;
> -
> - memblock_reserve(dt_phys, size);
> - return dt_virt;
> -}
> -
> int __init arch_ioremap_pud_supported(void)
> {
> /*
> --
> 2.20.1
>
--
Sincerely yours,
Mike.
