From: Hsin-Yi Wang hsinyi@chromium.org

commit e112b032a72c78f15d0c803c5dc6be444c2e6c66 upstream.

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.

Cc: stable@vger.kernel.org # 4.9+ Signed-off-by: Hsin-Yi Wang hsinyi@chromium.org Reviewed-by: Stephen Boyd swboyd@chromium.org Reviewed-by: Mike Rapoport rppt@linux.ibm.com Signed-off-by: Will Deacon will@kernel.org [mkbestas: fixed trivial conflicts for 4.9 backport] Signed-off-by: Michael Bestas mkbestas@gmail.com --- 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 f4377b005cba90..c944253b3a4b63 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -90,7 +90,7 @@ 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 allow_block_mappings); -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);

#endif /* !__ASSEMBLY__ */ #endif diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index c9ca903462a68d..6a9668f6e933f3 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, u64 modulo_offset) * 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 f534f492a26874..ae82d9694542cd 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -178,7 +178,11 @@ 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); + + if (dt_virt) + memblock_reserve(dt_phys, size);

if (!dt_virt || !early_init_dt_scan(dt_virt)) { pr_crit("\n" @@ -191,6 +195,9 @@ 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); + dump_stack_set_arch_desc("%s (DT)", of_flat_dt_get_machine_name()); }

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 36bd50091c4bbc..784ea7c8d99667 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -718,7 +718,7 @@ 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; @@ -771,19 +771,6 @@ 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) { /*