arm64: map FDT as RW for early_init_dt_scan()

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index f4377b005cba900a8fcc7b01e76447b63025e52a..c944253b3a4b639aab3163828885eb669e71bd1e 100644 (file)
--- 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 c9ca903462a68ddb298ee2e41daeec1c52809e47..6a9668f6e933f3457ee407b330fc16d43fa363ad 100644 (file)
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -65,9 +65,6 @@ out:
        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 f534f492a26874dec5b56e9ab7a6bef17ee08fc3..ae82d9694542cd1e29f2da2fa4558c4db1d27076 100644 (file)
--- 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 36bd50091c4bbc7fb2bd08bb28fb1008300a59e8..784ea7c8d99667e2778e66287c11f8d5e6e282d9 100644 (file)
--- 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)
 {
        /*