[PATCH v4 1/3] amr64: map FDT as RW for early_init_dt_scan()

Hsin-Yi Wang
2019-05-19T16:05:24Z

Currently in arm64, FDT is mapped to RO before it's passed to
early_init_dt_scan(). However, there might be some code that needs
to modify FDT during init. Map FDT to RW until unflatten DT.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
change log v2->v4:
* v3 abandoned
* add an arg pgprot_t to fixmap_remap_fdt()
---
arch/arm64/include/asm/mmu.h | 2 +-
arch/arm64/kernel/setup.c | 5 ++++-
arch/arm64/mm/mmu.c | 4 ++--
3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 67ef25d037ea..4499cb00ece7 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, pgprot_t prot);
extern void mark_linear_text_alias_ro(void);

#define INIT_MM_CONTEXT(name) \
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 413d566405d1..064df3de1d14 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -181,7 +181,7 @@ 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);
+ void *dt_virt = fixmap_remap_fdt(dt_phys, PAGE_KERNEL);
const char *name;

if (!dt_virt || !early_init_dt_scan(dt_virt)) {
@@ -320,6 +320,9 @@ void __init setup_arch(char **cmdline_p)
/* Parse the ACPI tables for possible boot-time configuration */
acpi_boot_table_init();

+ /* remap fdt to RO */
+ fixmap_remap_fdt(__fdt_pointer, PAGE_KERNEL_RO);
+
if (acpi_disabled)
unflatten_device_tree();

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a170c6369a68..29648e86f7e5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -940,12 +940,12 @@ 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 *__init fixmap_remap_fdt(phys_addr_t dt_phys, pgprot_t prot)
{
void *dt_virt;
int size;

- dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
+ dt_virt = __fixmap_remap_fdt(dt_phys, &size, prot);
if (!dt_virt)
return NULL;

--
2.20.1