[PATCH for-v4.2 1/4] of/fdt: split off FDT self reservation from memreserve processing

[Benjamin Herrenschmidt]

On Mon, 2015-06-01 at 13:40 +0200, Ard Biesheuvel wrote:
> This splits off the reservation of the memory occupied by the FDT
> binary itself from the processing of the memory reservations it
> contains. This is necessary because the physical address of the FDT,
> which is needed to perform the reservation, may not be known to the
> FDT driver core, i.e., it may be mapped outside the linear direct
> mapping, in which case __pa() returns a bogus value.
> 
> Cc: Russell King <linux at arm.linux.org.uk>

Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>

> Cc: Paul Mackerras <paulus at samba.org>
> Acked-by: Rob Herring <robh at kernel.org>
> Acked-by: Mark Rutland <mark.rutland at arm.com>
> Acked-by: Catalin Marinas <catalin.marinas at arm.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> ---
>  arch/arm/mm/init.c         |  1 +
>  arch/arm64/mm/init.c       |  1 +
>  arch/powerpc/kernel/prom.c |  1 +
>  drivers/of/fdt.c           | 19 ++++++++++++++-----
>  include/linux/of_fdt.h     |  2 ++
>  5 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> index be92fa0f2f35..8a63b4cdc0f2 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -268,6 +268,7 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
>  	if (mdesc->reserve)
>  		mdesc->reserve();
>  
> +	early_init_fdt_reserve_self();
>  	early_init_fdt_scan_reserved_mem();
>  
>  	/* reserve memory for DMA contiguous allocations */
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 597831bdddf3..89a05f467ffb 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -170,6 +170,7 @@ void __init arm64_memblock_init(void)
>  		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
>  #endif
>  
> +	early_init_fdt_reserve_self();
>  	early_init_fdt_scan_reserved_mem();
>  
>  	/* 4GB maximum for 32-bit only capable devices */
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index 308c5e15676b..51ea36f79307 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -573,6 +573,7 @@ static void __init early_reserve_mem_dt(void)
>  	int len;
>  	const __be32 *prop;
>  
> +	early_init_fdt_reserve_self();
>  	early_init_fdt_scan_reserved_mem();
>  
>  	dt_root = of_get_flat_dt_root();
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index cde35c5d0191..f2dd23a32267 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -580,11 +580,6 @@ void __init early_init_fdt_scan_reserved_mem(void)
>  	if (!initial_boot_params)
>  		return;
>  
> -	/* Reserve the dtb region */
> -	early_init_dt_reserve_memory_arch(__pa(initial_boot_params),
> -					  fdt_totalsize(initial_boot_params),
> -					  0);
> -
>  	/* Process header /memreserve/ fields */
>  	for (n = 0; ; n++) {
>  		fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
> @@ -598,6 +593,20 @@ void __init early_init_fdt_scan_reserved_mem(void)
>  }
>  
>  /**
> + * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
> + */
> +void __init early_init_fdt_reserve_self(void)
> +{
> +	if (!initial_boot_params)
> +		return;
> +
> +	/* Reserve the dtb region */
> +	early_init_dt_reserve_memory_arch(__pa(initial_boot_params),
> +					  fdt_totalsize(initial_boot_params),
> +					  0);
> +}
> +
> +/**
>   * of_scan_flat_dt - scan flattened tree blob and call callback on each.
>   * @it: callback function
>   * @data: context data pointer
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 587ee507965d..fd627a58068f 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -64,6 +64,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
>  extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
>  				     int depth, void *data);
>  extern void early_init_fdt_scan_reserved_mem(void);
> +extern void early_init_fdt_reserve_self(void);
>  extern void early_init_dt_add_memory_arch(u64 base, u64 size);
>  extern int early_init_dt_reserve_memory_arch(phys_addr_t base, phys_addr_t size,
>  					     bool no_map);
> @@ -91,6 +92,7 @@ extern u64 fdt_translate_address(const void *blob, int node_offset);
>  extern void of_fdt_limit_memory(int limit);
>  #else /* CONFIG_OF_FLATTREE */
>  static inline void early_init_fdt_scan_reserved_mem(void) {}
> +static inline void early_init_fdt_reserve_self(void) {}
>  static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }
>  static inline void unflatten_device_tree(void) {}
>  static inline void unflatten_and_copy_device_tree(void) {}