[PATCH v2 1/5] of/fdt: split off FDT self reservation from memreserve processing

[Rob Herring]

On Wed, Mar 11, 2015 at 11:00 AM, Ard Biesheuvel
<ard.biesheuvel at linaro.org> 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: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Cc: Paul Mackerras <paulus at samba.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

Not really the direction I like going by moving more things back to
arch code, but I haven't come up with any better suggestion so:

Acked-by: Rob Herring <robh at kernel.org>

BTW, I do want to move early_init_fdt_scan_reserved_mem out of the
arch code as well. Other arches don't call it, but it should be
harmless if they never use the reserved memory regions.

Rob

> ---
>  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 1609b022a72f..0b8657c36fe4 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -317,6 +317,7 @@ 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 ae85da6307bb..fa2389b0f7f0 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 b8e15c678960..093ccfb384af 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 3a896c9aeb74..bbb35cdb06e8 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -561,11 +561,6 @@ 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);
> @@ -579,6 +574,20 @@ 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 0ff360d5b3b3..6ef6b33238d3 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -62,6 +62,7 @@ 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);
> @@ -89,6 +90,7 @@ 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) {}
> --
> 1.8.3.2
>