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

[Ard Biesheuvel]

On 12 March 2015 at 22:54, Rob Herring <robh at kernel.org> wrote:
> 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>
>

Thanks.

@Russell, Benjamin, Paul: do any of you perhaps have any issues with this?

Regards,
Ard.


>> ---
>>  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
>>