by Rob Herring

[permalink] [raw]

Subject: Re: [PATCH 18/28] of: create default early_init_dt_add_memory_arch

On Tue, Sep 17, 2013 at 3:46 AM, Catalin Marinas
<[email protected]> wrote:
> On 17 Sep 2013, at 00:09, Rob Herring <[email protected]> wrote:
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -147,24 +147,6 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
>> pr_info("Machine: %s\n", machine_name);
>> }
>>
>> -void __init early_init_dt_add_memory_arch(u64 base, u64 size)
>> -{
>> - base &= PAGE_MASK;
>> - size &= PAGE_MASK;
>> - if (base + size < PHYS_OFFSET) {
>> - pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
>> - base, base + size);
>> - return;
>> - }
>> - if (base < PHYS_OFFSET) {
>> - pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
>> - base, PHYS_OFFSET);
>> - size -= PHYS_OFFSET - base;
>> - base = PHYS_OFFSET;
>> - }
>> - memblock_add(base, size);
>> -}
>> -
>> /*
>> * Limit the memory size that was specified via FDT.
>> */
>
> ...
>
>> --- a/drivers/of/fdt.c
>> +++ b/drivers/of/fdt.c
>> @@ -688,6 +688,17 @@ u64 __init dt_mem_next_cell(int s, __be32 **cellp)
>> return of_read_number(p, s);
>> }
>>
>> +void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
>> +{
>> +#ifdef CONFIG_HAVE_MEMBLOCK
>> + base &= PAGE_MASK;
>> + size &= PAGE_MASK;
>> + memblock_add(base, size);
>> +#else
>> + pr_err("%s: ignoring memory (%llx, %llx)\n", __func__, base, size);
>> +#endif
>> +}
>
> Are the arm64 changes equivalent here? There are some safety checks to
> cope with the kernel being loaded at a higher offset than the
> recommended one (PHYS_OFFSET calculated automatically).

I tried to keep that, but PHYS_OFFSET is not universally defined. My
reasoning is this range checking is hardly specific to an
architecture. Perhaps if memory always starts at 0 you don't need it.
If arm64 really needs these checks, then all architectures do.

Perhaps "__virt_to_phys(PAGE_OFFSET)" instead of PHYS_OFFSET would work for all?

Rob

2013-09-17 13:05:54

2013-09-23 09:59:07

On Mon, 16 Sep 2013 18:09:19 -0500, Rob Herring <[email protected]> wrote:
> From: Rob Herring <[email protected]>
>
> Introduce common of_flat_dt_match_machine and
> of_flat_dt_get_machine_name functions to unify architectures' handling
> of machine level model and compatible properties.
>
> Several architectures match the root compatible string with an arch
> specific list of machine descriptors duplicating the same search
> algorithm. Create a common implementation with a simple architecture
> specific hook to iterate over each machine's match table.
>
> Signed-off-by: Rob Herring <[email protected]>
> Cc: Grant Likely <[email protected]>
> ---
> drivers/of/fdt.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_fdt.h | 4 ++++
> 2 files changed, 64 insertions(+)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 83cdeb5..e21d1dc 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -619,6 +619,66 @@ int __init of_scan_flat_dt_by_path(const char *path,
> return ret;
> }
>
> +const char *of_flat_dt_get_machine_name(void)

Just discovered that this needs to be __init.

g.