[PATCH -fixes 2/2] riscv: Do not set initial_boot_params to the linear address of the dtb
Alexandre Ghiti
alex at ghiti.fr
Wed Mar 29 01:09:13 PDT 2023
On 3/27/23 13:16, Conor Dooley wrote:
> On Thu, Mar 23, 2023 at 05:33:47PM +0100, Alexandre Ghiti wrote:
>> Now that the dtb early mapping was moved in the fixmap region, we can
>> keep using this address since it is present in swapper_pg_dir, so remove
>> the dtb relocation which was wrong anyway since early_memremap is
>> restricted to 256K whereas the maximum fdt size is 2MB.
> I feel bad making this comment since only one of us is a native speaker,
> but for the future would you mind breaking up overly long sentences like
> the above? Say:
>
> Now that the dtb early mapping was moved in the fixmap region, we can
> keep using this address since it is present in swapper_pg_dir, and
> remove the dtb relocation.
> The relocation was wrong anyway since early_memremap() is restricted to
> 256K whereas the maximum fdt size is 2MB.
Sure!
>> Signed-off-by: Alexandre Ghiti <alexghiti at rivosinc.com>
>> ---
>> arch/riscv/kernel/setup.c | 5 +----
>> arch/riscv/mm/init.c | 21 ++-------------------
>> 2 files changed, 3 insertions(+), 23 deletions(-)
>>
>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
>> index 542eed85ad2c..a059b73f4ddb 100644
>> --- a/arch/riscv/kernel/setup.c
>> +++ b/arch/riscv/kernel/setup.c
>> @@ -278,10 +278,7 @@ void __init setup_arch(char **cmdline_p)
>> #if IS_ENABLED(CONFIG_BUILTIN_DTB)
>> unflatten_and_copy_device_tree();
>> #else
>> - if (early_init_dt_verify(__va(XIP_FIXUP(dtb_early_pa))))
> btw, how come it is safe now to drop this? This feels like a separate
> change that should be its own commit, no?
It is safe because early_init_dt_verify is already called in parse_dtb
and since the dtb address does not change anymore, no need to reset
initial_boot_params. So I'll split this one, thanks.
>
> Cheers,
> Conor.
>
>> - unflatten_device_tree();
>> - else
>> - pr_err("No DTB found in kernel mappings\n");
>> + unflatten_device_tree();
>> #endif
>> misc_mem_init();
>>
>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>> index fb78d6bbabae..0f14f4a8d179 100644
>> --- a/arch/riscv/mm/init.c
>> +++ b/arch/riscv/mm/init.c
>> @@ -249,25 +249,8 @@ static void __init setup_bootmem(void)
>> * early_init_fdt_reserve_self() since __pa() does
>> * not work for DTB pointers that are fixmap addresses
>> */
>> - if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) {
>> - /*
>> - * In case the DTB is not located in a memory region we won't
>> - * be able to locate it later on via the linear mapping and
>> - * get a segfault when accessing it via __va(dtb_early_pa).
>> - * To avoid this situation copy DTB to a memory region.
>> - * Note that memblock_phys_alloc will also reserve DTB region.
>> - */
>> - if (!memblock_is_memory(dtb_early_pa)) {
>> - size_t fdt_size = fdt_totalsize(dtb_early_va);
>> - phys_addr_t new_dtb_early_pa = memblock_phys_alloc(fdt_size, PAGE_SIZE);
>> - void *new_dtb_early_va = early_memremap(new_dtb_early_pa, fdt_size);
>> -
>> - memcpy(new_dtb_early_va, dtb_early_va, fdt_size);
>> - early_memunmap(new_dtb_early_va, fdt_size);
>> - _dtb_early_pa = new_dtb_early_pa;
>> - } else
>> - memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
>> - }
>> + if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
>> + memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
>>
>> dma_contiguous_reserve(dma32_phys_limit);
>> if (IS_ENABLED(CONFIG_64BIT))
>> --
>> 2.37.2
>>
>>
>>
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