Re: [PATCH] efi: Fix warning of int-to-pointer-cast on x86 32-bit builds

From: Ard Biesheuvel
Date: Thu Oct 22 2015 - 04:33:48 EST



> On 22 okt. 2015, at 19:28, Taku Izumi <izumi.taku@xxxxxxxxxxxxxx> wrote:
>
> commit-0f96a99 introduces the following warning message:
>
> drivers/firmware/efi/fake_mem.c:186:20: warning: cast to pointer
> from integer of different size [-Wint-to-pointer-cast]
>
> new_memmap_phy was defined as a u64 value and casted to void*.
> This causes a warning of int-to-pointer-cast on x86 32-bit
> environment.
>
> This patch changes the type of "new_memmap_phy" variable
> from "u64" into "phys_addr_t" to avoid it.

This assumes sizeof(void*) == sizeof(phys_addr_t), which is not always true, e.g., on 32-bit ARM (whose UEFI support is in development but not yet merged) with LPAE enabled.

Could we use unsigned long instead?

Ard.


> Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
> Signed-off-by: Taku Izumi <izumi.taku@xxxxxxxxxxxxxx>
> ---
> drivers/firmware/efi/fake_mem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c
> index 32bcb14..b65bc07 100644
> --- a/drivers/firmware/efi/fake_mem.c
> +++ b/drivers/firmware/efi/fake_mem.c
> @@ -59,7 +59,7 @@ void __init efi_fake_memmap(void)
> u64 start, end, m_start, m_end, m_attr;
> int new_nr_map = memmap.nr_map;
> efi_memory_desc_t *md;
> - u64 new_memmap_phy;
> + phys_addr_t new_memmap_phy;
> void *new_memmap;
> void *old, *new;
> int i;
> --
> 1.8.3.1
>
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