Re: [PATCH] ACPI: apei: Cast u64 to unsigned long, fix compile

Andrew Morton
2010-09-13T20:00:35Z

On Sun, 12 Sep 2010 09:48:25 -0400
Javier Martinez Canillas <martinez.javier@gmail.com> wrote:

> In today linux-net I got a compile warning in acpi/apei
>
> drivers/acpi/apei/erst.c: In function ___erst_exec_move_data___:
> drivers/acpi/apei/erst.c:273: warning: cast to pointer from integer of different size
> drivers/acpi/apei/erst.c:274: warning: cast to pointer from integer of different size
>
> The problem is that apei_exec_context->dst_base type is u64.
> But in 32 bits architecture void * is 32 bits long.
> Casting it to unsigned long solves the issue
>
> Signed-off-by: Javier Martinez Canillas <martinez.javier@gmail.com>
> ---
> drivers/acpi/apei/erst.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
> index a4904f1..37d7a05 100644
> --- a/drivers/acpi/apei/erst.c
> +++ b/drivers/acpi/apei/erst.c
> @@ -270,8 +270,8 @@ static int erst_exec_move_data(struct apei_exec_context *ctx,
> rc = __apei_exec_read_register(entry, &offset);
> if (rc)
> return rc;
> - memmove((void *)ctx->dst_base + offset,
> - (void *)ctx->src_base + offset,
> + memmove((void *)(unsigned long)ctx->dst_base + offset,
> + (void *)(unsigned long)ctx->src_base + offset,
> ctx->var2);
>
> return 0;

This might indicate that the incorrect types were used within the
`struct apei_exec_context'. I can't tell (or can't be bothered working
it out), because whoever wrote that didn't bother documenting any of it
at all.

Are those things kernel virtual addresses? If so, a pointer type
should have been used.