[adding linux-arch and relevant folk]
On Wed, Apr 17, 2019 at 08:35:25PM +0800, Boyang Zhou wrote:
> The error information is that “offset value too large for defined data type”.
> Reason:
> On the X86 platform, the data type of “off" is unsigned long; but on the
> ARM64 platform, the data type is defined as off_t, and off_t is by type long
> instead of unsigned long.
> When the off right shifts in the function “sys_mmap_pgoff(addr, len, prot,
> flags, fd, off >> PAGE_SHIFT)"on ARM64, high address of off is filled with
> sign bit 1instead of 0.
> In our case, we mmap GPU doorbell on both platform. On the x86 platform, the
> value of off is f009c00000000000, after shift the value becomes
> f009c00000000; while on the ARM64, the value of off changes from
> ed35c00000000000 to fffed35c00000000. This value is treated as unsigned long
> in later functions. So it is too big for off and the error happened.
> We have tested the patchs in Huawei ARM64 server with a couples of AMD GPUs.
It looks like the generic mmap uses unsigned long, as do sparc and x86.
However, arm64, microblase, powerpc and riscv all use off_t.
Should those all be using unsigned long? If so, that seems like it
should be a treewide cleanup.
Similar applies to pgoff for mmap2.
Thanks,
Mark.
>
> Signed-off-by: Boyang Zhou <zhouby...@126.com>
> ---
> arch/arm64/kernel/sys.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
> index b44065f..6f91e81 100644
> --- a/arch/arm64/kernel/sys.c
> +++ b/arch/arm64/kernel/sys.c
> @@ -31,7 +31,7 @@
>
> SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
> unsigned long, prot, unsigned long, flags,
> - unsigned long, fd, off_t, off)
> + unsigned long, fd, unsigned long, off)
> {
> if (offset_in_page(off) != 0)
> return -EINVAL;
> --
> 2.7.4
>
