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SubjectRe: [PATCH V9 21/21] csky: support dword access for get_user_size()
On Tue, Oct 16, 2018 at 5:33 AM Guo Ren <> wrote:
> Support dword access for get_user_size and redesign put_user_size with
> the same style of get_user_size. It's Ok to use xxx_user_asm_common for
> all size of variable with ldb, ldh, ldw, ld.d
> ld.d rx, (addr, 0) could "rx <= addr" "and r(x+1) <= addr+4" and this also
> follow abiv2 gcc ABI for dword access.

Are you sure this is correct for this?

static inline u32 get_64_to_32(__u64 __user *p)
u32 ret;
get_user(ret, p);
return ret;

If I read __get_user_asm_common() right, the ld.d would overwrite
two registers, but the caller only expects one, so it clobbers one
that might be in use.


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