| From | Arnd Bergmann <> | Date | Wed, 17 Oct 2018 17:44:17 +0200 | Subject | Re: [PATCH V9 21/21] csky: support dword access for get_user_size() |
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On Tue, Oct 16, 2018 at 5:33 AM Guo Ren <ren_guo@c-sky.com> 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.
Arnd
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