From: Jose Abreu
> Sent: 29 November 2018 14:29
>
> Some ARC CPU's do not support unaligned loads/stores. Currently, generic
> implementation of reads{b/w/l}()/writes{b/w/l}() is being used with ARC.
> This can lead to misfunction of some drivers as generic functions do a
> plain dereference of a pointer that can be unaligned.
>
> Let's use {get/put}_unaligned() helper instead of plain dereference of
> pointer in order to fix this.
...
> +#define __raw_readsx(t,f) \
> +static inline void __raw_reads##f(const volatile void __iomem *addr, \
> + void *buffer, unsigned int count) \
> +{ \
> + if (count) { \
> + const unsigned long bptr = (unsigned long)buffer; \
> + u##t *buf = buffer; \
> +\
> + do { \
> + u##t x = __raw_read##f(addr); \
> +\
> + /* Some ARC CPU's don't support unaligned accesses */ \
> + if (bptr % ((t) / 8)) { \
> + put_unaligned(x, buf++); \
> + } else { \
> + *buf++ = x; \
> + } \
> + } while (--count); \
> + } \
> +}
Does the compiler move the alignment test outside the loop?
You really want two copies of the loop body.
David
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