From: Colin Ian King > Sent: 02 September 2020 11:27 > > On 14/03/2020 10:23, Rafael J. Wysocki wrote: > > On Thursday, March 12, 2020 12:13:45 PM CET Colin King wrote: > >> From: Colin Ian King <colin.king@xxxxxxxxxxxxx> > >> > >> Reading ACPI data on ARM64 at a non-aligned offset from > >> /sys/firmware/acpi/tables/data/BERT will cause a splat because > >> the data is I/O memory mapped and being read with just a memcpy. > >> Fix this by introducing an I/O variant of memory_read_from_buffer > >> and using I/O memory mapped copies instead. .. > >> +/** > >> + * memory_read_from_io_buffer - copy data from a io memory mapped buffer > >> + * @to: the kernel space buffer to read to > >> + * @count: the maximum number of bytes to read > >> + * @ppos: the current position in the buffer > >> + * @from: the buffer to read from > >> + * @available: the size of the buffer > >> + * > >> + * The memory_read_from_buffer() function reads up to @count bytes from the > >> + * io memory mappy buffer @from at offset @ppos into the kernel space address > >> + * starting at @to. > >> + * > >> + * On success, the number of bytes read is returned and the offset @ppos is > >> + * advanced by this number, or negative value is returned on error. > >> + **/ Apart from the return value how is this different from the generic memcpy_from_io() ? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
