• Jose Abreu's avatar
    ARC: io.h: Implement reads{x}()/writes{x}() · 10d44343
    Jose Abreu authored
    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() helpers instead of plain dereference of
    pointer in order to fix. The helpers allow to get and store data from an
    unaligned address whilst preserving the CPU internal alignment.
    According to [1], the use of these helpers are costly in terms of
    performance so we added an initial check for a buffer already aligned so
    that the usage of the helpers can be avoided, when possible.
    
    [1] Documentation/unaligned-memory-access.txt
    
    Cc: Alexey Brodkin <abrodkin@synopsys.com>
    Cc: Joao Pinto <jpinto@synopsys.com>
    Cc: David Laight <David.Laight@ACULAB.COM>
    Tested-by: default avatarVitor Soares <soares@synopsys.com>
    Signed-off-by: default avatarJose Abreu <joabreu@synopsys.com>
    Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
    10d44343
io.h 6.42 KB