• Lynn Boger's avatar
    cmd/asm: detect invalid DS form offsets for ppc64x · 7d4cca07
    Lynn Boger authored
    While debugging a recent regression it was discovered that
    the assembler for ppc64x was not always generating the correct
    instruction for DS form loads and stores.  When an instruction
    is DS form then the offset must be a multiple of 4, and if it
    isn't then bits outside the offset field were being incorrectly
    set resulting in unexpected and incorrect instructions.
    
    This change adds a check to determine when the opcode is DS form
    and then verifies that the offset is a multiple of 4 before
    generating the instruction, otherwise logs an error.
    
    This also changes a few asm files that were using unaligned offsets
    for DS form loads and stores.  In the runtime package these were
    instructions intended to cause a crash so using aligned or unaligned
    offsets doesn't change that behavior.
    
    Change-Id: Ie3a7e1e65dcc9933b54de7a46a054da8459cb56f
    Reviewed-on: https://go-review.googlesource.com/40476Reviewed-by: 's avatarMichael Hudson-Doyle <michael.hudson@canonical.com>
    7d4cca07
sys_linux_ppc64x.s 8.67 KB