On 2021/01/15 11:46AM, Ravi Bangoria wrote:
> Compiling kernel with -Warray-bounds throws below warning:
>
> In function 'emulate_vsx_store':
> warning: array subscript is above array bounds [-Warray-bounds]
> buf.d[2] = byterev_8(reg->d[1]);
> ~~~~~^~~
> buf.d[3] = byterev_8(reg->d[0]);
> ~~~~~^~~
>
> Fix it by converting local variable 'union vsx_reg buf' into an array.
> Also consider function argument 'union vsx_reg *reg' as array instead
> of pointer because callers are actually passing an array to it.
I think you should change the function prototype to reflect this.
However, while I agree with this change in principle, it looks to be a
lot of code churn for a fairly narrow use. Perhaps we should just
address the specific bug. Something like the below (not tested)?
@@ -818,13 +818,15 @@ void emulate_vsx_store(struct instruction_op *op, const
union vsx_reg *reg,
break;
if (rev) {
/* reverse 32 bytes */
- buf.d[0] = byterev_8(reg->d[3]);
- buf.d[1] = byterev_8(reg->d[2]);
- buf.d[2] = byterev_8(reg->d[1]);
- buf.d[3] = byterev_8(reg->d[0]);
- reg = &buf;
+ union vsx_reg buf32[2];
+ buf32[0].d[0] = byterev_8(reg[1].d[1]);
+ buf32[0].d[1] = byterev_8(reg[1].d[0]);
+ buf32[1].d[0] = byterev_8(reg[0].d[1]);
+ buf32[1].d[1] = byterev_8(reg[0].d[0]);
+ memcpy(mem, buf32, size);
+ } else {
+ memcpy(mem, reg, size);
}
- memcpy(mem, reg, size);
break;
case 16:
/* stxv, stxvx, stxvl, stxvll */
- Naveen
