Commit 344717a1 authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Michael Ellerman
Browse files

powerpc/sstep: Fix array out of bound warning 



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 using temporary array variable 'union vsx_reg buf32[]' in
that code block. Also, with element_size = 32, 'union vsx_reg *reg'
is an array of size 2. So, use 'reg' as an array instead of pointer
in the same code block.

Fixes: af99da74 ("powerpc/sstep: Support VSX vector paired storage access instructions")
Suggested-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.ibm.com>
Tested-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210129071745.111466-1-ravi.bangoria@linux.ibm.com
parent 4025c784

arch/powerpc/lib/sstep.c

+8 −6
Original line number Diff line number Diff line
@@ -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);

		}

		break;

	case 16:

		/* stxv, stxvx, stxvl, stxvll */