Commit c9c831ae authored by Jordan Niethe's avatar Jordan Niethe Committed by Michael Ellerman
Browse files

powerpc/xmon: Don't allow breakpoints on suffixes 



Do not allow placing xmon breakpoints on the suffix of a prefix
instruction.

Signed-off-by: default avatarJordan Niethe <jniethe5@gmail.com>
[mpe: Don't split printf strings across lines]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-27-jniethe5@gmail.com
parent 785b79d1

arch/powerpc/xmon/xmon.c

+25 −2
Original line number Diff line number Diff line
@@ -889,8 +889,8 @@ static struct bpt *new_breakpoint(unsigned long a) 
static void insert_bpts(void)

{

	int i;

	struct ppc_inst instr;

	struct bpt *bp;

	struct ppc_inst instr, instr2;

	struct bpt *bp, *bp2;



	bp = bpts;

	for (i = 0; i < NBPTS; ++i, ++bp) {
@@ -908,6 +908,29 @@ static void insert_bpts(void) 
			bp->enabled = 0;

			continue;

		}

		/*

		 * Check the address is not a suffix by looking for a prefix in

		 * front of it.

		 */

		if (mread_instr(bp->address - 4, &instr2) == 8) {

			printf("Breakpoint at %lx is on the second word of a prefixed instruction, disabling it\n",

			       bp->address);

			bp->enabled = 0;

			continue;

		}

		/*

		 * We might still be a suffix - if the prefix has already been

		 * replaced by a breakpoint we won't catch it with the above

		 * test.

		 */

		bp2 = at_breakpoint(bp->address - 4);

		if (bp2 && ppc_inst_prefixed(ppc_inst_read(bp2->instr))) {

			printf("Breakpoint at %lx is on the second word of a prefixed instruction, disabling it\n",

			       bp->address);

			bp->enabled = 0;

			continue;

		}



		patch_instruction(bp->instr, instr);

		patch_instruction((void *)bp->instr + ppc_inst_len(instr),

				  ppc_inst(bpinstr));