Thread (53 messages) 53 messages, 4 authors, 2020-05-05

Re: [PATCH v7 19/28] powerpc/xmon: Move insertion of breakpoint for xol'ing

From: Alistair Popple <hidden>
Date: 2020-05-05 02:20:44

I can't see any side-effects from patching both instructions at the same time.

Reviewed-by: Alistair Popple <redacted>

On Friday, 1 May 2020 1:42:11 PM AEST Jordan Niethe wrote:
quoted hunk ↗ jump to hunk
When a new breakpoint is created, the second instruction of that
breakpoint is patched with a trap instruction. This assumes the length
of the instruction is always the same. In preparation for prefixed
instructions, remove this assumption. Insert the trap instruction at the
same time the first instruction is inserted.

Signed-off-by: Jordan Niethe <redacted>
---
 arch/powerpc/xmon/xmon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 1947821e425d..fb2563079046 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -878,7 +878,6 @@ static struct bpt *new_breakpoint(unsigned long a)
 		if (!bp->enabled && atomic_read(&bp->ref_count) == 0) {
 			bp->address = a;
 			bp->instr = (void *)(bpt_table + ((bp - bpts) * BPT_WORDS));
-			patch_instruction(bp->instr + 1, ppc_inst(bpinstr));
 			return bp;
 		}
 	}
@@ -910,6 +909,7 @@ static void insert_bpts(void)
 			continue;
 		}
 		patch_instruction(bp->instr, instr);
+		patch_instruction((void *)bp->instr + ppc_inst_len(instr),
ppc_inst(bpinstr)); if (bp->enabled & BP_CIABR)
 			continue;
 		if (patch_instruction((struct ppc_inst *)bp->address,


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