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authorJordan Niethe <jniethe5@gmail.com>2020-05-06 13:40:46 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2020-05-19 00:11:03 +1000
commitc9c831aebd8663d0129bbcee4d76be889f0627fe (patch)
treef03c984be94460f1d9a58239ceea3786c3cd8652 /arch/powerpc/xmon
parent785b79d1e02873c2088ee1301154c66dace66ce5 (diff)
downloadlinux-c9c831aebd8663d0129bbcee4d76be889f0627fe.tar.bz2
powerpc/xmon: Don't allow breakpoints on suffixes
Do not allow placing xmon breakpoints on the suffix of a prefix instruction. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> [mpe: Don't split printf strings across lines] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-27-jniethe5@gmail.com
Diffstat (limited to 'arch/powerpc/xmon')
-rw-r--r--arch/powerpc/xmon/xmon.c27
1 files changed, 25 insertions, 2 deletions
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index ac8ccf333d51..d1a79f9e0566 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -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));