Ravi Bangoria <[email protected]> writes: > As per ISA 3.1, prefixed instruction should not cross 64-byte > boundary. So don't allow Uprobe on such prefixed instruction. > > There are two ways probed instruction is changed in mapped pages. > First, when Uprobe is activated, it searches for all the relevant > pages and replace instruction in them. In this case, if that probe > is on the 64-byte unaligned prefixed instruction, error out > directly. Second, when Uprobe is already active and user maps a > relevant page via mmap(), instruction is replaced via mmap() code > path. But because Uprobe is invalid, entire mmap() operation can > not be stopped. In this case just print an error and continue. > > Signed-off-by: Ravi Bangoria <[email protected]> > Acked-by: Naveen N. Rao <[email protected]>
Do we have a Fixes: tag for this? > --- > v3: > https://lore.kernel.org/r/[email protected] > v3->v4: > - CONFIG_PPC64 check was not required, remove it. > - Use SZ_ macros instead of hardcoded numbers. > > arch/powerpc/kernel/uprobes.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c > index e8a63713e655..4cbfff6e94a3 100644 > --- a/arch/powerpc/kernel/uprobes.c > +++ b/arch/powerpc/kernel/uprobes.c > @@ -41,6 +41,13 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, > if (addr & 0x03) > return -EINVAL; > > + if (cpu_has_feature(CPU_FTR_ARCH_31) && > + ppc_inst_prefixed(auprobe->insn) && > + (addr & (SZ_64 - 4)) == SZ_64 - 4) { > + pr_info_ratelimited("Cannot register a uprobe on 64 byte > unaligned prefixed instruction\n"); > + return -EINVAL; I realise we already did the 0x03 check above, but I still think this would be clearer simply as: (addr & 0x3f == 60) cheers
