powerpc/watchpoint: Fix handling of vector instructions

Vector load/store instructions are special because they are always
aligned. Thus unaligned EA needs to be aligned down before comparing
it with watch ranges. Otherwise we might consider valid event as
invalid.

Fixes: 74c68810 ("powerpc/watchpoint: Prepare handler to handle more than one watchpoint")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902042945.129369-3-ravi.bangoria@linux.ibm.com

arch/powerpc/kernel/hw_breakpoint.c

@@ -644,6 +644,8 @@ static void get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
 	if (*type == CACHEOP) {
 		*size = cache_op_size();
 		*ea &= ~(*size - 1);
+	} else if (*type == LOAD_VMX || *type == STORE_VMX) {
+		*ea &= ~(*size - 1);
 	}
 }