powerpc/kprobes: Fix validation of prefixed instructions across page boundary

[sfrench/cifs-2.6.git] / arch / powerpc / kernel / kprobes.c

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 01ab2163659e4bb7763c0f22ed13d36349e1c9b4..e8c2a6373157dacacaf0d61ada1eab9acca62eab 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -108,7 +108,6 @@ int arch_prepare_kprobe(struct kprobe *p)
        int ret = 0;
        struct kprobe *prev;
        struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->addr);
        int ret = 0;
        struct kprobe *prev;
        struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->addr);

-       struct ppc_inst prefix = ppc_inst_read((struct ppc_inst *)(p->addr - 1));

 
        if ((unsigned long)p->addr & 0x03) {
                printk("Attempt to register kprobe at an unaligned address\n");
 
        if ((unsigned long)p->addr & 0x03) {
                printk("Attempt to register kprobe at an unaligned address\n");


@@ -116,7 +115,8 @@ int arch_prepare_kprobe(struct kprobe *p)
        } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
                printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
                ret = -EINVAL;
        } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
                printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
                ret = -EINVAL;

-       } else if (ppc_inst_prefixed(prefix)) {
+       } else if ((unsigned long)p->addr & ~PAGE_MASK &&
+                  ppc_inst_prefixed(ppc_inst_read((struct ppc_inst *)(p->addr - 1)))) {

                printk("Cannot register a kprobe on the second word of prefixed instruction\n");
                ret = -EINVAL;
        }
                printk("Cannot register a kprobe on the second word of prefixed instruction\n");
                ret = -EINVAL;
        }