diff options
Diffstat (limited to 'arch/s390/kernel/kprobes.c')
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 576368c4f605..a466bab6677e 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -155,15 +155,34 @@ void __kprobes get_instruction_type(struct arch_specific_insn *ainsn) static int __kprobes swap_instruction(void *aref) { struct ins_replace_args *args = aref; + u32 *addr; + u32 instr; int err = -EFAULT; + /* + * Text segment is read-only, hence we use stura to bypass dynamic + * address translation to exchange the instruction. Since stura + * always operates on four bytes, but we only want to exchange two + * bytes do some calculations to get things right. In addition we + * shall not cross any page boundaries (vmalloc area!) when writing + * the new instruction. + */ + addr = (u32 *)ALIGN((unsigned long)args->ptr, 4); + if ((unsigned long)args->ptr & 2) + instr = ((*addr) & 0xffff0000) | args->new; + else + instr = ((*addr) & 0x0000ffff) | args->new << 16; + asm volatile( - "0: mvc 0(2,%2),0(%3)\n" - "1: la %0,0\n" + " lra %1,0(%1)\n" + "0: stura %2,%1\n" + "1: la %0,0\n" "2:\n" EX_TABLE(0b,2b) - : "+d" (err), "=m" (*args->ptr) - : "a" (args->ptr), "a" (&args->new), "m" (args->new)); + : "+d" (err) + : "a" (addr), "d" (instr) + : "memory", "cc"); + return err; } @@ -356,7 +375,7 @@ no_kprobe: * - When the probed function returns, this probe * causes the handlers to fire */ -void __kprobes kretprobe_trampoline_holder(void) +void kretprobe_trampoline_holder(void) { asm volatile(".global kretprobe_trampoline\n" "kretprobe_trampoline: bcr 0,0\n"); @@ -365,7 +384,8 @@ void __kprobes kretprobe_trampoline_holder(void) /* * Called when the probe at kretprobe trampoline is hit */ -int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) +static int __kprobes trampoline_probe_handler(struct kprobe *p, + struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; struct hlist_head *head, empty_rp; |