diff options
Diffstat (limited to 'arch/powerpc/kernel/trace/ftrace_64_mprofile.S')
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S index fa0921410fa4..c98e90b4ea7b 100644 --- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S @@ -99,13 +99,39 @@ ftrace_call: bl ftrace_stub nop - /* Load ctr with the possibly modified NIP */ - ld r3, _NIP(r1) - mtctr r3 + /* Load the possibly modified NIP */ + ld r15, _NIP(r1) + #ifdef CONFIG_LIVEPATCH - cmpd r14,r3 /* has NIP been altered? */ + cmpd r14, r15 /* has NIP been altered? */ #endif +#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_KPROBES_ON_FTRACE) + /* NIP has not been altered, skip over further checks */ + beq 1f + + /* Check if there is an active kprobe on us */ + subi r3, r14, 4 + bl is_current_kprobe_addr + nop + + /* + * If r3 == 1, then this is a kprobe/jprobe. + * else, this is livepatched function. + * + * The conditional branch for livepatch_handler below will use the + * result of this comparison. For kprobe/jprobe, we just need to branch to + * the new NIP, not call livepatch_handler. The branch below is bne, so we + * want CR0[EQ] to be true if this is a kprobe/jprobe. Which means we want + * CR0[EQ] = (r3 == 1). + */ + cmpdi r3, 1 +1: +#endif + + /* Load CTR with the possibly modified NIP */ + mtctr r15 + /* Restore gprs */ REST_GPR(0,r1) REST_10GPRS(2,r1) @@ -123,7 +149,10 @@ ftrace_call: addi r1, r1, SWITCH_FRAME_SIZE #ifdef CONFIG_LIVEPATCH - /* Based on the cmpd above, if the NIP was altered handle livepatch */ + /* + * Based on the cmpd or cmpdi above, if the NIP was altered and we're + * not on a kprobe/jprobe, then handle livepatch. + */ bne- livepatch_handler #endif |