diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 10 | ||||
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 11 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ftrace.c | 59 |
3 files changed, 30 insertions, 50 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 22b45a4..ad837d8 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -1424,12 +1424,18 @@ _GLOBAL(ftrace_graph_caller) lwz r4, 44(r1) subi r4, r4, MCOUNT_INSN_SIZE - /* get the parent address */ - addi r3, r1, 52 + /* Grab the LR out of the caller stack frame */ + lwz r3,52(r1) bl prepare_ftrace_return nop + /* + * prepare_ftrace_return gives us the address we divert to. + * Change the LR in the callers stack frame to this. + */ + stw r3,52(r1) + MCOUNT_RESTORE_FRAME /* old link register ends up in ctr reg */ bctr diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 66f7ed3..194e46d 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -1227,13 +1227,20 @@ _GLOBAL(ftrace_graph_caller) ld r4, 128(r1) subi r4, r4, MCOUNT_INSN_SIZE - /* get the parent address */ + /* Grab the LR out of the caller stack frame */ ld r11, 112(r1) - addi r3, r11, 16 + ld r3, 16(r11) bl prepare_ftrace_return nop + /* + * prepare_ftrace_return gives us the address we divert to. + * Change the LR in the callers stack frame to this. + */ + ld r11, 112(r1) + std r3, 16(r11) + ld r0, 128(r1) mtlr r0 addi r1, r1, 112 diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index abf7921..d795031 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -512,67 +512,34 @@ int ftrace_disable_ftrace_graph_caller(void) /* * Hook the return address and push it in the stack of return addrs - * in current thread info. + * in current thread info. Return the address we want to divert to. */ -void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) +unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) { - unsigned long old; - int faulted; struct ftrace_graph_ent trace; unsigned long return_hooker; if (unlikely(ftrace_graph_is_dead())) - return; + goto out; if (unlikely(atomic_read(¤t->tracing_graph_pause))) - return; + goto out; return_hooker = ppc_function_entry(return_to_handler); - /* - * Protect against fault, even if it shouldn't - * happen. This tool is too much intrusive to - * ignore such a protection. - */ - asm volatile( - "1: " PPC_LL "%[old], 0(%[parent])\n" - "2: " PPC_STL "%[return_hooker], 0(%[parent])\n" - " li %[faulted], 0\n" - "3:\n" - - ".section .fixup, \"ax\"\n" - "4: li %[faulted], 1\n" - " b 3b\n" - ".previous\n" - - ".section __ex_table,\"a\"\n" - PPC_LONG_ALIGN "\n" - PPC_LONG "1b,4b\n" - PPC_LONG "2b,4b\n" - ".previous" - - : [old] "=&r" (old), [faulted] "=r" (faulted) - : [parent] "r" (parent), [return_hooker] "r" (return_hooker) - : "memory" - ); - - if (unlikely(faulted)) { - ftrace_graph_stop(); - WARN_ON(1); - return; - } - - trace.func = self_addr; + trace.func = ip; trace.depth = current->curr_ret_stack + 1; /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) { - *parent = old; - return; - } + if (!ftrace_graph_entry(&trace)) + goto out; + + if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY) + goto out; - if (ftrace_push_return_trace(old, self_addr, &trace.depth, 0) == -EBUSY) - *parent = old; + parent = return_hooker; +out: + return parent; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
