Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Code for tracing calls in Linux kernel. |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 3 | * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de> |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 4 | * |
| 5 | * based on code for x86 which is: |
| 6 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> |
| 7 | * |
| 8 | * future possible enhancements: |
| 9 | * - add CONFIG_DYNAMIC_FTRACE |
| 10 | * - add CONFIG_STACK_TRACER |
| 11 | */ |
| 12 | |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/ftrace.h> |
| 15 | |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 16 | #include <asm/assembly.h> |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 17 | #include <asm/sections.h> |
| 18 | #include <asm/ftrace.h> |
| 19 | |
| 20 | |
Helge Deller | 4df3c9e | 2016-04-29 22:07:31 +0200 | [diff] [blame] | 21 | #define __hot __attribute__ ((__section__ (".text.hot"))) |
| 22 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 23 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 24 | /* |
| 25 | * Hook the return address and push it in the stack of return addrs |
| 26 | * in current thread info. |
| 27 | */ |
Helge Deller | 4df3c9e | 2016-04-29 22:07:31 +0200 | [diff] [blame] | 28 | static void __hot prepare_ftrace_return(unsigned long *parent, |
| 29 | unsigned long self_addr) |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 30 | { |
| 31 | unsigned long old; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 32 | struct ftrace_graph_ent trace; |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 33 | extern int parisc_return_to_handler; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 34 | |
Steven Rostedt (Red Hat) | 3a46588 | 2014-06-25 10:17:48 -0400 | [diff] [blame] | 35 | if (unlikely(ftrace_graph_is_dead())) |
| 36 | return; |
| 37 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 38 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) |
| 39 | return; |
| 40 | |
| 41 | old = *parent; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 42 | |
| 43 | trace.func = self_addr; |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 44 | trace.depth = current->curr_ret_stack + 1; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 45 | |
| 46 | /* Only trace if the calling function expects to */ |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 47 | if (!ftrace_graph_entry(&trace)) |
| 48 | return; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 49 | |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 50 | if (ftrace_push_return_trace(old, self_addr, &trace.depth, |
Josh Poimboeuf | 9a7c348 | 2016-08-19 06:52:57 -0500 | [diff] [blame^] | 51 | 0, NULL) == -EBUSY) |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 52 | return; |
| 53 | |
| 54 | /* activate parisc_return_to_handler() as return point */ |
| 55 | *parent = (unsigned long) &parisc_return_to_handler; |
| 56 | } |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 57 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
| 58 | |
Helge Deller | 4df3c9e | 2016-04-29 22:07:31 +0200 | [diff] [blame] | 59 | void notrace __hot ftrace_function_trampoline(unsigned long parent, |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 60 | unsigned long self_addr, |
| 61 | unsigned long org_sp_gr3) |
| 62 | { |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 63 | extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */ |
| 64 | extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 65 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 66 | if (ftrace_trace_function != ftrace_stub) { |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 67 | /* struct ftrace_ops *op, struct pt_regs *regs); */ |
| 68 | ftrace_trace_function(parent, self_addr, NULL, NULL); |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 69 | return; |
| 70 | } |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 71 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 72 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 73 | if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub || |
| 74 | ftrace_graph_entry != ftrace_graph_entry_stub) { |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 75 | unsigned long *parent_rp; |
| 76 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 77 | /* calculate pointer to %rp in stack */ |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 78 | parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET); |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 79 | /* sanity check: parent_rp should hold parent */ |
| 80 | if (*parent_rp != parent) |
| 81 | return; |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 82 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 83 | prepare_ftrace_return(parent_rp, self_addr); |
| 84 | return; |
| 85 | } |
| 86 | #endif |
| 87 | } |
| 88 | |