Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 2 | /* |
| 3 | * Code for tracing calls in Linux kernel. |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 4 | * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de> |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 5 | * |
| 6 | * based on code for x86 which is: |
| 7 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> |
| 8 | * |
| 9 | * future possible enhancements: |
| 10 | * - add CONFIG_DYNAMIC_FTRACE |
| 11 | * - add CONFIG_STACK_TRACER |
| 12 | */ |
| 13 | |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/ftrace.h> |
| 16 | |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 17 | #include <asm/assembly.h> |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 18 | #include <asm/sections.h> |
| 19 | #include <asm/ftrace.h> |
| 20 | |
| 21 | |
Helge Deller | 4df3c9e | 2016-04-29 22:07:31 +0200 | [diff] [blame] | 22 | #define __hot __attribute__ ((__section__ (".text.hot"))) |
| 23 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 24 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 25 | /* |
| 26 | * Hook the return address and push it in the stack of return addrs |
| 27 | * in current thread info. |
| 28 | */ |
Helge Deller | 4df3c9e | 2016-04-29 22:07:31 +0200 | [diff] [blame] | 29 | static void __hot prepare_ftrace_return(unsigned long *parent, |
| 30 | unsigned long self_addr) |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 31 | { |
| 32 | unsigned long old; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 33 | struct ftrace_graph_ent trace; |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 34 | extern int parisc_return_to_handler; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 35 | |
Steven Rostedt (Red Hat) | 3a46588 | 2014-06-25 10:17:48 -0400 | [diff] [blame] | 36 | if (unlikely(ftrace_graph_is_dead())) |
| 37 | return; |
| 38 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 39 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) |
| 40 | return; |
| 41 | |
| 42 | old = *parent; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 43 | |
| 44 | trace.func = self_addr; |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 45 | trace.depth = current->curr_ret_stack + 1; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 46 | |
| 47 | /* Only trace if the calling function expects to */ |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 48 | if (!ftrace_graph_entry(&trace)) |
| 49 | return; |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 50 | |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 51 | if (ftrace_push_return_trace(old, self_addr, &trace.depth, |
Josh Poimboeuf | 9a7c348 | 2016-08-19 06:52:57 -0500 | [diff] [blame] | 52 | 0, NULL) == -EBUSY) |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 53 | return; |
| 54 | |
| 55 | /* activate parisc_return_to_handler() as return point */ |
| 56 | *parent = (unsigned long) &parisc_return_to_handler; |
| 57 | } |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 58 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
| 59 | |
Helge Deller | 4df3c9e | 2016-04-29 22:07:31 +0200 | [diff] [blame] | 60 | void notrace __hot ftrace_function_trampoline(unsigned long parent, |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 61 | unsigned long self_addr, |
| 62 | unsigned long org_sp_gr3) |
| 63 | { |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 64 | extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */ |
| 65 | extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 66 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 67 | if (ftrace_trace_function != ftrace_stub) { |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 68 | /* struct ftrace_ops *op, struct pt_regs *regs); */ |
| 69 | ftrace_trace_function(parent, self_addr, NULL, NULL); |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 70 | return; |
| 71 | } |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 72 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 73 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 74 | if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub || |
| 75 | ftrace_graph_entry != ftrace_graph_entry_stub) { |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 76 | unsigned long *parent_rp; |
| 77 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 78 | /* calculate pointer to %rp in stack */ |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 79 | parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET); |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 80 | /* sanity check: parent_rp should hold parent */ |
| 81 | if (*parent_rp != parent) |
| 82 | return; |
Helge Deller | 366dd4e | 2016-04-13 22:27:22 +0200 | [diff] [blame] | 83 | |
Helge Deller | d75f054 | 2009-02-09 00:43:36 +0100 | [diff] [blame] | 84 | prepare_ftrace_return(parent_rp, self_addr); |
| 85 | return; |
| 86 | } |
| 87 | #endif |
| 88 | } |
| 89 | |