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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-08 11:13:31 +0200
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-21 05:44:43 +0200
commit0c0593b45c9b4e5b212ffb3fb28bb8d3c0ec0dc8 (patch)
tree59c3f8fe9cfa47a20889f8264b6f6a12f27ccfeb /arch/x86/kernel
parentftrace/x86_64: Have function graph tracer depend on DYNAMIC_FTRACE (diff)
downloadlinux-0c0593b45c9b4e5b212ffb3fb28bb8d3c0ec0dc8.tar.xz
linux-0c0593b45c9b4e5b212ffb3fb28bb8d3c0ec0dc8.zip
x86/ftrace: Make function graph use ftrace directly
We don't need special hook for graph tracer entry point, but instead we can use graph_ops::func function to install the return_hooker. This moves the graph tracing setup _before_ the direct trampoline prepares the stack, so the return_hooker will be called when the direct trampoline is finished. This simplifies the code, because we don't need to take into account the direct trampoline setup when preparing the graph tracer hooker and we can allow function graph tracer on entries registered with direct trampoline. Link: https://lkml.kernel.org/r/20211008091336.33616-4-jolsa@kernel.org [fixed compile error reported by kernel test robot <lkp@intel.com>] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/ftrace.c37
-rw-r--r--arch/x86/kernel/ftrace_64.S29
2 files changed, 35 insertions, 31 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 7f12eacdf1ae..c39f906cdc4e 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -522,7 +522,7 @@ static void *addr_from_call(void *ptr)
return ptr + CALL_INSN_SIZE + call.disp;
}
-void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
+void prepare_ftrace_return(unsigned long ip, unsigned long *parent,
unsigned long frame_pointer);
/*
@@ -536,7 +536,8 @@ static void *static_tramp_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
void *ptr;
if (ops && ops->trampoline) {
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#if !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) && \
+ defined(CONFIG_FUNCTION_GRAPH_TRACER)
/*
* We only know about function graph tracer setting as static
* trampoline.
@@ -584,8 +585,9 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
-extern void ftrace_graph_call(void);
+#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+extern void ftrace_graph_call(void);
static const char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
{
return text_gen_insn(JMP32_INSN_OPCODE, (void *)ip, (void *)addr);
@@ -613,7 +615,17 @@ int ftrace_disable_ftrace_graph_caller(void)
return ftrace_mod_jmp(ip, &ftrace_stub);
}
+#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ return 0;
+}
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ return 0;
+}
+#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
#endif /* !CONFIG_DYNAMIC_FTRACE */
/*
@@ -624,6 +636,7 @@ void prepare_ftrace_return(unsigned long ip, unsigned long *parent,
unsigned long frame_pointer)
{
unsigned long return_hooker = (unsigned long)&return_to_handler;
+ int bit;
/*
* When resuming from suspend-to-ram, this function can be indirectly
@@ -643,7 +656,25 @@ void prepare_ftrace_return(unsigned long ip, unsigned long *parent,
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
+ bit = ftrace_test_recursion_trylock(ip, *parent);
+ if (bit < 0)
+ return;
+
if (!function_graph_enter(*parent, ip, frame_pointer, parent))
*parent = return_hooker;
+
+ ftrace_test_recursion_unlock(bit);
+}
+
+#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+ struct pt_regs *regs = &fregs->regs;
+ unsigned long *stack = (unsigned long *)kernel_stack_pointer(regs);
+
+ prepare_ftrace_return(ip, (unsigned long *)stack, 0);
}
+#endif
+
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index a8eb084a7a9a..7a879901f103 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -174,11 +174,6 @@ SYM_INNER_LABEL(ftrace_caller_end, SYM_L_GLOBAL)
SYM_FUNC_END(ftrace_caller);
SYM_FUNC_START(ftrace_epilogue)
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
- jmp ftrace_stub
-#endif
-
/*
* This is weak to keep gas from relaxing the jumps.
* It is also used to copy the retq for trampolines.
@@ -288,15 +283,6 @@ SYM_FUNC_START(__fentry__)
cmpq $ftrace_stub, ftrace_trace_function
jnz trace
-fgraph_trace:
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- cmpq $ftrace_stub, ftrace_graph_return
- jnz ftrace_graph_caller
-
- cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
- jnz ftrace_graph_caller
-#endif
-
SYM_INNER_LABEL(ftrace_stub, SYM_L_GLOBAL)
retq
@@ -314,25 +300,12 @@ trace:
CALL_NOSPEC r8
restore_mcount_regs
- jmp fgraph_trace
+ jmp ftrace_stub
SYM_FUNC_END(__fentry__)
EXPORT_SYMBOL(__fentry__)
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-SYM_FUNC_START(ftrace_graph_caller)
- /* Saves rbp into %rdx and fills first parameter */
- save_mcount_regs
-
- leaq MCOUNT_REG_SIZE+8(%rsp), %rsi
- movq $0, %rdx /* No framepointers needed */
- call prepare_ftrace_return
-
- restore_mcount_regs
-
- retq
-SYM_FUNC_END(ftrace_graph_caller)
-
SYM_FUNC_START(return_to_handler)
subq $24, %rsp