[PATCH 04/18] tracing/x86: Add arch_get_func_args() function

Steven Rostedt
2018-02-02T23:10:19Z

[-- Attachment #1: 0004-tracing-x86-Add-arch_get_func_args-function.patch --]
[-- Type: text/plain, Size: 1132 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add function to get the function arguments from pt_regs.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
arch/x86/kernel/ftrace.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 01ebcb6f263e..5e845c8cf89d 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -46,6 +46,34 @@ int ftrace_arch_code_modify_post_process(void)
return 0;
}

+int arch_get_func_args(struct pt_regs *regs,
+ int start, int end, long *args)
+{
+#ifdef CONFIG_X86_64
+# define MAX_ARGS 6
+# define INIT_REGS \
+ { regs->di, regs->si, regs->dx, \
+ regs->cx, regs->r8, regs->r9 \
+ }
+#else
+# define MAX_ARGS 3
+# define INIT_REGS \
+ { regs->ax, regs->dx, regs->cx }
+#endif
+ if (!regs)
+ return MAX_ARGS;
+
+ {
+ long pt_args[] = INIT_REGS;
+ int i;
+
+ for (i = start; i <= end && i < MAX_ARGS; i++)
+ args[i - start] = pt_args[i];
+
+ return i - start;
+ }
+}
+
union ftrace_code_union {
char code[MCOUNT_INSN_SIZE];
struct {
--
2.15.1