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Message-Id: <20221103170520.931305-2-mark.rutland@arm.com>
Date: Thu, 3 Nov 2022 17:05:17 +0000
From: Mark Rutland <mark.rutland@....com>
To: linux-kernel@...r.kernel.org
Cc: catalin.marinas@....com, linux-arm-kernel@...ts.infradead.org,
mark.rutland@....com, mhiramat@...nel.org, revest@...omium.org,
rostedt@...dmis.org, will@...nel.org
Subject: [PATCH v2 1/4] ftrace: pass fregs to arch_ftrace_set_direct_caller()
In subsequent patches we'll arrange for architectures to have an
ftrace_regs which is entirely distinct from pt_regs. In preparation for
this, we need to minimize the use of pt_regs to where strictly
necessary in the core ftrace code.
This patch changes the prototype of arch_ftrace_set_direct_caller() to
take ftrace_regs rather than pt_regs, and moves the extraction of the
pt_regs into arch_ftrace_set_direct_caller().
On x86, arch_ftrace_set_direct_caller() can be used even when
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n, and <linux/ftrace.h> defines
struct ftrace_regs. Due to this, it's necessary to define
arch_ftrace_set_direct_caller() as a macro to avoid using an incomplete
type. I've also moved the body of arch_ftrace_set_direct_caller() after
the CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y defineidion of struct
ftrace_regs.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Florent Revest <revest@...omium.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
---
arch/s390/include/asm/ftrace.h | 5 ++++-
arch/x86/include/asm/ftrace.h | 31 ++++++++++++++++++-------------
include/linux/ftrace.h | 9 ++++-----
kernel/trace/ftrace.c | 3 +--
4 files changed, 27 insertions(+), 21 deletions(-)
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 6f80ec9c04be9..85bc26ccdb872 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -60,6 +60,7 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f
fregs->regs.psw.addr = ip;
}
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* When an ftrace registered caller is tracing a function that is
* also set by a register_ftrace_direct() call, it needs to be
@@ -67,10 +68,12 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f
* place the direct caller in the ORIG_GPR2 part of pt_regs. This
* tells the ftrace_caller that there's a direct caller.
*/
-static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
+static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
{
+ struct pt_regs *regs = &fregs->regs;
regs->orig_gpr2 = addr;
}
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
/*
* Even though the system call numbers are identical for s390/s390x a
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 908d99b127d31..d2350a8351fa4 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -34,19 +34,6 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
return addr;
}
-/*
- * When a ftrace registered caller is tracing a function that is
- * also set by a register_ftrace_direct() call, it needs to be
- * differentiated in the ftrace_caller trampoline. To do this, we
- * place the direct caller in the ORIG_AX part of pt_regs. This
- * tells the ftrace_caller that there's a direct caller.
- */
-static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
-{
- /* Emulate a call */
- regs->orig_ax = addr;
-}
-
#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
struct ftrace_regs {
struct pt_regs regs;
@@ -72,6 +59,24 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR
#endif
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+/*
+ * When a ftrace registered caller is tracing a function that is
+ * also set by a register_ftrace_direct() call, it needs to be
+ * differentiated in the ftrace_caller trampoline. To do this, we
+ * place the direct caller in the ORIG_AX part of pt_regs. This
+ * tells the ftrace_caller that there's a direct caller.
+ */
+static inline void
+__arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
+{
+ /* Emulate a call */
+ regs->orig_ax = addr;
+}
+#define arch_ftrace_set_direct_caller(fregs, addr) \
+ __arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
#ifdef CONFIG_DYNAMIC_FTRACE
struct dyn_arch_ftrace {
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 62557d4bffc2b..f201fcbfffb07 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -37,9 +37,10 @@ extern void ftrace_boot_snapshot(void);
static inline void ftrace_boot_snapshot(void) { }
#endif
-#ifdef CONFIG_FUNCTION_TRACER
struct ftrace_ops;
struct ftrace_regs;
+
+#ifdef CONFIG_FUNCTION_TRACER
/*
* If the arch's mcount caller does not support all of ftrace's
* features, then it must call an indirect function that
@@ -427,9 +428,7 @@ static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsi
{
return -ENODEV;
}
-#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
-#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* This must be implemented by the architecture.
* It is the way the ftrace direct_ops helper, when called
@@ -443,9 +442,9 @@ static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsi
* the return from the trampoline jump to the direct caller
* instead of going back to the function it just traced.
*/
-static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
+static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
unsigned long addr) { }
-#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
#ifdef CONFIG_STACK_TRACER
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fbf2543111c05..234c5414deeeb 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2487,14 +2487,13 @@ ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
static void call_direct_funcs(unsigned long ip, unsigned long pip,
struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
- struct pt_regs *regs = ftrace_get_regs(fregs);
unsigned long addr;
addr = ftrace_find_rec_direct(ip);
if (!addr)
return;
- arch_ftrace_set_direct_caller(regs, addr);
+ arch_ftrace_set_direct_caller(fregs, addr);
}
struct ftrace_ops direct_ops = {
--
2.30.2
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