[for-next][PATCH 4/4] ftrace: Consolidate ftrace_regs accessor functions for archs using pt_regs

From: Steven Rostedt
Date: Fri Oct 11 2024 - 09:30:24 EST

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From: Steven Rostedt <rostedt@xxxxxxxxxxx>

Most architectures use pt_regs within ftrace_regs making a lot of the
accessor functions just calls to the pt_regs internally. Instead of
duplication this effort, use a HAVE_ARCH_FTRACE_REGS for architectures
that have their own ftrace_regs that is not based on pt_regs and will
define all the accessor functions, and for the architectures that just use
pt_regs, it will leave it undefined, and the default accessor functions
will be used.

Note, this will also make it easier to add new accessor functions to
ftrace_regs as it will mean having to touch less architectures.

Cc: <linux-arch@xxxxxxxxxxxxxxx>
Cc: "x86@xxxxxxxxxx" <x86@xxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: WANG Xuerui <kernel@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Naveen N Rao <naveen@xxxxxxxxxx>
Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/20241010202114.2289f6fd@xxxxxxxxxxxxxxxxxx
Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx> # s390
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Suggested-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
arch/arm64/include/asm/ftrace.h | 1 +
arch/loongarch/include/asm/ftrace.h | 25 +-------------------
arch/powerpc/include/asm/ftrace.h | 26 +--------------------
arch/riscv/include/asm/ftrace.h | 1 +
arch/s390/include/asm/ftrace.h | 26 +--------------------
arch/x86/include/asm/ftrace.h | 21 +----------------
include/linux/ftrace.h | 32 ++++++-------------------
include/linux/ftrace_regs.h | 36 +++++++++++++++++++++++++++++
8 files changed, 49 insertions(+), 119 deletions(-)
create mode 100644 include/linux/ftrace_regs.h

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index bbb69c7751b9..5ccff4de7f09 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -54,6 +54,7 @@ extern void return_to_handler(void);
unsigned long ftrace_call_adjust(unsigned long addr);

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
+#define HAVE_ARCH_FTRACE_REGS
struct dyn_ftrace;
struct ftrace_ops;
struct ftrace_regs;
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index 0e15d36ce251..8f13eaeaa325 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -43,43 +43,20 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent);

#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
struct ftrace_ops;
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))

-struct __arch_ftrace_regs {
- struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>

static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
{
return &arch_ftrace_regs(fregs)->regs;
}

-static __always_inline unsigned long
-ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
-{
- return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
-}
-
static __always_inline void
ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, unsigned long ip)
{
instruction_pointer_set(&arch_ftrace_regs(fregs)->regs, ip);
}

-#define ftrace_regs_get_argument(fregs, n) \
- regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
- kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
- regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
- regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
- override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
- regs_query_register_offset(name)
-
#define ftrace_graph_func ftrace_graph_func
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index e299fd47d201..0edfb874eb02 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -32,12 +32,7 @@ struct dyn_arch_ftrace {
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
#define ftrace_init_nop ftrace_init_nop

-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
-
-struct __arch_ftrace_regs {
- struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>

static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
{
@@ -52,25 +47,6 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
regs_set_return_ip(&arch_ftrace_regs(fregs)->regs, ip);
}

-static __always_inline unsigned long
-ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
-{
- return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
-}
-
-#define ftrace_regs_get_argument(fregs, n) \
- regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
- kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
- regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
- regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
- override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
- regs_query_register_offset(name)
-
struct ftrace_ops;

#define ftrace_graph_func ftrace_graph_func
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index c6bcdff105b5..3d66437a1029 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -125,6 +125,7 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
#define arch_ftrace_get_regs(regs) NULL
+#define HAVE_ARCH_FTRACE_REGS
struct ftrace_ops;
struct ftrace_regs;
#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 1498d0a9c762..fc97d75dc752 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -51,12 +51,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
return addr;
}

-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
-
-struct __arch_ftrace_regs {
- struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>

static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
{
@@ -84,12 +79,6 @@ static __always_inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

-static __always_inline unsigned long
-ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
-{
- return arch_ftrace_regs(fregs)->regs.psw.addr;
-}
-
static __always_inline void
ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
unsigned long ip)
@@ -97,19 +86,6 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
arch_ftrace_regs(fregs)->regs.psw.addr = ip;
}

-#define ftrace_regs_get_argument(fregs, n) \
- regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
- kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
- regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
- regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
- override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
- regs_query_register_offset(name)
-
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
* When an ftrace registered caller is tracing a function that is
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 87943f7a299b..8f02d28c571a 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -33,12 +33,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
}

#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))

-struct __arch_ftrace_regs {
- struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>

static __always_inline struct pt_regs *
arch_ftrace_get_regs(struct ftrace_regs *fregs)
@@ -52,21 +48,6 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
#define ftrace_regs_set_instruction_pointer(fregs, _ip) \
do { arch_ftrace_regs(fregs)->regs.ip = (_ip); } while (0)

-#define ftrace_regs_get_instruction_pointer(fregs) \
- arch_ftrace_regs(fregs)->regs.ip)
-
-#define ftrace_regs_get_argument(fregs, n) \
- regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
- kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
- regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
- regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
- override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
- regs_query_register_offset(name)

struct ftrace_ops;
#define ftrace_graph_func ftrace_graph_func
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 66f10291a0b2..aa9ddd1e4bb6 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -113,6 +113,8 @@ static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *val

#ifdef CONFIG_FUNCTION_TRACER

+#include <linux/ftrace_regs.h>
+
extern int ftrace_enabled;

/**
@@ -150,14 +152,11 @@ struct ftrace_regs {
#define ftrace_regs_size() sizeof(struct __arch_ftrace_regs)

#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
-
-struct __arch_ftrace_regs {
- struct pt_regs regs;
-};
-
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
-
+/*
+ * Architectures that define HAVE_DYNAMIC_FTRACE_WITH_ARGS must define their own
+ * arch_ftrace_get_regs() where it only returns pt_regs *if* it is fully
+ * populated. It should return NULL otherwise.
+ */
static inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
{
return &arch_ftrace_regs(fregs)->regs;
@@ -191,23 +190,6 @@ static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
return ftrace_get_regs(fregs) != NULL;
}

-#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
-#define ftrace_regs_get_instruction_pointer(fregs) \
- instruction_pointer(ftrace_get_regs(fregs))
-#define ftrace_regs_get_argument(fregs, n) \
- regs_get_kernel_argument(ftrace_get_regs(fregs), n)
-#define ftrace_regs_get_stack_pointer(fregs) \
- kernel_stack_pointer(ftrace_get_regs(fregs))
-#define ftrace_regs_return_value(fregs) \
- regs_return_value(ftrace_get_regs(fregs))
-#define ftrace_regs_set_return_value(fregs, ret) \
- regs_set_return_value(ftrace_get_regs(fregs), ret)
-#define ftrace_override_function_with_return(fregs) \
- override_function_with_return(ftrace_get_regs(fregs))
-#define ftrace_regs_query_register_offset(name) \
- regs_query_register_offset(name)
-#endif
-
typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);

diff --git a/include/linux/ftrace_regs.h b/include/linux/ftrace_regs.h
new file mode 100644
index 000000000000..dea6a0851b74
--- /dev/null
+++ b/include/linux/ftrace_regs.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_FTRACE_REGS_H
+#define _LINUX_FTRACE_REGS_H
+
+/*
+ * For archs that just copy pt_regs in ftrace regs, it can use this default.
+ * If an architecture does not use pt_regs, it must define all the below
+ * accessor functions.
+ */
+#ifndef HAVE_ARCH_FTRACE_REGS
+struct __arch_ftrace_regs {
+ struct pt_regs regs;
+};
+
+#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
+
+struct ftrace_regs;
+
+#define ftrace_regs_get_instruction_pointer(fregs) \
+ instruction_pointer(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_get_argument(fregs, n) \
+ regs_get_kernel_argument(arch_ftrace_get_regs(fregs), n)
+#define ftrace_regs_get_stack_pointer(fregs) \
+ kernel_stack_pointer(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_return_value(fregs) \
+ regs_return_value(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_set_return_value(fregs, ret) \
+ regs_set_return_value(arch_ftrace_get_regs(fregs), ret)
+#define ftrace_override_function_with_return(fregs) \
+ override_function_with_return(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_query_register_offset(name) \
+ regs_query_register_offset(name)
+
+#endif /* HAVE_ARCH_FTRACE_REGS */
+
+#endif /* _LINUX_FTRACE_REGS_H */
--
2.45.2

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