From: chenmiao <chenmiao...@gmail.com>
V1: The first version mainly involves modifications to the
configuration of the dynamic ftracer.
Link
https://lore.kernel.org/all/f7e12c6d-892e-4ca3-9ef0-fbb524d04...@ghiti.fr/
V2: After a series of discussions, Steven concluded that only
supporting the dynamic ftracer would suffice. Alex also pointed
out that if only the dynamic ftracer needs to be supported, the
code related to the static ftracer would become obsolete and
turn into dead code. He had already done some preliminary work on this.
Based on this, the modifications to the configuration were made,
and the dead code generated by the ftracer
(originally related to the static ftracer) was also removed.
Link
https://lore.kernel.org/all/20250703115222.2d7c8...@batman.local.home/
Link
https://github.com/linux-riscv/linux/pull/556/commits/0481092a5bec3818658981c11f629e06e66382b3
Signed-off-by: chenmiao <chenmiao...@gmail.com>
---
arch/riscv/Kconfig | 3 +-
arch/riscv/include/asm/ftrace.h | 3 --
arch/riscv/kernel/ftrace.c | 11 +-----
arch/riscv/kernel/mcount.S | 64 ---------------------------------
kernel/trace/Kconfig | 2 +-
5 files changed, 4 insertions(+), 79 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 36061f4732b7..95d24b19c466 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -97,8 +97,9 @@ config RISCV
select CLONE_BACKWARDS
select COMMON_CLK
select CPU_PM if CPU_IDLE || HIBERNATION || SUSPEND
+ select DYNAMIC_FTRACE if FUNCTION_TRACER
select EDAC_SUPPORT
- select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER &&
!DYNAMIC_FTRACE)
+ select FRAME_POINTER if PERF_EVENTS
select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if
DYNAMIC_FTRACE
select FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS
select GENERIC_ARCH_TOPOLOGY
diff --git a/arch/riscv/include/asm/ftrace.h
b/arch/riscv/include/asm/ftrace.h
index 22ebea3c2b26..77ddb6dce0a8 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -49,7 +49,6 @@ struct dyn_arch_ftrace {
};
#endif
-#ifdef CONFIG_DYNAMIC_FTRACE
/*
* A general call in RISC-V is a pair of insts:
* 1) auipc: setting high-20 pc-related bits to ra register
@@ -237,6 +236,4 @@ static inline void
arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsi
#endif /* __ASSEMBLY__ */
-#endif /* CONFIG_DYNAMIC_FTRACE */
-
#endif /* _ASM_RISCV_FTRACE_H */
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 4c6c24380cfd..93bad646d233 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -13,7 +13,6 @@
#include <asm/cacheflush.h>
#include <asm/text-patching.h>
-#ifdef CONFIG_DYNAMIC_FTRACE
unsigned long ftrace_call_adjust(unsigned long addr)
{
if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
@@ -191,13 +190,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
return 0;
}
-#else /* CONFIG_DYNAMIC_FTRACE */
-unsigned long ftrace_call_adjust(unsigned long addr)
-{
- return addr;
-}
-#endif /* CONFIG_DYNAMIC_FTRACE */
-
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
@@ -236,7 +228,6 @@ void prepare_ftrace_return(unsigned long *parent,
unsigned long self_addr,
*parent = return_hooker;
}
-#ifdef CONFIG_DYNAMIC_FTRACE
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
@@ -257,5 +248,5 @@ void ftrace_graph_func(unsigned long ip, unsigned
long parent_ip,
if (!function_graph_enter_regs(old, ip, frame_pointer, parent,
fregs))
*parent = return_hooker;
}
-#endif /* CONFIG_DYNAMIC_FTRACE */
+
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
index da4a4000e57e..bb550c15f1c9 100644
--- a/arch/riscv/kernel/mcount.S
+++ b/arch/riscv/kernel/mcount.S
@@ -14,13 +14,6 @@
.text
- .macro SAVE_ABI_STATE
- addi sp, sp, -16
- REG_S s0, 0*SZREG(sp)
- REG_S ra, 1*SZREG(sp)
- addi s0, sp, 16
- .endm
-
/*
* The call to ftrace_return_to_handler would overwrite the return
* register if a0 was not saved.
@@ -34,12 +27,6 @@
addi s0, sp, FREGS_SIZE_ON_STACK
.endm
- .macro RESTORE_ABI_STATE
- REG_L ra, 1*SZREG(sp)
- REG_L s0, 0*SZREG(sp)
- addi sp, sp, 16
- .endm
-
.macro RESTORE_RET_ABI_STATE
REG_L ra, FREGS_RA(sp)
REG_L s0, FREGS_S0(sp)
@@ -49,10 +36,8 @@
.endm
SYM_TYPED_FUNC_START(ftrace_stub)
-#ifdef CONFIG_DYNAMIC_FTRACE
.global _mcount
.set _mcount, ftrace_stub
-#endif
ret
SYM_FUNC_END(ftrace_stub)
@@ -79,53 +64,4 @@ SYM_FUNC_START(return_to_handler)
SYM_FUNC_END(return_to_handler)
#endif
-#ifndef CONFIG_DYNAMIC_FTRACE
-SYM_FUNC_START(_mcount)
- la t4, ftrace_stub
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- la t0, ftrace_graph_return
- REG_L t1, 0(t0)
- bne t1, t4, .Ldo_ftrace_graph_caller
-
- la t3, ftrace_graph_entry
- REG_L t2, 0(t3)
- la t6, ftrace_graph_entry_stub
- bne t2, t6, .Ldo_ftrace_graph_caller
-#endif
- la t3, ftrace_trace_function
- REG_L t5, 0(t3)
- bne t5, t4, .Ldo_trace
- ret
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-/*
- * A pseudo representation for the function graph tracer:
- * prepare_to_return(&ra_to_caller_of_caller, ra_to_caller)
- */
-.Ldo_ftrace_graph_caller:
- addi a0, s0, -SZREG
- mv a1, ra
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- REG_L a2, -2*SZREG(s0)
-#endif
- SAVE_ABI_STATE
- call prepare_ftrace_return
- RESTORE_ABI_STATE
- ret
-#endif
-
-/*
- * A pseudo representation for the function tracer:
- * (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller)
- */
-.Ldo_trace:
- REG_L a1, -SZREG(s0)
- mv a0, ra
-
- SAVE_ABI_STATE
- jalr t5
- RESTORE_ABI_STATE
- ret
-SYM_FUNC_END(_mcount)
-#endif
EXPORT_SYMBOL(_mcount)
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a3f35c7d83b6..28afc6941e7a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -275,7 +275,7 @@ config FUNCTION_TRACE_ARGS
funcgraph-args (for the function graph tracer)
config DYNAMIC_FTRACE
- bool "enable/disable function tracing dynamically"
+ bool
depends on FUNCTION_TRACER
depends on HAVE_DYNAMIC_FTRACE
default y
base-commit: fda589c286040d9ba2d72a0eaf0a13945fc48026
