[PATCH v2 3/6] ftrace: Pass retval through return in ftrace_dyn_arch_init

From: Jiri Slaby
Date: Mon Feb 24 2014 - 14:00:23 EST


No ftrace_dyn_arch_init uses the value in the "data" parameter in any
way, it just sets the value to 0. And this is used as a return value
in the caller -- ftrace_init, which just checks the retval against
zero.

Note there is also "return 0" in every ftrace_dyn_arch_init. So it is
enough to check the retval and remove all the indirect sets of data on
all archs.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
---
Documentation/trace/ftrace-design.txt | 3 ---
arch/arm/kernel/ftrace.c | 2 --
arch/blackfin/kernel/ftrace.c | 3 ---
arch/ia64/kernel/ftrace.c | 2 --
arch/metag/kernel/ftrace.c | 3 ---
arch/microblaze/kernel/ftrace.c | 3 ---
arch/mips/kernel/ftrace.c | 3 ---
arch/powerpc/kernel/ftrace.c | 5 -----
arch/s390/kernel/ftrace.c | 1 -
arch/sh/kernel/ftrace.c | 3 ---
arch/sparc/kernel/ftrace.c | 4 ----
arch/tile/kernel/ftrace.c | 2 --
arch/x86/kernel/ftrace.c | 3 ---
kernel/trace/ftrace.c | 6 ++----
14 files changed, 2 insertions(+), 41 deletions(-)

diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index 79fcafc7fd64..117168884023 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -360,9 +360,6 @@ function below should be sufficient for most people:

int __init ftrace_dyn_arch_init(void *data)
{
- /* return value is done indirectly via data */
- *(unsigned long *)data = 0;
-
return 0;
}

diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 34e56647dcee..5cd0d05edf35 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -158,8 +158,6 @@ int ftrace_make_nop(struct module *mod,

int __init ftrace_dyn_arch_init(void *data)
{
- *(unsigned long *)data = 0;
-
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
diff --git a/arch/blackfin/kernel/ftrace.c b/arch/blackfin/kernel/ftrace.c
index 9277905b82cf..f74c5ae6a25b 100644
--- a/arch/blackfin/kernel/ftrace.c
+++ b/arch/blackfin/kernel/ftrace.c
@@ -67,9 +67,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)

int __init ftrace_dyn_arch_init(void *data)
{
- /* return value is done indirectly via data */
- *(unsigned long *)data = 0;
-
return 0;
}

diff --git a/arch/ia64/kernel/ftrace.c b/arch/ia64/kernel/ftrace.c
index 7fc8c961b1f7..cfaa93a8bbdf 100644
--- a/arch/ia64/kernel/ftrace.c
+++ b/arch/ia64/kernel/ftrace.c
@@ -200,7 +200,5 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
/* run from kstop_machine */
int __init ftrace_dyn_arch_init(void *data)
{
- *(unsigned long *)data = 0;
-
return 0;
}
diff --git a/arch/metag/kernel/ftrace.c b/arch/metag/kernel/ftrace.c
index a774f321643f..bf593932b353 100644
--- a/arch/metag/kernel/ftrace.c
+++ b/arch/metag/kernel/ftrace.c
@@ -119,8 +119,5 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
/* run from kstop_machine */
int __init ftrace_dyn_arch_init(void *data)
{
- /* The return code is returned via data */
- writel(0, data);
-
return 0;
}
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index e8a5e9cf4ed1..ffa595c7fec2 100644
--- a/arch/microblaze/kernel/ftrace.c
+++ b/arch/microblaze/kernel/ftrace.c
@@ -173,9 +173,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

int __init ftrace_dyn_arch_init(void *data)
{
- /* The return code is retured via data */
- *(unsigned long *)data = 0;
-
return 0;
}

diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index ddcc3500248d..42a675ae0155 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -210,9 +210,6 @@ int __init ftrace_dyn_arch_init(void *data)
/* Remove "b ftrace_stub" to ensure ftrace_caller() is executed */
ftrace_modify_code(MCOUNT_ADDR, INSN_NOP);

- /* The return code is retured via data */
- *(unsigned long *)data = 0;
-
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 9b27b293a922..d059664cdf16 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -533,11 +533,6 @@ void arch_ftrace_update_code(int command)

int __init ftrace_dyn_arch_init(void *data)
{
- /* caller expects data to be zero */
- unsigned long *p = data;
-
- *p = 0;
-
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 224db03e9518..77b2f3a1f50a 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -132,7 +132,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)

int __init ftrace_dyn_arch_init(void *data)
{
- *(unsigned long *) data = 0;
return 0;
}

diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 30e13196d35b..493997541d2c 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -274,9 +274,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

int __init ftrace_dyn_arch_init(void *data)
{
- /* The return code is retured via data */
- __raw_writel(0, (unsigned long)data);
-
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c
index 03ab022e51c5..ee813b82da49 100644
--- a/arch/sparc/kernel/ftrace.c
+++ b/arch/sparc/kernel/ftrace.c
@@ -84,10 +84,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)

int __init ftrace_dyn_arch_init(void *data)
{
- unsigned long *p = data;
-
- *p = 0;
-
return 0;
}
#endif
diff --git a/arch/tile/kernel/ftrace.c b/arch/tile/kernel/ftrace.c
index f1c452092eeb..34d9ea0bca9f 100644
--- a/arch/tile/kernel/ftrace.c
+++ b/arch/tile/kernel/ftrace.c
@@ -169,8 +169,6 @@ int ftrace_make_nop(struct module *mod,

int __init ftrace_dyn_arch_init(void *data)
{
- *(unsigned long *)data = 0;
-
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index e6253195a301..a41f31f1cdc1 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -680,9 +680,6 @@ void arch_ftrace_update_code(int command)

int __init ftrace_dyn_arch_init(void *data)
{
- /* The return code is retured via data */
- *(unsigned long *)data = 0;
-
return 0;
}
#endif
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 76b6ed29d856..083c6d5fce25 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4379,11 +4379,9 @@ void __init ftrace_init(void)
addr = (unsigned long)ftrace_stub;

local_irq_save(flags);
- ftrace_dyn_arch_init(&addr);
+ ret = ftrace_dyn_arch_init(&addr);
local_irq_restore(flags);
-
- /* ftrace_dyn_arch_init places the return code in addr */
- if (addr)
+ if (ret)
goto failed;

count = __stop_mcount_loc - __start_mcount_loc;
--
1.8.5.2

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