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Message-Id: <1264230643-29434-1-git-send-email-vapier@gentoo.org>
Date: Sat, 23 Jan 2010 02:10:43 -0500
From: Mike Frysinger <vapier@...too.org>
To: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...hat.com>
Cc: David Miller <davem@...emloft.net>, heiko.carstens@...ibm.com,
Paul Mundt <lethal@...ux-sh.org>
Subject: [PATCH v2] ftrace: unify arch_syscall_addr() implementations
Most implementations of arch_syscall_addr() are the same, so create a
default weak version in common code. New arch ports don't have to waste
time copying & pasting this simple function. The Blackfin version is
going to be exactly the same for example.
The s390/sparc versions need to be different, so document why.
Signed-off-by: Mike Frysinger <vapier@...too.org>
---
v2
- document s390/sparc funkiness
Documentation/trace/ftrace-design.txt | 6 +++++-
arch/s390/kernel/ftrace.c | 7 ++++++-
arch/sh/kernel/ftrace.c | 9 ---------
arch/sparc/kernel/ftrace.c | 7 ++++++-
arch/x86/kernel/ftrace.c | 10 ----------
include/linux/ftrace.h | 6 ++++++
kernel/trace/trace_syscalls.c | 6 ++++++
7 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index 6a5a579..1a67b8c 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -240,8 +240,12 @@ You need very few things to get the syscalls tracing in an arch.
- Have a NR_syscalls variable in <asm/unistd.h> that provides the number
of syscalls supported by the arch.
+- Implement <asm/syscall.h>.
- Implement arch_syscall_addr() that resolves a syscall address from a
- syscall number.
+ syscall number. For the simple arches where your syscall table is an
+ array of longs named "sys_call_table", there is a default implementation
+ in kernel/trace/trace_syscalls.c. If your arch needs something weird,
+ then you'll have to define the function yourself.
- Support the TIF_SYSCALL_TRACEPOINT thread flags
- Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace
in the ptrace syscalls tracing path.
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 5a82bc6..d5fa352 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -203,7 +203,12 @@ out:
#ifdef CONFIG_FTRACE_SYSCALLS
-extern unsigned int sys_call_table[];
+/*
+ * The syscall table always contains 32 bit pointers since we know that the
+ * address of the function to be called is (way) below 4GB. So the "int"
+ * type here is what we want [need] for both 32 bit and 64 bit systems.
+ */
+extern const unsigned int sys_call_table[];
unsigned long __init arch_syscall_addr(int nr)
{
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index a48cded..30e1319 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -399,12 +399,3 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
}
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-
-#ifdef CONFIG_FTRACE_SYSCALLS
-extern unsigned long *sys_call_table;
-
-unsigned long __init arch_syscall_addr(int nr)
-{
- return (unsigned long)sys_call_table[nr];
-}
-#endif /* CONFIG_FTRACE_SYSCALLS */
diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c
index 29973da..deeeaa6 100644
--- a/arch/sparc/kernel/ftrace.c
+++ b/arch/sparc/kernel/ftrace.c
@@ -94,7 +94,12 @@ int __init ftrace_dyn_arch_init(void *data)
#ifdef CONFIG_FTRACE_SYSCALLS
-extern unsigned int sys_call_table[];
+/*
+ * The syscall table always contains 32 bit pointers since we know that the
+ * address of the function to be called is (way) below 4GB. So the "int"
+ * type here is what we want [need] for both 32 bit and 64 bit systems.
+ */
+extern const unsigned int sys_call_table[];
unsigned long __init arch_syscall_addr(int nr)
{
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 3096892..0d93a94 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -484,13 +484,3 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
}
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-
-#ifdef CONFIG_FTRACE_SYSCALLS
-
-extern unsigned long *sys_call_table;
-
-unsigned long __init arch_syscall_addr(int nr)
-{
- return (unsigned long)(&sys_call_table)[nr];
-}
-#endif
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 0b4f97d..1cbb36f 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -511,4 +511,10 @@ static inline void trace_hw_branch_oops(void) {}
#endif /* CONFIG_HW_BRANCH_TRACER */
+#ifdef CONFIG_FTRACE_SYSCALLS
+
+unsigned long arch_syscall_addr(int nr);
+
+#endif /* CONFIG_FTRACE_SYSCALLS */
+
#endif /* _LINUX_FTRACE_H */
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 75289f3..671c670 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -394,6 +394,12 @@ int init_syscall_trace(struct ftrace_event_call *call)
return 0;
}
+unsigned long __init __weak arch_syscall_addr(int nr)
+{
+ extern const unsigned long sys_call_table[];
+ return sys_call_table[nr];
+}
+
int __init init_ftrace_syscalls(void)
{
struct syscall_metadata *meta;
--
1.6.6.1
--
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