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Message-ID: <53048C19.6040509@linaro.org>
Date: Wed, 19 Feb 2014 19:48:57 +0900
From: AKASHI Takahiro <takahiro.akashi@...aro.org>
To: Will Deacon <will.deacon@....com>
CC: "rostedt@...dmis.org" <rostedt@...dmis.org>,
"fweisbec@...il.com" <fweisbec@...il.com>,
"mingo@...hat.com" <mingo@...hat.com>,
Catalin Marinas <Catalin.Marinas@....com>,
"gkulkarni@...iumnetworks.com" <gkulkarni@...iumnetworks.com>,
"tim.bird@...ymobile.com" <tim.bird@...ymobile.com>,
"arndb@...db.de" <arndb@...db.de>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linaro-kernel@...ts.linaro.org" <linaro-kernel@...ts.linaro.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"patches@...aro.org" <patches@...aro.org>
Subject: Re: [PATCH v3 5/6] arm64: ftrace: Add system call tracepoint
On 02/18/2014 04:29 AM, Will Deacon wrote:
> On Fri, Feb 07, 2014 at 10:18:55AM +0000, AKASHI Takahiro wrote:
>> This patch allows system call entry or exit to be traced as ftrace events,
>> ie. sys_enter_*/sys_exit_*, if CONFIG_FTRACE_SYSCALLS is enabled.
>> Those events appear and can be controlled under
>> ${sysfs}/tracing/events/syscalls/
>>
>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@...aro.org>
>> ---
>> arch/arm64/Kconfig | 1 +
>> arch/arm64/include/asm/syscall.h | 1 +
>> arch/arm64/include/asm/unistd.h | 2 ++
>> arch/arm64/kernel/ptrace.c | 5 +++++
>> 4 files changed, 9 insertions(+)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 43fce76..9bdaf5c 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -42,6 +42,7 @@ config ARM64
>> select HAVE_HW_BREAKPOINT if PERF_EVENTS
>> select HAVE_MEMBLOCK
>> select HAVE_PERF_EVENTS
>> + select HAVE_SYSCALL_TRACEPOINTS
>> select IRQ_DOMAIN
>> select MODULES_USE_ELF_RELA
>> select NO_BOOTMEM
>> diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
>> index 70ba9d4..383771e 100644
>> --- a/arch/arm64/include/asm/syscall.h
>> +++ b/arch/arm64/include/asm/syscall.h
>> @@ -18,6 +18,7 @@
>>
>> #include <linux/err.h>
>>
>> +extern const void *sys_call_table[];
>>
>> static inline int syscall_get_nr(struct task_struct *task,
>> struct pt_regs *regs)
>> diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
>> index 82ce217..c335479 100644
>> --- a/arch/arm64/include/asm/unistd.h
>> +++ b/arch/arm64/include/asm/unistd.h
>> @@ -28,3 +28,5 @@
>> #endif
>> #define __ARCH_WANT_SYS_CLONE
>> #include <uapi/asm/unistd.h>
>> +
>> +#define NR_syscalls (__NR_syscalls)
>> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
>> index 64ce39f..f4c3c4e 100644
>> --- a/arch/arm64/kernel/ptrace.c
>> +++ b/arch/arm64/kernel/ptrace.c
>> @@ -41,6 +41,9 @@
>> #include <asm/traps.h>
>> #include <asm/system_misc.h>
>>
>> +#define CREATE_TRACE_POINTS
>> +#include <trace/events/syscalls.h>
>> +
>> /*
>> * TODO: does not yet catch signals sent when the child dies.
>> * in exit.c or in signal.c.
>> @@ -1076,10 +1079,12 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
>> }
>>
>> if (dir) {
>> + trace_sys_exit(regs, regs->syscallno);
>> tracehook_report_syscall_exit(regs, 0);
>> } else {
>> if (tracehook_report_syscall_entry(regs))
>> regs->syscallno = ~0UL;
>> + trace_sys_enter(regs, regs->syscallno);
>
> Shouldn't these calls be guarded by a TIF_SYSCALL_TRACEPOINT check?
Yes. I will add the guard.
-Takahiro AKASHI
> Will
>
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