From: wade_farnsworth@mentor•com (Wade Farnsworth)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/3] ARM: support syscall tracing
Date: Fri, 24 Feb 2012 08:48:29 -0700 [thread overview]
Message-ID: <4F47B14D.7010702@mentor.com> (raw)
In-Reply-To: <20120224110522.GF13504@mudshark.cambridge.arm.com>
Will Deacon wrote:
> On Wed, Feb 22, 2012 at 02:47:00PM +0000, Wade Farnsworth wrote:
>> As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
>> added, as well as NR_syscalls in asm/unistd.h. Additionally,
>> __sys_trace was modified to call trace_sys_enter and
>> trace_sys_exit when appropriate.
>>
>> Tests #2 - #4 of "perf test" now complete successfully.
>>
>> Signed-off-by: Steven Walter<stevenrwalter@gmail•com>
>> Signed-off-by: Wade Farnsworth<wade_farnsworth@mentor•com>
>> ---
>
> [...]
>
>> diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
>> index 512cd14..e4a2e78 100644
>> --- a/arch/arm/include/asm/unistd.h
>> +++ b/arch/arm/include/asm/unistd.h
>> @@ -405,6 +405,18 @@
>> #define __NR_process_vm_readv (__NR_SYSCALL_BASE+376)
>> #define __NR_process_vm_writev (__NR_SYSCALL_BASE+377)
>>
>> +#ifdef __KERNEL__
>> +
>> +/* This may need to be greater than __NR_last_syscall+1 in order to
>> + * account for the padding in the syscall table */
>> +#define __NR_syscalls (380)
>
> Do we actually have padding in the syscall table? It looks like a list of
> .long to me. I'd rather put the correct number in if possible.
This patch will calculate NR_syscalls by counting the number of entries
in calls.S. calls.S may add up to three entries of padding at the end
of that file that __NR_syscalls needs to account for.
>
>> +#ifndef __ASSEMBLY__
>> +#define NR_syscalls (__NR_syscalls)
>> +#endif /* __ASSEMBLY__ */
>
> Hmm, these guards feel like a hack. Would moving the define into syscall.h
> help?
I'll give this a shot, though I'll also note that adding the guards on
!__ASSEMBLY__ was suggested by Russel:
http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074506.html
>
>> diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
>> index 9fd0ba9..9bed212 100644
>> --- a/arch/arm/kernel/entry-common.S
>> +++ b/arch/arm/kernel/entry-common.S
>> @@ -79,6 +79,11 @@ no_work_pending:
>> ENDPROC(ret_to_user_from_irq)
>> ENDPROC(ret_to_user)
>>
>> +.macro test_syscall_tracing reg
>> + tst \reg, #_TIF_SYSCALL_WORK
>> + tsteq \reg, #_TIF_SYSCALL_TRACEPOINT
>> +.endm
>> +
>> /*
>> * This is how we return from a fork.
>> */
>> @@ -87,7 +92,7 @@ ENTRY(ret_from_fork)
>> get_thread_info tsk
>> ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
>> mov why, #1
>> - tst r1, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
>> + test_syscall_tracing r1
>> beq ret_slow_syscall
>> mov r1, sp
>> mov r0, #1 @ trace exit [IP = 1]
>> @@ -98,6 +103,13 @@ ENDPROC(ret_from_fork)
>> .equ NR_syscalls,0
>> #define CALL(x) .equ NR_syscalls,NR_syscalls+1
>> #include "calls.S"
>> +
>> +/* Ensure that the system call table is not larger than __NR_syscalls,
>> + * which is the value the rest of the system sees */
>> +.ifgt NR_syscalls - __NR_syscalls
>> +.error "__NR_syscalls is less than the size of the syscall table"
>> +.endif
>
> I think it would also be nice to check for equality here if we can.
Should be doable.
>
> Rest of the code looks alright, but it should be tested with OABI if it
> hasn't been already.
>
I might be able to build my userspace against OABI. I'll see what I can
dig up.
Thanks for the review!
-Wade
next prev parent reply other threads:[~2012-02-24 15:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-22 14:44 [PATCH 0/3] ARM support for syscall tracing Wade Farnsworth
2012-02-22 14:45 ` [PATCH 1/3] ARM: add support for the generic syscall.h interface Wade Farnsworth
2012-02-24 11:00 ` Will Deacon
2012-02-24 15:47 ` Wade Farnsworth
2012-02-22 14:46 ` [PATCH 2/3] ARM: add TRACEHOOK support Wade Farnsworth
2012-02-22 14:47 ` [PATCH 3/3] ARM: support syscall tracing Wade Farnsworth
2012-02-24 11:05 ` Will Deacon
2012-02-24 15:48 ` Wade Farnsworth [this message]
2012-02-29 14:34 ` [PATCH v2 0/3] ARM support for " Wade Farnsworth
2012-02-29 14:35 ` [PATCH v2 1/3] ARM: add support for the generic syscall.h interface Wade Farnsworth
2012-02-29 14:36 ` [PATCH v2 2/3] ARM: add TRACEHOOK support Wade Farnsworth
2012-02-29 14:36 ` [PATCH v2 3/3] ARM: support syscall tracing Wade Farnsworth
2012-02-29 18:29 ` [PATCH v2 0/3] ARM support for " Will Deacon
2012-03-05 14:42 ` [PATCH v3 " Wade Farnsworth
2012-03-05 14:43 ` [PATCH v3 1/3] ARM: add support for the generic syscall.h interface Wade Farnsworth
2012-03-05 14:43 ` [PATCH v3 2/3] ARM: add TRACEHOOK support Wade Farnsworth
2012-03-05 14:44 ` [PATCH v3 3/3] ARM: support syscall tracing Wade Farnsworth
2012-03-23 14:50 ` [PATCH v4 0/3] ARM support for " Wade Farnsworth
2012-03-23 14:51 ` [PATCH v4 1/3] ARM: add support for the generic syscall.h interface Wade Farnsworth
2012-03-23 14:52 ` [PATCH v4 2/3] ARM: add TRACEHOOK support Wade Farnsworth
2012-03-23 14:53 ` [PATCH v4 3/3] ARM: support syscall tracing Wade Farnsworth
2012-03-30 16:55 ` [PATCH v4 0/3] ARM support for " Will Deacon
-- strict thread matches above, loose matches on Subject: below --
2011-11-29 16:28 [RFC] " Steven Walter
2011-11-29 16:28 ` [PATCH 3/3] ARM: support " Steven Walter
2011-11-29 17:24 ` Will Deacon
2011-11-29 18:02 ` Steven Walter
2011-11-29 17:46 ` Russell King - ARM Linux
2011-11-29 18:12 ` Steven Walter
2011-11-29 21:55 ` Russell King - ARM Linux
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