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SubjectRe: [PATCH] ARM: Wire up HAVE_SYSCALL_TRACEPOINTS
Hello,
I am glad to start getting responses.
(2012/02/01 10:47), Indan Zupancic wrote:
> Hello,
>
> CC'ing Roland.
>
> On Thu, December 1, 2011 12:01, takuo.koguchi.sw@hitachi.com wrote:
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index 44789ef..84181b3 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -13,6 +13,7 @@ config ARM
>> select HAVE_KPROBES if !XIP_KERNEL
>> select HAVE_KRETPROBES if (HAVE_KPROBES)
>> select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
>> + select HAVE_SYSCALL_TRACEPOINTS
> Your patch totally ignores OABI, it should at least depend on CONFIG_AEABI
> and on !CONFIG_OABI_COMPAT.
Right. As Russel King suggested, this patch depends on those configs
until very large NR_syscalls is properly handled by ftrace.

>> select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
>> select HAVE_DYNAMIC_FTRACE if (!XIP_KERNEL)
>> select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
>> diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
>> new file mode 100644
>> index 0000000..cabeb67
>> --- /dev/null
>> +++ b/arch/arm/include/asm/syscall.h
>> @@ -0,0 +1,45 @@
>> +#ifndef _ASM_ARM_SYSCALL_H
>> +#define _ASM_ARM_SYSCALL_H
>> +
>> +extern const unsigned long sys_call_table[];
>> +
>> +#include<linux/sched.h>
>> +
>> +static inline long syscall_get_nr(struct task_struct *task,
>> + struct pt_regs *regs)
>> +{
>> + return regs->ARM_r7;
>> +}
>> +
>> +static inline long syscall_get_return_value(struct task_struct *task,
>> + struct pt_regs *regs)
>> +{
>> + return regs->ARM_r0;
>> +}
>> +
>> +static inline void syscall_get_arguments(struct task_struct *task,
>> + struct pt_regs *regs,
>> + unsigned int i, unsigned int n,
>> + unsigned long *args)
>> +{
>> + BUG_ON(i);
> This is unacceptable, that would make this function useless.
>
> See Rolands patch:
>
> https://lkml.org/lkml/2009/4/24/399 for a better implementation.
Thanks. My apology for the lack of investigation.

>> +#endif /* _ASM_ARM_SYSCALL_H */
>> diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
>> index 7b5cc8d..2509028 100644
>> --- a/arch/arm/include/asm/thread_info.h
>> +++ b/arch/arm/include/asm/thread_info.h
>> @@ -139,6 +139,7 @@ extern void vfp_flush_hwstate(struct thread_info *);
>> #define TIF_NEED_RESCHED 1
>> #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
>> #define TIF_SYSCALL_TRACE 8
>> +#define TIF_SYSCALL_TRACEPOINT 15
>> #define TIF_POLLING_NRFLAG 16
>> #define TIF_USING_IWMMXT 17
>> #define TIF_MEMDIE 18 /* is terminating due to OOM killer */
>> @@ -150,11 +151,13 @@ extern void vfp_flush_hwstate(struct thread_info *);
>> #define _TIF_NEED_RESCHED (1<< TIF_NEED_RESCHED)
>> #define _TIF_NOTIFY_RESUME (1<< TIF_NOTIFY_RESUME)
>> #define _TIF_SYSCALL_TRACE (1<< TIF_SYSCALL_TRACE)
>> +#define _TIF_SYSCALL_TRACEPOINT (1<< TIF_SYSCALL_TRACEPOINT)
>> #define _TIF_POLLING_NRFLAG (1<< TIF_POLLING_NRFLAG)
>> #define _TIF_USING_IWMMXT (1<< TIF_USING_IWMMXT)
>> #define _TIF_FREEZE (1<< TIF_FREEZE)
>> #define _TIF_RESTORE_SIGMASK (1<< TIF_RESTORE_SIGMASK)
>> #define _TIF_SECCOMP (1<< TIF_SECCOMP)
>> +#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)
> What does 'A' stand for?
'A' originally stands for AUDIT. I should have used a better name as
there is no _TIF_SYSCALL_AUDIT for ARM.
Probably it is better to define _TIF_WORK_SYSCALL_ENTRY and
_TIF_WORK_SYSCALL_EXIT properly.

>> /*
>> * Change these and you break ASM code in entry-common.S
>> diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
>> index 4a11237..f4eac2d 100644
>> --- a/arch/arm/include/asm/unistd.h
>> +++ b/arch/arm/include/asm/unistd.h
>> @@ -405,6 +405,9 @@
>> #define __NR_process_vm_readv (__NR_SYSCALL_BASE+376)
>> #define __NR_process_vm_writev (__NR_SYSCALL_BASE+377)
>>
>> +#ifndef __ASSEMBLY__
>> +#define NR_syscalls 378
>> +#endif
>> /*
>> * The following SWIs are ARM private.
>> */
>> diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
>> index b2a27b6..a1577c2 100644
>> --- a/arch/arm/kernel/entry-common.S
>> +++ b/arch/arm/kernel/entry-common.S
>> @@ -87,7 +87,7 @@ ENTRY(ret_from_fork)
>> get_thread_info tsk
>> ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
>> mov why, #1
>> - tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
>> + tst r1, #_TIF_SYSCALL_T_OR_A @ are we tracing syscalls?
>> beq ret_slow_syscall
>> mov r1, sp
>> mov r0, #1 @ trace exit [IP = 1]
>> @@ -443,7 +443,7 @@ ENTRY(vector_swi)
>> 1:
>> #endif
>>
>> - tst r10, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
>> + tst r10, #_TIF_SYSCALL_T_OR_A @ are we tracing syscalls?
>> bne __sys_trace
>>
>> cmp scno, #NR_syscalls @ check upper syscall limit
>> diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
>> index 483727a..a690c9f 100644
>> --- a/arch/arm/kernel/ptrace.c
>> +++ b/arch/arm/kernel/ptrace.c
>> @@ -28,6 +28,9 @@
>> #include<asm/system.h>
>> #include<asm/traps.h>
>>
>> +#define CREATE_TRACE_POINTS
>> +#include<trace/events/syscalls.h>
>> +
>> #define REG_PC 15
>> #define REG_PSR 16
>> /*
>> @@ -906,6 +909,13 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int
>> scno)
>> {
>> unsigned long ip;
> Not used, you get the same info from 'why'.
Sorry. But I do not understand what you suggest here. This is the
existing code.

>
>> + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) {
>> + if (why)
>> + trace_sys_exit(regs, regs->ARM_r0);
>> + else
>> + trace_sys_enter(regs, scno);
>> + }
>> +
>> if (!test_thread_flag(TIF_SYSCALL_TRACE))
>> return scno;
>> if (!(current->ptrace& PT_PTRACED))
>

Thanks,

Takuo




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