Messages in this thread | | | Subject | Re: [PATCH 10/15] powerpc/watchpoint: Use loop for thread_struct->ptrace_bps | From | Ravi Bangoria <> | Date | Wed, 18 Mar 2020 15:13:01 +0530 |
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>> @@ -1628,6 +1628,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, >> void (*f)(void); >> unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; >> struct thread_info *ti = task_thread_info(p); >> +#ifdef CONFIG_HAVE_HW_BREAKPOINT >> + int i; >> +#endif > > Could we avoid all those #ifdefs ? > > I think if we make p->thread.ptrace_bps[] exist all the time, with a size of 0 when CONFIG_HAVE_HW_BREAKPOINT is not set, then we can drop a lot of #ifdefs.
Hmm.. what you are saying seems possible. But IMO it should be done as independent series. Will work on it.
> >> klp_init_thread_info(p); >> @@ -1687,7 +1690,8 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, >> p->thread.ksp_limit = (unsigned long)end_of_stack(p); >> #endif >> #ifdef CONFIG_HAVE_HW_BREAKPOINT >> - p->thread.ptrace_bps[0] = NULL; >> + for (i = 0; i < nr_wp_slots(); i++) >> + p->thread.ptrace_bps[i] = NULL; >> #endif >> p->thread.fp_save_area = NULL; >> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c >> index f6d7955fc61e..e2651f86d56f 100644 >> --- a/arch/powerpc/kernel/ptrace.c >> +++ b/arch/powerpc/kernel/ptrace.c > > You'll have to rebase all this on the series https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=161356 which is about to go into powerpc-next
Sure. Thanks for heads up.
> >> @@ -2829,6 +2829,19 @@ static int set_dac_range(struct task_struct *child, >> } >> #endif /* CONFIG_PPC_ADV_DEBUG_DAC_RANGE */ >> +#ifdef CONFIG_HAVE_HW_BREAKPOINT >> +static int empty_ptrace_bp(struct thread_struct *thread) >> +{ >> + int i; >> + >> + for (i = 0; i < nr_wp_slots(); i++) { >> + if (!thread->ptrace_bps[i]) >> + return i; >> + } >> + return -1; >> +} >> +#endif > > What does this function do exactly ? I seems to do more than what its name suggests.
It finds an empty breakpoint in ptrace_bps[]. But yeah, function name is misleading. I'll rename it to find_empty_ptrace_bp().
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>> @@ -2979,10 +2993,10 @@ static long ppc_del_hwdebug(struct task_struct *child, long data) >> return -EINVAL; >> #ifdef CONFIG_HAVE_HW_BREAKPOINT >> - bp = thread->ptrace_bps[0]; >> + bp = thread->ptrace_bps[data - 1]; > > Is data checked somewhere to ensure it is not out of boundaries ? Or are we sure it is always within ?
Yes. it's checked. See patch #9:
@@ -2955,7 +2975,7 @@ static long ppc_del_hwdebug(struct task_struct *child, long data) } return rc; #else - if (data != 1) + if (data < 1 || data > nr_wp_slots()) return -EINVAL; #ifdef CONFIG_HAVE_HW_BREAKPOINT
Thanks, Ravi
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