| Message ID | 20200309085806.155823-11-ravi.bangoria@linux.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | powerpc/watchpoint: Preparation for more than one watchpoint | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (ab326587bb5fb91cc97df9b9f48e9e1469f04621) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 92 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
Le 09/03/2020 à 09:58, Ravi Bangoria a écrit : > ptrace_bps is already an array of size HBP_NUM_MAX. But we use > hardcoded index 0 while fetching/updating it. Convert such code > to loop over array. > > Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> > --- > arch/powerpc/kernel/hw_breakpoint.c | 7 +++++-- > arch/powerpc/kernel/process.c | 6 +++++- > arch/powerpc/kernel/ptrace.c | 28 +++++++++++++++++++++------- > 3 files changed, 31 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c > index f4d48f87dcb8..b27aca623267 100644 > --- a/arch/powerpc/kernel/hw_breakpoint.c > +++ b/arch/powerpc/kernel/hw_breakpoint.c > @@ -419,10 +419,13 @@ NOKPROBE_SYMBOL(hw_breakpoint_exceptions_notify); > */ > void flush_ptrace_hw_breakpoint(struct task_struct *tsk) > { > + int i; > struct thread_struct *t = &tsk->thread; > > - unregister_hw_breakpoint(t->ptrace_bps[0]); > - t->ptrace_bps[0] = NULL; > + for (i = 0; i < nr_wp_slots(); i++) { > + unregister_hw_breakpoint(t->ptrace_bps[i]); > + t->ptrace_bps[i] = NULL; > + } > } > > void hw_breakpoint_pmu_read(struct perf_event *bp) > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > index 42ff62ef749c..b9ab740fcacf 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -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. > > 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 > @@ -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. > + > #ifndef CONFIG_PPC_ADV_DEBUG_REGS > static int empty_hw_brk(struct thread_struct *thread) > { > @@ -2915,8 +2928,9 @@ static long ppc_set_hwdebug(struct task_struct *child, > len = 1; > else > return -EINVAL; > - bp = thread->ptrace_bps[0]; > - if (bp) > + > + i = empty_ptrace_bp(thread); > + if (i < 0) > return -ENOSPC; > > /* Create a new breakpoint request if one doesn't exist already */ > @@ -2925,14 +2939,14 @@ static long ppc_set_hwdebug(struct task_struct *child, > attr.bp_len = len; > arch_bp_generic_fields(brk.type, &attr.bp_type); > > - thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr, > + thread->ptrace_bps[i] = bp = register_user_hw_breakpoint(&attr, > ptrace_triggered, NULL, child); > if (IS_ERR(bp)) { > - thread->ptrace_bps[0] = NULL; > + thread->ptrace_bps[i] = NULL; > return PTR_ERR(bp); > } > > - return 1; > + return i + 1; > #endif /* CONFIG_HAVE_HW_BREAKPOINT */ > > if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) > @@ -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 ? > if (bp) { > unregister_hw_breakpoint(bp); > - thread->ptrace_bps[0] = NULL; > + thread->ptrace_bps[data - 1] = NULL; > } else > ret = -ENOENT; > return ret; > Christophe
>> @@ -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(). ... >> @@ -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
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index f4d48f87dcb8..b27aca623267 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -419,10 +419,13 @@ NOKPROBE_SYMBOL(hw_breakpoint_exceptions_notify); */ void flush_ptrace_hw_breakpoint(struct task_struct *tsk) { + int i; struct thread_struct *t = &tsk->thread; - unregister_hw_breakpoint(t->ptrace_bps[0]); - t->ptrace_bps[0] = NULL; + for (i = 0; i < nr_wp_slots(); i++) { + unregister_hw_breakpoint(t->ptrace_bps[i]); + t->ptrace_bps[i] = NULL; + } } void hw_breakpoint_pmu_read(struct perf_event *bp) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 42ff62ef749c..b9ab740fcacf 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -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 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 @@ -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 + #ifndef CONFIG_PPC_ADV_DEBUG_REGS static int empty_hw_brk(struct thread_struct *thread) { @@ -2915,8 +2928,9 @@ static long ppc_set_hwdebug(struct task_struct *child, len = 1; else return -EINVAL; - bp = thread->ptrace_bps[0]; - if (bp) + + i = empty_ptrace_bp(thread); + if (i < 0) return -ENOSPC; /* Create a new breakpoint request if one doesn't exist already */ @@ -2925,14 +2939,14 @@ static long ppc_set_hwdebug(struct task_struct *child, attr.bp_len = len; arch_bp_generic_fields(brk.type, &attr.bp_type); - thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr, + thread->ptrace_bps[i] = bp = register_user_hw_breakpoint(&attr, ptrace_triggered, NULL, child); if (IS_ERR(bp)) { - thread->ptrace_bps[0] = NULL; + thread->ptrace_bps[i] = NULL; return PTR_ERR(bp); } - return 1; + return i + 1; #endif /* CONFIG_HAVE_HW_BREAKPOINT */ if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) @@ -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]; if (bp) { unregister_hw_breakpoint(bp); - thread->ptrace_bps[0] = NULL; + thread->ptrace_bps[data - 1] = NULL; } else ret = -ENOENT; return ret;
ptrace_bps is already an array of size HBP_NUM_MAX. But we use hardcoded index 0 while fetching/updating it. Convert such code to loop over array. Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> --- arch/powerpc/kernel/hw_breakpoint.c | 7 +++++-- arch/powerpc/kernel/process.c | 6 +++++- arch/powerpc/kernel/ptrace.c | 28 +++++++++++++++++++++------- 3 files changed, 31 insertions(+), 10 deletions(-)