From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
mpe@ellerman.id.au, mikey@neuling.org
Cc: apopple@linux.ibm.com, paulus@samba.org, npiggin@gmail.com,
naveen.n.rao@linux.vnet.ibm.com, peterz@infradead.org,
jolsa@kernel.org, oleg@redhat.com, fweisbec@gmail.com,
mingo@kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/15] powerpc/watchpoint: Use loop for thread_struct->ptrace_bps
Date: Tue, 17 Mar 2020 11:48:12 +0100 [thread overview]
Message-ID: <0eeeac90-b5e3-722b-2d2c-bb95c81d851a@c-s.fr> (raw)
In-Reply-To: <20200309085806.155823-11-ravi.bangoria@linux.ibm.com>
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
next prev parent reply other threads:[~2020-03-17 10:48 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 8:57 [PATCH 00/15] powerpc/watchpoint: Preparation for more than one watchpoint Ravi Bangoria
2020-03-09 8:57 ` [PATCH 01/15] powerpc/watchpoint: Rename current DAWR macros Ravi Bangoria
2020-03-17 10:14 ` Christophe Leroy
2020-03-18 12:40 ` Ravi Bangoria
2020-03-09 8:57 ` [PATCH 02/15] powerpc/watchpoint: Add SPRN macros for second DAWR Ravi Bangoria
2020-03-17 10:16 ` Christophe Leroy
2020-03-18 18:30 ` Segher Boessenkool
2020-03-09 8:57 ` [PATCH 03/15] powerpc/watchpoint: Introduce function to get nr watchpoints dynamically Ravi Bangoria
2020-03-17 10:21 ` Christophe Leroy
2020-03-18 5:50 ` Ravi Bangoria
2020-03-09 8:57 ` [PATCH 04/15] powerpc/watchpoint/ptrace: Return actual num of available watchpoints Ravi Bangoria
2020-03-09 8:57 ` [PATCH 05/15] powerpc/watchpoint: Provide DAWR number to set_dawr Ravi Bangoria
2020-03-17 10:28 ` Christophe Leroy
2020-03-18 6:18 ` Ravi Bangoria
2020-03-09 8:57 ` [PATCH 06/15] powerpc/watchpoint: Provide DAWR number to __set_breakpoint Ravi Bangoria
2020-03-09 8:57 ` [PATCH 07/15] powerpc/watchpoint: Get watchpoint count dynamically while disabling them Ravi Bangoria
2020-03-17 10:32 ` Christophe Leroy
2020-03-18 6:57 ` Ravi Bangoria
2020-03-26 3:32 ` Ravi Bangoria
2020-03-09 8:57 ` [PATCH 08/15] powerpc/watchpoint: Disable all available watchpoints when !dawr_force_enable Ravi Bangoria
2020-03-17 10:35 ` Christophe Leroy
2020-03-18 7:32 ` Ravi Bangoria
2020-03-09 8:58 ` [PATCH 09/15] powerpc/watchpoint: Convert thread_struct->hw_brk to an array Ravi Bangoria
2020-03-17 10:37 ` Christophe Leroy
2020-03-18 8:36 ` Ravi Bangoria
2020-03-18 8:56 ` Christophe Leroy
2020-03-18 9:22 ` Ravi Bangoria
2020-03-09 8:58 ` [PATCH 10/15] powerpc/watchpoint: Use loop for thread_struct->ptrace_bps Ravi Bangoria
2020-03-17 10:48 ` Christophe Leroy [this message]
2020-03-18 9:43 ` Ravi Bangoria
2020-03-09 8:58 ` [PATCH 11/15] powerpc/watchpoint: Introduce is_ptrace_bp() function Ravi Bangoria
2020-03-17 10:49 ` Christophe Leroy
2020-03-09 8:58 ` [PATCH 12/15] powerpc/watchpoint: Prepare handler to handle more than one watcnhpoint Ravi Bangoria
2020-03-17 10:59 ` Christophe Leroy
2020-03-18 11:35 ` Michael Ellerman
2020-03-18 11:44 ` Christophe Leroy
2020-03-18 21:27 ` Segher Boessenkool
2020-03-18 23:36 ` Michael Ellerman
2020-03-18 12:14 ` Ravi Bangoria
2020-03-09 8:58 ` [PATCH 13/15] powerpc/watchpoint: Don't allow concurrent perf and ptrace events Ravi Bangoria
2020-03-17 11:08 ` Christophe Leroy
2020-03-18 12:35 ` Ravi Bangoria
2020-03-09 8:58 ` [PATCH 14/15] powerpc/watchpoint/xmon: Don't allow breakpoint overwriting Ravi Bangoria
2020-03-17 11:10 ` Christophe Leroy
2020-03-18 12:37 ` Ravi Bangoria
2020-03-18 13:31 ` Christophe Leroy
2020-03-09 8:58 ` [PATCH 15/15] powerpc/watchpoint/xmon: Support 2nd dawr Ravi Bangoria
2020-03-17 11:14 ` Christophe Leroy
2020-03-18 12:39 ` Ravi Bangoria
2020-03-16 15:05 ` [PATCH 00/15] powerpc/watchpoint: Preparation for more than one watchpoint Christophe Leroy
2020-03-16 18:43 ` Segher Boessenkool
2020-03-17 5:56 ` Christophe Leroy
2020-03-18 12:52 ` Ravi Bangoria
2020-03-23 13:37 ` Ravi Bangoria
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