From: "tiejun.chen" <tiejun.chen@windriver•com>
To: <benh@kernel•crashing.org>
Cc: linuxppc-dev@lists•ozlabs.org, jason.wessel@windriver•com
Subject: Re: [v2][PATCH 1/2] powerpc/kgdb: Fix a single stgep case of lazy IRQ
Date: Wed, 24 Oct 2012 09:17:39 +0800 [thread overview]
Message-ID: <508741B3.5000002@windriver.com> (raw)
In-Reply-To: <1350528455-4751-1-git-send-email-tiejun.chen@windriver.com>
Please ignore v2 temporarily since I have to correct something lately.
Sorry for any inconvenience.
Tiejun
On 10/18/2012 10:47 AM, Tiejun Chen wrote:
> When we're in kgdb_singlestep(), we have to work around to get
> thread_info by copying from the kernel stack before calling
> kgdb_handle_exception(), then copying it back afterwards.
>
> But for PPC64, we have a lazy interrupt implementation. So after
> copying thread info frome kernle stack, if we need to replay an
> interrupt, we shouldn't restore that previous backup thread info
> to make sure we can replay an interrupt lately with a proper
> thread info.
>
> This patch use __check_irq_replay() to guarantee this process.
>
> Signed-off-by: Tiejun Chen <tiejun.chen@windriver•com>
> ---
> arch/powerpc/kernel/irq.c | 12 +++++++++++-
> arch/powerpc/kernel/kgdb.c | 7 ++++---
> 2 files changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 71413f4..a773789 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -332,7 +332,17 @@ bool prep_irq_for_idle(void)
> return true;
> }
>
> -#endif /* CONFIG_PPC64 */
> +notrace unsigned int check_irq_replay(void)
> +{
> + return __check_irq_replay();
> +}
> +#else /* CONFIG_PPC64 */
> +notrace unsigned int check_irq_replay(void)
> +{
> + return 0;
> +}
> +#endif /* !CONFIG_PPC64 */
> +EXPORT_SYMBOL(check_irq_replay);
>
> int arch_show_interrupts(struct seq_file *p, int prec)
> {
> diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
> index c470a40..c4af341 100644
> --- a/arch/powerpc/kernel/kgdb.c
> +++ b/arch/powerpc/kernel/kgdb.c
> @@ -151,6 +151,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
> return 1;
> }
>
> +extern notrace unsigned int check_irq_replay(void);
> static int kgdb_singlestep(struct pt_regs *regs)
> {
> struct thread_info *thread_info, *exception_thread_info;
> @@ -181,9 +182,9 @@ static int kgdb_singlestep(struct pt_regs *regs)
>
> kgdb_handle_exception(0, SIGTRAP, 0, regs);
>
> - if (thread_info != exception_thread_info)
> - /* Restore current_thread_info lastly. */
> - memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);
> + if ((thread_info != exception_thread_info) && (!check_irq_replay()))
> + /* Restore current_thread_info lastly only if we don't replay interrupt. */
> + memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);
>
> return 1;
> }
>
prev parent reply other threads:[~2012-10-24 1:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-18 2:47 [v2][PATCH 1/2] powerpc/kgdb: Fix a single stgep case of lazy IRQ Tiejun Chen
2012-10-18 2:47 ` [v2][PATCH 2/2] PPC_BOOK3E/KGDB: support kgdb kernel space Tiejun Chen
2012-10-24 1:17 ` tiejun.chen [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=508741B3.5000002@windriver.com \
--to=tiejun.chen@windriver$(echo .)com \
--cc=benh@kernel$(echo .)crashing.org \
--cc=jason.wessel@windriver$(echo .)com \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox