| Message ID | 1409079338-14001-1-git-send-email-jcm@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 26, 2014 at 7:55 PM, Jon Masters <jcm@redhat.com> wrote: > The kernel wants to enable reporting of asynchronous interrupts (i.e. > System Errors) as early as possible. But if this happens too early > then a pending System Error on initial entry into the kernel will > never be reported where a user can see it (instead it will remain > in the kernel ring buffer and be visible only via hardware debug). > Therefore, move the enabling of asynchronous interrupts to after > parsing any possible earlycon parameters setting up earlycon. > > Signed-off-by: Jon Masters <jcm@redhat.com> That sounds wrong. Why aren't early log messages getting flushed out when the console shows up? g. > --- > arch/arm64/kernel/setup.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index f6f0ccf..f849b88 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -362,11 +362,6 @@ u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID }; > > void __init setup_arch(char **cmdline_p) > { > - /* > - * Unmask asynchronous aborts early to catch possible system errors. > - */ > - local_async_enable(); > - > setup_processor(); > > setup_machine_fdt(__fdt_pointer); > @@ -382,6 +377,12 @@ void __init setup_arch(char **cmdline_p) > > parse_early_param(); > > + /* > + * Unmask asynchronous aborts after bringing up possible earlycon. > + * (Report possible System Errors once we can report this occurred) > + */ > + local_async_enable(); > + > efi_init(); > arm64_memblock_init(); > > -- > 1.8.3.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Hi Grant, On 08/26/2014 04:01 PM, Grant Likely wrote: > On Tue, Aug 26, 2014 at 7:55 PM, Jon Masters <jcm@redhat.com> wrote: >> The kernel wants to enable reporting of asynchronous interrupts (i.e. >> System Errors) as early as possible. But if this happens too early >> then a pending System Error on initial entry into the kernel will >> never be reported where a user can see it (instead it will remain >> in the kernel ring buffer and be visible only via hardware debug). >> Therefore, move the enabling of asynchronous interrupts to after >> parsing any possible earlycon parameters setting up earlycon. >> >> Signed-off-by: Jon Masters <jcm@redhat.com> > > That sounds wrong. Why aren't early log messages getting flushed out > when the console shows up? The problem is that when such an error occurs, we immediately panic. And we've not setup the earlycon yet so there's no way to ever see it. I wasted a bunch of time last week so it's worth saving someone else. Jon.
On Tue, Aug 26, 2014 at 9:05 PM, Jon Masters <jcm@redhat.com> wrote: > Hi Grant, > > On 08/26/2014 04:01 PM, Grant Likely wrote: >> On Tue, Aug 26, 2014 at 7:55 PM, Jon Masters <jcm@redhat.com> wrote: >>> The kernel wants to enable reporting of asynchronous interrupts (i.e. >>> System Errors) as early as possible. But if this happens too early >>> then a pending System Error on initial entry into the kernel will >>> never be reported where a user can see it (instead it will remain >>> in the kernel ring buffer and be visible only via hardware debug). >>> Therefore, move the enabling of asynchronous interrupts to after >>> parsing any possible earlycon parameters setting up earlycon. >>> >>> Signed-off-by: Jon Masters <jcm@redhat.com> >> >> That sounds wrong. Why aren't early log messages getting flushed out >> when the console shows up? > > The problem is that when such an error occurs, we immediately panic. And > we've not setup the earlycon yet so there's no way to ever see it. I > wasted a bunch of time last week so it's worth saving someone else. Reasonable reason. Perhaps put that in the patch description. g.
On 08/26/2014 04:05 PM, Jon Masters wrote: > Hi Grant, > > On 08/26/2014 04:01 PM, Grant Likely wrote: >> On Tue, Aug 26, 2014 at 7:55 PM, Jon Masters <jcm@redhat.com> wrote: >>> The kernel wants to enable reporting of asynchronous interrupts (i.e. >>> System Errors) as early as possible. But if this happens too early >>> then a pending System Error on initial entry into the kernel will >>> never be reported where a user can see it (instead it will remain >>> in the kernel ring buffer and be visible only via hardware debug). >>> Therefore, move the enabling of asynchronous interrupts to after >>> parsing any possible earlycon parameters setting up earlycon. >>> >>> Signed-off-by: Jon Masters <jcm@redhat.com> >> >> That sounds wrong. Why aren't early log messages getting flushed out >> when the console shows up? > > The problem is that when such an error occurs, we immediately panic. And > we've not setup the earlycon yet so there's no way to ever see it. I > wasted a bunch of time last week so it's worth saving someone else. Admittedly this is more likely to be an issue for Enterprise vendor kernels, where the default config (should be always) is PANIC_ON_OOPS. Jon.
On 08/26/2014 04:09 PM, Grant Likely wrote: > On Tue, Aug 26, 2014 at 9:05 PM, Jon Masters <jcm@redhat.com> wrote: >> Hi Grant, >> >> On 08/26/2014 04:01 PM, Grant Likely wrote: >>> On Tue, Aug 26, 2014 at 7:55 PM, Jon Masters <jcm@redhat.com> wrote: >>>> The kernel wants to enable reporting of asynchronous interrupts (i.e. >>>> System Errors) as early as possible. But if this happens too early >>>> then a pending System Error on initial entry into the kernel will >>>> never be reported where a user can see it (instead it will remain >>>> in the kernel ring buffer and be visible only via hardware debug). >>>> Therefore, move the enabling of asynchronous interrupts to after >>>> parsing any possible earlycon parameters setting up earlycon. >>>> >>>> Signed-off-by: Jon Masters <jcm@redhat.com> >>> >>> That sounds wrong. Why aren't early log messages getting flushed out >>> when the console shows up? >> >> The problem is that when such an error occurs, we immediately panic. And >> we've not setup the earlycon yet so there's no way to ever see it. I >> wasted a bunch of time last week so it's worth saving someone else. > > Reasonable reason. Perhaps put that in the patch description. Sent a V2 with that fixed. Forgot to copy you, apologies. Jon.
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index f6f0ccf..f849b88 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -362,11 +362,6 @@ u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID }; void __init setup_arch(char **cmdline_p) { - /* - * Unmask asynchronous aborts early to catch possible system errors. - */ - local_async_enable(); - setup_processor(); setup_machine_fdt(__fdt_pointer); @@ -382,6 +377,12 @@ void __init setup_arch(char **cmdline_p) parse_early_param(); + /* + * Unmask asynchronous aborts after bringing up possible earlycon. + * (Report possible System Errors once we can report this occurred) + */ + local_async_enable(); + efi_init(); arm64_memblock_init();
The kernel wants to enable reporting of asynchronous interrupts (i.e. System Errors) as early as possible. But if this happens too early then a pending System Error on initial entry into the kernel will never be reported where a user can see it (instead it will remain in the kernel ring buffer and be visible only via hardware debug). Therefore, move the enabling of asynchronous interrupts to after parsing any possible earlycon parameters setting up earlycon. Signed-off-by: Jon Masters <jcm@redhat.com> --- arch/arm64/kernel/setup.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)