Messages in this thread | | | Date | Fri, 14 Aug 2015 15:09:34 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH] ARM: keystone: add a work around to handle asynchronous external abort |
| |
On Fri, Aug 14, 2015 at 10:04:41AM -0400, Murali Karicheri wrote: > On 08/11/2015 03:13 PM, Murali Karicheri wrote: > >Currently on some devices, an asynchronous external abort exception > >happens during boot up when exception handlers are enabled in kernel > >before switching to user space. This patch adds a workaround to handle > >this once during boot. Many customers are already using this > >with out any issues and is required to workaround the above issue. > > > >Signed-off-by: Murali Karicheri <m-karicheri2@ti.com> > >--- > > arch/arm/mach-keystone/keystone.c | 26 ++++++++++++++++++++++++++ > > 1 file changed, 26 insertions(+) > > > >diff --git a/arch/arm/mach-keystone/keystone.c b/arch/arm/mach-keystone/keystone.c > >index e2880105..c1d0fe5 100644 > >--- a/arch/arm/mach-keystone/keystone.c > >+++ b/arch/arm/mach-keystone/keystone.c > >@@ -15,6 +15,7 @@ > > #include <linux/of_platform.h> > > #include <linux/of_address.h> > > #include <linux/memblock.h> > >+#include <linux/signal.h> > > > > #include <asm/setup.h> > > #include <asm/mach/map.h> > >@@ -52,6 +53,24 @@ static struct notifier_block platform_nb = { > > .notifier_call = keystone_platform_notifier, > > }; > > > >+static bool ignore_first = true; > >+static int keystone_async_ext_abort_fault(unsigned long addr, unsigned int fsr, > >+ struct pt_regs *regs) > >+{ > >+ /* > >+ * if first time, ignore this as this is a asynchronous external abort > >+ * happening only some devices that couldn't be root caused and we add > >+ * this work around to handle this first time. > >+ */ > >+ if (ignore_first) { > >+ ignore_first = false; > >+ return 0; > >+ } > >+ > >+ /* Subsequent ones should be handled as fault */ > >+ return 1; > >+} > >+ > > static void __init keystone_init(void) > > { > > if (PHYS_OFFSET >= KEYSTONE_HIGH_PHYS_START) { > >@@ -61,6 +80,13 @@ static void __init keystone_init(void) > > } > > keystone_pm_runtime_init(); > > of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); > >+ > >+ /* > >+ * Add a one time exception handler to catch asynchronous external > >+ * abort > >+ */ > >+ hook_fault_code(17, keystone_async_ext_abort_fault, SIGBUS, 0, > >+ "async external abort handler"); > > } > > > > static phys_addr_t keystone_virt_to_idmap(unsigned long x) > > > Can this be applied if it looks good?
What causes the abort? We shouldn't be adding hacks like this to the kernel without having the full picture...
-- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net.
| |