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-kariche...@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? Murali -- Murali Karicheri Linux Kernel, Keystone -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
