| Message ID | 1388965601-18329-5-git-send-email-hauke@hauke-m.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Monday 06 January 2014, Hauke Mehrtens wrote: > Without this patch I am getting a unhandled fault exception like this > one after "Freeing unused kernel memory": > > Freeing unused kernel memory: 1260K (c02c1000 - c03fc000) > Unhandled fault: imprecise external abort (0x1c06) at 0xb6f89005 > Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007 > > The address which is here 0xb6f89005 changes from boot to boot, with a > new build the changes are bigger. With kernel 3.10 I have also seen > this fault at different places in the boot process, but starting with > 3.11 they are mostly occurring after the "Freeing unused kernel memory" > message. I never was able to completely boot to userspace without this > handler. The abort code is constant 0x1c06. This fault just happens > once in the boot process I have never seen it happing twice or more. > > I also tried changing the CPSR.A bit to 0 in init_early, with this code > like Afzal suggested, but that did not change anything: > asm volatile("mrs r12, cpsr\n" > "bic r12, r12, #0x00000100\n" > "msr cpsr_c, r12" ::: "r12", "cc", "memory"); > > Disabling the L2 cache by building with CONFIG_CACHE_L2X0 unset did not > help. > > This workaround was copied from the vendor code including most of the > comments. It says it they think this is caused by the CFE boot loader > used on this device. I do not have any access to any datasheet or > errata document to check this. > > Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm/mach-bcm/bcm_5301x.c b/arch/arm/mach-bcm/bcm_5301x.c index ef9740a..edff6976 100644 --- a/arch/arm/mach-bcm/bcm_5301x.c +++ b/arch/arm/mach-bcm/bcm_5301x.c @@ -9,8 +9,40 @@ #include <asm/hardware/cache-l2x0.h> #include <asm/mach/arch.h> +#include <asm/siginfo.h> +#include <asm/signal.h> +static bool first_fault = true; + +static int bcm5301x_abort_handler(unsigned long addr, unsigned int fsr, + struct pt_regs *regs) +{ + if (fsr == 0x1c06 && first_fault) { + first_fault = false; + + /* + * These faults with code 0x1c06 happens for no good reason, + * possibly left over from the CFE boot loader. + */ + pr_warn("External imprecise Data abort at addr=%#lx, fsr=%#x ignored.\n", + addr, fsr); + + /* Returning non-zero causes fault display and panic */ + return 0; + } + + /* Others should cause a fault */ + return 1; +} + +static void __init bcm5301x_init_early(void) +{ + /* Install our hook */ + hook_fault_code(16 + 6, bcm5301x_abort_handler, SIGBUS, BUS_OBJERR, + "imprecise external abort"); +} + static void __init bcm5301x_dt_init(void) { l2x0_of_init(0, ~0UL); @@ -23,6 +55,7 @@ static const char __initconst *bcm5301x_dt_compat[] = { }; DT_MACHINE_START(BCM5301X, "BCM5301X") + .init_early = bcm5301x_init_early, .init_machine = bcm5301x_dt_init, .dt_compat = bcm5301x_dt_compat, MACHINE_END
Without this patch I am getting a unhandled fault exception like this one after "Freeing unused kernel memory": Freeing unused kernel memory: 1260K (c02c1000 - c03fc000) Unhandled fault: imprecise external abort (0x1c06) at 0xb6f89005 Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007 The address which is here 0xb6f89005 changes from boot to boot, with a new build the changes are bigger. With kernel 3.10 I have also seen this fault at different places in the boot process, but starting with 3.11 they are mostly occurring after the "Freeing unused kernel memory" message. I never was able to completely boot to userspace without this handler. The abort code is constant 0x1c06. This fault just happens once in the boot process I have never seen it happing twice or more. I also tried changing the CPSR.A bit to 0 in init_early, with this code like Afzal suggested, but that did not change anything: asm volatile("mrs r12, cpsr\n" "bic r12, r12, #0x00000100\n" "msr cpsr_c, r12" ::: "r12", "cc", "memory"); Disabling the L2 cache by building with CONFIG_CACHE_L2X0 unset did not help. This workaround was copied from the vendor code including most of the comments. It says it they think this is caused by the CFE boot loader used on this device. I do not have any access to any datasheet or errata document to check this. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> --- arch/arm/mach-bcm/bcm_5301x.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)