Hi Guenter, On 12/4/19 4:16 PM, Guenter Roeck wrote: > On Wed, Dec 04, 2019 at 01:58:25PM +0000, Vincenzo Frascino wrote: >> Hi Guenter, >> >> On 12/4/19 1:51 PM, Guenter Roeck wrote: >>> On Fri, Jun 21, 2019 at 10:52:43AM +0100, Vincenzo Frascino wrote: >>>> The arm vDSO library requires some adaptations to use to take advantage >>>> of the newly introduced generic vDSO library. >>>> >>>> Introduce the following changes: >>>> - Modification vdso.c to be compliant with the common vdso datapage >>>> - Use of lib/vdso for gettimeofday >>>> - Implementation of elf note >>>> >>>> Cc: Russell King <linux@xxxxxxxxxxxxxxx> >>>> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> >>> >>> This patch causes a crash with qemu's mcimx6ul-evk emulation while running >>> imx_v6_v7_defconfig. >>> >> >> Thank you for reporting this. Could you please provide some details on how I can >> reproduce the scenario you are describing? >> > - Build imx_v6_v7_defconfig > - Get root file system or initrd, for example from > https://github.com/groeck/linux-build-test/tree/master/rootfs/arm > - Run image. Example, with initrd: > qemu-system-arm -M mcimx6ul-evk -kernel arch/arm/boot/zImage \ > -no-reboot -initrd rootfs-armv7a.cpio \ > -m 256 -display none -serial null \ > --append 'rdinit=/sbin/init earlycon=ec_imx6q,mmio,0x21e8000,115200n8 console=ttymxc1,115200' > -dtb arch/arm/boot/dts/imx6ul-14x14-evk.dtb \ > -nographic -monitor null -serial stdio > > qemu has to be v3.1 or later to support the machine. > Thanks for this. Could you please try the patch below the scissors? Seems fixing the issue for me. > Hope this helps, > Guenter > -- Regards, Vincenzo --->8--- Author: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Date: Wed Dec 4 16:58:55 2019 +0000 arm: Fix __arch_get_hw_counter() access to CNTVCT __arch_get_hw_counter() should check clock_mode to see if it can access CNTVCT. With the conversion to unified vDSO this check has been left out. This causes on imx v6 and v7 (imx_v6_v7_defconfig) and other platforms to hang at boot during the execution of the init process as per below: [ 19.976852] Run /sbin/init as init process [ 20.044931] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004 Fix the problem verifying that clock_mode is set coherently before accessing CNTVCT. Cc: Russell King <linux@xxxxxxxxxxxxxxx> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx> Investigated-by: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h index 5b879ae7afc1..0ad2429c324f 100644 --- a/arch/arm/include/asm/vdso/gettimeofday.h +++ b/arch/arm/include/asm/vdso/gettimeofday.h @@ -75,6 +75,9 @@ static __always_inline u64 __arch_get_hw_counter(int clock_mode) #ifdef CONFIG_ARM_ARCH_TIMER u64 cycle_now; + if (!clock_mode) + return -EINVAL; + isb(); cycle_now = read_sysreg(CNTVCT);
