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ARM: 8947/1: Fix __arch_get_hw_counter() access to CNTVCT

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__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.

Investigated-by: Arnd Bergmann <arnd@arndb.de>

Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Vincenzo Frascino 2019-12-05 11:04:51 +01:00 committed by Russell King
parent ff98a5f624
commit 04bb96427d
1 changed files with 3 additions and 0 deletions
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3
arch/arm/include/asm/vdso/gettimeofday.h
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@ -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);