[U-Boot] [PATCH 2/9] x86: braswell: Fix unexpected crash during Linux kernel boot

[Simon Glass]

On 19 October 2017 at 03:20, Bin Meng <bmeng.cn at gmail.com> wrote:
> It was observed that when booting Linux kernel on Intel Cherry Hill
> board, unexpected crash happens quite randomly. Sometimes kernel
> just oops, while sometimes kernel throws MCE errors and hangs:
>
>   mce: [Hardware Error]: Machine check events logged
>   mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 4: c400000000010151
>   mce: [Hardware Error]: TSC 0 ADDR 130f3f2c0
>   mce: [Hardware Error]: PROCESSOR 0:406c3 TIME 1508160686 SOCKET 0 APIC 0 microcode 363
>
> This looks like a hardware error per mcelog. After debugging, it
> seems turning off turbo mode on the processor does not expose this
> behavior, although U-Boot runs OK with turbo mode on. Suspect it is
> related to an errata of Braswell processor.
>
> To fix this, remove the Braswell cpu driver which does the turbo
> mode configuration, and switch to use the generic cpu-x86 driver.
> Also there is a configuration option in the FSP that turns on the
> turbo mode and that has been turned off too.
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> ---
>
>  arch/x86/cpu/braswell/Makefile |   2 +-
>  arch/x86/cpu/braswell/cpu.c    | 170 -----------------------------------------
>  arch/x86/dts/cherryhill.dts    |   9 +--
>  3 files changed, 5 insertions(+), 176 deletions(-)
>  delete mode 100644 arch/x86/cpu/braswell/cpu.c

Oh dear, what a sad patch.

Reviewed-by: Simon Glass <sjg at chromium.org>