ACK: [SRU][K/raspi][PATCH 0/3] armhf kernels are compiled with gcc-11 (LP: #1995853)

[Tim Gardner]

On 11/8/22 3:46 AM, Juerg Haefliger wrote:
> [Impact]
> 
> We currently compile the Kinetic raspi armhf kernels with gcc-11 because a gcc-12-compiled armhf raspi kernel won't boot or hang. We need to figure out what's going on and fix it to be able to go back to the default compiler.
> 
> Turns out that the downstream dwc_otg driver is broken when compiled with gcc-12 and 'standard' kernel compiler flags. I confirmed that the system seems to work reliably after switching to the upstream dwc2 driver.
> 
> Relevant gcc-12 changes:
> 
> arm
>      Support is added for accessing the stack canary value via the TLS register through the -fstack-protector-guard=tls and -mstack-protector-guard-offset= options. This intended for use in Linux kernel development. Please refer to the documentation for more details.
> 
> [Test Case]
> 
> Boot armhf kernel and exercise the system. It either won't come up at all or hang/freeze later on.
> 
> [Fix]
> 1a62e5b2363d ("drivers: dwc_otg: stop GCC from patching FIQ functions") from github.com/raspberrypi/linux
> 
> [Regression Potential]
> 
> Setting a specific compiler flag and switching to a new GCC version. What could possibly go wrong?
> 
> Jonathan Bell (1):
>    drivers: dwc_otg: stop GCC from patching FIQ functions
> 
> Juerg Haefliger (2):
>    UBUNTU: Revert "UBUNTU: [Packaging] raspi: Use gcc-11 for armhf"
>    UBUNTU: [Config] raspi: updateconfigs for gcc-12 for armhf
> 
>   debian.raspi/config/arm64/config.common.arm64 | 1 -
>   debian.raspi/config/armhf/config.common.armhf | 3 +--
>   debian.raspi/config/config.common.ubuntu      | 2 ++
>   debian/rules.d/0-common-vars.mk               | 9 ++-------
>   debian/scripts/misc/kernelconfig              | 9 +--------
>   drivers/usb/host/dwc_otg/Makefile             | 1 +
>   drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c    | 2 +-
>   7 files changed, 8 insertions(+), 19 deletions(-)
> 
Acked-by: Tim Gardner <tim.gardner at canonical.com>
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Tim Gardner
Canonical, Inc