[PATCH 1/9] ARM: vexpress: remove automatic errata workaround selection

[Rob Herring]

On 07/11/2012 08:36 AM, Pawel Moll wrote:
> From: Will Deacon <will.deacon at arm.com>
> 
> The vexpress Kconfig setup tries to be clever^Whelpful and selects some
> errata workarounds for certain revisions of the Cortex-A9 and PL310,
> which may be required depending on the coretile.
> 
> Since the mach-vexpress can support A5, A7 and A15 coretiles, let's
> defer errata workaround selection to the user and instead propose
> recommended workarounds in the defconfig. Note that the use of the
> savedefconfig target removed some unrelated, redundant entries from the
> file.

Most workarounds are runtime conditioned or don't have significant
impact, so why not leave them enabled? For a single kernel image, we're
going to have to basically turn on every errata work-around. Perhaps we
should only have config options if they are not runtime enabled and have
significant performance impact. I think having the settings in the
defconfig is error prone, not mention if threats from Linus to remove
all defconfigs actually happened it would be lost. In general, I don't
think end users have enough information to determine what needs to be
turned on. You need the errata list as well which is not public. Some of
the errata help text says "rXpY and all later revisions" which changes
when a new core revision comes out.

Rob

> 
> Signed-off-by: Will Deacon <will.deacon at arm.com>
> Signed-off-by: Pawel Moll <pawel.moll at arm.com>
> ---
>  arch/arm/configs/vexpress_defconfig |   25 +++++++------------------
>  arch/arm/mach-vexpress/Kconfig      |   13 -------------
>  2 files changed, 7 insertions(+), 31 deletions(-)
> 
> diff --git a/arch/arm/configs/vexpress_defconfig b/arch/arm/configs/vexpress_defconfig
> index f2de51f..8af0213 100644
> --- a/arch/arm/configs/vexpress_defconfig
> +++ b/arch/arm/configs/vexpress_defconfig
> @@ -8,11 +8,9 @@ CONFIG_CGROUPS=y
>  CONFIG_CPUSETS=y
>  # CONFIG_UTS_NS is not set
>  # CONFIG_IPC_NS is not set
> -# CONFIG_USER_NS is not set
>  # CONFIG_PID_NS is not set
>  # CONFIG_NET_NS is not set
>  CONFIG_BLK_DEV_INITRD=y
> -# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
>  CONFIG_PROFILING=y
>  CONFIG_OPROFILE=y
>  CONFIG_MODULES=y
> @@ -24,9 +22,14 @@ CONFIG_MODULE_UNLOAD=y
>  CONFIG_ARCH_VEXPRESS=y
>  CONFIG_ARCH_VEXPRESS_CA9X4=y
>  # CONFIG_SWP_EMULATE is not set
> +CONFIG_ARM_ERRATA_720789=y
> +CONFIG_ARM_ERRATA_751472=y
> +CONFIG_PL310_ERRATA_753970=y
> +CONFIG_ARM_ERRATA_754327=y
> +CONFIG_ARM_ERRATA_764369=y
> +CONFIG_PL310_ERRATA_769419=y
>  CONFIG_SMP=y
>  CONFIG_VMSPLIT_2G=y
> -CONFIG_HOTPLUG_CPU=y
>  CONFIG_AEABI=y
>  CONFIG_ZBOOT_ROM_TEXT=0x0
>  CONFIG_ZBOOT_ROM_BSS=0x0
> @@ -46,33 +49,26 @@ CONFIG_IP_PNP_BOOTP=y
>  # CONFIG_WIRELESS is not set
>  CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
>  CONFIG_MTD=y
> -CONFIG_MTD_CONCAT=y
> -CONFIG_MTD_PARTITIONS=y
>  CONFIG_MTD_CMDLINE_PARTS=y
>  CONFIG_MTD_CHAR=y
>  CONFIG_MTD_BLOCK=y
>  CONFIG_MTD_CFI=y
>  CONFIG_MTD_CFI_INTELEXT=y
>  CONFIG_MTD_CFI_AMDSTD=y
> -CONFIG_MTD_ARM_INTEGRATOR=y
> -CONFIG_MISC_DEVICES=y
>  # CONFIG_SCSI_PROC_FS is not set
>  CONFIG_BLK_DEV_SD=y
>  # CONFIG_SCSI_LOWLEVEL is not set
>  CONFIG_ATA=y
>  # CONFIG_SATA_PMP is not set
>  CONFIG_NETDEVICES=y
> -CONFIG_NET_ETHERNET=y
>  CONFIG_SMSC911X=y
> -# CONFIG_NETDEV_1000 is not set
> -# CONFIG_NETDEV_10000 is not set
>  # CONFIG_WLAN is not set
>  CONFIG_INPUT_EVDEV=y
>  # CONFIG_SERIO_SERPORT is not set
>  CONFIG_SERIO_AMBAKMI=y
> +CONFIG_LEGACY_PTY_COUNT=16
>  CONFIG_SERIAL_AMBA_PL011=y
>  CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
> -CONFIG_LEGACY_PTY_COUNT=16
>  # CONFIG_HW_RANDOM is not set
>  # CONFIG_HWMON is not set
>  CONFIG_FB=y
> @@ -103,7 +99,6 @@ CONFIG_HID_THRUSTMASTER=y
>  CONFIG_HID_ZEROPLUS=y
>  CONFIG_USB=y
>  CONFIG_USB_ANNOUNCE_NEW_DEVICES=y
> -# CONFIG_USB_DEVICE_CLASS is not set
>  CONFIG_USB_MON=y
>  CONFIG_USB_ISP1760_HCD=y
>  CONFIG_USB_STORAGE=y
> @@ -120,9 +115,7 @@ CONFIG_TMPFS=y
>  CONFIG_JFFS2_FS=y
>  CONFIG_CRAMFS=y
>  CONFIG_NFS_FS=y
> -CONFIG_NFS_V3=y
>  CONFIG_ROOT_NFS=y
> -# CONFIG_RPCSEC_GSS_KRB5 is not set
>  CONFIG_NLS_CODEPAGE_437=y
>  CONFIG_NLS_ISO8859_1=y
>  CONFIG_MAGIC_SYSRQ=y
> @@ -131,10 +124,6 @@ CONFIG_DEBUG_KERNEL=y
>  CONFIG_DETECT_HUNG_TASK=y
>  # CONFIG_SCHED_DEBUG is not set
>  CONFIG_DEBUG_INFO=y
> -# CONFIG_RCU_CPU_STALL_DETECTOR is not set
>  CONFIG_DEBUG_USER=y
> -CONFIG_DEBUG_ERRORS=y
>  CONFIG_DEBUG_LL=y
>  CONFIG_EARLY_PRINTK=y
> -# CONFIG_CRYPTO_ANSI_CPRNG is not set
> -# CONFIG_CRYPTO_HW is not set
> diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig
> index cf8730d..6a165fa7 100644
> --- a/arch/arm/mach-vexpress/Kconfig
> +++ b/arch/arm/mach-vexpress/Kconfig
> @@ -1,20 +1,8 @@
>  menu "Versatile Express platform type"
>  	depends on ARCH_VEXPRESS
>  
> -config ARCH_VEXPRESS_CORTEX_A5_A9_ERRATA
> -	bool
> -	select ARM_ERRATA_720789
> -	select ARM_ERRATA_751472
> -	select PL310_ERRATA_753970 if CACHE_PL310
> -	help
> -	  Provides common dependencies for Versatile Express platforms
> -	  based on Cortex-A5 and Cortex-A9 processors. In order to
> -	  build a working kernel, you must also enable relevant core
> -	  tile support or Flattened Device Tree based support options.
> -
>  config ARCH_VEXPRESS_CA9X4
>  	bool "Versatile Express Cortex-A9x4 tile"
> -	select ARCH_VEXPRESS_CORTEX_A5_A9_ERRATA
>  	select ARM_GIC
>  	select CPU_V7
>  	select HAVE_SMP
> @@ -22,7 +10,6 @@ config ARCH_VEXPRESS_CA9X4
>  
>  config ARCH_VEXPRESS_DT
>  	bool "Device Tree support for Versatile Express platforms"
> -	select ARCH_VEXPRESS_CORTEX_A5_A9_ERRATA
>  	select ARM_GIC
>  	select ARM_PATCH_PHYS_VIRT
>  	select AUTO_ZRELADDR
>