[RFC PATCH linux dev-5.4 2/4] ARM: configs: aspeed-g5: Enable modules

[Milton Miller II]

On May 14, 2020 around 8:53AM in some timezone, Patrick Williams  wrote:

>On Thu, May 14, 2020 at 10:57:01PM +0930, Andrew Jeffery wrote:>> This is a step on the path to enabling kprobes, which depend on
>> CONFIG_MODULES=y.
>> 
>> Setting CONFIG_MODULES=y results in the following change in kernel
>size:
>> 
>> Before:
>>          $ size vmlinux
>>             text    data     bss     dec     hex filename
>>          8140500 2440582  178904 10759986         a42f32 vmlinux
>>          $ stat --printf '%s\n' arch/arm/boot/zImage
>>          3445200
>> 
>> After:
>>          $ size vmlinux
>>             text    data     bss     dec     hex filename
>>          8240349 2388862  172304 10801515         a4d16b vmlinux
>>          $ stat --printf '%s\n' arch/arm/boot/zImage
>>          3458368
>> 
>> This gives a 41,529 byte increase to vmlinux and a 13,168 byte
>increase
>> to the size of the compressed kernel image. In the most constrained
>BMC
>> flash layout (arch/arm/boot/dts/openbmc-flash-layout.dtsi) this
>change
>> decreases the free space in the kernel partition from 1,011,248
>bytes to
>> 998,080 bytes.
>> 
>> CONFIG_HW_RANDOM=y seems to come along for the ride with the
>> `./scripts/config -e modules && make olddefconfig && make
>> savedefconfig`. The measurements above include it, I haven't
>> investigated why it gets enabled or what effect disabling it might
>have
>> on the numbers.
>> 
>> Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
>> ---
>>  arch/arm/configs/aspeed_g5_defconfig | 2 ++
>>  1 file changed, 2 insertions(+)
>> 
>> diff --git a/arch/arm/configs/aspeed_g5_defconfig
>b/arch/arm/configs/aspeed_g5_defconfig
>> index e124b4ddd442..e30f27a413f4 100644
>> --- a/arch/arm/configs/aspeed_g5_defconfig
>> +++ b/arch/arm/configs/aspeed_g5_defconfig
>> @@ -46,6 +46,7 @@ CONFIG_NEON=y
>>  CONFIG_KERNEL_MODE_NEON=y
>>  CONFIG_FIRMWARE_MEMMAP=y
>>  CONFIG_JUMP_LABEL=y
>> +CONFIG_MODULES=y
>>  # CONFIG_BLK_DEV_BSG is not set
>>  # CONFIG_BLK_DEBUG_FS is not set
>>  # CONFIG_MQ_IOSCHED_DEADLINE is not set
>> @@ -152,6 +153,7 @@ CONFIG_SERIAL_8250_DW=y
>>  CONFIG_SERIAL_OF_PLATFORM=y
>>  CONFIG_ASPEED_KCS_IPMI_BMC=y
>>  CONFIG_ASPEED_BT_IPMI_BMC=y
>> +CONFIG_HW_RANDOM=y
>>  CONFIG_HW_RANDOM_TIMERIOMEM=y
>>  # CONFIG_I2C_COMPAT is not set
>>  CONFIG_I2C_CHARDEV=y
>> -- 
>> 2.25.1
>> 
>
>We're already using modules on the facebook/openbmc kernels and it
>hasn't seemed to cause any issues.  Is there any argument why we
>shouldn't begin moving some of the drivers to be modules?  Any easy
>change would be to make all the hwmon content as modules and load
>them
>based on the device tree.
>
>I think there is a DISTRO_FEATURE we should enable for userspace
>support
>of modules.  Let me know if you want me to investigate that.

This gerrit is still open.  It also adds content to the rootfs b
ecause it tries to pull in vmlinux into the root fs as part of the 
base kernel recipie:

https://gerrit.openbmc-project.xyz/c/openbmc/meta-phosphor/+/26092

actually this one that has failed since September:

https://gerrit.openbmc-project.xyz/c/openbmc/meta-phosphor/+/25536/2

milton