[U-Boot] [PATCH 1/4] ARM: fix u-boot.lds for -ffunction-sections/-fdata-sections

Stephen Warren
2012-10-18T20:58:36Z

On 10/18/2012 02:36 PM, Albert ARIBAUD wrote:
> Hi Stephen,
>
> On Wed, 17 Oct 2012 21:17:45 -0600, Stephen Warren
> <swarren@wwwdotorg.org> wrote:
>
>> On 10/17/2012 05:58 PM, Simon Glass wrote:
>>> Hi Stephen,
>>>
>>> On Tue, Oct 16, 2012 at 2:50 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>>> From: Stephen Warren <swarren@nvidia.com>
>>>>
>>>> When -ffunction-sections or -fdata-section are used, symbols are placed
>>>> into sections such as .data.eserial1_device and .bss.serial_current.
>>>> Update the linker script to explicitly include these. Without this
>>>> change (at least with my gcc-4.5.3 built using crosstool-ng), I see that
>>>> the sections do end up being included, but __bss_end__ gets set to the
>>>> same value as __bss_start.
>>>>
>>>> Signed-off-by: Stephen Warren <swarren@nvidia.com>
>>>> ---
>>>> This series fixes an SPL size overflow problem on Tegra. Tom Warren is
>>>> out on vacation until Oct 25th, so he certainly won't be able to review
>>>> this. Perhaps it could be applied directly to the ARM tree if enough
>>>> Tegra people ack the series?
>>>>
>>>> Note that this series is not enough to make Tegra support work; either
>>>> you must hack ./arch/arm/cpu/arm720t/tegra-common/spl.c to call
>>>> serial_initialize() right before serial_init() in preloader_console_init()
>>>> or wait for Allen Martin to rework Tegra's SPL support using the common
>>>> SPL code.
>>>
>>> Are you going to submit a patch to enable function-sections, or is
>>> that a separate discussion?
>>
>> For the SPL on Tegra, those flags were already on; this patch fixes a
>> bug rather than prepares for new functionality.
>>
>>>> diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
>>
>>>> - .u_boot_cmd : { *(.u_boot_cmd) }
>>>> + .u_boot_cmd : { *(.u_boot_cmd*) }
>>>
>>> I don't think this line is needed?
>>>
>> ...
>>>> - *(.dynsym)
>>>> + *(.dynsym*)
>>>
>>> Nor this one?
>>
>> Possibly. I changed all the section names to be future-proof. Perhaps a
>> more targeted patch is warranted.
>
> Has this been (at least build-)tested on all boards which have
> -ffunction-sections or -fdata-sections?

Yes; those flags both appear to be turned on when building the SPL for
Tegra (although strangely, not when building the main U-Boot):

xxx-gcc -M -g -Os -fno-common -ffixed-r8 -msoft-float -D__KERNEL__
-ffunction-sections -fdata-sections -DCONFIG_SYS_TEXT_BASE=0x0010c000
-DCONFIG_SPL_TEXT_BASE=0x00108000 -DCONFIG_SPL_BUILD
-I/home/swarren/shared/git_wa/u-boot/include -fno-builtin -ffreestanding
-nostdinc -isystem xxx -pipe -DCONFIG_ARM -D__ARM__ -marm
-mno-thumb-interwork -mabi=aapcs-linux -march=armv4 -mtune=arm7tdmi -MQ
xxx/spl/arch/arm/cpu/arm720t/interrupts.o interrupts.c >
xxx/spl/arch/arm/cpu/arm720t/.depend.interrupts