[PATCH] xilinx: versal: Enable CONFIG_POSITION_INDEPENDENT

Michal Simek michal.simek at xilinx.com
Wed May 12 14:35:37 CEST 2021


From: T Karthik Reddy <t.karthik.reddy at xilinx.com>

U-Boot expects to be linked to a specific hard-coded address and to
be loaded to and run from that address. CONFIG_POSITION_INDEPENDENT
config lifts that restriction & allowing the code to be loaded to
and executed from almost any address.

As we enabled CONFIG_POSITION_INDEPENDENT, CONFIG_INIT_SP_RELATIVE
is enabled by default, where it will set the early stack pointer at
runtime by adding an offset value to &_bss_start. The offset value
is taken from SYS_INIT_SP_BSS_OFFSET.

SYS_INIT_SP_BSS_OFFSET offset should be large enough so that the
early malloc region, global data (gd), and early stack should fit.
With commit d8fabcc424bd ("arm64: versal: Increase SYS_MALLOC_F_LEN")
SYS_MALLOC_F_LEN is increased from 32KB to 1MB, so we need to
accommodate this space with SYS_INIT_SP_BSS_OFFSET. Hence increasing
SYS_INIT_SP_BSS_OFFSET to 1.5MB.

Signed-off-by: T Karthik Reddy <t.karthik.reddy at xilinx.com>
Acked-by: Ashok Reddy Soma <ashok.reddy.soma at xilinx.com>
Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---

 configs/xilinx_versal_virt_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configs/xilinx_versal_virt_defconfig b/configs/xilinx_versal_virt_defconfig
index 707693713a7e..f4e9a80728d7 100644
--- a/configs/xilinx_versal_virt_defconfig
+++ b/configs/xilinx_versal_virt_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_POSITION_INDEPENDENT=y
+CONFIG_SYS_INIT_SP_BSS_OFFSET=1572864
 CONFIG_ARCH_VERSAL=y
 CONFIG_SYS_TEXT_BASE=0x8000000
 CONFIG_SYS_MALLOC_F_LEN=0x100000
-- 
2.31.1



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