From c06059b8b1732bba3746e2c1b2cfcdb64b72fe73 Mon Sep 17 00:00:00 2001
From: Ville Juven <ville.juven@unikie.com>
Date: Fri, 22 Mar 2024 14:19:00 +0200
Subject: [PATCH] arm64_head.S: Add explicit input section for __start

As __start must be placed at a precise location, a separate, explicit
input section is needed to guarantee this.

Why is this an issue ? NuttX uses --entry=__start which puts __start in
its correct location, but out-of-tree builds won't work, so it more robust
to use an explicit section for the startup code and enforce its placement
in the linker script.
---
 arch/arm64/src/common/arm64_head.S                   | 2 ++
 boards/arm64/a64/pinephone/scripts/dramboot.ld       | 1 +
 boards/arm64/fvp-v8r/fvp-armv8r/scripts/dramboot.ld  | 1 +
 boards/arm64/imx8/imx8qm-mek/scripts/dramboot.ld     | 1 +
 boards/arm64/imx9/imx93-evk/scripts/dramboot.ld      | 2 +-
 boards/arm64/qemu/qemu-armv8a/scripts/dramboot.ld    | 1 +
 boards/arm64/rk3399/nanopi_m4/scripts/dramboot.ld    | 1 +
 boards/arm64/rk3399/pinephonepro/scripts/dramboot.ld | 1 +
 8 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/src/common/arm64_head.S b/arch/arm64/src/common/arm64_head.S
index 18ea5c97ea72f..f10dcd4005b68 100644
--- a/arch/arm64/src/common/arm64_head.S
+++ b/arch/arm64/src/common/arm64_head.S
@@ -89,6 +89,8 @@ label:  .asciz msg;                             \
      * This must be the very first address in the loaded image.
      * It should be loaded at any 4K-aligned address.
      */
+
+    .section .start, "ax"
     .globl __start;
 __start:
 
diff --git a/boards/arm64/a64/pinephone/scripts/dramboot.ld b/boards/arm64/a64/pinephone/scripts/dramboot.ld
index 15c82c9d32304..f5f515d4b819a 100644
--- a/boards/arm64/a64/pinephone/scripts/dramboot.ld
+++ b/boards/arm64/a64/pinephone/scripts/dramboot.ld
@@ -33,6 +33,7 @@ SECTIONS
   _start = .;
   .text : {
         _stext = .;            /* Text section */
+       *(.start .start.*)      /* Place __start here */
        *(.text)
        *(.text.cold)
        *(.text.unlikely)
diff --git a/boards/arm64/fvp-v8r/fvp-armv8r/scripts/dramboot.ld b/boards/arm64/fvp-v8r/fvp-armv8r/scripts/dramboot.ld
index ec2d6956c52ad..50d5ba78d41cd 100644
--- a/boards/arm64/fvp-v8r/fvp-armv8r/scripts/dramboot.ld
+++ b/boards/arm64/fvp-v8r/fvp-armv8r/scripts/dramboot.ld
@@ -33,6 +33,7 @@ SECTIONS
   _start = .;
   .text : {
         _stext = .;            /* Text section */
+       *(.start .start.*)      /* Place __start here */
        *(.text)
        *(.text.cold)
        *(.text.unlikely)
diff --git a/boards/arm64/imx8/imx8qm-mek/scripts/dramboot.ld b/boards/arm64/imx8/imx8qm-mek/scripts/dramboot.ld
index 160a5f8f86db7..24e385d9948b5 100644
--- a/boards/arm64/imx8/imx8qm-mek/scripts/dramboot.ld
+++ b/boards/arm64/imx8/imx8qm-mek/scripts/dramboot.ld
@@ -33,6 +33,7 @@ SECTIONS
   _start = .;
   .text : {
         _stext = .;            /* Text section */
+       *(.start .start.*)      /* Place __start here */
        *(.text)
        *(.text.cold)
        *(.text.unlikely)
diff --git a/boards/arm64/imx9/imx93-evk/scripts/dramboot.ld b/boards/arm64/imx9/imx93-evk/scripts/dramboot.ld
index 6f3f0afde5457..f437d8d13745a 100644
--- a/boards/arm64/imx9/imx93-evk/scripts/dramboot.ld
+++ b/boards/arm64/imx9/imx93-evk/scripts/dramboot.ld
@@ -50,7 +50,7 @@ SECTIONS
   .text  :
     {
       _stext = ABSOLUTE(.);  /* Text section */
-      *(.text.__start)       /* Place __start here */
+      *(.start .start.*)     /* Place __start here */
       *(.text .text.*)
       *(.text.cold)
       *(.text.unlikely)
diff --git a/boards/arm64/qemu/qemu-armv8a/scripts/dramboot.ld b/boards/arm64/qemu/qemu-armv8a/scripts/dramboot.ld
index c8857860ea1cd..c4cbc49957987 100644
--- a/boards/arm64/qemu/qemu-armv8a/scripts/dramboot.ld
+++ b/boards/arm64/qemu/qemu-armv8a/scripts/dramboot.ld
@@ -33,6 +33,7 @@ SECTIONS
   _start = .;
   .text : {
         _stext = .;            /* Text section */
+       *(.start .start.*)      /* Place __start here */
        *(.text)
        *(.text.cold)
        *(.text.unlikely)
diff --git a/boards/arm64/rk3399/nanopi_m4/scripts/dramboot.ld b/boards/arm64/rk3399/nanopi_m4/scripts/dramboot.ld
index bebe73fff0013..d202807ea601c 100644
--- a/boards/arm64/rk3399/nanopi_m4/scripts/dramboot.ld
+++ b/boards/arm64/rk3399/nanopi_m4/scripts/dramboot.ld
@@ -43,6 +43,7 @@ SECTIONS
   _start = .;
   .text : {
         _stext = .;            /* Text section */
+       *(.start .start.*)      /* Place __start here */
        *(.text)
        *(.text.cold)
        *(.text.unlikely)
diff --git a/boards/arm64/rk3399/pinephonepro/scripts/dramboot.ld b/boards/arm64/rk3399/pinephonepro/scripts/dramboot.ld
index e50ea0b0ea1c3..f3a47b2719846 100644
--- a/boards/arm64/rk3399/pinephonepro/scripts/dramboot.ld
+++ b/boards/arm64/rk3399/pinephonepro/scripts/dramboot.ld
@@ -34,6 +34,7 @@ SECTIONS
   _start = .;
   .text : {
         _stext = .;            /* Text section */
+       *(.start .start.*)      /* Place __start here */
        *(.text)
        *(.text.cold)
        *(.text.unlikely)