From ebd63c499c713f41aa7d213c85d11fc410bc89b0 Mon Sep 17 00:00:00 2001
From: Omar Chebib <omar.chebib@espressif.com>
Date: Thu, 24 Feb 2022 15:24:11 +0800
Subject: [PATCH] (Xtensa) Build: add .xt.prop and .xt.lit to the compiled ELF
 file

Adding prop and lit sections to the ELF will let the debugger and the disassembler
have more info about data bytes present in the middle of the Xtensa
instructions, usually used for padding.
---
 .../subproject/main/ld/esp32/bootloader.ld    | 19 +++++++++++++++++++
 .../subproject/main/ld/esp32s2/bootloader.ld  | 19 +++++++++++++++++++
 components/esp32/ld/esp32.project.ld.in       | 19 +++++++++++++++++++
 components/esp32s2/ld/esp32s2.project.ld.in   | 19 +++++++++++++++++++
 4 files changed, 76 insertions(+)

diff --git a/components/bootloader/subproject/main/ld/esp32/bootloader.ld b/components/bootloader/subproject/main/ld/esp32/bootloader.ld
index dd2e887e3c..033d799ff0 100644
--- a/components/bootloader/subproject/main/ld/esp32/bootloader.ld
+++ b/components/bootloader/subproject/main/ld/esp32/bootloader.ld
@@ -176,4 +176,23 @@ SECTIONS
     _etext = .;
   } > iram_seg
 
+  /** This section will be used by the debugger and disassembler to get more information
+   * about raw data present in the code.
+   * Indeed, it may be required to add some padding at some points in the code
+   * in order to align a branch/jump destination on a particular bound.
+   * Padding these instructions will generate null bytes that shall be
+   * interpreted as data, and not code by the debugger or disassembler.
+   * This section will only be present in the ELF file, not in the final binary
+   * For more details, check GCC-212
+   */
+  .xt.prop 0 :
+  {
+    KEEP (*(.xt.prop .gnu.linkonce.prop.*))
+  }
+
+  .xt.lit 0 :
+  {
+    KEEP (*(.xt.lit .gnu.linkonce.p.*))
+  }
+
 }
diff --git a/components/bootloader/subproject/main/ld/esp32s2/bootloader.ld b/components/bootloader/subproject/main/ld/esp32s2/bootloader.ld
index 93f1cc7eb0..ecb31d0509 100644
--- a/components/bootloader/subproject/main/ld/esp32s2/bootloader.ld
+++ b/components/bootloader/subproject/main/ld/esp32s2/bootloader.ld
@@ -162,4 +162,23 @@ SECTIONS
     _etext = .;
   } > iram_seg
 
+  /** This section will be used by the debugger and disassembler to get more information
+   * about raw data present in the code.
+   * Indeed, it may be required to add some padding at some points in the code
+   * in order to align a branch/jump destination on a particular bound.
+   * Padding these instructions will generate null bytes that shall be
+   * interpreted as data, and not code by the debugger or disassembler.
+   * This section will only be present in the ELF file, not in the final binary
+   * For more details, check GCC-212
+   */
+  .xt.prop 0 :
+  {
+    KEEP (*(.xt.prop .gnu.linkonce.prop.*))
+  }
+
+  .xt.lit 0 :
+  {
+    KEEP (*(.xt.lit .gnu.linkonce.p.*))
+  }
+
 }
diff --git a/components/esp32/ld/esp32.project.ld.in b/components/esp32/ld/esp32.project.ld.in
index d5a7b401b8..8272f73868 100644
--- a/components/esp32/ld/esp32.project.ld.in
+++ b/components/esp32/ld/esp32.project.ld.in
@@ -388,6 +388,25 @@ SECTIONS
     . = ALIGN (8);
     _heap_start = ABSOLUTE(.);
   } > dram0_0_seg
+
+  /** This section will be used by the debugger and disassembler to get more information
+    * about raw data present in the code.
+    * Indeed, it may be required to add some padding at some points in the code
+    * in order to align a branch/jump destination on a particular bound.
+    * Padding these instructions will generate null bytes that shall be
+    * interpreted as data, and not code by the debugger or disassembler.
+    * This section will only be present in the ELF file, not in the final binary
+    * For more details, check GCC-212
+    */
+  .xt.prop 0 :
+  {
+    KEEP (*(.xt.prop .gnu.linkonce.prop.*))
+  }
+
+  .xt.lit 0 :
+  {
+    KEEP (*(.xt.lit .gnu.linkonce.p.*))
+  }
 }
 
 ASSERT(((_iram_end - ORIGIN(iram0_0_seg)) <= LENGTH(iram0_0_seg)),
diff --git a/components/esp32s2/ld/esp32s2.project.ld.in b/components/esp32s2/ld/esp32s2.project.ld.in
index 878339850c..dda6ade146 100644
--- a/components/esp32s2/ld/esp32s2.project.ld.in
+++ b/components/esp32s2/ld/esp32s2.project.ld.in
@@ -353,6 +353,25 @@ SECTIONS
     . = ALIGN (8);
     _heap_start = ABSOLUTE(.);
   } > dram0_0_seg
+
+  /** This section will be used by the debugger and disassembler to get more information
+    * about raw data present in the code.
+    * Indeed, it may be required to add some padding at some points in the code
+    * in order to align a branch/jump destination on a particular bound.
+    * Padding these instructions will generate null bytes that shall be
+    * interpreted as data, and not code by the debugger or disassembler.
+    * This section will only be present in the ELF file, not in the final binary
+    * For more details, check GCC-212
+    */
+  .xt.prop 0 :
+  {
+    KEEP (*(.xt.prop .gnu.linkonce.prop.*))
+  }
+
+  .xt.lit 0 :
+  {
+    KEEP (*(.xt.lit .gnu.linkonce.p.*))
+  }
 }
 
 ASSERT(((_iram_text_end - ORIGIN(iram0_0_seg)) <= LENGTH(iram0_0_seg)),