From f696a5c237534c40700a74dcdb8b3dd846709629 Mon Sep 17 00:00:00 2001
From: Nikolay Agishev <agishev@synopsys.com>
Date: Thu, 7 Jul 2022 18:30:56 +0400
Subject: [PATCH] boards: qemu_arc: fix of MPU regions setup for !XIP config

Add some changes to ARC linker script. They make correct alignment
for ROMable region. Now regions borders are aligned with respect
to MPU settings.

Signed-off-by: Nikolay Agishev <agishev@synopsys.com>
---
 boards/arc/qemu_arc/arc_mpu_regions.c | 22 +++++++++++++++++-
 include/zephyr/arch/arc/arch.h        |  4 ++++
 include/zephyr/arch/arc/v2/linker.ld  | 32 ++++++++++++++++++---------
 3 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/boards/arc/qemu_arc/arc_mpu_regions.c b/boards/arc/qemu_arc/arc_mpu_regions.c
index d9f53e3d19577..227cd831d4647 100644
--- a/boards/arc/qemu_arc/arc_mpu_regions.c
+++ b/boards/arc/qemu_arc/arc_mpu_regions.c
@@ -6,6 +6,7 @@
 
 #include <zephyr/devicetree.h>
 #include <zephyr/arch/arc/v2/mpu/arc_mpu.h>
+#include <zephyr/arch/arc/arch.h>
 #include <zephyr/linker/linker-defs.h>
 
 /*
@@ -23,12 +24,31 @@ static struct arc_mpu_region mpu_regions[] = {
 #endif /* CONFIG_COVERAGE_GCOV && CONFIG_USERSPACE */
 
 #if DT_REG_SIZE(DT_CHOSEN(zephyr_sram)) > 0
+
+#ifdef CONFIG_XIP
 	/* Region RAM */
 	MPU_REGION_ENTRY("RAM",
 			 DT_REG_ADDR(DT_CHOSEN(zephyr_sram)),
 			 DT_REG_SIZE(DT_CHOSEN(zephyr_sram)),
 			 REGION_KERNEL_RAM_ATTR | REGION_DYNAMIC),
-#endif
+#else
+	/* Region RAM */
+	/*
+	 * In case if Zephyr is configured with CONFIG_XIP=n it linked into
+	 * SRAM. So RAM region should have EXECUTE permission.
+	 */
+	MPU_REGION_ENTRY("RAM_RX",
+			 (uintptr_t)__rom_region_start,
+			 (uintptr_t)__rom_region_size,
+			 REGION_ROM_ATTR),
+
+	 MPU_REGION_ENTRY("RAM_RW",
+			(uintptr_t)_image_ram_start,
+			(uintptr_t)__arc_rw_sram_size,
+			REGION_KERNEL_RAM_ATTR | REGION_DYNAMIC),
+#endif /* CONFIG_XIP */
+
+#endif /* zephyr_sram > 0 */
 
 #if DT_REG_SIZE(DT_CHOSEN(zephyr_flash)) > 0
 	/* Region DCCM */
diff --git a/include/zephyr/arch/arc/arch.h b/include/zephyr/arch/arc/arch.h
index 59730aa5aa7ef..50e211641d3bf 100644
--- a/include/zephyr/arch/arc/arch.h
+++ b/include/zephyr/arch/arc/arch.h
@@ -344,6 +344,10 @@ static ALWAYS_INLINE void arch_nop(void)
 	__builtin_arc_nop();
 }
 
+#ifndef CONFIG_XIP
+extern char __arc_rw_sram_size[];
+#endif /* CONFIG_XIP */
+
 #endif /* _ASMLANGUAGE */
 
 #ifdef __cplusplus
diff --git a/include/zephyr/arch/arc/v2/linker.ld b/include/zephyr/arch/arc/v2/linker.ld
index bfbc08cc9c4ce..120ba618b03d8 100644
--- a/include/zephyr/arch/arc/v2/linker.ld
+++ b/include/zephyr/arch/arc/v2/linker.ld
@@ -93,6 +93,11 @@ SECTIONS {
 
 #include <zephyr/linker/common-rom.ld>
 #include <zephyr/linker/thread-local-storage.ld>
+#ifdef __MWDT_LINKER_CMD__
+/* TODO: add mwdt specific ROM C++ sections */
+#else
+#include <zephyr/linker/cplusplus-rom.ld>
+#endif /* __MWDT_LINKER_CMD__ */
 
 	SECTION_PROLOGUE(_RODATA_SECTION_NAME,,) {
 		*(".rodata")
@@ -103,7 +108,6 @@ SECTIONS {
  * zephyr_linker_sources() Cmake function.
  */
 #include <snippets-rodata.ld>
-
 #include <zephyr/linker/kobject-rom.ld>
 
 #if defined(CONFIG_CPLUSPLUS) && !defined(CONFIG_CPP_STATIC_INIT_GNU) && defined(__MWDT_LINKER_CMD__)
@@ -112,15 +116,12 @@ SECTIONS {
 		KEEP(*(.ctors*))
 		_ectors = .;
 #endif /* CONFIG_CPLUSPLUS && !CONFIG_CPP_STATIC_INIT_GNU && __MWDT_LINKER_CMD__ */
-	} GROUP_LINK_IN(ROMABLE_REGION)
 
-#ifdef __MWDT_LINKER_CMD__
-/* TODO: add mwdt specific ROM C++ sections */
-#else
-#include <zephyr/linker/cplusplus-rom.ld>
-#endif /* __MWDT_LINKER_CMD__ */
+		MPU_ALIGN(ABSOLUTE(.) - __rom_region_start);
+	} GROUP_LINK_IN(ROMABLE_REGION)
 
 	__rodata_region_end = .;
+
 	MPU_ALIGN(__rodata_region_end - __rom_region_start);
 	__rom_region_end = .;
 	__rom_region_size = __rom_region_end - __rom_region_start;
@@ -129,6 +130,10 @@ SECTIONS {
 
 	GROUP_START(RAMABLE_REGION)
 
+	MPU_MIN_SIZE_ALIGN
+
+	_image_ram_start = .;
+
 #include <app_data_alignment.ld>
 
 /* Located in generated directory. This file is populated by the
@@ -141,8 +146,6 @@ SECTIONS {
 #define SMEM_PARTITION_ALIGN MPU_ALIGN
 
 #include <app_smem.ld>
-
-	_image_ram_start = _app_smem_start;
 	_app_smem_size = _app_smem_end - _app_smem_start;
 	_app_smem_rom_start = LOADADDR(_APP_SMEM_SECTION_NAME);
 #endif /* CONFIG_USERSPACE */
@@ -155,7 +158,6 @@ SECTIONS {
 		 */
 		. = ALIGN(4);
 		__bss_start = .;
-		_image_ram_start = .;
 		__kernel_ram_start = .;
 		*(".bss")
 		*(".bss.*")
@@ -244,6 +246,16 @@ SECTIONS {
 		KEEP(*(.gnu.attributes))
 	}
 
+#if !defined(CONFIG_XIP)
+	/*
+	 * Zephyr uses _estack as a start of heap allocation area.
+	 * Region [_estack .. sram_end] should be defined in MPU.
+	 * Including _image_ram region which is [_image_ram_start .. _image_ram_end]
+	 * we get [_image_ram_start .. sram_end] region to be defined in MPU.
+	 */
+	__arc_rw_sram_size = SRAM_START + SRAM_SIZE - _image_ram_start;
+#endif
+
 	/DISCARD/ : {
 #if defined(CONFIG_CPLUSPLUS) && !defined(CONFIG_CPP_STATIC_INIT_GNU) && defined(__MWDT_LINKER_CMD__)
 		*(.dtors*)