x86: fix XIP SOC support and defaults

XIP support in x86 was something of a mess. This
patch does the following:

- Generic ia32 SOC no longer defines a "flash" region
  as generic X86 devices don't have a microcontroller-
  like concept of flash. The same has been done for apollo_lake.
- Generic ia32 and apollo_lake SOCs starts memory at 1MB.
- Generic ia32 SOC may optionally have CONFIG_XIP enabled.
  The board definition must provide a flash region definition
  that gets exposed as DT_PHYS_LOAD_ADDR.
- Fixed definitions for RAM/ROM source addresses in ia32's
  linker.ld when XIP is turned off.
- Support for enabling XIP on apollo_lake SOC removed, there's
  no use-case.
- acrn and gpmrb boards have flash and XIP related definitions
  removed.
- qemu_x86 has a fake flash region added, immediately after system
  RAM, for use when XIP is enabled. This used to be in the ia32 SOC.
  However, the default for qemu_x86 is to now have XIP disabled.
- Fixed tests/kernel/xip to run by default on boards that enable
  XIP by default, plus an additional test to exercise XIP on
  qemu_x86 (which supports it but has XIP switched off by default)

The overall effect of this patch is to:

- Remove XIP configuration for SOC/boards where it does not make
  any sense to have it
- Support testing XIP on qemu_x86 via tests/kernel/xip, but leave
  it off by default for other tests, to ensure it doesn't bit-rot
  and that the system works in both scenarios.
- XIP remains an available feature for boards that need it.

Fixes: #18956

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

boards/x86/acrn/acrn.dts

@@ -8,7 +8,6 @@
 
 #include <mem.h>
 
-#define DT_FLASH_SIZE	DT_SIZE_K(8192)
 #define DT_SRAM_SIZE	DT_SIZE_K(8192)
 
 #include <ia32.dtsi>
@@ -24,7 +23,6 @@
 
 	chosen {
 		zephyr,sram = &sram0;
-		zephyr,flash = &flash0;
 		zephyr,console = &uart0;
 		zephyr,shell-uart = &uart0;
 	};
@@ -39,11 +37,3 @@
 	status = "okay";
 	current-speed = <115200>;
 };
-
-&flash0 {
-	reg = <0x100000 DT_FLASH_SIZE>;
-};
-
-&sram0 {
-	reg = <0x400000 DT_SRAM_SIZE>;
-};

boards/x86/acrn/acrn.yaml

@@ -5,4 +5,4 @@ arch: x86
 toolchain:
   - zephyr
 ram: 8192
-flash: 8192
+

boards/x86/acrn/acrn_defconfig

@@ -10,6 +10,5 @@ CONFIG_SERIAL=y
 CONFIG_UART_NS16550=y
 CONFIG_UART_CONSOLE=y
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=25000000
-CONFIG_XIP=n
 CONFIG_BUILD_OUTPUT_BIN=y
 CONFIG_SHELL_BACKEND_SERIAL_INTERRUPT_DRIVEN=n

boards/x86/gpmrb/gpmrb.dts

@@ -8,7 +8,6 @@
 
 #include <mem.h>
 
-#define DT_FLASH_SIZE		DT_SIZE_K(8912)
 #define DT_SRAM_SIZE		DT_SIZE_M(2048)
 
 #include <apollo_lake.dtsi>
@@ -19,7 +18,6 @@
 
 	chosen {
 		zephyr,sram = &sram0;
-		zephyr,flash = &flash0;
 		zephyr,console = &uart2;
 		zephyr,shell-uart = &uart2;
 		zephyr,bt-uart = &uart1;

boards/x86/qemu_x86/Kconfig.board

@@ -1,9 +1,4 @@
 # SPDX-License-Identifier: Apache-2.0
-#
-# The QEMU targets themselves are not XIP, everything is actually RAM, but we
-# pretend the first 4 megabytes are a memory-mapped flash region. This is done
-# to ensure that the XIP data copying infrastructure doesn't bit-rot on
-# x86.
 
 config BOARD_QEMU_X86
 	bool "QEMU x86"
@@ -12,4 +7,3 @@ config BOARD_QEMU_X86
 	select HAS_DTS_ETHERNET
 	select CPU_HAS_FPU
 	select HAS_COVERAGE_SUPPORT
-	select XIP

boards/x86/qemu_x86/qemu_x86.dts

@@ -4,8 +4,8 @@
 
 #include <mem.h>
 
-#define DT_FLASH_SIZE		DT_SIZE_K(4096)
 #define DT_SRAM_SIZE		DT_SIZE_K(4096)
+#define DT_FLASH_SIZE		DT_SIZE_K(4096)
 
 #include <ia32.dtsi>
 
@@ -13,6 +13,11 @@
 	model = "QEMU X86";
 	compatible = "intel,ia32";
 
+	flash0: flash@500000 {
+		compatible = "soc-nv-flash";
+		reg = <0x00500000 DT_FLASH_SIZE>;
+	};
+
 	aliases {
 		uart-0 = &uart0;
 		uart-1 = &uart1;

boards/x86/qemu_x86/qemu_x86_coverage_defconfig

@@ -14,7 +14,6 @@ CONFIG_UART_NS16550=y
 CONFIG_UART_CONSOLE=y
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=25000000
 CONFIG_TEST_RANDOM_GENERATOR=y
-CONFIG_XIP=y
 CONFIG_X86_MMU=y
 CONFIG_X86_MMU_PAGE_POOL_PAGES=15
 CONFIG_DEBUG_INFO=y

boards/x86/up_squared/up_squared.dts

@@ -8,7 +8,6 @@
 
 #include <mem.h>
 
-#define DT_FLASH_SIZE		DT_SIZE_K(8912)
 #define DT_SRAM_SIZE		DT_SIZE_M(2048)
 
 #include <apollo_lake.dtsi>
@@ -19,7 +18,6 @@
 
 	chosen {
 		zephyr,sram = &sram0;
-		zephyr,flash = &flash0;
 		zephyr,console = &uart0;
 		zephyr,shell-uart = &uart0;
 		zephyr,bt-uart = &uart1;