# x86 general configuration options # Copyright (c) 2014-2015 Wind River Systems, Inc. # SPDX-License-Identifier: Apache-2.0 menu "X86 Architecture Options" depends on X86 config ARCH default "x86" # # CPU Families - the SoC configuration should select the right one. # config CPU_ATOM bool select CPU_HAS_FPU select ARCH_HAS_STACK_PROTECTION if X86_MMU select ARCH_HAS_USERSPACE if X86_MMU select X86_CPU_HAS_MMX select X86_CPU_HAS_SSE select X86_CPU_HAS_SSE2 select X86_CPU_HAS_SSE3 help This option signifies the use of a CPU from the Atom family. config CPU_APOLLO_LAKE bool select CPU_HAS_FPU select ARCH_HAS_STACK_PROTECTION if X86_MMU select ARCH_HAS_USERSPACE if X86_MMU select X86_MMU select X86_CPU_HAS_MMX select X86_CPU_HAS_SSE select X86_CPU_HAS_SSE2 select X86_CPU_HAS_SSE3 select X86_CPU_HAS_SSSE3 select X86_CPU_HAS_SSE41 select X86_CPU_HAS_SSE42 help This option signifies the use of a CPU from the Apollo Lake family. config CPU_LAKEMONT bool select CPU_HAS_FPU select ARCH_HAS_STACK_PROTECTION if X86_MMU select ARCH_HAS_USERSPACE if X86_MMU select X86_CPU_HAS_MMX select X86_CPU_HAS_SSE select X86_CPU_HAS_SSE2 select X86_CPU_HAS_SSE3 select X86_CPU_HAS_SSSE3 help This option signifies the use of a CPU from the Lakemont family. # # Configuration common to both IA32 and Intel64 sub-architectures. # config X86_64 bool "Run in 64-bit mode" select 64BIT select USE_SWITCH select USE_SWITCH_SUPPORTED select SCHED_IPI_SUPPORTED select X86_MMU select X86_CPU_HAS_MMX select X86_CPU_HAS_SSE select X86_CPU_HAS_SSE2 select X86_MMX select X86_SSE select X86_SSE2 menu "x86 Features" config X86_CPU_HAS_MMX bool config X86_CPU_HAS_SSE bool config X86_CPU_HAS_SSE2 bool config X86_CPU_HAS_SSE3 bool config X86_CPU_HAS_SSSE3 bool config X86_CPU_HAS_SSE41 bool config X86_CPU_HAS_SSE42 bool config X86_CPU_HAS_SSE4A bool if FPU || X86_64 config X86_MMX bool "MMX Support" depends on X86_CPU_HAS_MMX help This option enables MMX support, and the use of MMX registers by threads. config X86_SSE bool "SSE Support" depends on X86_CPU_HAS_SSE help This option enables SSE support, and the use of SSE registers by threads. config X86_SSE2 bool "SSE2 Support" depends on X86_CPU_HAS_SSE2 select X86_SSE help This option enables SSE2 support. config X86_SSE3 bool "SSE3 Support" depends on X86_CPU_HAS_SSE3 select X86_SSE help This option enables SSE3 support. config X86_SSSE3 bool "SSSE3 (Supplemental SSE3) Support" depends on X86_CPU_HAS_SSSE3 select X86_SSE help This option enables Supplemental SSE3 support. config X86_SSE41 bool "SSE4.1 Support" depends on X86_CPU_HAS_SSE41 select X86_SSE help This option enables SSE4.1 support. config X86_SSE42 bool "SSE4.2 Support" depends on X86_CPU_HAS_SSE42 select X86_SSE help This option enables SSE4.2 support. config X86_SSE4A bool "SSE4A Support" depends on X86_CPU_HAS_SSE4A select X86_SSE help This option enables SSE4A support. config X86_SSE_FP_MATH bool "Compiler-generated SSEx instructions for floating point math" depends on X86_SSE help This option allows the compiler to generate SSEx instructions for performing floating point math. This can greatly improve performance when exactly the same operations are to be performed on multiple data objects; however, it can also significantly reduce performance when preemptive task switches occur because of the larger register set that must be saved and restored. Disabling this option means that the compiler utilizes only the x87 instruction set for floating point operations. endif # FPU || X86_64 endmenu config SRAM_OFFSET default 0x100000 if X86_PC_COMPATIBLE help A lot of x86 that resemble PCs have many reserved physical memory regions within the first megabyte. Specify an offset from the beginning of RAM to load the kernel in physical memory, avoiding these regions. Note that this does not include the "locore" which contains real mode bootstrap code within the first 64K of physical memory. This value normally need to be page-aligned. config KERNEL_VM_OFFSET default 0x100000 if MMU config MAX_IRQ_LINES int "Number of IRQ lines" default 128 range 0 224 help This option specifies the number of IRQ lines in the system. It determines the size of the _irq_to_interrupt_vector_table, which is used to track the association between vectors and IRQ numbers. config IRQ_OFFLOAD_VECTOR int "IDT vector to use for IRQ offload" default 33 range 32 255 depends on IRQ_OFFLOAD config PIC_DISABLE bool "Disable PIC" help This option disables all interrupts on the legacy i8259 PICs at boot. choice prompt "Reboot implementation" depends on REBOOT default REBOOT_RST_CNT config REBOOT_RST_CNT bool "Reboot via RST_CNT register" help Reboot via the RST_CNT register, going back to BIOS. endchoice config ACPI bool "ACPI (Advanced Configuration and Power Interface) support" depends on X86_PC_COMPATIBLE help Allow retrieval of platform configuration at runtime. config PCIE_MMIO_CFG bool "Use MMIO PCI configuration space access" select ACPI help Selects the use of the memory-mapped PCI Express Extended Configuration Space instead of the traditional 0xCF8/0xCFC IO Port registers. config KERNEL_VM_SIZE default 0x40000000 if ACPI config X86_PC_COMPATIBLE bool default y select ARCH_HAS_RESERVED_PAGE_FRAMES select HAS_SRAM_OFFSET help Hidden option to signal building for PC-compatible platforms with BIOS, ACPI, etc. config X86_MEMMAP bool "Use memory map" select ARCH_HAS_RESERVED_PAGE_FRAMES help Enable the use of memory map to identify regions of memory. The memory map can be populated via Multiboot (CONFIG_MULTIBOOT=y and CONFIG_MULTIBOOT_MEMMAP=y) or can be manually defined via x86_memmap[]. config X86_MEMMAP_ENTRIES int "Number of memory map entries" depends on X86_MEMMAP range 1 256 default 1 if !MULTIBOOT_MEMMAP default 64 if MULTIBOOT_MEMMAP help Maximum number of memory regions to hold in the memory map. config MULTIBOOT bool "Generate multiboot header" depends on X86_PC_COMPATIBLE default y help Embed a multiboot header in the output executable. This is used by some boot loaders (e.g., GRUB) when loading Zephyr. It is safe to leave this option on if you're not sure. It only expands the text segment by 12-16 bytes and is typically ignored if not needed. if MULTIBOOT config MULTIBOOT_INFO bool "Preserve multiboot information structure" help Multiboot passes a pointer to an information structure to the kernel entry point. Some drivers (e.g., the multiboot framebuffer display driver) need to refer to information in this structure, and so set this option to preserve the data in a permanent location. config MULTIBOOT_MEMMAP bool "Use multiboot memory map if provided" select MULTIBOOT_INFO select X86_MEMMAP help Use the multiboot memory map if the loader provides one. config MULTIBOOT_FRAMEBUF bool "Multiboot framebuffer support" select DISPLAY select FRAMEBUF_DISPLAY select MULTIBOOT_INFO if MULTIBOOT_FRAMEBUF config MULTIBOOT_FRAMEBUF_X int "Multiboot framebuffer X pixels" default 640 config MULTIBOOT_FRAMEBUF_Y int "Multiboot framebuffer Y pixels" default 480 endif # MULTIBOOT_FRAMEBUF endif # MULTIBOOT config EXCEPTION_DEBUG bool "Unhandled exception debugging" default y depends on LOG help Install handlers for various CPU exception/trap vectors to make debugging them easier, at a small expense in code size. This prints out the specific exception vector and any associated error codes. config X86_VERY_EARLY_CONSOLE bool "Support very early boot printk" depends on PRINTK help Non-emulated X86 devices often require special hardware to attach a debugger, which may not be easily available. This option adds a very minimal serial driver which gets initialized at the very beginning of z_cstart(), via arch_kernel_init(). This driver enables printk to emit messages to the 16550 UART port 0 instance in device tree. This mini-driver assumes I/O to the UART is done via ports. config X86_MMU bool "Memory Management Unit" select MMU help This options enables the memory management unit present in x86 and creates a set of page tables at boot time that is runtime- mutable. config X86_COMMON_PAGE_TABLE bool "Use a single page table for all threads" default n depends on USERSPACE depends on !SMP depends on !X86_KPTI help If this option is enabled, userspace memory domains will not have their own page tables. Instead, context switching operations will modify page tables in place. This is much slower, but uses much less RAM for page tables. config X86_MAX_ADDITIONAL_MEM_DOMAINS int "Maximum number of memory domains" default 3 depends on X86_MMU && USERSPACE && !X86_COMMON_PAGE_TABLE help The initial page tables at boot are pre-allocated, and used for the default memory domain. Instantiation of additional memory domains if common page tables are in use requires a pool of free pinned memory pages for constructing page tables. Zephyr test cases assume 3 additional domains can be instantiated. config X86_EXTRA_PAGE_TABLE_PAGES int "Reserve extra pages in page table" default 1 if X86_PAE && (KERNEL_VM_BASE != SRAM_BASE_ADDRESS) default 0 depends on X86_MMU help The whole page table is pre-allocated at build time and is dependent on the range of address space. This allows reserving extra pages (of size CONFIG_MMU_PAGE_SIZE) to the page table so that gen_mmu.py can make use of these extra pages. Says 0 unless absolutely sure that this is necessary. config X86_NO_MELTDOWN bool help This hidden option should be set on a per-SOC basis to indicate that a particular SOC is not vulnerable to the Meltdown CPU vulnerability, as described in CVE-2017-5754. config X86_NO_SPECTRE_V1 bool help This hidden option should be set on a per-SOC basis to indicate that a particular SOC is not vulnerable to the Spectre V1, V1.1, V1.2, and swapgs CPU vulnerabilities as described in CVE-2017-5753, CVE-2018-3693, and CVE-2019-1125. config X86_NO_SPECTRE_V2 bool help This hidden option should be set on a per-SOC basis to indicate that a particular SOC is not vulnerable to the Spectre V2 CPU vulnerability, as described in CVE-2017-5715. config X86_NO_SPECTRE_V4 bool help This hidden option should be set on a per-SOC basis to indicate that a particular SOC is not vulnerable to the Spectre V4 CPU vulnerability, as described in CVE-2018-3639. config X86_NO_LAZY_FP bool help This hidden option should be set on a per-SOC basis to indicate that a particular SOC is not vulnerable to the Lazy FP CPU vulnerability, as described in CVE-2018-3665. config X86_NO_SPECULATIVE_VULNERABILITIES bool select X86_NO_MELTDOWN select X86_NO_SPECTRE_V1 select X86_NO_SPECTRE_V2 select X86_NO_SPECTRE_V4 select X86_NO_LAZY_FP help This hidden option should be set on a per-SOC basis to indicate that a particular SOC does not perform any kind of speculative execution, or is a newer chip which is immune to the class of vulnerabilities which exploit speculative execution side channel attacks. config DISABLE_SSBD bool "Disable Speculative Store Bypass" depends on USERSPACE default y if !X86_NO_SPECTRE_V4 help This option will disable Speculative Store Bypass in order to mitigate against certain kinds of side channel attacks. Quoting the "Speculative Execution Side Channels" document, version 2.0: When SSBD is set, loads will not execute speculatively until the addresses of all older stores are known. This ensure s that a load does not speculatively consume stale data values due to bypassing an older store on the same logical processor. If enabled, this applies to all threads in the system. Even if enabled, will have no effect on CPUs that do not require this feature. config ENABLE_EXTENDED_IBRS bool "Extended IBRS" depends on USERSPACE default y if !X86_NO_SPECTRE_V2 help This option will enable the Extended Indirect Branch Restricted Speculation 'always on' feature. This mitigates Indirect Branch Control vulnerabilities (aka Spectre V2). config X86_BOUNDS_CHECK_BYPASS_MITIGATION bool depends on USERSPACE default y if !X86_NO_SPECTRE_V1 select BOUNDS_CHECK_BYPASS_MITIGATION help Hidden config to select arch-independent option to enable Spectre V1 mitigations by default if the CPU is not known to be immune to it. config X86_KPTI bool "Kernel page table isolation" default y depends on USERSPACE depends on !X86_NO_MELTDOWN help Implements kernel page table isolation to mitigate Meltdown exploits to read Kernel RAM. Incurs a significant performance cost for user thread interrupts and system calls, and significant footprint increase for additional page tables and trampoline stacks. config X86_EFI bool "EFI" default y depends on BUILD_OUTPUT_EFI help Enable EFI support. This means you build your image with zefi support. See arch/x86/zefi/README.txt for more information. config X86_EFI_CONSOLE bool depends on X86_EFI && X86_64 && !X86_VERY_EARLY_CONSOLE select EFI_CONSOLE default y help This enables the use of the UEFI console device as the Zephyr printk handler. It requires that no interferences with hardware used by the firmware console (e.g. a UART or framebuffer) happens from Zephyr code, and that all memory used by the firmware environment and its page tables be separate and preserved. In general this is safe to assume, but no automatic checking exists at runtime to verify. Likewise be sure to disable any other console/printk drivers! source "arch/x86/core/Kconfig.ia32" source "arch/x86/core/Kconfig.intel64" endmenu