From: Juergen Gross Date: Tue, 20 Nov 2018 08:25:28 +0100 Subject: x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address to setup_header") Origin: https://git.kernel.org/linus/3841840449817ba6cf3e636008bc4e1061a03388 Peter Anvin pointed out that commit: ae7e1238e68f2a ("x86/boot: Add ACPI RSDP address to setup_header") should be reverted as setup_header should only contain items set by the legacy BIOS. So revert said commit. Instead of fully reverting the dependent commit of: e7b66d16fe4172 ("x86/acpi, x86/boot: Take RSDP address for boot params if available") just remove the setup_header reference in order to replace it by a boot_params in a followup patch. Suggested-by: "H. Peter Anvin" Signed-off-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: daniel.kiper@oracle.com Cc: sstabellini@kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181120072529.5489-2-jgross@suse.com Signed-off-by: Ingo Molnar --- Documentation/x86/boot.txt | 32 +-------------------------- arch/x86/boot/header.S | 6 +---- arch/x86/include/asm/x86_init.h | 2 -- arch/x86/include/uapi/asm/bootparam.h | 4 ---- arch/x86/kernel/acpi/boot.c | 2 +- arch/x86/kernel/head32.c | 1 - arch/x86/kernel/head64.c | 2 -- arch/x86/kernel/setup.c | 17 -------------- 8 files changed, 3 insertions(+), 63 deletions(-) Index: linux/Documentation/x86/boot.txt =================================================================== --- linux.orig/Documentation/x86/boot.txt +++ linux/Documentation/x86/boot.txt @@ -61,18 +61,6 @@ Protocol 2.12: (Kernel 3.8) Added the xl to struct boot_params for loading bzImage and ramdisk above 4G in 64bit. -Protocol 2.13: (Kernel 3.14) Support 32- and 64-bit flags being set in - xloadflags to support booting a 64-bit kernel from 32-bit - EFI - -Protocol 2.14: (Kernel 4.20) Added acpi_rsdp_addr holding the physical - address of the ACPI RSDP table. - The bootloader updates version with: - 0x8000 | min(kernel-version, bootloader-version) - kernel-version being the protocol version supported by - the kernel and bootloader-version the protocol version - supported by the bootloader. - **** MEMORY LAYOUT The traditional memory map for the kernel loader, used for Image or @@ -209,7 +197,6 @@ Offset Proto Name Meaning 0258/8 2.10+ pref_address Preferred loading address 0260/4 2.10+ init_size Linear memory required during initialization 0264/4 2.11+ handover_offset Offset of handover entry point -0268/8 2.14+ acpi_rsdp_addr Physical address of RSDP table (1) For backwards compatibility, if the setup_sects field contains 0, the real value is 4. @@ -322,7 +309,7 @@ Protocol: 2.00+ Contains the magic number "HdrS" (0x53726448). Field name: version -Type: modify +Type: read Offset/size: 0x206/2 Protocol: 2.00+ @@ -330,12 +317,6 @@ Protocol: 2.00+ e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version 10.17. - Up to protocol version 2.13 this information is only read by the - bootloader. From protocol version 2.14 onwards the bootloader will - write the used protocol version or-ed with 0x8000 to the field. The - used protocol version will be the minimum of the supported protocol - versions of the bootloader and the kernel. - Field name: realmode_swtch Type: modify (optional) Offset/size: 0x208/4 @@ -763,17 +744,6 @@ Offset/size: 0x264/4 See EFI HANDOVER PROTOCOL below for more details. -Field name: acpi_rsdp_addr -Type: write -Offset/size: 0x268/8 -Protocol: 2.14+ - - This field can be set by the boot loader to tell the kernel the - physical address of the ACPI RSDP table. - - A value of 0 indicates the kernel should fall back to the standard - methods to locate the RSDP. - **** THE IMAGE CHECKSUM Index: linux/arch/x86/boot/header.S =================================================================== --- linux.orig/arch/x86/boot/header.S +++ linux/arch/x86/boot/header.S @@ -300,7 +300,7 @@ _start: # Part 2 of the header, from the old setup.S .ascii "HdrS" # header signature - .word 0x020e # header version number (>= 0x0105) + .word 0x020d # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -558,10 +558,6 @@ pref_address: .quad LOAD_PHYSICAL_ADDR init_size: .long INIT_SIZE # kernel initialization size handover_offset: .long 0 # Filled in by build.c -acpi_rsdp_addr: .quad 0 # 64-bit physical pointer to the - # ACPI RSDP table, added with - # version 2.14 - # End of setup header ##################################################### .section ".entrytext", "ax" Index: linux/arch/x86/include/asm/x86_init.h =================================================================== --- linux.orig/arch/x86/include/asm/x86_init.h +++ linux/arch/x86/include/asm/x86_init.h @@ -303,6 +303,4 @@ extern void x86_init_noop(void); extern void x86_init_uint_noop(unsigned int unused); extern bool x86_pnpbios_disabled(void); -void x86_verify_bootdata_version(void); - #endif Index: linux/arch/x86/include/uapi/asm/bootparam.h =================================================================== --- linux.orig/arch/x86/include/uapi/asm/bootparam.h +++ linux/arch/x86/include/uapi/asm/bootparam.h @@ -16,9 +16,6 @@ #define RAMDISK_PROMPT_FLAG 0x8000 #define RAMDISK_LOAD_FLAG 0x4000 -/* version flags */ -#define VERSION_WRITTEN 0x8000 - /* loadflags */ #define LOADED_HIGH (1<<0) #define KASLR_FLAG (1<<1) @@ -89,7 +86,6 @@ struct setup_header { __u64 pref_address; __u32 init_size; __u32 handover_offset; - __u64 acpi_rsdp_addr; } __attribute__((packed)); struct sys_desc_table { Index: linux/arch/x86/kernel/acpi/boot.c =================================================================== --- linux.orig/arch/x86/kernel/acpi/boot.c +++ linux/arch/x86/kernel/acpi/boot.c @@ -1775,5 +1775,5 @@ void __init arch_reserve_mem_area(acpi_p u64 x86_default_get_root_pointer(void) { - return boot_params.hdr.acpi_rsdp_addr; + return 0; } Index: linux/arch/x86/kernel/head32.c =================================================================== --- linux.orig/arch/x86/kernel/head32.c +++ linux/arch/x86/kernel/head32.c @@ -37,7 +37,6 @@ asmlinkage __visible void __init i386_st cr4_init_shadow(); sanitize_boot_params(&boot_params); - x86_verify_bootdata_version(); x86_early_init_platform_quirks(); Index: linux/arch/x86/kernel/head64.c =================================================================== --- linux.orig/arch/x86/kernel/head64.c +++ linux/arch/x86/kernel/head64.c @@ -477,8 +477,6 @@ void __init x86_64_start_reservations(ch if (!boot_params.hdr.version) copy_bootdata(__va(real_mode_data)); - x86_verify_bootdata_version(); - x86_early_init_platform_quirks(); switch (boot_params.hdr.hardware_subarch) { Index: linux/arch/x86/kernel/setup.c =================================================================== --- linux.orig/arch/x86/kernel/setup.c +++ linux/arch/x86/kernel/setup.c @@ -1281,23 +1281,6 @@ void __init setup_arch(char **cmdline_p) unwind_init(); } -/* - * From boot protocol 2.14 onwards we expect the bootloader to set the - * version to "0x8000 | ". In case we find a version >= 2.14 - * without the 0x8000 we assume the boot loader supports 2.13 only and - * reset the version accordingly. The 0x8000 flag is removed in any case. - */ -void __init x86_verify_bootdata_version(void) -{ - if (boot_params.hdr.version & VERSION_WRITTEN) - boot_params.hdr.version &= ~VERSION_WRITTEN; - else if (boot_params.hdr.version >= 0x020e) - boot_params.hdr.version = 0x020d; - - if (boot_params.hdr.version < 0x020e) - boot_params.hdr.acpi_rsdp_addr = 0; -} - #ifdef CONFIG_X86_32 static struct resource video_ram_resource = {