diff options
| -rw-r--r-- | Documentation/x86/boot.txt | 32 | ||||
| -rw-r--r-- | arch/x86/boot/header.S | 6 | ||||
| -rw-r--r-- | arch/x86/include/asm/x86_init.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/bootparam.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/head32.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/head64.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 17 |
7 files changed, 62 insertions, 2 deletions
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt index 5e9b826b5f62..7727db8f94bc 100644 --- a/Documentation/x86/boot.txt +++ b/Documentation/x86/boot.txt @@ -61,6 +61,18 @@ Protocol 2.12: (Kernel 3.8) Added the xloadflags field and extension fields 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 @@ -197,6 +209,7 @@ 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. @@ -309,7 +322,7 @@ Protocol: 2.00+ Contains the magic number "HdrS" (0x53726448). Field name: version -Type: read +Type: modify Offset/size: 0x206/2 Protocol: 2.00+ @@ -317,6 +330,12 @@ 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 @@ -744,6 +763,17 @@ 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 diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 850b8762e889..4c881c850125 100644 --- a/arch/x86/boot/header.S +++ b/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 0x020d # header version number (>= 0x0105) + .word 0x020e # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -558,6 +558,10 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load 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" diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index b85a7c54c6a1..0f842104862c 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -303,4 +303,6 @@ 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 diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h index a06cbf019744..22f89d040ddd 100644 --- a/arch/x86/include/uapi/asm/bootparam.h +++ b/arch/x86/include/uapi/asm/bootparam.h @@ -16,6 +16,9 @@ #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) @@ -86,6 +89,7 @@ struct setup_header { __u64 pref_address; __u32 init_size; __u32 handover_offset; + __u64 acpi_rsdp_addr; } __attribute__((packed)); struct sys_desc_table { diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index ec6fefbfd3c0..76fa3b836598 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -37,6 +37,7 @@ asmlinkage __visible void __init i386_start_kernel(void) cr4_init_shadow(); sanitize_boot_params(&boot_params); + x86_verify_bootdata_version(); x86_early_init_platform_quirks(); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index ddee1f0870c4..5dc377dc9d7b 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -457,6 +457,8 @@ void __init x86_64_start_reservations(char *real_mode_data) 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) { diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index b4866badb235..8e226b7a1753 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1281,6 +1281,23 @@ 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 | <used version>". 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 = { |