diff options
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/boot.txt | 32 |
1 files changed, 31 insertions, 1 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 |