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-rw-r--r--Documentation/x86/00-INDEX18
-rw-r--r--Documentation/x86/boot.txt138
-rw-r--r--Documentation/x86/early-microcode.txt42
-rw-r--r--Documentation/x86/earlyprintk.txt2
-rw-r--r--Documentation/x86/entry_64.txt95
-rw-r--r--Documentation/x86/i386/IO-APIC.txt2
-rw-r--r--Documentation/x86/x86_64/boot-options.txt74
-rw-r--r--Documentation/x86/x86_64/mm.txt13
-rw-r--r--Documentation/x86/zero-page.txt4
9 files changed, 317 insertions, 71 deletions
diff --git a/Documentation/x86/00-INDEX b/Documentation/x86/00-INDEX
index f37b46d3486..692264456f0 100644
--- a/Documentation/x86/00-INDEX
+++ b/Documentation/x86/00-INDEX
@@ -1,6 +1,20 @@
00-INDEX
- this file
-mtrr.txt
- - how to use x86 Memory Type Range Registers to increase performance
+boot.txt
+ - List of boot protocol versions
+early-microcode.txt
+ - How to load microcode from an initrd-CPIO archive early to fix CPU issues.
+earlyprintk.txt
+ - Using earlyprintk with a USB2 debug port key.
+entry_64.txt
+ - Describe (some of the) kernel entry points for x86.
exception-tables.txt
- why and how Linux kernel uses exception tables on x86
+mtrr.txt
+ - how to use x86 Memory Type Range Registers to increase performance
+pat.txt
+ - Page Attribute Table intro and API
+usb-legacy-support.txt
+ - how to fix/avoid quirks when using emulated PS/2 mouse/keyboard.
+zero-page.txt
+ - layout of the first page of memory.
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 30b43e1b269..a75e3adaa39 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -54,6 +54,13 @@ Protocol 2.10: (Kernel 2.6.31) Added a protocol for relaxed alignment
beyond the kernel_alignment added, new init_size and
pref_address fields. Added extended boot loader IDs.
+Protocol 2.11: (Kernel 3.6) Added a field for offset of EFI handover
+ protocol entry point.
+
+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.
+
**** MEMORY LAYOUT
The traditional memory map for the kernel loader, used for Image or
@@ -175,11 +182,11 @@ Offset Proto Name Meaning
0226/1 2.02+(3 ext_loader_ver Extended boot loader version
0227/1 2.02+(3 ext_loader_type Extended boot loader ID
0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line
-022C/4 2.03+ ramdisk_max Highest legal initrd address
+022C/4 2.03+ initrd_addr_max Highest legal initrd address
0230/4 2.05+ kernel_alignment Physical addr alignment required for kernel
0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not
0235/1 2.10+ min_alignment Minimum alignment, as a power of two
-0236/2 N/A pad3 Unused
+0236/2 2.12+ xloadflags Boot protocol option flags
0238/4 2.06+ cmdline_size Maximum size of the kernel command line
023C/4 2.07+ hardware_subarch Hardware subarchitecture
0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data
@@ -189,6 +196,7 @@ Offset Proto Name Meaning
of struct setup_data
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
(1) For backwards compatibility, if the setup_sects field contains 0, the
real value is 4.
@@ -363,12 +371,13 @@ Protocol: 2.00+
ext_loader_type <- 0x05
ext_loader_ver <- 0x23
- Assigned boot loader ids:
+ Assigned boot loader ids (hexadecimal):
+
0 LILO (0x00 reserved for pre-2.00 bootloader)
1 Loadlin
2 bootsect-loader (0x20, all other values reserved)
3 Syslinux
- 4 Etherboot/gPXE
+ 4 Etherboot/gPXE/iPXE
5 ELILO
7 GRUB
8 U-Boot
@@ -376,8 +385,12 @@ Protocol: 2.00+
A Gujin
B Qemu
C Arcturus Networks uCbootloader
+ D kexec-tools
E Extended (see ext_loader_type)
F Special (0xFF = undefined)
+ 10 Reserved
+ 11 Minimal Linux Bootloader <http://sebastian-plotz.blogspot.de>
+ 12 OVMF UEFI virtualization stack
Please contact <hpa@zytor.com> if you need a bootloader ID
value assigned.
@@ -521,7 +534,7 @@ Protocol: 2.02+
zero, the kernel will assume that your boot loader does not support
the 2.02+ protocol.
-Field name: ramdisk_max
+Field name: initrd_addr_max
Type: read
Offset/size: 0x22c/4
Protocol: 2.03+
@@ -574,6 +587,30 @@ Protocol: 2.10+
misaligned kernel. Therefore, a loader should typically try each
power-of-two alignment from kernel_alignment down to this alignment.
+Field name: xloadflags
+Type: read
+Offset/size: 0x236/2
+Protocol: 2.12+
+
+ This field is a bitmask.
+
+ Bit 0 (read): XLF_KERNEL_64
+ - If 1, this kernel has the legacy 64-bit entry point at 0x200.
+
+ Bit 1 (read): XLF_CAN_BE_LOADED_ABOVE_4G
+ - If 1, kernel/boot_params/cmdline/ramdisk can be above 4G.
+
+ Bit 2 (read): XLF_EFI_HANDOVER_32
+ - If 1, the kernel supports the 32-bit EFI handoff entry point
+ given at handover_offset.
+
+ Bit 3 (read): XLF_EFI_HANDOVER_64
+ - If 1, the kernel supports the 64-bit EFI handoff entry point
+ given at handover_offset + 0x200.
+
+ Bit 4 (read): XLF_EFI_KEXEC
+ - If 1, the kernel supports kexec EFI boot with EFI runtime support.
+
Field name: cmdline_size
Type: read
Offset/size: 0x238/4
@@ -600,6 +637,7 @@ Protocol: 2.07+
0x00000001 lguest
0x00000002 Xen
0x00000003 Moorestown MID
+ 0x00000004 CE4100 TV Platform
Field name: hardware_subarch_data
Type: write (subarch-dependent)
@@ -621,10 +659,11 @@ Protocol: 2.08+
The payload may be compressed. The format of both the compressed and
uncompressed data should be determined using the standard magic
numbers. The currently supported compression formats are gzip
- (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A) and LZMA
- (magic number 5D 00). The uncompressed payload is currently always ELF
- (magic number 7F 45 4C 46).
-
+ (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA
+ (magic number 5D 00), XZ (magic number FD 37), and LZ4 (magic number
+ 02 21). The uncompressed payload is currently always ELF (magic
+ number 7F 45 4C 46).
+
Field name: payload_length
Type: read
Offset/size: 0x24c/4
@@ -673,7 +712,7 @@ Protocol: 2.10+
Field name: init_size
Type: read
-Offset/size: 0x25c/4
+Offset/size: 0x260/4
This field indicates the amount of linear contiguous memory starting
at the kernel runtime start address that the kernel needs before it
@@ -689,6 +728,16 @@ Offset/size: 0x25c/4
else
runtime_start = pref_address
+Field name: handover_offset
+Type: read
+Offset/size: 0x264/4
+
+ This field is the offset from the beginning of the kernel image to
+ the EFI handover protocol entry point. Boot loaders using the EFI
+ handover protocol to boot the kernel should jump to this offset.
+
+ See EFI HANDOVER PROTOCOL below for more details.
+
**** THE IMAGE CHECKSUM
@@ -995,7 +1044,7 @@ boot_params as that of 16-bit boot protocol, the boot loader should
also fill the additional fields of the struct boot_params as that
described in zero-page.txt.
-After setupping the struct boot_params, the boot loader can load the
+After setting up the struct boot_params, the boot loader can load the
32/64-bit kernel in the same way as that of 16-bit boot protocol.
In 32-bit boot protocol, the kernel is started by jumping to the
@@ -1005,7 +1054,72 @@ In 32-bit boot protocol, the kernel is started by jumping to the
At entry, the CPU must be in 32-bit protected mode with paging
disabled; a GDT must be loaded with the descriptors for selectors
__BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat
-segment; __BOOS_CS must have execute/read permission, and __BOOT_DS
+segment; __BOOT_CS must have execute/read permission, and __BOOT_DS
must have read/write permission; CS must be __BOOT_CS and DS, ES, SS
must be __BOOT_DS; interrupt must be disabled; %esi must hold the base
address of the struct boot_params; %ebp, %edi and %ebx must be zero.
+
+**** 64-bit BOOT PROTOCOL
+
+For machine with 64bit cpus and 64bit kernel, we could use 64bit bootloader
+and we need a 64-bit boot protocol.
+
+In 64-bit boot protocol, the first step in loading a Linux kernel
+should be to setup the boot parameters (struct boot_params,
+traditionally known as "zero page"). The memory for struct boot_params
+could be allocated anywhere (even above 4G) and initialized to all zero.
+Then, the setup header at offset 0x01f1 of kernel image on should be
+loaded into struct boot_params and examined. The end of setup header
+can be calculated as follows:
+
+ 0x0202 + byte value at offset 0x0201
+
+In addition to read/modify/write the setup header of the struct
+boot_params as that of 16-bit boot protocol, the boot loader should
+also fill the additional fields of the struct boot_params as described
+in zero-page.txt.
+
+After setting up the struct boot_params, the boot loader can load
+64-bit kernel in the same way as that of 16-bit boot protocol, but
+kernel could be loaded above 4G.
+
+In 64-bit boot protocol, the kernel is started by jumping to the
+64-bit kernel entry point, which is the start address of loaded
+64-bit kernel plus 0x200.
+
+At entry, the CPU must be in 64-bit mode with paging enabled.
+The range with setup_header.init_size from start address of loaded
+kernel and zero page and command line buffer get ident mapping;
+a GDT must be loaded with the descriptors for selectors
+__BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat
+segment; __BOOT_CS must have execute/read permission, and __BOOT_DS
+must have read/write permission; CS must be __BOOT_CS and DS, ES, SS
+must be __BOOT_DS; interrupt must be disabled; %rsi must hold the base
+address of the struct boot_params.
+
+**** EFI HANDOVER PROTOCOL
+
+This protocol allows boot loaders to defer initialisation to the EFI
+boot stub. The boot loader is required to load the kernel/initrd(s)
+from the boot media and jump to the EFI handover protocol entry point
+which is hdr->handover_offset bytes from the beginning of
+startup_{32,64}.
+
+The function prototype for the handover entry point looks like this,
+
+ efi_main(void *handle, efi_system_table_t *table, struct boot_params *bp)
+
+'handle' is the EFI image handle passed to the boot loader by the EFI
+firmware, 'table' is the EFI system table - these are the first two
+arguments of the "handoff state" as described in section 2.3 of the
+UEFI specification. 'bp' is the boot loader-allocated boot params.
+
+The boot loader *must* fill out the following fields in bp,
+
+ o hdr.code32_start
+ o hdr.cmd_line_ptr
+ o hdr.cmdline_size
+ o hdr.ramdisk_image (if applicable)
+ o hdr.ramdisk_size (if applicable)
+
+All other fields should be zero.
diff --git a/Documentation/x86/early-microcode.txt b/Documentation/x86/early-microcode.txt
new file mode 100644
index 00000000000..d62bea6796d
--- /dev/null
+++ b/Documentation/x86/early-microcode.txt
@@ -0,0 +1,42 @@
+Early load microcode
+====================
+By Fenghua Yu <fenghua.yu@intel.com>
+
+Kernel can update microcode in early phase of boot time. Loading microcode early
+can fix CPU issues before they are observed during kernel boot time.
+
+Microcode is stored in an initrd file. The microcode is read from the initrd
+file and loaded to CPUs during boot time.
+
+The format of the combined initrd image is microcode in cpio format followed by
+the initrd image (maybe compressed). Kernel parses the combined initrd image
+during boot time. The microcode file in cpio name space is:
+on Intel: kernel/x86/microcode/GenuineIntel.bin
+on AMD : kernel/x86/microcode/AuthenticAMD.bin
+
+During BSP boot (before SMP starts), if the kernel finds the microcode file in
+the initrd file, it parses the microcode and saves matching microcode in memory.
+If matching microcode is found, it will be uploaded in BSP and later on in all
+APs.
+
+The cached microcode patch is applied when CPUs resume from a sleep state.
+
+There are two legacy user space interfaces to load microcode, either through
+/dev/cpu/microcode or through /sys/devices/system/cpu/microcode/reload file
+in sysfs.
+
+In addition to these two legacy methods, the early loading method described
+here is the third method with which microcode can be uploaded to a system's
+CPUs.
+
+The following example script shows how to generate a new combined initrd file in
+/boot/initrd-3.5.0.ucode.img with original microcode microcode.bin and
+original initrd image /boot/initrd-3.5.0.img.
+
+mkdir initrd
+cd initrd
+mkdir -p kernel/x86/microcode
+cp ../microcode.bin kernel/x86/microcode/GenuineIntel.bin (or AuthenticAMD.bin)
+find . | cpio -o -H newc >../ucode.cpio
+cd ..
+cat ucode.cpio /boot/initrd-3.5.0.img >/boot/initrd-3.5.0.ucode.img
diff --git a/Documentation/x86/earlyprintk.txt b/Documentation/x86/earlyprintk.txt
index f19802c0f48..688e3eeed21 100644
--- a/Documentation/x86/earlyprintk.txt
+++ b/Documentation/x86/earlyprintk.txt
@@ -33,7 +33,7 @@ and two USB cables, connected like this:
...
( If your system does not list a debug port capability then you probably
- wont be able to use the USB debug key. )
+ won't be able to use the USB debug key. )
b.) You also need a Netchip USB debug cable/key:
diff --git a/Documentation/x86/entry_64.txt b/Documentation/x86/entry_64.txt
new file mode 100644
index 00000000000..bc7226ef505
--- /dev/null
+++ b/Documentation/x86/entry_64.txt
@@ -0,0 +1,95 @@
+This file documents some of the kernel entries in
+arch/x86/kernel/entry_64.S. A lot of this explanation is adapted from
+an email from Ingo Molnar:
+
+http://lkml.kernel.org/r/<20110529191055.GC9835%40elte.hu>
+
+The x86 architecture has quite a few different ways to jump into
+kernel code. Most of these entry points are registered in
+arch/x86/kernel/traps.c and implemented in arch/x86/kernel/entry_64.S
+and arch/x86/ia32/ia32entry.S.
+
+The IDT vector assignments are listed in arch/x86/include/irq_vectors.h.
+
+Some of these entries are:
+
+ - system_call: syscall instruction from 64-bit code.
+
+ - ia32_syscall: int 0x80 from 32-bit or 64-bit code; compat syscall
+ either way.
+
+ - ia32_syscall, ia32_sysenter: syscall and sysenter from 32-bit
+ code
+
+ - interrupt: An array of entries. Every IDT vector that doesn't
+ explicitly point somewhere else gets set to the corresponding
+ value in interrupts. These point to a whole array of
+ magically-generated functions that make their way to do_IRQ with
+ the interrupt number as a parameter.
+
+ - APIC interrupts: Various special-purpose interrupts for things
+ like TLB shootdown.
+
+ - Architecturally-defined exceptions like divide_error.
+
+There are a few complexities here. The different x86-64 entries
+have different calling conventions. The syscall and sysenter
+instructions have their own peculiar calling conventions. Some of
+the IDT entries push an error code onto the stack; others don't.
+IDT entries using the IST alternative stack mechanism need their own
+magic to get the stack frames right. (You can find some
+documentation in the AMD APM, Volume 2, Chapter 8 and the Intel SDM,
+Volume 3, Chapter 6.)
+
+Dealing with the swapgs instruction is especially tricky. Swapgs
+toggles whether gs is the kernel gs or the user gs. The swapgs
+instruction is rather fragile: it must nest perfectly and only in
+single depth, it should only be used if entering from user mode to
+kernel mode and then when returning to user-space, and precisely
+so. If we mess that up even slightly, we crash.
+
+So when we have a secondary entry, already in kernel mode, we *must
+not* use SWAPGS blindly - nor must we forget doing a SWAPGS when it's
+not switched/swapped yet.
+
+Now, there's a secondary complication: there's a cheap way to test
+which mode the CPU is in and an expensive way.
+
+The cheap way is to pick this info off the entry frame on the kernel
+stack, from the CS of the ptregs area of the kernel stack:
+
+ xorl %ebx,%ebx
+ testl $3,CS+8(%rsp)
+ je error_kernelspace
+ SWAPGS
+
+The expensive (paranoid) way is to read back the MSR_GS_BASE value
+(which is what SWAPGS modifies):
+
+ movl $1,%ebx
+ movl $MSR_GS_BASE,%ecx
+ rdmsr
+ testl %edx,%edx
+ js 1f /* negative -> in kernel */
+ SWAPGS
+ xorl %ebx,%ebx
+1: ret
+
+and the whole paranoid non-paranoid macro complexity is about whether
+to suffer that RDMSR cost.
+
+If we are at an interrupt or user-trap/gate-alike boundary then we can
+use the faster check: the stack will be a reliable indicator of
+whether SWAPGS was already done: if we see that we are a secondary
+entry interrupting kernel mode execution, then we know that the GS
+base has already been switched. If it says that we interrupted
+user-space execution then we must do the SWAPGS.
+
+But if we are in an NMI/MCE/DEBUG/whatever super-atomic entry context,
+which might have triggered right after a normal entry wrote CS to the
+stack but before we executed SWAPGS, then the only safe way to check
+for GS is the slower method: the RDMSR.
+
+So we try only to mark those entry methods 'paranoid' that absolutely
+need the more expensive check for the GS base - and we generate all
+'normal' entry points with the regular (faster) entry macros.
diff --git a/Documentation/x86/i386/IO-APIC.txt b/Documentation/x86/i386/IO-APIC.txt
index 30b4c714fbe..15f5baf7e1b 100644
--- a/Documentation/x86/i386/IO-APIC.txt
+++ b/Documentation/x86/i386/IO-APIC.txt
@@ -87,7 +87,7 @@ your PCI configuration:
echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g'
-note that this script wont work if you have skipped a few slots or if your
+note that this script won't work if you have skipped a few slots or if your
board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins
connected in some strange way). E.g. if in the above case you have your SCSI
card (IRQ11) in Slot3, and have Slot1 empty:
diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 7fbbaf85f5b..5223479291a 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -50,6 +50,13 @@ Machine check
monarchtimeout:
Sets the time in us to wait for other CPUs on machine checks. 0
to disable.
+ mce=bios_cmci_threshold
+ Don't overwrite the bios-set CMCI threshold. This boot option
+ prevents Linux from overwriting the CMCI threshold set by the
+ bios. Without this option, Linux always sets the CMCI
+ threshold to 1. Enabling this may make memory predictive failure
+ analysis less effective if the bios sets thresholds for memory
+ errors since we will not see details for all errors.
nomce (for compatibility with i386): same as mce=off
@@ -71,33 +78,11 @@ APICs
no_timer_check Don't check the IO-APIC timer. This can work around
problems with incorrect timer initialization on some boards.
-
- apicmaintimer Run time keeping from the local APIC timer instead
- of using the PIT/HPET interrupt for this. This is useful
- when the PIT/HPET interrupts are unreliable.
-
- noapicmaintimer Don't do time keeping using the APIC timer.
- Useful when this option was auto selected, but doesn't work.
-
apicpmtimer
Do APIC timer calibration using the pmtimer. Implies
apicmaintimer. Useful when your PIT timer is totally
broken.
-Early Console
-
- syntax: earlyprintk=vga
- earlyprintk=serial[,ttySn[,baudrate]]
-
- The early console is useful when the kernel crashes before the
- normal console is initialized. It is not enabled by
- default because it has some cosmetic problems.
- Append ,keep to not disable it when the real console takes over.
- Only vga or serial at a time, not both.
- Currently only ttyS0 and ttyS1 are supported.
- Interaction with the standard serial driver is not very good.
- The VGA output is eventually overwritten by the real console.
-
Timing
notsc
@@ -105,10 +90,6 @@ Timing
This can be used to work around timing problems on multiprocessor systems
with not properly synchronized CPUs.
- report_lost_ticks
- Report when timer interrupts are lost because some code turned off
- interrupts for too long.
-
nohpet
Don't use the HPET timer.
@@ -155,11 +136,6 @@ Non Executable Mappings
on Enable(default)
off Disable
-SMP
-
- additional_cpus=NUM Allow NUM more CPUs for hotplug
- (defaults are specified by the BIOS, see Documentation/x86/x86_64/cpu-hotplug-spec)
-
NUMA
numa=off Only set up a single NUMA node spanning all memory.
@@ -187,15 +163,20 @@ ACPI
acpi=noirq Don't route interrupts
+ acpi=nocmcff Disable firmware first mode for corrected errors. This
+ disables parsing the HEST CMC error source to check if
+ firmware has set the FF flag. This may result in
+ duplicate corrected error reports.
+
PCI
- pci=off Don't use PCI
- pci=conf1 Use conf1 access.
- pci=conf2 Use conf2 access.
- pci=rom Assign ROMs.
- pci=assign-busses Assign busses
- pci=irqmask=MASK Set PCI interrupt mask to MASK
- pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says.
+ pci=off Don't use PCI
+ pci=conf1 Use conf1 access.
+ pci=conf2 Use conf2 access.
+ pci=rom Assign ROMs.
+ pci=assign-busses Assign busses
+ pci=irqmask=MASK Set PCI interrupt mask to MASK
+ pci=lastbus=NUMBER Scan up to NUMBER busses, no matter what the mptable says.
pci=noacpi Don't use ACPI to set up PCI interrupt routing.
IOMMU (input/output memory management unit)
@@ -206,7 +187,7 @@ IOMMU (input/output memory management unit)
(e.g. because you have < 3 GB memory).
Kernel boot message: "PCI-DMA: Disabling IOMMU"
- 2. <arch/x86_64/kernel/pci-gart.c>: AMD GART based hardware IOMMU.
+ 2. <arch/x86/kernel/amd_gart_64.c>: AMD GART based hardware IOMMU.
Kernel boot message: "PCI-DMA: using GART IOMMU"
3. <arch/x86_64/kernel/pci-swiotlb.c> : Software IOMMU implementation. Used
@@ -293,23 +274,8 @@ IOMMU (input/output memory management unit)
Debugging
- oops=panic Always panic on oopses. Default is to just kill the process,
- but there is a small probability of deadlocking the machine.
- This will also cause panics on machine check exceptions.
- Useful together with panic=30 to trigger a reboot.
-
kstack=N Print N words from the kernel stack in oops dumps.
- pagefaulttrace Dump all page faults. Only useful for extreme debugging
- and will create a lot of output.
-
- call_trace=[old|both|newfallback|new]
- old: use old inexact backtracer
- new: use new exact dwarf2 unwinder
- both: print entries from both
- newfallback: use new unwinder but fall back to old if it gets
- stuck (default)
-
Miscellaneous
nogbpages
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index d6498e3cd71..afe68ddbe6a 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -12,8 +12,12 @@ ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
... unused hole ...
+ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
+... unused hole ...
ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0
-ffffffffa0000000 - fffffffffff00000 (=1536 MB) module mapping space
+ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space
+ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls
+ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
The direct mapping covers all memory in the system up to the highest
memory address (this means in some cases it can also include PCI memory
@@ -26,4 +30,11 @@ reference.
Current X86-64 implementations only support 40 bits of address space,
but we support up to 46 bits. This expands into MBZ space in the page tables.
+->trampoline_pgd:
+
+We map EFI runtime services in the aforementioned PGD in the virtual
+range of 64Gb (arbitrarily set, can be raised if needed)
+
+0xffffffef00000000 - 0xffffffff00000000
+
-Andi Kleen, Jul 2004
diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index cf5437deda8..199f453cb4d 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -19,6 +19,9 @@ Offset Proto Name Meaning
090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!!
0A0/010 ALL sys_desc_table System description table (struct sys_desc_table)
0B0/010 ALL olpc_ofw_header OLPC's OpenFirmware CIF and friends
+0C0/004 ALL ext_ramdisk_image ramdisk_image high 32bits
+0C4/004 ALL ext_ramdisk_size ramdisk_size high 32bits
+0C8/004 ALL ext_cmd_line_ptr cmd_line_ptr high 32bits
140/080 ALL edid_info Video mode setup (struct edid_info)
1C0/020 ALL efi_info EFI 32 information (struct efi_info)
1E0/004 ALL alk_mem_k Alternative mem check, in KB
@@ -27,6 +30,7 @@ Offset Proto Name Meaning
1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below)
1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer
(below)
+1EF/001 ALL sentinel Used to detect broken bootloaders
290/040 ALL edd_mbr_sig_buffer EDD MBR signatures
2D0/A00 ALL e820_map E820 memory map table
(array of struct e820entry)
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 13:21:29 +0000