Merge branch 'x86' into docs-next

Merge the x86 docs conversion from Changbin Du, who writes:

> The kernel now uses Sphinx to generate intelligent and beautiful
> documentation from reStructuredText files. I converted all of the Linux
> x86 docs to rst format in this serias.
>
> For you to preview, please visit below url:
> http://www.bytemem.com:8080/kernel-doc/index.html
>
> Thank you!

The whole series was:
Acked-by: Ingo Molnar <mingo@kernel.org>

Documentation/index.rst

@@ -101,6 +101,7 @@ implementation.
 .. toctree::
    :maxdepth: 2
 
+   x86/index
    sh/index
 
 Filesystem Documentation

Documentation/x86/amd-memory-encryption.txt → Documentation/x86/amd-memory-encryption.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=====================
+AMD Memory Encryption
+=====================
+
 Secure Memory Encryption (SME) and Secure Encrypted Virtualization (SEV) are
 features found on AMD processors.
 
@@ -34,7 +40,7 @@ is operating in 64-bit or 32-bit PAE mode, in all other modes the SEV hardware
 forces the memory encryption bit to 1.
 
 Support for SME and SEV can be determined through the CPUID instruction. The
-CPUID function 0x8000001f reports information related to SME:
+CPUID function 0x8000001f reports information related to SME::
 
 	0x8000001f[eax]:
 		Bit[0] indicates support for SME
@@ -48,14 +54,14 @@ CPUID function 0x8000001f reports information related to SME:
 			   addresses)
 
 If support for SME is present, MSR 0xc00100010 (MSR_K8_SYSCFG) can be used to
-determine if SME is enabled and/or to enable memory encryption:
+determine if SME is enabled and/or to enable memory encryption::
 
 	0xc0010010:
 		Bit[23]   0 = memory encryption features are disabled
 			  1 = memory encryption features are enabled
 
 If SEV is supported, MSR 0xc0010131 (MSR_AMD64_SEV) can be used to determine if
-SEV is active:
+SEV is active::
 
 	0xc0010131:
 		Bit[0]	  0 = memory encryption is not active
@@ -68,6 +74,7 @@ requirements for the system.  If this bit is not set upon Linux startup then
 Linux itself will not set it and memory encryption will not be possible.
 
 The state of SME in the Linux kernel can be documented as follows:
+
 	- Supported:
 	  The CPU supports SME (determined through CPUID instruction).
 

Documentation/x86/earlyprintk.txt → Documentation/x86/earlyprintk.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+============
+Early Printk
+============
 
 Mini-HOWTO for using the earlyprintk=dbgp boot option with a
 USB2 Debug port key and a debug cable, on x86 systems.
 
 You need two computers, the 'USB debug key' special gadget and
-and two USB cables, connected like this:
+and two USB cables, connected like this::
 
   [host/target] <-------> [USB debug key] <-------> [client/console]
 
-1. There are a number of specific hardware requirements:
-
- a.) Host/target system needs to have USB debug port capability.
-
- You can check this capability by looking at a 'Debug port' bit in
- the lspci -vvv output:
-
- # lspci -vvv
- ...
- 00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03) (prog-if 20 [EHCI])
-         Subsystem: Lenovo ThinkPad T61
-         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx-
-         Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
-         Latency: 0
-         Interrupt: pin D routed to IRQ 19
-         Region 0: Memory at fe227000 (32-bit, non-prefetchable) [size=1K]
-         Capabilities: [50] Power Management version 2
-                 Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
-                 Status: D0 PME-Enable- DSel=0 DScale=0 PME+
-         Capabilities: [58] Debug port: BAR=1 offset=00a0
+Hardware requirements
+=====================
+
+  a) Host/target system needs to have USB debug port capability.
+
+     You can check this capability by looking at a 'Debug port' bit in
+     the lspci -vvv output::
+
+       # lspci -vvv
+       ...
+       00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03) (prog-if 20 [EHCI])
+               Subsystem: Lenovo ThinkPad T61
+               Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx-
+               Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
+               Latency: 0
+               Interrupt: pin D routed to IRQ 19
+               Region 0: Memory at fe227000 (32-bit, non-prefetchable) [size=1K]
+               Capabilities: [50] Power Management version 2
+                       Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
+                       Status: D0 PME-Enable- DSel=0 DScale=0 PME+
+               Capabilities: [58] Debug port: BAR=1 offset=00a0
                             ^^^^^^^^^^^ <==================== [ HERE ]
-	 Kernel driver in use: ehci_hcd
-         Kernel modules: ehci-hcd
- ...
+               Kernel driver in use: ehci_hcd
+               Kernel modules: ehci-hcd
+       ...
 
-( If your system does not list a debug port capability then you probably
-  won't be able to use the USB debug key. )
+     .. note::
+       If your system does not list a debug port capability then you probably
+       won't be able to use the USB debug key.
 
- b.) You also need a NetChip USB debug cable/key:
+  b) You also need a NetChip USB debug cable/key:
 
         http://www.plxtech.com/products/NET2000/NET20DC/default.asp
 
      This is a small blue plastic connector with two USB connections;
      it draws power from its USB connections.
 
- c.) You need a second client/console system with a high speed USB 2.0
-     port.
+  c) You need a second client/console system with a high speed USB 2.0 port.
 
- d.) The NetChip device must be plugged directly into the physical
-     debug port on the "host/target" system.  You cannot use a USB hub in
+  d) The NetChip device must be plugged directly into the physical
+     debug port on the "host/target" system. You cannot use a USB hub in
      between the physical debug port and the "host/target" system.
 
      The EHCI debug controller is bound to a specific physical USB
@@ -65,29 +71,31 @@ and two USB cables, connected like this:
      to the hardware vendor, because there is no reason not to wire
      this port into one of the physically accessible ports.
 
- e.) It is also important to note, that many versions of the NetChip
+  e) It is also important to note, that many versions of the NetChip
      device require the "client/console" system to be plugged into the
      right hand side of the device (with the product logo facing up and
      readable left to right).  The reason being is that the 5 volt
      power supply is taken from only one side of the device and it
      must be the side that does not get rebooted.
 
-2. Software requirements:
+Software requirements
+=====================
 
- a.) On the host/target system:
+  a) On the host/target system:
 
-    You need to enable the following kernel config option:
+    You need to enable the following kernel config option::
 
       CONFIG_EARLY_PRINTK_DBGP=y
 
     And you need to add the boot command line: "earlyprintk=dbgp".
 
-    (If you are using Grub, append it to the 'kernel' line in
-     /etc/grub.conf.  If you are using Grub2 on a BIOS firmware system,
-     append it to the 'linux' line in /boot/grub2/grub.cfg. If you are
-     using Grub2 on an EFI firmware system, append it to the 'linux'
-     or 'linuxefi' line in /boot/grub2/grub.cfg or
-     /boot/efi/EFI/<distro>/grub.cfg.)
+    .. note::
+      If you are using Grub, append it to the 'kernel' line in
+      /etc/grub.conf.  If you are using Grub2 on a BIOS firmware system,
+      append it to the 'linux' line in /boot/grub2/grub.cfg. If you are
+      using Grub2 on an EFI firmware system, append it to the 'linux'
+      or 'linuxefi' line in /boot/grub2/grub.cfg or
+      /boot/efi/EFI/<distro>/grub.cfg.
 
     On systems with more than one EHCI debug controller you must
     specify the correct EHCI debug controller number.  The ordering
@@ -96,14 +104,15 @@ and two USB cables, connected like this:
     controller.  To use the second EHCI debug controller, you would
     use the command line: "earlyprintk=dbgp1"
 
-    NOTE: normally earlyprintk console gets turned off once the
-    regular console is alive - use "earlyprintk=dbgp,keep" to keep
-    this channel open beyond early bootup. This can be useful for
-    debugging crashes under Xorg, etc.
+    .. note::
+      normally earlyprintk console gets turned off once the
+      regular console is alive - use "earlyprintk=dbgp,keep" to keep
+      this channel open beyond early bootup. This can be useful for
+      debugging crashes under Xorg, etc.
 
- b.) On the client/console system:
+  b) On the client/console system:
 
-    You should enable the following kernel config option:
+    You should enable the following kernel config option::
 
       CONFIG_USB_SERIAL_DEBUG=y
 
@@ -115,27 +124,28 @@ and two USB cables, connected like this:
     it up to use /dev/ttyUSB0 - or use a raw 'cat /dev/ttyUSBx' to
     see the raw output.
 
- c.) On Nvidia Southbridge based systems: the kernel will try to probe
+  c) On Nvidia Southbridge based systems: the kernel will try to probe
      and find out which port has a debug device connected.
 
-3. Testing that it works fine:
+Testing
+=======
 
-   You can test the output by using earlyprintk=dbgp,keep and provoking
-   kernel messages on the host/target system. You can provoke a harmless
-   kernel message by for example doing:
+You can test the output by using earlyprintk=dbgp,keep and provoking
+kernel messages on the host/target system. You can provoke a harmless
+kernel message by for example doing::
 
      echo h > /proc/sysrq-trigger
 
-   On the host/target system you should see this help line in "dmesg" output:
+On the host/target system you should see this help line in "dmesg" output::
 
      SysRq : HELP : loglevel(0-9) reBoot Crashdump terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) unRaw Sync show-task-states(T) Unmount show-blocked-tasks(W) dump-ftrace-buffer(Z)
 
-   On the client/console system do:
+On the client/console system do::
 
        cat /dev/ttyUSB0
 
-   And you should see the help line above displayed shortly after you've
-   provoked it on the host system.
+And you should see the help line above displayed shortly after you've
+provoked it on the host system.
 
 If it does not work then please ask about it on the linux-kernel@vger.kernel.org
 mailing list or contact the x86 maintainers.

Documentation/x86/entry_64.txt → Documentation/x86/entry_64.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+==============
+Kernel Entries
+==============
+
 This file documents some of the kernel entries in
 arch/x86/entry/entry_64.S.  A lot of this explanation is adapted from
 an email from Ingo Molnar:
@@ -59,7 +65,7 @@ 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:
+stack, from the CS of the ptregs area of the kernel stack::
 
 	xorl %ebx,%ebx
 	testl $3,CS+8(%rsp)
@@ -67,7 +73,7 @@ stack, from the CS of the ptregs area of the kernel stack:
 	SWAPGS
 
 The expensive (paranoid) way is to read back the MSR_GS_BASE value
-(which is what SWAPGS modifies):
+(which is what SWAPGS modifies)::
 
 	movl $1,%ebx
 	movl $MSR_GS_BASE,%ecx
@@ -76,7 +82,7 @@ The expensive (paranoid) way is to read back the MSR_GS_BASE value
 	js 1f   /* negative -> in kernel */
 	SWAPGS
 	xorl %ebx,%ebx
-1:	ret
+  1:	ret
 
 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

Documentation/x86/i386/IO-APIC.txt → Documentation/x86/i386/IO-APIC.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=======
+IO-APIC
+=======
+
+:Author: Ingo Molnar <mingo@kernel.org>
+
 Most (all) Intel-MP compliant SMP boards have the so-called 'IO-APIC',
 which is an enhanced interrupt controller. It enables us to route
 hardware interrupts to multiple CPUs, or to CPU groups. Without an
@@ -13,9 +21,8 @@ usually worked around by the kernel. If your MP-compliant SMP board does
 not boot Linux, then consult the linux-smp mailing list archives first.
 
 If your box boots fine with enabled IO-APIC IRQs, then your
-/proc/interrupts will look like this one:
+/proc/interrupts will look like this one::
 
-   ---------------------------->
   hell:~> cat /proc/interrupts
              CPU0
     0:    1360293    IO-APIC-edge  timer
@@ -28,7 +35,6 @@ If your box boots fine with enabled IO-APIC IRQs, then your
   NMI:          0
   ERR:          0
   hell:~>
-  <----------------------------
 
 Some interrupts are still listed as 'XT PIC', but this is not a problem;
 none of those IRQ sources is performance-critical.
@@ -37,14 +43,14 @@ none of those IRQ sources is performance-critical.
 In the unlikely case that your board does not create a working mp-table,
 you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This
 is non-trivial though and cannot be automated. One sample /etc/lilo.conf
-entry:
+entry::
 
 	append="pirq=15,11,10"
 
 The actual numbers depend on your system, on your PCI cards and on their
 PCI slot position. Usually PCI slots are 'daisy chained' before they are
 connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4
-lines):
+lines)::
 
                ,-.        ,-.        ,-.        ,-.        ,-.
      PIRQ4 ----| |-.    ,-| |-.    ,-| |-.    ,-| |--------| |
@@ -56,7 +62,7 @@ lines):
      PIRQ1 ----| |-  `----| |-  `----| |-  `----| |--------| |
                `-'        `-'        `-'        `-'        `-'
 
-Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD:
+Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD::
 
                                ,-.
                          INTD--| |
@@ -78,19 +84,19 @@ to have non shared interrupts). Slot5 should be used for videocards, they
 do not use interrupts normally, thus they are not daisy chained either.
 
 so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in
-Slot2, then you'll have to specify this pirq= line:
+Slot2, then you'll have to specify this pirq= line::
 
 	append="pirq=11,9"
 
 the following script tries to figure out such a default pirq= line from
-your PCI configuration:
+your PCI configuration::
 
 	echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g'
 
 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:
+card (IRQ11) in Slot3, and have Slot1 empty::
 
 	append="pirq=0,9,11"
 
@@ -105,7 +111,7 @@ won't function properly (e.g. if it's inserted as a module).
 If you have 2 PCI buses, then you can use up to 8 pirq values, although such
 boards tend to have a good configuration.
 
-Be prepared that it might happen that you need some strange pirq line:
+Be prepared that it might happen that you need some strange pirq line::
 
 	append="pirq=0,0,0,0,0,0,9,11"
 
@@ -115,5 +121,3 @@ Good luck and mail to linux-smp@vger.kernel.org or
 linux-kernel@vger.kernel.org if you have any problems that are not covered
 by this document.
 
--- mingo
-

Documentation/x86/i386/index.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+============
+i386 Support
+============
+
+.. toctree::
+   :maxdepth: 2
+
+   IO-APIC

Documentation/x86/index.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+x86-specific Documentation
+==========================
+
+.. toctree::
+   :maxdepth: 2
+   :numbered:
+
+   boot
+   topology
+   exception-tables
+   kernel-stacks
+   entry_64
+   earlyprintk
+   orc-unwinder
+   zero-page
+   tlb
+   mtrr
+   pat
+   protection-keys
+   intel_mpx
+   amd-memory-encryption
+   pti
+   microcode
+   resctrl_ui
+   usb-legacy-support
+   i386/index
+   x86_64/index

Documentation/x86/intel_mpx.txt → Documentation/x86/intel_mpx.rst

-1. Intel(R) MPX Overview
-========================
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================================
+Intel(R) Memory Protection Extensions (MPX)
+===========================================
+
+Intel(R) MPX Overview
+=====================
 
 Intel(R) Memory Protection Extensions (Intel(R) MPX) is a new capability
 introduced into Intel Architecture. Intel MPX provides hardware features
@@ -7,7 +13,7 @@ that can be used in conjunction with compiler changes to check memory
 references, for those references whose compile-time normal intentions are
 usurped at runtime due to buffer overflow or underflow.
 
-You can tell if your CPU supports MPX by looking in /proc/cpuinfo:
+You can tell if your CPU supports MPX by looking in /proc/cpuinfo::
 
 	cat /proc/cpuinfo  | grep ' mpx '
 
@@ -21,8 +27,8 @@ can be downloaded from
 http://software.intel.com/en-us/articles/intel-software-development-emulator
 
 
-2. How to get the advantage of MPX
-==================================
+How to get the advantage of MPX
+===============================
 
 For MPX to work, changes are required in the kernel, binutils and compiler.
 No source changes are required for applications, just a recompile.
@@ -84,14 +90,15 @@ Kernel MPX Code:
    is unmapped.
 
 
-3. How does MPX kernel code work
-================================
+How does MPX kernel code work
+=============================
 
 Handling #BR faults caused by MPX
 ---------------------------------
 
 When MPX is enabled, there are 2 new situations that can generate
 #BR faults.
+
   * new bounds tables (BT) need to be allocated to save bounds.
   * bounds violation caused by MPX instructions.
 
@@ -124,37 +131,37 @@ the kernel. It can theoretically be done completely from userspace. Here
 are a few ways this could be done. We don't think any of them are practical
 in the real-world, but here they are.
 
-Q: Can virtual space simply be reserved for the bounds tables so that we
-   never have to allocate them?
-A: MPX-enabled application will possibly create a lot of bounds tables in
-   process address space to save bounds information. These tables can take
-   up huge swaths of memory (as much as 80% of the memory on the system)
-   even if we clean them up aggressively. In the worst-case scenario, the
-   tables can be 4x the size of the data structure being tracked. IOW, a
-   1-page structure can require 4 bounds-table pages. An X-GB virtual
-   area needs 4*X GB of virtual space, plus 2GB for the bounds directory.
-   If we were to preallocate them for the 128TB of user virtual address
-   space, we would need to reserve 512TB+2GB, which is larger than the
-   entire virtual address space today. This means they can not be reserved
-   ahead of time. Also, a single process's pre-populated bounds directory
-   consumes 2GB of virtual *AND* physical memory. IOW, it's completely
-   infeasible to prepopulate bounds directories.
-
-Q: Can we preallocate bounds table space at the same time memory is
-   allocated which might contain pointers that might eventually need
-   bounds tables?
-A: This would work if we could hook the site of each and every memory
-   allocation syscall. This can be done for small, constrained applications.
-   But, it isn't practical at a larger scale since a given app has no
-   way of controlling how all the parts of the app might allocate memory
-   (think libraries). The kernel is really the only place to intercept
-   these calls.
-
-Q: Could a bounds fault be handed to userspace and the tables allocated
-   there in a signal handler instead of in the kernel?
-A: mmap() is not on the list of safe async handler functions and even
-   if mmap() would work it still requires locking or nasty tricks to
-   keep track of the allocation state there.
+:Q: Can virtual space simply be reserved for the bounds tables so that we
+    never have to allocate them?
+:A: MPX-enabled application will possibly create a lot of bounds tables in
+    process address space to save bounds information. These tables can take
+    up huge swaths of memory (as much as 80% of the memory on the system)
+    even if we clean them up aggressively. In the worst-case scenario, the
+    tables can be 4x the size of the data structure being tracked. IOW, a
+    1-page structure can require 4 bounds-table pages. An X-GB virtual
+    area needs 4*X GB of virtual space, plus 2GB for the bounds directory.
+    If we were to preallocate them for the 128TB of user virtual address
+    space, we would need to reserve 512TB+2GB, which is larger than the
+    entire virtual address space today. This means they can not be reserved
+    ahead of time. Also, a single process's pre-populated bounds directory
+    consumes 2GB of virtual *AND* physical memory. IOW, it's completely
+    infeasible to prepopulate bounds directories.
+
+:Q: Can we preallocate bounds table space at the same time memory is
+    allocated which might contain pointers that might eventually need
+    bounds tables?
+:A: This would work if we could hook the site of each and every memory
+    allocation syscall. This can be done for small, constrained applications.
+    But, it isn't practical at a larger scale since a given app has no
+    way of controlling how all the parts of the app might allocate memory
+    (think libraries). The kernel is really the only place to intercept
+    these calls.
+
+:Q: Could a bounds fault be handed to userspace and the tables allocated
+    there in a signal handler instead of in the kernel?
+:A: mmap() is not on the list of safe async handler functions and even
+    if mmap() would work it still requires locking or nasty tricks to
+    keep track of the allocation state there.
 
 Having ruled out all of the userspace-only approaches for managing
 bounds tables that we could think of, we create them on demand in
@@ -167,20 +174,20 @@ If a #BR is generated due to a bounds violation caused by MPX.
 We need to decode MPX instructions to get violation address and
 set this address into extended struct siginfo.
 
-The _sigfault field of struct siginfo is extended as follow:
-
-87		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
-88		struct {
-89			void __user *_addr; /* faulting insn/memory ref. */
-90 #ifdef __ARCH_SI_TRAPNO
-91			int _trapno;	/* TRAP # which caused the signal */
-92 #endif
-93			short _addr_lsb; /* LSB of the reported address */
-94			struct {
-95				void __user *_lower;
-96				void __user *_upper;
-97			} _addr_bnd;
-98		} _sigfault;
+The _sigfault field of struct siginfo is extended as follow::
+
+  87		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
+  88		struct {
+  89			void __user *_addr; /* faulting insn/memory ref. */
+  90 #ifdef __ARCH_SI_TRAPNO
+  91			int _trapno;	/* TRAP # which caused the signal */
+  92 #endif
+  93			short _addr_lsb; /* LSB of the reported address */
+  94			struct {
+  95				void __user *_lower;
+  96				void __user *_upper;
+  97			} _addr_bnd;
+  98		} _sigfault;
 
 The '_addr' field refers to violation address, and new '_addr_and'
 field refers to the upper/lower bounds when a #BR is caused.
@@ -209,9 +216,10 @@ Adding new prctl commands
 
 Two new prctl commands are added to enable and disable MPX bounds tables
 management in kernel.
+::
 
-155	#define PR_MPX_ENABLE_MANAGEMENT	43
-156	#define PR_MPX_DISABLE_MANAGEMENT	44
+  155	#define PR_MPX_ENABLE_MANAGEMENT	43
+  156	#define PR_MPX_DISABLE_MANAGEMENT	44
 
 Runtime library in userspace is responsible for allocation of bounds
 directory. So kernel have to use XSAVE instruction to get the base
@@ -223,8 +231,8 @@ into struct mm_struct to be used in future during PR_MPX_ENABLE_MANAGEMENT
 command execution.
 
 
-4. Special rules
-================
+Special rules
+=============
 
 1) If userspace is requesting help from the kernel to do the management
 of bounds tables, it may not create or modify entries in the bounds directory.

Documentation/x86/kernel-stacks → Documentation/x86/kernel-stacks.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+Kernel Stacks
+=============
+
 Kernel stacks on x86-64 bit
----------------------------
+===========================
 
 Most of the text from Keith Owens, hacked by AK
 
@@ -57,7 +63,7 @@ IST events with the same code to be nested.  However in most cases, the
 stack size allocated to an IST assumes no nesting for the same code.
 If that assumption is ever broken then the stacks will become corrupt.
 
-The currently assigned IST stacks are :-
+The currently assigned IST stacks are:
 
 * DOUBLEFAULT_STACK.  EXCEPTION_STKSZ (PAGE_SIZE).
 
@@ -98,7 +104,7 @@ For more details see the Intel IA32 or AMD AMD64 architecture manuals.
 
 
 Printing backtraces on x86
---------------------------
+==========================
 
 The question about the '?' preceding function names in an x86 stacktrace
 keeps popping up, here's an indepth explanation. It helps if the reader
@@ -108,7 +114,7 @@ arch/x86/kernel/dumpstack.c.
 Adapted from Ingo's mail, Message-ID: <20150521101614.GA10889@gmail.com>:
 
 We always scan the full kernel stack for return addresses stored on
-the kernel stack(s) [*], from stack top to stack bottom, and print out
+the kernel stack(s) [1]_, from stack top to stack bottom, and print out
 anything that 'looks like' a kernel text address.
 
 If it fits into the frame pointer chain, we print it without a question
@@ -136,6 +142,6 @@ that look like kernel text addresses, so if debug information is wrong,
 we still print out the real call chain as well - just with more question
 marks than ideal.
 
-[*] For things like IRQ and IST stacks, we also scan those stacks, in
-    the right order, and try to cross from one stack into another
-    reconstructing the call chain. This works most of the time.
+.. [1] For things like IRQ and IST stacks, we also scan those stacks, in
+       the right order, and try to cross from one stack into another
+       reconstructing the call chain. This works most of the time.

Documentation/x86/microcode.txt → Documentation/x86/microcode.rst

-	The Linux Microcode Loader
+.. SPDX-License-Identifier: GPL-2.0
 
-Authors: Fenghua Yu <fenghua.yu@intel.com>
-	 Borislav Petkov <bp@suse.de>
+==========================
+The Linux Microcode Loader
+==========================
+
+:Authors: - Fenghua Yu <fenghua.yu@intel.com>
+          - Borislav Petkov <bp@suse.de>
 
 The kernel has a x86 microcode loading facility which is supposed to
 provide microcode loading methods in the OS. Potential use cases are
@@ -10,8 +14,8 @@ and updating the microcode on long-running systems without rebooting.
 
 The loader supports three loading methods:
 
-1. Early load microcode
-=======================
+Early load microcode
+====================
 
 The kernel can update microcode very early during boot. Loading
 microcode early can fix CPU issues before they are observed during
@@ -26,8 +30,10 @@ loader parses the combined initrd image during boot.
 
 The microcode files in cpio name space are:
 
-on Intel: kernel/x86/microcode/GenuineIntel.bin
-on AMD  : kernel/x86/microcode/AuthenticAMD.bin
+on Intel:
+  kernel/x86/microcode/GenuineIntel.bin
+on AMD  :
+  kernel/x86/microcode/AuthenticAMD.bin
 
 During BSP (BootStrapping Processor) boot (pre-SMP), the kernel
 scans the microcode file in the initrd. If microcode matching the
@@ -42,8 +48,8 @@ Here's a crude example how to prepare an initrd with microcode (this is
 normally done automatically by the distribution, when recreating the
 initrd, so you don't really have to do it yourself. It is documented
 here for future reference only).
+::
 
----
   #!/bin/bash
 
   if [ -z "$1" ]; then
@@ -76,15 +82,15 @@ here for future reference only).
   cat ucode.cpio $INITRD.orig > $INITRD
 
   rm -rf $TMPDIR
----
+
 
 The system needs to have the microcode packages installed into
 /lib/firmware or you need to fixup the paths above if yours are
 somewhere else and/or you've downloaded them directly from the processor
 vendor's site.
 
-2. Late loading
-===============
+Late loading
+============
 
 There are two legacy user space interfaces to load microcode, either through
 /dev/cpu/microcode or through /sys/devices/system/cpu/microcode/reload file
@@ -94,9 +100,9 @@ The /dev/cpu/microcode method is deprecated because it needs a special
 userspace tool for that.
 
 The easier method is simply installing the microcode packages your distro
-supplies and running:
+supplies and running::
 
-# echo 1 > /sys/devices/system/cpu/microcode/reload
+  # echo 1 > /sys/devices/system/cpu/microcode/reload
 
 as root.
 
@@ -104,29 +110,29 @@ The loading mechanism looks for microcode blobs in
 /lib/firmware/{intel-ucode,amd-ucode}. The default distro installation
 packages already put them there.
 
-3. Builtin microcode
-====================
+Builtin microcode
+=================
 
 The loader supports also loading of a builtin microcode supplied through
 the regular builtin firmware method CONFIG_EXTRA_FIRMWARE. Only 64-bit is
 currently supported.
 
-Here's an example:
+Here's an example::
 
-CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
-CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
+  CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09 amd-ucode/microcode_amd_fam15h.bin"
+  CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"
 
-This basically means, you have the following tree structure locally:
+This basically means, you have the following tree structure locally::
 
-/lib/firmware/
-|-- amd-ucode
-...
-|   |-- microcode_amd_fam15h.bin
-...
-|-- intel-ucode
-...
-|   |-- 06-3a-09
-...
+  /lib/firmware/
+  |-- amd-ucode
+  ...
+  |   |-- microcode_amd_fam15h.bin
+  ...
+  |-- intel-ucode
+  ...
+  |   |-- 06-3a-09
+  ...
 
 so that the build system can find those files and integrate them into
 the final kernel image. The early loader finds them and applies them.

Documentation/x86/orc-unwinder.txt → Documentation/x86/orc-unwinder.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+============
 ORC unwinder
 ============
 
 Overview
---------
+========
 
 The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is
 similar in concept to a DWARF unwinder.  The difference is that the
@@ -23,12 +26,12 @@ correlate instruction addresses with their stack states at run time.
 
 
 ORC vs frame pointers
----------------------
+=====================
 
 With frame pointers enabled, GCC adds instrumentation code to every
 function in the kernel.  The kernel's .text size increases by about
 3.2%, resulting in a broad kernel-wide slowdown.  Measurements by Mel
-Gorman [1] have shown a slowdown of 5-10% for some workloads.
+Gorman [1]_ have shown a slowdown of 5-10% for some workloads.
 
 In contrast, the ORC unwinder has no effect on text size or runtime
 performance, because the debuginfo is out of band.  So if you disable
@@ -55,7 +58,7 @@ depending on the kernel config.
 
 
 ORC vs DWARF
-------------
+============
 
 ORC debuginfo's advantage over DWARF itself is that it's much simpler.
 It gets rid of the complex DWARF CFI state machine and also gets rid of
@@ -65,7 +68,7 @@ mission critical oops code.
 
 The simpler debuginfo format also enables the unwinder to be much faster
 than DWARF, which is important for perf and lockdep.  In a basic
-performance test by Jiri Slaby [2], the ORC unwinder was about 20x
+performance test by Jiri Slaby [2]_, the ORC unwinder was about 20x
 faster than an out-of-tree DWARF unwinder.  (Note: That measurement was
 taken before some performance tweaks were added, which doubled
 performance, so the speedup over DWARF may be closer to 40x.)
@@ -85,7 +88,7 @@ still be able to control the format, e.g. no complex state machines.
 
 
 ORC unwind table generation
----------------------------
+===========================
 
 The ORC data is generated by objtool.  With the existing compile-time
 stack metadata validation feature, objtool already follows all code
@@ -133,7 +136,7 @@ objtool follows GCC code quite well.
 
 
 Unwinder implementation details
--------------------------------
+===============================
 
 Objtool generates the ORC data by integrating with the compile-time
 stack metadata validation feature, which is described in detail in
@@ -154,7 +157,7 @@ subset of the table needs to be searched.
 
 
 Etymology
----------
+=========
 
 Orcs, fearsome creatures of medieval folklore, are the Dwarves' natural
 enemies.  Similarly, the ORC unwinder was created in opposition to the
@@ -162,7 +165,7 @@ complexity and slowness of DWARF.
 
 "Although Orcs rarely consider multiple solutions to a problem, they do
 excel at getting things done because they are creatures of action, not
-thought." [3]  Similarly, unlike the esoteric DWARF unwinder, the
+thought." [3]_  Similarly, unlike the esoteric DWARF unwinder, the
 veracious ORC unwinder wastes no time or siloconic effort decoding
 variable-length zero-extended unsigned-integer byte-coded
 state-machine-based debug information entries.
@@ -174,6 +177,6 @@ brutal, unyielding efficiency.
 ORC stands for Oops Rewind Capability.
 
 
-[1] https://lkml.kernel.org/r/20170602104048.jkkzssljsompjdwy@suse.de
-[2] https://lkml.kernel.org/r/d2ca5435-6386-29b8-db87-7f227c2b713a@suse.cz
-[3] http://dustin.wikidot.com/half-orcs-and-orcs
+.. [1] https://lkml.kernel.org/r/20170602104048.jkkzssljsompjdwy@suse.de
+.. [2] https://lkml.kernel.org/r/d2ca5435-6386-29b8-db87-7f227c2b713a@suse.cz
+.. [3] http://dustin.wikidot.com/half-orcs-and-orcs

Documentation/x86/protection-keys.txt → Documentation/x86/protection-keys.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+Memory Protection Keys
+======================
+
 Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
 which is found on Intel's Skylake "Scalable Processor" Server CPUs.
 It will be avalable in future non-server parts.
@@ -23,9 +29,10 @@ even though there is theoretically space in the PAE PTEs.  These
 permissions are enforced on data access only and have no effect on
 instruction fetches.
 
-=========================== Syscalls ===========================
+Syscalls
+========
 
-There are 3 system calls which directly interact with pkeys:
+There are 3 system calls which directly interact with pkeys::
 
 	int pkey_alloc(unsigned long flags, unsigned long init_access_rights)
 	int pkey_free(int pkey);
@@ -37,6 +44,7 @@ pkey_alloc().  An application calls the WRPKRU instruction
 directly in order to change access permissions to memory covered
 with a key.  In this example WRPKRU is wrapped by a C function
 called pkey_set().
+::
 
 	int real_prot = PROT_READ|PROT_WRITE;
 	pkey = pkey_alloc(0, PKEY_DISABLE_WRITE);
@@ -45,43 +53,44 @@ called pkey_set().
 	... application runs here
 
 Now, if the application needs to update the data at 'ptr', it can
-gain access, do the update, then remove its write access:
+gain access, do the update, then remove its write access::
 
 	pkey_set(pkey, 0); // clear PKEY_DISABLE_WRITE
 	*ptr = foo; // assign something
 	pkey_set(pkey, PKEY_DISABLE_WRITE); // set PKEY_DISABLE_WRITE again
 
 Now when it frees the memory, it will also free the pkey since it
-is no longer in use:
+is no longer in use::
 
 	munmap(ptr, PAGE_SIZE);
 	pkey_free(pkey);
 
-(Note: pkey_set() is a wrapper for the RDPKRU and WRPKRU instructions.
- An example implementation can be found in
- tools/testing/selftests/x86/protection_keys.c)
+.. note:: pkey_set() is a wrapper for the RDPKRU and WRPKRU instructions.
+          An example implementation can be found in
+          tools/testing/selftests/x86/protection_keys.c.
 
-=========================== Behavior ===========================
+Behavior
+========
 
 The kernel attempts to make protection keys consistent with the
-behavior of a plain mprotect().  For instance if you do this:
+behavior of a plain mprotect().  For instance if you do this::
 
 	mprotect(ptr, size, PROT_NONE);
 	something(ptr);
 
-you can expect the same effects with protection keys when doing this:
+you can expect the same effects with protection keys when doing this::
 
 	pkey = pkey_alloc(0, PKEY_DISABLE_WRITE | PKEY_DISABLE_READ);
 	pkey_mprotect(ptr, size, PROT_READ|PROT_WRITE, pkey);
 	something(ptr);
 
 That should be true whether something() is a direct access to 'ptr'
-like:
+like::
 
 	*ptr = foo;
 
 or when the kernel does the access on the application's behalf like
-with a read():
+with a read()::
 
 	read(fd, ptr, 1);
 

Documentation/x86/pti.txt → Documentation/x86/pti.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+Page Table Isolation (PTI)
+==========================
+
 Overview
 ========
 
-Page Table Isolation (pti, previously known as KAISER[1]) is a
+Page Table Isolation (pti, previously known as KAISER [1]_) is a
 countermeasure against attacks on the shared user/kernel address
-space such as the "Meltdown" approach[2].
+space such as the "Meltdown" approach [2]_.
 
 To mitigate this class of attacks, we create an independent set of
 page tables for use only when running userspace applications.  When
@@ -60,6 +66,7 @@ Protection against side-channel attacks is important.  But,
 this protection comes at a cost:
 
 1. Increased Memory Use
+
   a. Each process now needs an order-1 PGD instead of order-0.
      (Consumes an additional 4k per process).
   b. The 'cpu_entry_area' structure must be 2MB in size and 2MB
@@ -68,6 +75,7 @@ this protection comes at a cost:
      is decompressed, but no space in the kernel image itself.
 
 2. Runtime Cost
+
   a. CR3 manipulation to switch between the page table copies
      must be done at interrupt, syscall, and exception entry
      and exit (it can be skipped when the kernel is interrupted,
@@ -142,6 +150,7 @@ ideally doing all of these in parallel:
    interrupted, including nested NMIs.  Using "-c" boosts the rate of
    NMIs, and using two -c with separate counters encourages nested NMIs
    and less deterministic behavior.
+   ::
 
 	while true; do perf record -c 10000 -e instructions,cycles -a sleep 10; done
 
@@ -182,5 +191,5 @@ that are worth noting here.
    tended to be TLB invalidation issues.  Usually invalidating
    the wrong PCID, or otherwise missing an invalidation.
 
-1. https://gruss.cc/files/kaiser.pdf
-2. https://meltdownattack.com/meltdown.pdf
+.. [1] https://gruss.cc/files/kaiser.pdf
+.. [2] https://meltdownattack.com/meltdown.pdf

Documentation/x86/tlb.txt → Documentation/x86/tlb.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=======
+The TLB
+=======
+
 When the kernel unmaps or modified the attributes of a range of
 memory, it has two choices:
+
  1. Flush the entire TLB with a two-instruction sequence.  This is
     a quick operation, but it causes collateral damage: TLB entries
     from areas other than the one we are trying to flush will be
@@ -10,6 +17,7 @@ memory, it has two choices:
     damage to other TLB entries.
 
 Which method to do depends on a few things:
+
  1. The size of the flush being performed.  A flush of the entire
     address space is obviously better performed by flushing the
     entire TLB than doing 2^48/PAGE_SIZE individual flushes.
@@ -33,7 +41,7 @@ well.  There is essentially no "right" point to choose.
 You may be doing too many individual invalidations if you see the
 invlpg instruction (or instructions _near_ it) show up high in
 profiles.  If you believe that individual invalidations being
-called too often, you can lower the tunable:
+called too often, you can lower the tunable::
 
 	/sys/kernel/debug/x86/tlb_single_page_flush_ceiling
 
@@ -43,7 +51,7 @@ Setting it to 1 is a very conservative setting and it should
 never need to be 0 under normal circumstances.
 
 Despite the fact that a single individual flush on x86 is
-guaranteed to flush a full 2MB [1], hugetlbfs always uses the full
+guaranteed to flush a full 2MB [1]_, hugetlbfs always uses the full
 flushes.  THP is treated exactly the same as normal memory.
 
 You might see invlpg inside of flush_tlb_mm_range() show up in
@@ -54,15 +62,15 @@ Essentially, you are balancing the cycles you spend doing invlpg
 with the cycles that you spend refilling the TLB later.
 
 You can measure how expensive TLB refills are by using
-performance counters and 'perf stat', like this:
+performance counters and 'perf stat', like this::
 
-perf stat -e
-	cpu/event=0x8,umask=0x84,name=dtlb_load_misses_walk_duration/,
-	cpu/event=0x8,umask=0x82,name=dtlb_load_misses_walk_completed/,
-	cpu/event=0x49,umask=0x4,name=dtlb_store_misses_walk_duration/,
-	cpu/event=0x49,umask=0x2,name=dtlb_store_misses_walk_completed/,
-	cpu/event=0x85,umask=0x4,name=itlb_misses_walk_duration/,
-	cpu/event=0x85,umask=0x2,name=itlb_misses_walk_completed/
+  perf stat -e
+    cpu/event=0x8,umask=0x84,name=dtlb_load_misses_walk_duration/,
+    cpu/event=0x8,umask=0x82,name=dtlb_load_misses_walk_completed/,
+    cpu/event=0x49,umask=0x4,name=dtlb_store_misses_walk_duration/,
+    cpu/event=0x49,umask=0x2,name=dtlb_store_misses_walk_completed/,
+    cpu/event=0x85,umask=0x4,name=itlb_misses_walk_duration/,
+    cpu/event=0x85,umask=0x2,name=itlb_misses_walk_completed/
 
 That works on an IvyBridge-era CPU (i5-3320M).  Different CPUs
 may have differently-named counters, but they should at least
@@ -70,6 +78,6 @@ be there in some form.  You can use pmu-tools 'ocperf list'
 (https://github.com/andikleen/pmu-tools) to find the right
 counters for a given CPU.
 
-1. A footnote in Intel's SDM "4.10.4.2 Recommended Invalidation"
+.. [1] A footnote in Intel's SDM "4.10.4.2 Recommended Invalidation"
    says: "One execution of INVLPG is sufficient even for a page
    with size greater than 4 KBytes."

Documentation/x86/topology.txt → Documentation/x86/topology.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+============
 x86 Topology
 ============
 
@@ -33,14 +36,14 @@ The topology of a system is described in the units of:
     - cores
     - threads
 
-* Package:
-
-  Packages contain a number of cores plus shared resources, e.g. DRAM
-  controller, shared caches etc.
+Package
+=======
+Packages contain a number of cores plus shared resources, e.g. DRAM
+controller, shared caches etc.
 
-  AMD nomenclature for package is 'Node'.
+AMD nomenclature for package is 'Node'.
 
-  Package-related topology information in the kernel:
+Package-related topology information in the kernel:
 
   - cpuinfo_x86.x86_max_cores:
 
@@ -66,40 +69,41 @@ The topology of a system is described in the units of:
   - cpu_llc_id:
 
     A per-CPU variable containing:
-    - On Intel, the first APIC ID of the list of CPUs sharing the Last Level
-    Cache
 
-    - On AMD, the Node ID or Core Complex ID containing the Last Level
-    Cache. In general, it is a number identifying an LLC uniquely on the
-    system.
+      - On Intel, the first APIC ID of the list of CPUs sharing the Last Level
+        Cache
 
-* Cores:
+      - On AMD, the Node ID or Core Complex ID containing the Last Level
+        Cache. In general, it is a number identifying an LLC uniquely on the
+        system.
 
-  A core consists of 1 or more threads. It does not matter whether the threads
-  are SMT- or CMT-type threads.
+Cores
+=====
+A core consists of 1 or more threads. It does not matter whether the threads
+are SMT- or CMT-type threads.
 
-  AMDs nomenclature for a CMT core is "Compute Unit". The kernel always uses
-  "core".
+AMDs nomenclature for a CMT core is "Compute Unit". The kernel always uses
+"core".
 
-  Core-related topology information in the kernel:
+Core-related topology information in the kernel:
 
   - smp_num_siblings:
 
     The number of threads in a core. The number of threads in a package can be
-    calculated by:
+    calculated by::
 
 	threads_per_package = cpuinfo_x86.x86_max_cores * smp_num_siblings
 
 
-* Threads:
+Threads
+=======
+A thread is a single scheduling unit. It's the equivalent to a logical Linux
+CPU.
 
-  A thread is a single scheduling unit. It's the equivalent to a logical Linux
-  CPU.
+AMDs nomenclature for CMT threads is "Compute Unit Core". The kernel always
+uses "thread".
 
-  AMDs nomenclature for CMT threads is "Compute Unit Core". The kernel always
-  uses "thread".
-
-  Thread-related topology information in the kernel:
+Thread-related topology information in the kernel:
 
   - topology_core_cpumask():
 
@@ -113,15 +117,15 @@ The topology of a system is described in the units of:
     The cpumask contains all online threads in the core to which a thread
     belongs.
 
-   - topology_logical_package_id():
+  - topology_logical_package_id():
 
     The logical package ID to which a thread belongs.
 
-   - topology_physical_package_id():
+  - topology_physical_package_id():
 
     The physical package ID to which a thread belongs.
 
-   - topology_core_id();
+  - topology_core_id();
 
     The ID of the core to which a thread belongs. It is also printed in /proc/cpuinfo
     "core_id."
@@ -129,41 +133,41 @@ The topology of a system is described in the units of:
 
 
 System topology examples
+========================
 
-Note:
-
-The alternative Linux CPU enumeration depends on how the BIOS enumerates the
-threads. Many BIOSes enumerate all threads 0 first and then all threads 1.
-That has the "advantage" that the logical Linux CPU numbers of threads 0 stay
-the same whether threads are enabled or not. That's merely an implementation
-detail and has no practical impact.
+.. note::
+  The alternative Linux CPU enumeration depends on how the BIOS enumerates the
+  threads. Many BIOSes enumerate all threads 0 first and then all threads 1.
+  That has the "advantage" that the logical Linux CPU numbers of threads 0 stay
+  the same whether threads are enabled or not. That's merely an implementation
+  detail and has no practical impact.
 
-1) Single Package, Single Core
+1) Single Package, Single Core::
 
    [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 
 2) Single Package, Dual Core
 
-   a) One thread per core
+   a) One thread per core::
 
 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 		    -> [core 1] -> [thread 0] -> Linux CPU 1
 
-   b) Two threads per core
+   b) Two threads per core::
 
 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 				-> [thread 1] -> Linux CPU 1
 		    -> [core 1] -> [thread 0] -> Linux CPU 2
 				-> [thread 1] -> Linux CPU 3
 
-      Alternative enumeration:
+      Alternative enumeration::
 
 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 				-> [thread 1] -> Linux CPU 2
 		    -> [core 1] -> [thread 0] -> Linux CPU 1
 				-> [thread 1] -> Linux CPU 3
 
-      AMD nomenclature for CMT systems:
+      AMD nomenclature for CMT systems::
 
 	[node 0] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 0
 				     -> [Compute Unit Core 1] -> Linux CPU 1
@@ -172,7 +176,7 @@ detail and has no practical impact.
 
 4) Dual Package, Dual Core
 
-   a) One thread per core
+   a) One thread per core::
 
 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 		    -> [core 1] -> [thread 0] -> Linux CPU 1
@@ -180,7 +184,7 @@ detail and has no practical impact.
 	[package 1] -> [core 0] -> [thread 0] -> Linux CPU 2
 		    -> [core 1] -> [thread 0] -> Linux CPU 3
 
-   b) Two threads per core
+   b) Two threads per core::
 
 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 				-> [thread 1] -> Linux CPU 1
@@ -192,7 +196,7 @@ detail and has no practical impact.
 		    -> [core 1] -> [thread 0] -> Linux CPU 6
 				-> [thread 1] -> Linux CPU 7
 
-      Alternative enumeration:
+      Alternative enumeration::
 
 	[package 0] -> [core 0] -> [thread 0] -> Linux CPU 0
 				-> [thread 1] -> Linux CPU 4
@@ -204,7 +208,7 @@ detail and has no practical impact.
 		    -> [core 1] -> [thread 0] -> Linux CPU 3
 				-> [thread 1] -> Linux CPU 7
 
-      AMD nomenclature for CMT systems:
+      AMD nomenclature for CMT systems::
 
 	[node 0] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 0
 				     -> [Compute Unit Core 1] -> Linux CPU 1

Documentation/x86/usb-legacy-support.txt → Documentation/x86/usb-legacy-support.rst

+
+.. SPDX-License-Identifier: GPL-2.0
+
+==================
 USB Legacy support
-~~~~~~~~~~~~~~~~~~
+==================
 
-Vojtech Pavlik <vojtech@suse.cz>, January 2004
+:Author: Vojtech Pavlik <vojtech@suse.cz>, January 2004
 
 
 Also known as "USB Keyboard" or "USB Mouse support" in the BIOS Setup is a
@@ -27,18 +31,20 @@ It has several drawbacks, though:
 
 Solutions:
 
-Problem 1) can be solved by loading the USB drivers prior to loading the
-PS/2 mouse driver. Since the PS/2 mouse driver is in 2.6 compiled into
-the kernel unconditionally, this means the USB drivers need to be
-compiled-in, too.
-
-Problem 2) can currently only be solved by either disabling HIGHMEM64G
-in the kernel config or USB Legacy support in the BIOS. A BIOS update
-could help, but so far no such update exists.
-
-Problem 3) is usually fixed by a BIOS update. Check the board
-manufacturers web site. If an update is not available, disable USB
-Legacy support in the BIOS. If this alone doesn't help, try also adding
-idle=poll on the kernel command line. The BIOS may be entering the SMM
-on the HLT instruction as well.
-
+Problem 1)
+  can be solved by loading the USB drivers prior to loading the
+  PS/2 mouse driver. Since the PS/2 mouse driver is in 2.6 compiled into
+  the kernel unconditionally, this means the USB drivers need to be
+  compiled-in, too.
+
+Problem 2)
+  can currently only be solved by either disabling HIGHMEM64G
+  in the kernel config or USB Legacy support in the BIOS. A BIOS update
+  could help, but so far no such update exists.
+
+Problem 3)
+  is usually fixed by a BIOS update. Check the board
+  manufacturers web site. If an update is not available, disable USB
+  Legacy support in the BIOS. If this alone doesn't help, try also adding
+  idle=poll on the kernel command line. The BIOS may be entering the SMM
+  on the HLT instruction as well.

Documentation/x86/x86_64/5level-paging.txt → Documentation/x86/x86_64/5level-paging.rst

-== Overview ==
+.. SPDX-License-Identifier: GPL-2.0
 
+==============
+5-level paging
+==============
+
+Overview
+========
 Original x86-64 was limited by 4-level paing to 256 TiB of virtual address
 space and 64 TiB of physical address space. We are already bumping into
 this limit: some vendors offers servers with 64 TiB of memory today.
@@ -16,16 +22,17 @@ QEMU 2.9 and later support 5-level paging.
 Virtual memory layout for 5-level paging is described in
 Documentation/x86/x86_64/mm.txt
 
-== Enabling 5-level paging ==
 
+Enabling 5-level paging
+=======================
 CONFIG_X86_5LEVEL=y enables the feature.
 
 Kernel with CONFIG_X86_5LEVEL=y still able to boot on 4-level hardware.
 In this case additional page table level -- p4d -- will be folded at
 runtime.
 
-== User-space and large virtual address space ==
-
+User-space and large virtual address space
+==========================================
 On x86, 5-level paging enables 56-bit userspace virtual address space.
 Not all user space is ready to handle wide addresses. It's known that
 at least some JIT compilers use higher bits in pointers to encode their
@@ -58,4 +65,3 @@ One important case we need to handle here is interaction with MPX.
 MPX (without MAWA extension) cannot handle addresses above 47-bit, so we
 need to make sure that MPX cannot be enabled we already have VMA above
 the boundary and forbid creating such VMAs once MPX is enabled.
-

Documentation/x86/x86_64/cpu-hotplug-spec → Documentation/x86/x86_64/cpu-hotplug-spec.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+===================================================
 Firmware support for CPU hotplug under Linux/x86-64
----------------------------------------------------
+===================================================
 
 Linux/x86-64 supports CPU hotplug now. For various reasons Linux wants to
 know in advance of boot time the maximum number of CPUs that could be plugged

Documentation/x86/x86_64/fake-numa-for-cpusets → Documentation/x86/x86_64/fake-numa-for-cpusets.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=====================
+Fake NUMA For CPUSets
+=====================
+
+:Author: David Rientjes <rientjes@cs.washington.edu>
+
 Using numa=fake and CPUSets for Resource Management
-Written by David Rientjes <rientjes@cs.washington.edu>
 
 This document describes how the numa=fake x86_64 command-line option can be used
 in conjunction with cpusets for coarse memory management.  Using this feature,
@@ -20,7 +27,7 @@ you become more familiar with using this combination for resource control,
 you'll determine a better setup to minimize the number of nodes you have to deal
 with.
 
-A machine may be split as follows with "numa=fake=4*512," as reported by dmesg:
+A machine may be split as follows with "numa=fake=4*512," as reported by dmesg::
 
 	Faking node 0 at 0000000000000000-0000000020000000 (512MB)
 	Faking node 1 at 0000000020000000-0000000040000000 (512MB)
@@ -34,7 +41,7 @@ A machine may be split as follows with "numa=fake=4*512," as reported by dmesg:
 
 Now following the instructions for mounting the cpusets filesystem from
 Documentation/cgroup-v1/cpusets.txt, you can assign fake nodes (i.e. contiguous memory
-address spaces) to individual cpusets:
+address spaces) to individual cpusets::
 
 	[root@xroads /]# mkdir exampleset
 	[root@xroads /]# mount -t cpuset none exampleset
@@ -47,7 +54,7 @@ Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for
 memory allocations (1G).
 
 You can now assign tasks to these cpusets to limit the memory resources
-available to them according to the fake nodes assigned as mems:
+available to them according to the fake nodes assigned as mems::
 
 	[root@xroads /exampleset/ddset]# echo $$ > tasks
 	[root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G
@@ -57,9 +64,13 @@ Notice the difference between the system memory usage as reported by
 /proc/meminfo between the restricted cpuset case above and the unrestricted
 case (i.e. running the same 'dd' command without assigning it to a fake NUMA
 cpuset):
-				Unrestricted	Restricted
-	MemTotal:		3091900 kB	3091900 kB
-	MemFree:		  42113 kB	1513236 kB
+
+	========	============	==========
+	Name		Unrestricted	Restricted
+	========	============	==========
+	MemTotal	3091900 kB	3091900 kB
+	MemFree		42113 kB	1513236 kB
+	========	============	==========
 
 This allows for coarse memory management for the tasks you assign to particular
 cpusets.  Since cpusets can form a hierarchy, you can create some pretty

Documentation/x86/x86_64/index.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+==============
+x86_64 Support
+==============
+
+.. toctree::
+   :maxdepth: 2
+
+   boot-options
+   uefi
+   mm
+   5level-paging
+   fake-numa-for-cpusets
+   cpu-hotplug-spec
+   machinecheck

Documentation/x86/x86_64/machinecheck → Documentation/x86/x86_64/machinecheck.rst

+.. SPDX-License-Identifier: GPL-2.0
 
-Configurable sysfs parameters for the x86-64 machine check code.
+===============================================================
+Configurable sysfs parameters for the x86-64 machine check code
+===============================================================
 
 Machine checks report internal hardware error conditions detected
 by the CPU. Uncorrected errors typically cause a machine check
@@ -16,14 +19,13 @@ log then mcelog should run to collect and decode machine check entries
 from /dev/mcelog. Normally mcelog should be run regularly from a cronjob.
 
 Each CPU has a directory in /sys/devices/system/machinecheck/machinecheckN
-(N = CPU number)
+(N = CPU number).
 
 The directory contains some configurable entries:
 
-Entries:
-
 bankNctl
-(N bank number)
+	(N bank number)
+
 	64bit Hex bitmask enabling/disabling specific subevents for bank N
 	When a bit in the bitmask is zero then the respective
 	subevent will not be reported.