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Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Browse Source 
Pull ia64 removal and asm-generic updates from Arnd Bergmann:

 - The ia64 architecture gets its well-earned retirement as planned,
   now that there is one last (mostly) working release that will be
   maintained as an LTS kernel.

 - The architecture specific system call tables are updated for the
   added map_shadow_stack() syscall and to remove references to the
   long-gone sys_lookup_dcookie() syscall.

* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  hexagon: Remove unusable symbols from the ptrace.h uapi
  asm-generic: Fix spelling of architecture
  arch: Reserve map_shadow_stack() syscall number for all architectures
  syscalls: Cleanup references to sys_lookup_dcookie()
  Documentation: Drop or replace remaining mentions of IA64
  lib/raid6: Drop IA64 support
  Documentation: Drop IA64 from feature descriptions
  kernel: Drop IA64 support from sig_fault handlers
  arch: Remove Itanium (IA-64) architecture
This commit is contained in:
Linus Torvalds
2023-11-01 15:28:33 -10:00
parent 4684e928db 550087a0ba
commit 1e0c505e13
453 changed files with 142 additions and 65219 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Documentation/ABI/testing/sysfs-devices-system-cpu
-3
View File
@@ -354,9 +354,6 @@ Description: Parameters for the CPU cache attributes
- ReadWriteAllocate:
both writeallocate and readallocate
attributes:
LEGACY used only on IA64 and is same as write_policy
coherency_line_size:
the minimum amount of data in bytes that gets
transferred from memory to cache
Documentation/ABI/testing/sysfs-firmware-dmi-entries
+1 -1
View File
@@ -2,7 +2,7 @@ What: /sys/firmware/dmi/entries/
Date: February 2011
Contact: Mike Waychison <mikew@google.com>
Description:
Many machines' firmware (x86 and ia64) export DMI /
Many machines' firmware (x86 and arm64) export DMI /
SMBIOS tables to the operating system. Getting at this
information is often valuable to userland, especially in
cases where there are OEM extensions used.
Documentation/admin-guide/kdump/kdump.rst
+3 -34
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@@ -17,7 +17,7 @@ You can use common commands, such as cp, scp or makedumpfile to copy
the memory image to a dump file on the local disk, or across the network
to a remote system.
Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64,
Kdump and kexec are currently supported on the x86, x86_64, ppc64,
s390x, arm and arm64 architectures.
When the system kernel boots, it reserves a small section of memory for
@@ -113,7 +113,7 @@ There are two possible methods of using Kdump.
2) Or use the system kernel binary itself as dump-capture kernel and there is
no need to build a separate dump-capture kernel. This is possible
only with the architectures which support a relocatable kernel. As
of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support
of today, i386, x86_64, ppc64, arm and arm64 architectures support
relocatable kernel.
Building a relocatable kernel is advantageous from the point of view that
@@ -236,24 +236,6 @@ Dump-capture kernel config options (Arch Dependent, ppc64)
Make and install the kernel and its modules.
Dump-capture kernel config options (Arch Dependent, ia64)
----------------------------------------------------------
- No specific options are required to create a dump-capture kernel
for ia64, other than those specified in the arch independent section
above. This means that it is possible to use the system kernel
as a dump-capture kernel if desired.
The crashkernel region can be automatically placed by the system
kernel at runtime. This is done by specifying the base address as 0,
or omitting it all together::
crashkernel=256M@0
or::
crashkernel=256M
Dump-capture kernel config options (Arch Dependent, arm)
----------------------------------------------------------
@@ -348,11 +330,6 @@ Boot into System Kernel
On ppc64, use "crashkernel=128M@32M".
On ia64, 256M@256M is a generous value that typically works.
The region may be automatically placed on ia64, see the
dump-capture kernel config option notes above.
If use sparse memory, the size should be rounded to GRANULE boundaries.
On s390x, typically use "crashkernel=xxM". The value of xx is dependent
on the memory consumption of the kdump system. In general this is not
dependent on the memory size of the production system.
@@ -383,10 +360,6 @@ For ppc64:
- Use vmlinux
For ia64:
- Use vmlinux or vmlinuz.gz
For s390x:
- Use image or bzImage
@@ -428,14 +401,10 @@ to load dump-capture kernel::
--initrd=<initrd-for-dump-capture-kernel> \
--append="root=<root-dev> <arch-specific-options>"
Please note, that --args-linux does not need to be specified for ia64.
It is planned to make this a no-op on that architecture, but for now
it should be omitted
Following are the arch specific command line options to be used while
loading dump-capture kernel.
For i386, x86_64 and ia64:
For i386 and x86_64:
"1 irqpoll nr_cpus=1 reset_devices"
Documentation/admin-guide/kdump/vmcoreinfo.rst
-30
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@@ -413,36 +413,6 @@ of a higher page table lookup overhead, and also consumes more page
table space per process. Used to check whether PAE was enabled in the
crash kernel when converting virtual addresses to physical addresses.
ia64
====
pgdat_list|(pgdat_list, MAX_NUMNODES)
-------------------------------------
pg_data_t array storing all NUMA nodes information. MAX_NUMNODES
indicates the number of the nodes.
node_memblk|(node_memblk, NR_NODE_MEMBLKS)
------------------------------------------
List of node memory chunks. Filled when parsing the SRAT table to obtain
information about memory nodes. NR_NODE_MEMBLKS indicates the number of
node memory chunks.
These values are used to compute the number of nodes the crashed kernel used.
node_memblk_s|(node_memblk_s, start_paddr)|(node_memblk_s, size)
----------------------------------------------------------------
The size of a struct node_memblk_s and the offsets of the
node_memblk_s's members. Used to compute the number of nodes.
PGTABLE_3|PGTABLE_4
-------------------
User-space tools need to know whether the crash kernel was in 3-level or
4-level paging mode. Used to distinguish the page table.
ARM64
=====
Documentation/admin-guide/kernel-parameters.txt
+1 -7
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@@ -1453,7 +1453,7 @@
See comment before function elanfreq_setup() in
arch/x86/kernel/cpu/cpufreq/elanfreq.c.
elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
elfcorehdr=[size[KMG]@]offset[KMG] [PPC,SH,X86,S390]
Specifies physical address of start of kernel core
image elf header and optionally the size. Generally
kexec loader will pass this option to capture kernel.
@@ -1516,12 +1516,6 @@
floppy= [HW]
See Documentation/admin-guide/blockdev/floppy.rst.
force_pal_cache_flush
[IA-64] Avoid check_sal_cache_flush which may hang on
buggy SAL_CACHE_FLUSH implementations. Using this
parameter will force ia64_sal_cache_flush to call
ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
forcepae [X86-32]
Forcefully enable Physical Address Extension (PAE).
Many Pentium M systems disable PAE but may have a
Documentation/admin-guide/mm/memory-hotplug.rst
+1 -1
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@@ -33,7 +33,7 @@ used to expose persistent memory, other performance-differentiated memory and
reserved memory regions as ordinary system RAM to Linux.
Linux only supports memory hot(un)plug on selected 64 bit architectures, such as
x86_64, arm64, ppc64, s390x and ia64.
x86_64, arm64, ppc64 and s390x.
Memory Hot(Un)Plug Granularity
------------------------------
Documentation/admin-guide/sysctl/kernel.rst
+2 -21
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@@ -436,7 +436,7 @@ ignore-unaligned-usertrap
On architectures where unaligned accesses cause traps, and where this
feature is supported (``CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN``;
currently, ``arc``, ``ia64`` and ``loongarch``), controls whether all
currently, ``arc`` and ``loongarch``), controls whether all
unaligned traps are logged.
= =============================================================
@@ -445,10 +445,7 @@ unaligned traps are logged.
setting.
= =============================================================
See also `unaligned-trap`_ and `unaligned-dump-stack`_. On ``ia64``,
this allows system administrators to override the
``IA64_THREAD_UAC_NOPRINT`` ``prctl`` and avoid logs being flooded.
See also `unaligned-trap`_.
io_uring_disabled
=================
@@ -1539,22 +1536,6 @@ See Documentation/admin-guide/kernel-parameters.rst and
Documentation/trace/boottime-trace.rst.
.. _unaligned-dump-stack:
unaligned-dump-stack (ia64)
===========================
When logging unaligned accesses, controls whether the stack is
dumped.
= ===================================================
0 Do not dump the stack. This is the default setting.
1 Dump the stack.
= ===================================================
See also `ignore-unaligned-usertrap`_.
unaligned-trap
==============
Documentation/arch/ia64/aliasing.rst
-246
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@@ -1,246 +0,0 @@
==================================
Memory Attribute Aliasing on IA-64
==================================
Bjorn Helgaas <bjorn.helgaas@hp.com>
May 4, 2006
Memory Attributes
=================
Itanium supports several attributes for virtual memory references.
The attribute is part of the virtual translation, i.e., it is
contained in the TLB entry. The ones of most interest to the Linux
kernel are:
== ======================
WB Write-back (cacheable)
UC Uncacheable
WC Write-coalescing
== ======================
System memory typically uses the WB attribute. The UC attribute is
used for memory-mapped I/O devices. The WC attribute is uncacheable
like UC is, but writes may be delayed and combined to increase
performance for things like frame buffers.
The Itanium architecture requires that we avoid accessing the same
page with both a cacheable mapping and an uncacheable mapping[1].
The design of the chipset determines which attributes are supported
on which regions of the address space. For example, some chipsets
support either WB or UC access to main memory, while others support
only WB access.
Memory Map
==========
Platform firmware describes the physical memory map and the
supported attributes for each region. At boot-time, the kernel uses
the EFI GetMemoryMap() interface. ACPI can also describe memory
devices and the attributes they support, but Linux/ia64 currently
doesn't use this information.
The kernel uses the efi_memmap table returned from GetMemoryMap() to
learn the attributes supported by each region of physical address
space. Unfortunately, this table does not completely describe the
address space because some machines omit some or all of the MMIO
regions from the map.
The kernel maintains another table, kern_memmap, which describes the
memory Linux is actually using and the attribute for each region.
This contains only system memory; it does not contain MMIO space.
The kern_memmap table typically contains only a subset of the system
memory described by the efi_memmap. Linux/ia64 can't use all memory
in the system because of constraints imposed by the identity mapping
scheme.
The efi_memmap table is preserved unmodified because the original
boot-time information is required for kexec.
Kernel Identity Mappings
========================
Linux/ia64 identity mappings are done with large pages, currently
either 16MB or 64MB, referred to as "granules." Cacheable mappings
are speculative[2], so the processor can read any location in the
page at any time, independent of the programmer's intentions. This
means that to avoid attribute aliasing, Linux can create a cacheable
identity mapping only when the entire granule supports cacheable
access.
Therefore, kern_memmap contains only full granule-sized regions that
can referenced safely by an identity mapping.
Uncacheable mappings are not speculative, so the processor will
generate UC accesses only to locations explicitly referenced by
software. This allows UC identity mappings to cover granules that
are only partially populated, or populated with a combination of UC
and WB regions.
User Mappings
=============
User mappings are typically done with 16K or 64K pages. The smaller
page size allows more flexibility because only 16K or 64K has to be
homogeneous with respect to memory attributes.
Potential Attribute Aliasing Cases
==================================
There are several ways the kernel creates new mappings:
mmap of /dev/mem
----------------
This uses remap_pfn_range(), which creates user mappings. These
mappings may be either WB or UC. If the region being mapped
happens to be in kern_memmap, meaning that it may also be mapped
by a kernel identity mapping, the user mapping must use the same
attribute as the kernel mapping.
If the region is not in kern_memmap, the user mapping should use
an attribute reported as being supported in the EFI memory map.
Since the EFI memory map does not describe MMIO on some
machines, this should use an uncacheable mapping as a fallback.
mmap of /sys/class/pci_bus/.../legacy_mem
-----------------------------------------
This is very similar to mmap of /dev/mem, except that legacy_mem
only allows mmap of the one megabyte "legacy MMIO" area for a
specific PCI bus. Typically this is the first megabyte of
physical address space, but it may be different on machines with
several VGA devices.
"X" uses this to access VGA frame buffers. Using legacy_mem
rather than /dev/mem allows multiple instances of X to talk to
different VGA cards.
The /dev/mem mmap constraints apply.
mmap of /proc/bus/pci/.../??.?
------------------------------
This is an MMIO mmap of PCI functions, which additionally may or
may not be requested as using the WC attribute.
If WC is requested, and the region in kern_memmap is either WC
or UC, and the EFI memory map designates the region as WC, then
the WC mapping is allowed.
Otherwise, the user mapping must use the same attribute as the
kernel mapping.
read/write of /dev/mem
----------------------
This uses copy_from_user(), which implicitly uses a kernel
identity mapping. This is obviously safe for things in
kern_memmap.
There may be corner cases of things that are not in kern_memmap,
but could be accessed this way. For example, registers in MMIO
space are not in kern_memmap, but could be accessed with a UC
mapping. This would not cause attribute aliasing. But
registers typically can be accessed only with four-byte or
eight-byte accesses, and the copy_from_user() path doesn't allow
any control over the access size, so this would be dangerous.
ioremap()
---------
This returns a mapping for use inside the kernel.
If the region is in kern_memmap, we should use the attribute
specified there.
If the EFI memory map reports that the entire granule supports
WB, we should use that (granules that are partially reserved
or occupied by firmware do not appear in kern_memmap).
If the granule contains non-WB memory, but we can cover the
region safely with kernel page table mappings, we can use
ioremap_page_range() as most other architectures do.
Failing all of the above, we have to fall back to a UC mapping.
Past Problem Cases
==================
mmap of various MMIO regions from /dev/mem by "X" on Intel platforms
--------------------------------------------------------------------
The EFI memory map may not report these MMIO regions.
These must be allowed so that X will work. This means that
when the EFI memory map is incomplete, every /dev/mem mmap must
succeed. It may create either WB or UC user mappings, depending
on whether the region is in kern_memmap or the EFI memory map.
mmap of 0x0-0x9FFFF /dev/mem by "hwinfo" on HP sx1000 with VGA enabled
----------------------------------------------------------------------
The EFI memory map reports the following attributes:
=============== ======= ==================
0x00000-0x9FFFF WB only
0xA0000-0xBFFFF UC only (VGA frame buffer)
0xC0000-0xFFFFF WB only
=============== ======= ==================
This mmap is done with user pages, not kernel identity mappings,
so it is safe to use WB mappings.
The kernel VGA driver may ioremap the VGA frame buffer at 0xA0000,
which uses a granule-sized UC mapping. This granule will cover some
WB-only memory, but since UC is non-speculative, the processor will
never generate an uncacheable reference to the WB-only areas unless
the driver explicitly touches them.
mmap of 0x0-0xFFFFF legacy_mem by "X"
-------------------------------------
If the EFI memory map reports that the entire range supports the
same attributes, we can allow the mmap (and we will prefer WB if
supported, as is the case with HP sx[12]000 machines with VGA
disabled).
If EFI reports the range as partly WB and partly UC (as on sx[12]000
machines with VGA enabled), we must fail the mmap because there's no
safe attribute to use.
If EFI reports some of the range but not all (as on Intel firmware
that doesn't report the VGA frame buffer at all), we should fail the
mmap and force the user to map just the specific region of interest.
mmap of 0xA0000-0xBFFFF legacy_mem by "X" on HP sx1000 with VGA disabled
------------------------------------------------------------------------
The EFI memory map reports the following attributes::
0x00000-0xFFFFF WB only (no VGA MMIO hole)
This is a special case of the previous case, and the mmap should
fail for the same reason as above.
read of /sys/devices/.../rom
----------------------------
For VGA devices, this may cause an ioremap() of 0xC0000. This
used to be done with a UC mapping, because the VGA frame buffer
at 0xA0000 prevents use of a WB granule. The UC mapping causes
an MCA on HP sx[12]000 chipsets.
We should use WB page table mappings to avoid covering the VGA
frame buffer.
Notes
=====
[1] SDM rev 2.2, vol 2, sec 4.4.1.
[2] SDM rev 2.2, vol 2, sec 4.4.6.
Documentation/arch/ia64/efirtc.rst
-144
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@@ -1,144 +0,0 @@
==========================
EFI Real Time Clock driver
==========================
S. Eranian <eranian@hpl.hp.com>
March 2000
1. Introduction
===============
This document describes the efirtc.c driver has provided for
the IA-64 platform.
The purpose of this driver is to supply an API for kernel and user applications
to get access to the Time Service offered by EFI version 0.92.
EFI provides 4 calls one can make once the OS is booted: GetTime(),
SetTime(), GetWakeupTime(), SetWakeupTime() which are all supported by this
driver. We describe those calls as well the design of the driver in the
following sections.
2. Design Decisions
===================
The original ideas was to provide a very simple driver to get access to,
at first, the time of day service. This is required in order to access, in a
portable way, the CMOS clock. A program like /sbin/hwclock uses such a clock
to initialize the system view of the time during boot.
Because we wanted to minimize the impact on existing user-level apps using
the CMOS clock, we decided to expose an API that was very similar to the one
used today with the legacy RTC driver (driver/char/rtc.c). However, because
EFI provides a simpler services, not all ioctl() are available. Also
new ioctl()s have been introduced for things that EFI provides but not the
legacy.
EFI uses a slightly different way of representing the time, noticeably
the reference date is different. Year is the using the full 4-digit format.
The Epoch is January 1st 1998. For backward compatibility reasons we don't
expose this new way of representing time. Instead we use something very
similar to the struct tm, i.e. struct rtc_time, as used by hwclock.
One of the reasons for doing it this way is to allow for EFI to still evolve
without necessarily impacting any of the user applications. The decoupling
enables flexibility and permits writing wrapper code is ncase things change.
The driver exposes two interfaces, one via the device file and a set of
ioctl()s. The other is read-only via the /proc filesystem.
As of today we don't offer a /proc/sys interface.
To allow for a uniform interface between the legacy RTC and EFI time service,
we have created the include/linux/rtc.h header file to contain only the
"public" API of the two drivers. The specifics of the legacy RTC are still
in include/linux/mc146818rtc.h.
3. Time of day service
======================
The part of the driver gives access to the time of day service of EFI.
Two ioctl()s, compatible with the legacy RTC calls:
Read the CMOS clock::
ioctl(d, RTC_RD_TIME, &rtc);
Write the CMOS clock::
ioctl(d, RTC_SET_TIME, &rtc);
The rtc is a pointer to a data structure defined in rtc.h which is close
to a struct tm::
struct rtc_time {
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year;
int tm_wday;
int tm_yday;
int tm_isdst;
};
The driver takes care of converting back an forth between the EFI time and
this format.
Those two ioctl()s can be exercised with the hwclock command:
For reading::
# /sbin/hwclock --show
Mon Mar 6 15:32:32 2000 -0.910248 seconds
For setting::
# /sbin/hwclock --systohc
Root privileges are required to be able to set the time of day.
4. Wakeup Alarm service
=======================
EFI provides an API by which one can program when a machine should wakeup,
i.e. reboot. This is very different from the alarm provided by the legacy
RTC which is some kind of interval timer alarm. For this reason we don't use
the same ioctl()s to get access to the service. Instead we have
introduced 2 news ioctl()s to the interface of an RTC.
We have added 2 new ioctl()s that are specific to the EFI driver:
Read the current state of the alarm::
ioctl(d, RTC_WKALM_RD, &wkt)
Set the alarm or change its status::
ioctl(d, RTC_WKALM_SET, &wkt)
The wkt structure encapsulates a struct rtc_time + 2 extra fields to get
status information::
struct rtc_wkalrm {
unsigned char enabled; /* =1 if alarm is enabled */
unsigned char pending; /* =1 if alarm is pending */
struct rtc_time time;
}
As of today, none of the existing user-level apps supports this feature.
However writing such a program should be hard by simply using those two
ioctl().
Root privileges are required to be able to set the alarm.
5. References
=============
Checkout the following Web site for more information on EFI:
http://developer.intel.com/technology/efi/
Documentation/arch/ia64/err_inject.rst
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Documentation/arch/ia64/features.rst
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@@ -1,3 +0,0 @@
.. SPDX-License-Identifier: GPL-2.0
.. kernel-feat:: $srctree/Documentation/features ia64
Documentation/arch/ia64/fsys.rst
-303
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@@ -1,303 +0,0 @@
===================================
Light-weight System Calls for IA-64
===================================
Started: 13-Jan-2003
Last update: 27-Sep-2003
David Mosberger-Tang
<davidm@hpl.hp.com>
Using the "epc" instruction effectively introduces a new mode of
execution to the ia64 linux kernel. We call this mode the
"fsys-mode". To recap, the normal states of execution are:
- kernel mode:
Both the register stack and the memory stack have been
switched over to kernel memory. The user-level state is saved
in a pt-regs structure at the top of the kernel memory stack.
- user mode:
Both the register stack and the kernel stack are in
user memory. The user-level state is contained in the
CPU registers.
- bank 0 interruption-handling mode:
This is the non-interruptible state which all
interruption-handlers start execution in. The user-level
state remains in the CPU registers and some kernel state may
be stored in bank 0 of registers r16-r31.
In contrast, fsys-mode has the following special properties:
- execution is at privilege level 0 (most-privileged)
- CPU registers may contain a mixture of user-level and kernel-level
state (it is the responsibility of the kernel to ensure that no
security-sensitive kernel-level state is leaked back to
user-level)
- execution is interruptible and preemptible (an fsys-mode handler
can disable interrupts and avoid all other interruption-sources
to avoid preemption)
- neither the memory-stack nor the register-stack can be trusted while
in fsys-mode (they point to the user-level stacks, which may
be invalid, or completely bogus addresses)
In summary, fsys-mode is much more similar to running in user-mode
than it is to running in kernel-mode. Of course, given that the
privilege level is at level 0, this means that fsys-mode requires some
care (see below).
How to tell fsys-mode
=====================
Linux operates in fsys-mode when (a) the privilege level is 0 (most
privileged) and (b) the stacks have NOT been switched to kernel memory
yet. For convenience, the header file <asm-ia64/ptrace.h> provides
three macros::
user_mode(regs)
user_stack(task,regs)
fsys_mode(task,regs)
The "regs" argument is a pointer to a pt_regs structure. The "task"
argument is a pointer to the task structure to which the "regs"
pointer belongs to. user_mode() returns TRUE if the CPU state pointed
to by "regs" was executing in user mode (privilege level 3).
user_stack() returns TRUE if the state pointed to by "regs" was
executing on the user-level stack(s). Finally, fsys_mode() returns
TRUE if the CPU state pointed to by "regs" was executing in fsys-mode.
The fsys_mode() macro is equivalent to the expression::
!user_mode(regs) && user_stack(task,regs)
How to write an fsyscall handler
================================
The file arch/ia64/kernel/fsys.S contains a table of fsyscall-handlers
(fsyscall_table). This table contains one entry for each system call.
By default, a system call is handled by fsys_fallback_syscall(). This
routine takes care of entering (full) kernel mode and calling the
normal Linux system call handler. For performance-critical system
calls, it is possible to write a hand-tuned fsyscall_handler. For
example, fsys.S contains fsys_getpid(), which is a hand-tuned version
of the getpid() system call.
The entry and exit-state of an fsyscall handler is as follows:
Machine state on entry to fsyscall handler
------------------------------------------
========= ===============================================================
r10 0
r11 saved ar.pfs (a user-level value)
r15 system call number
r16 "current" task pointer (in normal kernel-mode, this is in r13)
r32-r39 system call arguments
b6 return address (a user-level value)
ar.pfs previous frame-state (a user-level value)
PSR.be cleared to zero (i.e., little-endian byte order is in effect)
- all other registers may contain values passed in from user-mode
========= ===============================================================
Required machine state on exit to fsyscall handler
--------------------------------------------------
========= ===========================================================
r11 saved ar.pfs (as passed into the fsyscall handler)
r15 system call number (as passed into the fsyscall handler)
r32-r39 system call arguments (as passed into the fsyscall handler)
b6 return address (as passed into the fsyscall handler)
ar.pfs previous frame-state (as passed into the fsyscall handler)
========= ===========================================================
Fsyscall handlers can execute with very little overhead, but with that
speed comes a set of restrictions:
* Fsyscall-handlers MUST check for any pending work in the flags
member of the thread-info structure and if any of the
TIF_ALLWORK_MASK flags are set, the handler needs to fall back on
doing a full system call (by calling fsys_fallback_syscall).
* Fsyscall-handlers MUST preserve incoming arguments (r32-r39, r11,
r15, b6, and ar.pfs) because they will be needed in case of a
system call restart. Of course, all "preserved" registers also
must be preserved, in accordance to the normal calling conventions.
* Fsyscall-handlers MUST check argument registers for containing a
NaT value before using them in any way that could trigger a
NaT-consumption fault. If a system call argument is found to
contain a NaT value, an fsyscall-handler may return immediately
with r8=EINVAL, r10=-1.
* Fsyscall-handlers MUST NOT use the "alloc" instruction or perform
any other operation that would trigger mandatory RSE
(register-stack engine) traffic.
* Fsyscall-handlers MUST NOT write to any stacked registers because
it is not safe to assume that user-level called a handler with the
proper number of arguments.
* Fsyscall-handlers need to be careful when accessing per-CPU variables:
unless proper safe-guards are taken (e.g., interruptions are avoided),
execution may be pre-empted and resumed on another CPU at any given
time.
* Fsyscall-handlers must be careful not to leak sensitive kernel'
information back to user-level. In particular, before returning to
user-level, care needs to be taken to clear any scratch registers
that could contain sensitive information (note that the current
task pointer is not considered sensitive: it's already exposed
through ar.k6).
* Fsyscall-handlers MUST NOT access user-memory without first
validating access-permission (this can be done typically via
probe.r.fault and/or probe.w.fault) and without guarding against
memory access exceptions (this can be done with the EX() macros
defined by asmmacro.h).
The above restrictions may seem draconian, but remember that it's
possible to trade off some of the restrictions by paying a slightly
higher overhead. For example, if an fsyscall-handler could benefit
from the shadow register bank, it could temporarily disable PSR.i and
PSR.ic, switch to bank 0 (bsw.0) and then use the shadow registers as
needed. In other words, following the above rules yields extremely
fast system call execution (while fully preserving system call
semantics), but there is also a lot of flexibility in handling more
complicated cases.
Signal handling
===============
The delivery of (asynchronous) signals must be delayed until fsys-mode
is exited. This is accomplished with the help of the lower-privilege
transfer trap: arch/ia64/kernel/process.c:do_notify_resume_user()
checks whether the interrupted task was in fsys-mode and, if so, sets
PSR.lp and returns immediately. When fsys-mode is exited via the
"br.ret" instruction that lowers the privilege level, a trap will
occur. The trap handler clears PSR.lp again and returns immediately.
The kernel exit path then checks for and delivers any pending signals.
PSR Handling
============
The "epc" instruction doesn't change the contents of PSR at all. This
is in contrast to a regular interruption, which clears almost all
bits. Because of that, some care needs to be taken to ensure things
work as expected. The following discussion describes how each PSR bit
is handled.
======= =======================================================================
PSR.be Cleared when entering fsys-mode. A srlz.d instruction is used
to ensure the CPU is in little-endian mode before the first
load/store instruction is executed. PSR.be is normally NOT
restored upon return from an fsys-mode handler. In other
words, user-level code must not rely on PSR.be being preserved
across a system call.
PSR.up Unchanged.
PSR.ac Unchanged.
PSR.mfl Unchanged. Note: fsys-mode handlers must not write-registers!
PSR.mfh Unchanged. Note: fsys-mode handlers must not write-registers!
PSR.ic Unchanged. Note: fsys-mode handlers can clear the bit, if needed.
PSR.i Unchanged. Note: fsys-mode handlers can clear the bit, if needed.
PSR.pk Unchanged.
PSR.dt Unchanged.
PSR.dfl Unchanged. Note: fsys-mode handlers must not write-registers!
PSR.dfh Unchanged. Note: fsys-mode handlers must not write-registers!
PSR.sp Unchanged.
PSR.pp Unchanged.
PSR.di Unchanged.
PSR.si Unchanged.
PSR.db Unchanged. The kernel prevents user-level from setting a hardware
breakpoint that triggers at any privilege level other than
3 (user-mode).
PSR.lp Unchanged.
PSR.tb Lazy redirect. If a taken-branch trap occurs while in
fsys-mode, the trap-handler modifies the saved machine state
such that execution resumes in the gate page at
syscall_via_break(), with privilege level 3. Note: the
taken branch would occur on the branch invoking the
fsyscall-handler, at which point, by definition, a syscall
restart is still safe. If the system call number is invalid,
the fsys-mode handler will return directly to user-level. This
return will trigger a taken-branch trap, but since the trap is
taken _after_ restoring the privilege level, the CPU has already
left fsys-mode, so no special treatment is needed.
PSR.rt Unchanged.
PSR.cpl Cleared to 0.
PSR.is Unchanged (guaranteed to be 0 on entry to the gate page).
PSR.mc Unchanged.
PSR.it Unchanged (guaranteed to be 1).
PSR.id Unchanged. Note: the ia64 linux kernel never sets this bit.
PSR.da Unchanged. Note: the ia64 linux kernel never sets this bit.
PSR.dd Unchanged. Note: the ia64 linux kernel never sets this bit.
PSR.ss Lazy redirect. If set, "epc" will cause a Single Step Trap to
be taken. The trap handler then modifies the saved machine
state such that execution resumes in the gate page at
syscall_via_break(), with privilege level 3.
PSR.ri Unchanged.
PSR.ed Unchanged. Note: This bit could only have an effect if an fsys-mode
handler performed a speculative load that gets NaTted. If so, this
would be the normal & expected behavior, so no special treatment is
needed.
PSR.bn Unchanged. Note: fsys-mode handlers may clear the bit, if needed.
Doing so requires clearing PSR.i and PSR.ic as well.
PSR.ia Unchanged. Note: the ia64 linux kernel never sets this bit.
======= =======================================================================
Using fast system calls
=======================
To use fast system calls, userspace applications need simply call
__kernel_syscall_via_epc(). For example
-- example fgettimeofday() call --
-- fgettimeofday.S --
::
#include <asm/asmmacro.h>
GLOBAL_ENTRY(fgettimeofday)
.prologue
.save ar.pfs, r11
mov r11 = ar.pfs
.body
mov r2 = 0xa000000000020660;; // gate address
// found by inspection of System.map for the
// __kernel_syscall_via_epc() function. See
// below for how to do this for real.
mov b7 = r2
mov r15 = 1087 // gettimeofday syscall
;;
br.call.sptk.many b6 = b7
;;
.restore sp
mov ar.pfs = r11
br.ret.sptk.many rp;; // return to caller
END(fgettimeofday)
-- end fgettimeofday.S --
In reality, getting the gate address is accomplished by two extra
values passed via the ELF auxiliary vector (include/asm-ia64/elf.h)
* AT_SYSINFO : is the address of __kernel_syscall_via_epc()
* AT_SYSINFO_EHDR : is the address of the kernel gate ELF DSO
The ELF DSO is a pre-linked library that is mapped in by the kernel at
the gate page. It is a proper ELF shared object so, with a dynamic
loader that recognises the library, you should be able to make calls to
the exported functions within it as with any other shared library.
AT_SYSINFO points into the kernel DSO at the
__kernel_syscall_via_epc() function for historical reasons (it was
used before the kernel DSO) and as a convenience.
Documentation/arch/ia64/ia64.rst
-49
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@@ -1,49 +0,0 @@
===========================================
Linux kernel release for the IA-64 Platform
===========================================
These are the release notes for Linux since version 2.4 for IA-64
platform. This document provides information specific to IA-64
ONLY, to get additional information about the Linux kernel also
read the original Linux README provided with the kernel.
Installing the Kernel
=====================
- IA-64 kernel installation is the same as the other platforms, see
original README for details.
Software Requirements
=====================
Compiling and running this kernel requires an IA-64 compliant GCC
compiler. And various software packages also compiled with an
IA-64 compliant GCC compiler.
Configuring the Kernel
======================
Configuration is the same, see original README for details.
Compiling the Kernel:
- Compiling this kernel doesn't differ from other platform so read
the original README for details BUT make sure you have an IA-64
compliant GCC compiler.
IA-64 Specifics
===============
- General issues:
* Hardly any performance tuning has been done. Obvious targets
include the library routines (IP checksum, etc.). Less
obvious targets include making sure we don't flush the TLB
needlessly, etc.
* SMP locks cleanup/optimization
* IA32 support. Currently experimental. It mostly works.
Documentation/arch/ia64/index.rst
-19
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@@ -1,19 +0,0 @@
.. SPDX-License-Identifier: GPL-2.0
==================
IA-64 Architecture
==================
.. toctree::
:maxdepth: 1
ia64
aliasing
efirtc
err_inject
fsys
irq-redir
mca
serial
features
Documentation/arch/ia64/irq-redir.rst
-80
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@@ -1,80 +0,0 @@
==============================
IRQ affinity on IA64 platforms
==============================
07.01.2002, Erich Focht <efocht@ess.nec.de>
By writing to /proc/irq/IRQ#/smp_affinity the interrupt routing can be
controlled. The behavior on IA64 platforms is slightly different from
that described in Documentation/core-api/irq/irq-affinity.rst for i386 systems.
Because of the usage of SAPIC mode and physical destination mode the
IRQ target is one particular CPU and cannot be a mask of several
CPUs. Only the first non-zero bit is taken into account.
Usage examples
==============
The target CPU has to be specified as a hexadecimal CPU mask. The
first non-zero bit is the selected CPU. This format has been kept for
compatibility reasons with i386.
Set the delivery mode of interrupt 41 to fixed and route the
interrupts to CPU #3 (logical CPU number) (2^3=0x08)::
echo "8" >/proc/irq/41/smp_affinity
Set the default route for IRQ number 41 to CPU 6 in lowest priority
delivery mode (redirectable)::
echo "r 40" >/proc/irq/41/smp_affinity
The output of the command::
cat /proc/irq/IRQ#/smp_affinity
gives the target CPU mask for the specified interrupt vector. If the CPU
mask is preceded by the character "r", the interrupt is redirectable
(i.e. lowest priority mode routing is used), otherwise its route is
fixed.
Initialization and default behavior
===================================
If the platform features IRQ redirection (info provided by SAL) all
IO-SAPIC interrupts are initialized with CPU#0 as their default target
and the routing is the so called "lowest priority mode" (actually
fixed SAPIC mode with hint). The XTP chipset registers are used as hints
for the IRQ routing. Currently in Linux XTP registers can have three
values:
- minimal for an idle task,
- normal if any other task runs,
- maximal if the CPU is going to be switched off.
The IRQ is routed to the CPU with lowest XTP register value, the
search begins at the default CPU. Therefore most of the interrupts
will be handled by CPU #0.
If the platform doesn't feature interrupt redirection IOSAPIC fixed
routing is used. The target CPUs are distributed in a round robin
manner. IRQs will be routed only to the selected target CPUs. Check
with::
cat /proc/interrupts
Comments
========
On large (multi-node) systems it is recommended to route the IRQs to
the node to which the corresponding device is connected.
For systems like the NEC AzusA we get IRQ node-affinity for free. This
is because usually the chipsets on each node redirect the interrupts
only to their own CPUs (as they cannot see the XTP registers on the
other nodes).
Documentation/arch/ia64/mca.rst
-198
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@@ -1,198 +0,0 @@
=============================================================
An ad-hoc collection of notes on IA64 MCA and INIT processing
=============================================================
Feel free to update it with notes about any area that is not clear.
---
MCA/INIT are completely asynchronous. They can occur at any time, when
the OS is in any state. Including when one of the cpus is already
holding a spinlock. Trying to get any lock from MCA/INIT state is
asking for deadlock. Also the state of structures that are protected
by locks is indeterminate, including linked lists.
---
The complicated ia64 MCA process. All of this is mandated by Intel's
specification for ia64 SAL, error recovery and unwind, it is not as
if we have a choice here.
* MCA occurs on one cpu, usually due to a double bit memory error.
This is the monarch cpu.
* SAL sends an MCA rendezvous interrupt (which is a normal interrupt)
to all the other cpus, the slaves.
* Slave cpus that receive the MCA interrupt call down into SAL, they
end up spinning disabled while the MCA is being serviced.
* If any slave cpu was already spinning disabled when the MCA occurred
then it cannot service the MCA interrupt. SAL waits ~20 seconds then
sends an unmaskable INIT event to the slave cpus that have not
already rendezvoused.
* Because MCA/INIT can be delivered at any time, including when the cpu
is down in PAL in physical mode, the registers at the time of the
event are _completely_ undefined. In particular the MCA/INIT
handlers cannot rely on the thread pointer, PAL physical mode can
(and does) modify TP. It is allowed to do that as long as it resets
TP on return. However MCA/INIT events expose us to these PAL
internal TP changes. Hence curr_task().
* If an MCA/INIT event occurs while the kernel was running (not user
space) and the kernel has called PAL then the MCA/INIT handler cannot
assume that the kernel stack is in a fit state to be used. Mainly
because PAL may or may not maintain the stack pointer internally.
Because the MCA/INIT handlers cannot trust the kernel stack, they
have to use their own, per-cpu stacks. The MCA/INIT stacks are
preformatted with just enough task state to let the relevant handlers
do their job.
* Unlike most other architectures, the ia64 struct task is embedded in
the kernel stack[1]. So switching to a new kernel stack means that
we switch to a new task as well. Because various bits of the kernel
assume that current points into the struct task, switching to a new
stack also means a new value for current.
* Once all slaves have rendezvoused and are spinning disabled, the
monarch is entered. The monarch now tries to diagnose the problem
and decide if it can recover or not.
* Part of the monarch's job is to look at the state of all the other
tasks. The only way to do that on ia64 is to call the unwinder,
as mandated by Intel.
* The starting point for the unwind depends on whether a task is
running or not. That is, whether it is on a cpu or is blocked. The
monarch has to determine whether or not a task is on a cpu before it
knows how to start unwinding it. The tasks that received an MCA or
INIT event are no longer running, they have been converted to blocked
tasks. But (and its a big but), the cpus that received the MCA
rendezvous interrupt are still running on their normal kernel stacks!
* To distinguish between these two cases, the monarch must know which
tasks are on a cpu and which are not. Hence each slave cpu that
switches to an MCA/INIT stack, registers its new stack using
set_curr_task(), so the monarch can tell that the _original_ task is
no longer running on that cpu. That gives us a decent chance of
getting a valid backtrace of the _original_ task.
* MCA/INIT can be nested, to a depth of 2 on any cpu. In the case of a
nested error, we want diagnostics on the MCA/INIT handler that
failed, not on the task that was originally running. Again this
requires set_curr_task() so the MCA/INIT handlers can register their
own stack as running on that cpu. Then a recursive error gets a
trace of the failing handler's "task".
[1]
My (Keith Owens) original design called for ia64 to separate its
struct task and the kernel stacks. Then the MCA/INIT data would be
chained stacks like i386 interrupt stacks. But that required
radical surgery on the rest of ia64, plus extra hard wired TLB
entries with its associated performance degradation. David
Mosberger vetoed that approach. Which meant that separate kernel
stacks meant separate "tasks" for the MCA/INIT handlers.
---
INIT is less complicated than MCA. Pressing the nmi button or using
the equivalent command on the management console sends INIT to all
cpus. SAL picks one of the cpus as the monarch and the rest are
slaves. All the OS INIT handlers are entered at approximately the same
time. The OS monarch prints the state of all tasks and returns, after
which the slaves return and the system resumes.
At least that is what is supposed to happen. Alas there are broken
versions of SAL out there. Some drive all the cpus as monarchs. Some
drive them all as slaves. Some drive one cpu as monarch, wait for that
cpu to return from the OS then drive the rest as slaves. Some versions
of SAL cannot even cope with returning from the OS, they spin inside
SAL on resume. The OS INIT code has workarounds for some of these
broken SAL symptoms, but some simply cannot be fixed from the OS side.
---
The scheduler hooks used by ia64 (curr_task, set_curr_task) are layer
violations. Unfortunately MCA/INIT start off as massive layer
violations (can occur at _any_ time) and they build from there.
At least ia64 makes an attempt at recovering from hardware errors, but
it is a difficult problem because of the asynchronous nature of these
errors. When processing an unmaskable interrupt we sometimes need
special code to cope with our inability to take any locks.
---
How is ia64 MCA/INIT different from x86 NMI?
* x86 NMI typically gets delivered to one cpu. MCA/INIT gets sent to
all cpus.
* x86 NMI cannot be nested. MCA/INIT can be nested, to a depth of 2
per cpu.
* x86 has a separate struct task which points to one of multiple kernel
stacks. ia64 has the struct task embedded in the single kernel
stack, so switching stack means switching task.
* x86 does not call the BIOS so the NMI handler does not have to worry
about any registers having changed. MCA/INIT can occur while the cpu
is in PAL in physical mode, with undefined registers and an undefined
kernel stack.
* i386 backtrace is not very sensitive to whether a process is running
or not. ia64 unwind is very, very sensitive to whether a process is
running or not.
---
What happens when MCA/INIT is delivered what a cpu is running user
space code?
The user mode registers are stored in the RSE area of the MCA/INIT on
entry to the OS and are restored from there on return to SAL, so user
mode registers are preserved across a recoverable MCA/INIT. Since the
OS has no idea what unwind data is available for the user space stack,
MCA/INIT never tries to backtrace user space. Which means that the OS
does not bother making the user space process look like a blocked task,
i.e. the OS does not copy pt_regs and switch_stack to the user space
stack. Also the OS has no idea how big the user space RSE and memory
stacks are, which makes it too risky to copy the saved state to a user
mode stack.
---
How do we get a backtrace on the tasks that were running when MCA/INIT
was delivered?
mca.c:::ia64_mca_modify_original_stack(). That identifies and
verifies the original kernel stack, copies the dirty registers from
the MCA/INIT stack's RSE to the original stack's RSE, copies the
skeleton struct pt_regs and switch_stack to the original stack, fills
in the skeleton structures from the PAL minstate area and updates the
original stack's thread.ksp. That makes the original stack look
exactly like any other blocked task, i.e. it now appears to be
sleeping. To get a backtrace, just start with thread.ksp for the
original task and unwind like any other sleeping task.
---
How do we identify the tasks that were running when MCA/INIT was
delivered?
If the previous task has been verified and converted to a blocked
state, then sos->prev_task on the MCA/INIT stack is updated to point to
the previous task. You can look at that field in dumps or debuggers.
To help distinguish between the handler and the original tasks,
handlers have _TIF_MCA_INIT set in thread_info.flags.
The sos data is always in the MCA/INIT handler stack, at offset
MCA_SOS_OFFSET. You can get that value from mca_asm.h or calculate it
as KERNEL_STACK_SIZE - sizeof(struct pt_regs) - sizeof(struct
ia64_sal_os_state), with 16 byte alignment for all structures.
Also the comm field of the MCA/INIT task is modified to include the pid
of the original task, for humans to use. For example, a comm field of
'MCA 12159' means that pid 12159 was running when the MCA was
delivered.
Documentation/arch/ia64/serial.rst
-165
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@@ -1,165 +0,0 @@
==============
Serial Devices
==============
Serial Device Naming
====================
As of 2.6.10, serial devices on ia64 are named based on the
order of ACPI and PCI enumeration. The first device in the
ACPI namespace (if any) becomes /dev/ttyS0, the second becomes
/dev/ttyS1, etc., and PCI devices are named sequentially
starting after the ACPI devices.
Prior to 2.6.10, there were confusing exceptions to this:
- Firmware on some machines (mostly from HP) provides an HCDP
table[1] that tells the kernel about devices that can be used
as a serial console. If the user specified "console=ttyS0"
or the EFI ConOut path contained only UART devices, the
kernel registered the device described by the HCDP as
/dev/ttyS0.
- If there was no HCDP, we assumed there were UARTs at the
legacy COM port addresses (I/O ports 0x3f8 and 0x2f8), so
the kernel registered those as /dev/ttyS0 and /dev/ttyS1.
Any additional ACPI or PCI devices were registered sequentially
after /dev/ttyS0 as they were discovered.
With an HCDP, device names changed depending on EFI configuration
and "console=" arguments. Without an HCDP, device names didn't
change, but we registered devices that might not really exist.
For example, an HP rx1600 with a single built-in serial port
(described in the ACPI namespace) plus an MP[2] (a PCI device) has
these ports:
========== ========== ============ ============ =======
Type MMIO pre-2.6.10 pre-2.6.10 2.6.10+
address
(EFI console (EFI console
on builtin) on MP port)
========== ========== ============ ============ =======
builtin 0xff5e0000 ttyS0 ttyS1 ttyS0
MP UPS 0xf8031000 ttyS1 ttyS2 ttyS1
MP Console 0xf8030000 ttyS2 ttyS0 ttyS2
MP 2 0xf8030010 ttyS3 ttyS3 ttyS3
MP 3 0xf8030038 ttyS4 ttyS4 ttyS4
========== ========== ============ ============ =======
Console Selection
=================
EFI knows what your console devices are, but it doesn't tell the
kernel quite enough to actually locate them. The DIG64 HCDP
table[1] does tell the kernel where potential serial console
devices are, but not all firmware supplies it. Also, EFI supports
multiple simultaneous consoles and doesn't tell the kernel which
should be the "primary" one.
So how do you tell Linux which console device to use?
- If your firmware supplies the HCDP, it is simplest to
configure EFI with a single device (either a UART or a VGA
card) as the console. Then you don't need to tell Linux
anything; the kernel will automatically use the EFI console.
(This works only in 2.6.6 or later; prior to that you had
to specify "console=ttyS0" to get a serial console.)
- Without an HCDP, Linux defaults to a VGA console unless you
specify a "console=" argument.
NOTE: Don't assume that a serial console device will be /dev/ttyS0.
It might be ttyS1, ttyS2, etc. Make sure you have the appropriate
entries in /etc/inittab (for getty) and /etc/securetty (to allow
root login).
Early Serial Console
====================
The kernel can't start using a serial console until it knows where
the device lives. Normally this happens when the driver enumerates
all the serial devices, which can happen a minute or more after the
kernel starts booting.
2.6.10 and later kernels have an "early uart" driver that works
very early in the boot process. The kernel will automatically use
this if the user supplies an argument like "console=uart,io,0x3f8",
or if the EFI console path contains only a UART device and the
firmware supplies an HCDP.
Troubleshooting Serial Console Problems
=======================================
No kernel output after elilo prints "Uncompressing Linux... done":
- You specified "console=ttyS0" but Linux changed the device
to which ttyS0 refers. Configure exactly one EFI console
device[3] and remove the "console=" option.
- The EFI console path contains both a VGA device and a UART.
EFI and elilo use both, but Linux defaults to VGA. Remove
the VGA device from the EFI console path[3].
- Multiple UARTs selected as EFI console devices. EFI and
elilo use all selected devices, but Linux uses only one.
Make sure only one UART is selected in the EFI console
path[3].
- You're connected to an HP MP port[2] but have a non-MP UART
selected as EFI console device. EFI uses the MP as a
console device even when it isn't explicitly selected.
Either move the console cable to the non-MP UART, or change
the EFI console path[3] to the MP UART.
Long pause (60+ seconds) between "Uncompressing Linux... done" and
start of kernel output:
- No early console because you used "console=ttyS<n>". Remove
the "console=" option if your firmware supplies an HCDP.
- If you don't have an HCDP, the kernel doesn't know where
your console lives until the driver discovers serial
devices. Use "console=uart,io,0x3f8" (or appropriate
address for your machine).
Kernel and init script output works fine, but no "login:" prompt:
- Add getty entry to /etc/inittab for console tty. Look for
the "Adding console on ttyS<n>" message that tells you which
device is the console.
"login:" prompt, but can't login as root:
- Add entry to /etc/securetty for console tty.
No ACPI serial devices found in 2.6.17 or later:
- Turn on CONFIG_PNP and CONFIG_PNPACPI. Prior to 2.6.17, ACPI
serial devices were discovered by 8250_acpi. In 2.6.17,
8250_acpi was replaced by the combination of 8250_pnp and
CONFIG_PNPACPI.
[1]
http://www.dig64.org/specifications/agreement
The table was originally defined as the "HCDP" for "Headless
Console/Debug Port." The current version is the "PCDP" for
"Primary Console and Debug Port Devices."
[2]
The HP MP (management processor) is a PCI device that provides
several UARTs. One of the UARTs is often used as a console; the
EFI Boot Manager identifies it as "Acpi(HWP0002,700)/Pci(...)/Uart".
The external connection is usually a 25-pin connector, and a
special dongle converts that to three 9-pin connectors, one of
which is labelled "Console."
[3]
EFI console devices are configured using the EFI Boot Manager
"Boot option maintenance" menu. You may have to interrupt the
boot sequence to use this menu, and you will have to reset the
box after changing console configuration.
Documentation/arch/index.rst
-1
View File
@@ -12,7 +12,6 @@ implementation.
arc/index
arm/index
arm64/index
ia64/index
loongarch/index
m68k/index
mips/index
Documentation/block/ioprio.rst
-3
View File
@@ -80,9 +80,6 @@ ionice.c tool::
#elif defined(__x86_64__)
#define __NR_ioprio_set 251
#define __NR_ioprio_get 252
#elif defined(__ia64__)
#define __NR_ioprio_set 1274
#define __NR_ioprio_get 1275
#else
#error "Unsupported arch"
#endif
Documentation/core-api/cpu_hotplug.rst
-6
View File
@@ -40,12 +40,6 @@ Command Line Switches
supplied here is lower than the number of physically available CPUs, then
those CPUs can not be brought online later.
``additional_cpus=n``
Use this to limit hotpluggable CPUs. This option sets
``cpu_possible_mask = cpu_present_mask + additional_cpus``
This option is limited to the IA64 architecture.
``possible_cpus=n``
This option sets ``possible_cpus`` bits in ``cpu_possible_mask``.

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