linux-stable.git/arch/openrisc/kernel/head.S, branch linux-rolling-stable

arch, mm: consolidate empty_zero_page

2026-04-05T20:53:01+00:00

Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of
ZERO_PAGE() to 4.

Every architecture defines empty_zero_page that way or another, but for the
most of them it is always a page aligned page in BSS and most definitions
of ZERO_PAGE do virt_to_page(empty_zero_page).

Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to the
core MM and drop these definitions in architectures that do not implement
colored zero page (MIPS and s390).

ZERO_PAGE() remains a macro because turning it to a wrapper for a static
inline causes severe pain in header dependencies.

For the most part the change is mechanical, with these being noteworthy:

* alpha: aliased empty_zero_page with ZERO_PGE that was also used for boot
  parameters. Switching to a generic empty_zero_page removes the aliasing
  and keeps ZERO_PGE for boot parameters only
* arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of
  ZERO_PAGE() is kept intact.
* m68k/parisc/um: allocated empty_zero_page from memblock,
  although they do not support zero page coloring and having it in BSS
  will work fine.
* sparc64 can have empty_zero_page in BSS rather allocate it, but it
  can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE()
  but instead of allocating it, make mem_map_zero point to
  empty_zero_page.
* sh: used empty_zero_page for boot parameters at the very early boot.
  Rename the parameters page to boot_params_page and let sh use the generic
  empty_zero_page.
* hexagon: had an amusing comment about empty_zero_page

	/* A handy thing to have if one has the RAM. Declared in head.S */

  that unfortunately had to go :)

Link: https://lkml.kernel.org/r/20260211103141.3215197-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) 
Acked-by: Helge Deller 		[parisc]
Tested-by: Helge Deller 		[parisc]
Reviewed-by: Christophe Leroy (CS GROUP) 
Acked-by: Dave Hansen 
Acked-by: Catalin Marinas 
Acked-by: Magnus Lindholm 	[alpha]
Acked-by: Dinh Nguyen 	[nios2]
Acked-by: Andreas Larsson 	[sparc]
Acked-by: David Hildenbrand (Arm) 
Acked-by: Liam R. Howlett 
Cc: "Borislav Petkov (AMD)" 
Cc: David S. Miller 
Cc: Geert Uytterhoeven 
Cc: Guo Ren 
Cc: Huacai Chen 
Cc: Ingo Molnar 
Cc: Johannes Berg 
Cc: John Paul Adrian Glaubitz 
Cc: Lorenzo Stoakes 
Cc: Madhavan Srinivasan 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Hocko 
Cc: Michal Simek 
Cc: Palmer Dabbelt 
Cc: Richard Weinberger 
Cc: Russell King 
Cc: Stafford Horne 
Cc: Suren Baghdasaryan 
Cc: Vineet Gupta 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

openrisc: Fix misalignments in head.S

2024-12-10T12:04:19+00:00

Align all line continuations and (sub)section headers in a consistent
way.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Stafford Horne

openrisc: place exception table at the head of vmlinux

2024-12-10T12:04:19+00:00

Since commit 0043ecea2399 ("vmlinux.lds.h: Adjust symbol ordering in
text output section"), the exception table in arch/openrisc/kernel/head.S
is no longer positioned at the very beginning of the kernel image, which
causes a boot failure.

Currently, the exception table resides in the regular .text section.
Previously, it was placed at the head by relying on the linker receiving
arch/openrisc/kernel/head.o as the first object. However, this behavior
has changed because sections like .text.{asan,unknown,unlikely,hot} now
precede the regular .text section.

The .head.text section is intended for entry points requiring special
placement. However, in OpenRISC, this section has been misused: instead
of the entry points, it contains boot code meant to be discarded after
booting. This feature is typically handled by the .init.text section.

This commit addresses the issue by replacing the current __HEAD marker
with __INIT and re-annotating the entry points with __HEAD. Additionally,
it adds __REF to entry.S to suppress the following modpost warning:

WARNING: modpost: vmlinux: section mismatch in reference: _tng_kernel_start+0x70 (section: .text) -> _start (section: .init.text)

Fixes: 0043ecea2399 ("vmlinux.lds.h: Adjust symbol ordering in text output section")
Reported-by: Guenter Roeck
Closes: https://lore.kernel.org/all/5e032233-5b65-4ad5-ac50-d2eb6c00171c@roeck-us.net/#t
Signed-off-by: Masahiro Yamada
Tested-by: Guenter Roeck
Reviewed-by: Rong Xu
Signed-off-by: Stafford Horne

openrisc: Support floating point user api

2023-04-26T14:08:06+00:00

Add support for handling floating point exceptions and forwarding the
SIGFPE signal to processes.  Also, add fpu state to sigcontext.

Signed-off-by: Stafford Horne

Merge tag 'for-linus' of https://github.com/openrisc/linux

2022-05-27T00:27:49+00:00

Pull OpenRISC updates from Stafford Horne:

 - A few sparse warning fixups and other cleanups I noticed when working
   on a recent TLB bug found on a new OpenRISC core bring up.

 - A few fixup's from me and Jason A Donenfeld to help shutdown OpenRISC
   platforms when running CI tests

* tag 'for-linus' of https://github.com/openrisc/linux:
  openrisc: Allow power off handler overriding
  openrisc: Remove unused IMMU tlb workardound
  openrisc/fault: Fix symbol scope warnings
  openrisc/delay: Add include to fix symbol not declared warning
  openrisc/time: Fix symbol scope warnings
  openrisc/traps: Declare unhandled_exception for asmlinkage
  openrisc/traps: Remove die_if_kernel function
  openrisc/traps: Declare file scope symbols as static
  openrisc: Update litex defconfig to support glibc userland
  openrisc: Pretty print show_registers memory dumps
  openrisc: Add syscall details to emergency syscall debugging
  openrisc: Add support for liteuart emergency printing
  openrisc: Cleanup emergency print handling
  openrisc: Add gcc machine instruction flag configuration
  openrisc: define nop command for simulator reboot
  openrisc: remove bogus nops and shutdowns
  openrisc: fix typos in comments

openrisc: Remove unused IMMU tlb workardound

2022-05-23T08:15:50+00:00

This looks to be some historical code that was used to convert TLB
misses on branches from l.bf, l.jal, l.j etc all to a trampoline
using l.jr (jump register).  I don't see this being used and I don't
know the history of it so remove it.

Signed-off-by: Stafford Horne

openrisc: Add support for liteuart emergency printing

2022-05-23T08:15:49+00:00

This patch adds support for sending emergency print output, such as
unhandled exception details, to a liteuart serial device.  This is the
default device available on litex platforms.

If a developer want to use this they should update UART_BASE_ADD
to the address of liteuart.

Signed-off-by: Stafford Horne

openrisc: Cleanup emergency print handling

2022-05-23T08:15:49+00:00

The emergency print support only works for 8250 compatible serial ports.
Now that OpenRISC platforms may be configured with different serial port
hardware we don't want emergency print to try to print to non-existent
hardware which will cause lockups.

This patch contains several fixes to get emergency print working again:

 - Update symbol loading to not assume the location of symbols
 - Split the putc print operation out to its own function to allow
   for different future implementations.
 - Update _emergency_print_nr and _emergency_print to use the putc
   function.
 - Guard serial 8250 specific sequences by CONFIG_SERIAL_8250
 - Update string line feed from lf,cr to cr,lf.

Signed-off-by: Stafford Horne

random: handle latent entropy and command line from random_init()

2022-05-18T13:53:53+00:00

Currently, start_kernel() adds latent entropy and the command line to
the entropy bool *after* the RNG has been initialized, deferring when
it's actually used by things like stack canaries until the next time
the pool is seeded. This surely is not intended.

Rather than splitting up which entropy gets added where and when between
start_kernel() and random_init(), just do everything in random_init(),
which should eliminate these kinds of bugs in the future.

While we're at it, rename the awkwardly titled "rand_initialize()" to
the more standard "random_init()" nomenclature.

Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld

openrisc: start CPU timer early in boot

2022-05-13T21:59:23+00:00

In order to measure the boot process, the timer should be switched on as
early in boot as possible. As well, the commit defines the get_cycles
macro, like the previous patches in this series, so that generic code is
aware that it's implemented by the platform, as is done on other archs.

Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Cc: Jonas Bonn 
Cc: Stefan Kristiansson 
Acked-by: Stafford Horne 
Reported-by: Guenter Roeck 
Signed-off-by: Jason A. Donenfeld