linux-toradex.git/arch/arm/include/asm/assembler.h, branch v5.11 Linux kernel for Apalis and Colibri modules ARM: kernel: use relative references for UP/SMP alternatives 2020-10-28T16:05:39+00:00 Ard Biesheuvel ardb@kernel.org 2020-09-14T08:48:20+00:00 450abd38fe6c6313ce9bdd9dce81c1dd604f6fb0 Currently, the .alt.smp.init section contains the virtual addresses of the patch sites. Since patching may occur both before and after switching into virtual mode, this requires some manual handling of the address when applying the UP alternative. Let's simplify this by using relative offsets in the table entries: this allows us to simply add each entry's address to its contents, regardless of whether we are running in virtual mode or not. Reviewed-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Currently, the .alt.smp.init section contains the virtual addresses
of the patch sites. Since patching may occur both before and after
switching into virtual mode, this requires some manual handling of
the address when applying the UP alternative.

Let's simplify this by using relative offsets in the table entries:
this allows us to simply add each entry's address to its contents,
regardless of whether we are running in virtual mode or not.

Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
ARM: assembler: introduce adr_l, ldr_l and str_l macros 2020-10-28T15:59:43+00:00 Ard Biesheuvel ardb@kernel.org 2020-09-14T08:23:39+00:00 0b1674638a5c69cbace63278625c199100955490 Like arm64, ARM supports position independent code sequences that produce symbol references with a greater reach than the ordinary adr/ldr instructions. Since on ARM, the adrl pseudo-instruction is only supported in ARM mode (and not at all when using Clang), having a adr_l macro like we do on arm64 is useful, and increases symmetry as well. Currently, we use open coded instruction sequences involving literals and arithmetic operations. Instead, we can use movw/movt pairs on v7 CPUs, circumventing the D-cache entirely. E.g., on v7+ CPUs, we can emit a PC-relative reference as follows: movw <reg>, #:lower16:<sym> - (1f + 8) movt <reg>, #:upper16:<sym> - (1f + 8) 1: add <reg>, <reg>, pc For older CPUs, we can emit the literal into a subsection, allowing it to be emitted out of line while retaining the ability to perform arithmetic on label offsets. E.g., on pre-v7 CPUs, we can emit a PC-relative reference as follows: ldr <reg>, 2f 1: add <reg>, <reg>, pc .subsection 1 2: .long <sym> - (1b + 8) .previous This is allowed by the assembler because, unlike ordinary sections, subsections are combined into a single section in the object file, and so the label references are not true cross-section references that are visible as relocations. (Subsections have been available in binutils since 2004 at least, so they should not cause any issues with older toolchains.) So use the above to implement the macros mov_l, adr_l, ldr_l and str_l, all of which will use movw/movt pairs on v7 and later CPUs, and use PC-relative literals otherwise. Reviewed-by: Nicolas Pitre <nico@fluxnic.net> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
Like arm64, ARM supports position independent code sequences that
produce symbol references with a greater reach than the ordinary
adr/ldr instructions. Since on ARM, the adrl pseudo-instruction is
only supported in ARM mode (and not at all when using Clang), having
a adr_l macro like we do on arm64 is useful, and increases symmetry
as well.

Currently, we use open coded instruction sequences involving literals
and arithmetic operations. Instead, we can use movw/movt pairs on v7
CPUs, circumventing the D-cache entirely.

E.g., on v7+ CPUs, we can emit a PC-relative reference as follows:

       movw         <reg>, #:lower16:<sym> - (1f + 8)
       movt         <reg>, #:upper16:<sym> - (1f + 8)
  1:   add          <reg>, <reg>, pc

For older CPUs, we can emit the literal into a subsection, allowing it
to be emitted out of line while retaining the ability to perform
arithmetic on label offsets.

E.g., on pre-v7 CPUs, we can emit a PC-relative reference as follows:

       ldr          <reg>, 2f
  1:   add          <reg>, <reg>, pc
       .subsection  1
  2:   .long        <sym> - (1b + 8)
       .previous

This is allowed by the assembler because, unlike ordinary sections,
subsections are combined into a single section in the object file, and
so the label references are not true cross-section references that are
visible as relocations. (Subsections have been available in binutils
since 2004 at least, so they should not cause any issues with older
toolchains.)

So use the above to implement the macros mov_l, adr_l, ldr_l and str_l,
all of which will use movw/movt pairs on v7 and later CPUs, and use
PC-relative literals otherwise.

Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2020-06-01T22:36:32+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-06-01T22:36:32+00:00 c2b0fc847f3122e5a4176c3772626a7a8facced0 Pull ARM updates from Russell King: - remove a now unnecessary usage of the KERNEL_DS for sys_oabi_epoll_ctl() - update my email address in a number of drivers - decompressor EFI updates from Ard Biesheuvel - module unwind section handling updates - sparsemem Kconfig cleanups - make act_mm macro respect THREAD_SIZE * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8980/1: Allow either FLATMEM or SPARSEMEM on the multiplatform build ARM: 8979/1: Remove redundant ARCH_SPARSEMEM_DEFAULT setting ARM: 8978/1: mm: make act_mm() respect THREAD_SIZE ARM: decompressor: run decompressor in place if loaded via UEFI ARM: decompressor: move GOT into .data for EFI enabled builds ARM: decompressor: defer loading of the contents of the LC0 structure ARM: decompressor: split off _edata and stack base into separate object ARM: decompressor: move headroom variable out of LC0 ARM: 8976/1: module: allow arch overrides for .init section names ARM: 8975/1: module: fix handling of unwind init sections ARM: 8974/1: use SPARSMEM_STATIC when SPARSEMEM is enabled ARM: 8971/1: replace the sole use of a symbol with its definition ARM: 8969/1: decompressor: simplify libfdt builds Update rmk's email address in various drivers ARM: compat: remove KERNEL_DS usage in sys_oabi_epoll_ctl() 
Pull ARM updates from Russell King:

 - remove a now unnecessary usage of the KERNEL_DS for
   sys_oabi_epoll_ctl()

 - update my email address in a number of drivers

 - decompressor EFI updates from Ard Biesheuvel

 - module unwind section handling updates

 - sparsemem Kconfig cleanups

 - make act_mm macro respect THREAD_SIZE

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8980/1: Allow either FLATMEM or SPARSEMEM on the multiplatform build
  ARM: 8979/1: Remove redundant ARCH_SPARSEMEM_DEFAULT setting
  ARM: 8978/1: mm: make act_mm() respect THREAD_SIZE
  ARM: decompressor: run decompressor in place if loaded via UEFI
  ARM: decompressor: move GOT into .data for EFI enabled builds
  ARM: decompressor: defer loading of the contents of the LC0 structure
  ARM: decompressor: split off _edata and stack base into separate object
  ARM: decompressor: move headroom variable out of LC0
  ARM: 8976/1: module: allow arch overrides for .init section names
  ARM: 8975/1: module: fix handling of unwind init sections
  ARM: 8974/1: use SPARSMEM_STATIC when SPARSEMEM is enabled
  ARM: 8971/1: replace the sole use of a symbol with its definition
  ARM: 8969/1: decompressor: simplify libfdt builds
  Update rmk's email address in various drivers
  ARM: compat: remove KERNEL_DS usage in sys_oabi_epoll_ctl()
ARM: uaccess: consolidate uaccess asm to asm/uaccess-asm.h 2020-05-03T16:30:24+00:00 Russell King rmk+kernel@armlinux.org.uk 2020-05-03T12:03:54+00:00 747ffc2fcf969eff9309d7f2d1d61cb8b9e1bb40 Consolidate the user access assembly code to asm/uaccess-asm.h. This moves the csdb, check_uaccess, uaccess_mask_range_ptr, uaccess_enable, uaccess_disable, uaccess_save, uaccess_restore macros, and creates two new ones for exception entry and exit - uaccess_entry and uaccess_exit. This makes the uaccess_save and uaccess_restore macros private to asm/uaccess-asm.h. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> 
Consolidate the user access assembly code to asm/uaccess-asm.h.  This
moves the csdb, check_uaccess, uaccess_mask_range_ptr, uaccess_enable,
uaccess_disable, uaccess_save, uaccess_restore macros, and creates two
new ones for exception entry and exit - uaccess_entry and uaccess_exit.

This makes the uaccess_save and uaccess_restore macros private to
asm/uaccess-asm.h.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
ARM: 8971/1: replace the sole use of a symbol with its definition 2020-04-29T12:30:20+00:00 Jian Cai caij2003@gmail.com 2020-04-29T00:20:11+00:00 a780e485b5768e78aef087502499714901b68cc4 ALT_UP_B macro sets symbol up_b_offset via .equ to an expression involving another symbol. The macro gets expanded twice when arch/arm/kernel/sleep.S is assembled, creating a scenario where up_b_offset is set to another expression involving symbols while its current value is based on symbols. LLVM integrated assembler does not allow such cases, and based on the documentation of binutils, "Values that are based on expressions involving other symbols are allowed, but some targets may restrict this to only being done once per assembly", so it may be better to avoid such cases as it is not clearly stated which targets should support or disallow them. The fix in this case is simple, as up_b_offset has only one use, so we can replace the use with the definition and get rid of up_b_offset. Link:https://github.com/ClangBuiltLinux/linux/issues/920 Reviewed-by: Stefan Agner <stefan@agner.ch> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Jian Cai <caij2003@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> 
ALT_UP_B macro sets symbol up_b_offset via .equ to an expression
involving another symbol. The macro gets expanded twice when
arch/arm/kernel/sleep.S is assembled, creating a scenario where
up_b_offset is set to another expression involving symbols while its
current value is based on symbols. LLVM integrated assembler does not
allow such cases, and based on the documentation of binutils, "Values
that are based on expressions involving other symbols are allowed, but
some targets may restrict this to only being done once per assembly", so
it may be better to avoid such cases as it is not clearly stated which
targets should support or disallow them. The fix in this case is simple,
as up_b_offset has only one use, so we can replace the use with the
definition and get rid of up_b_offset.

 Link:https://github.com/ClangBuiltLinux/linux/issues/920

 Reviewed-by: Stefan Agner <stefan@agner.ch>

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Jian Cai <caij2003@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19T15:09:55+00:00 Thomas Gleixner tglx@linutronix.de 2019-06-04T08:11:33+00:00 d2912cb15bdda8ba4a5dd73396ad62641af2f520 Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 8843/1: use unified assembler in headers 2019-02-26T11:26:06+00:00 Stefan Agner stefan@agner.ch 2019-02-17T23:56:58+00:00 c001899a5d6c2d7a0f3b75b2307ddef137fb46a6 Use unified assembler syntax (UAL) in headers. Divided syntax is considered deprecated. This will also allow to build the kernel using LLVM's integrated assembler. Signed-off-by: Stefan Agner <stefan@agner.ch> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> 
Use unified assembler syntax (UAL) in headers. Divided syntax is
considered deprecated. This will also allow to build the kernel
using LLVM's integrated assembler.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
ARM: 8812/1: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS 2018-11-12T10:51:59+00:00 Vincent Whitchurch vincent.whitchurch@axis.com 2018-11-09T09:09:48+00:00 f441882a5229ffaef61a47bccd4518f7e2749cbc ARMv6+ processors do not use CONFIG_CPU_USE_DOMAINS and use privileged ldr/str instructions in copy_{from/to}_user. They are currently unnecessarily using single ldr/str instructions and can use ldm/stm instructions instead like memcpy does (but with appropriate fixup tables). This speeds up a "dd if=foo of=bar bs=32k" on a tmpfs filesystem by about 4% on my Cortex-A9. before:134217728 bytes (128.0MB) copied, 0.543848 seconds, 235.4MB/s before:134217728 bytes (128.0MB) copied, 0.538610 seconds, 237.6MB/s before:134217728 bytes (128.0MB) copied, 0.544356 seconds, 235.1MB/s before:134217728 bytes (128.0MB) copied, 0.544364 seconds, 235.1MB/s before:134217728 bytes (128.0MB) copied, 0.537130 seconds, 238.3MB/s before:134217728 bytes (128.0MB) copied, 0.533443 seconds, 240.0MB/s before:134217728 bytes (128.0MB) copied, 0.545691 seconds, 234.6MB/s before:134217728 bytes (128.0MB) copied, 0.534695 seconds, 239.4MB/s before:134217728 bytes (128.0MB) copied, 0.540561 seconds, 236.8MB/s before:134217728 bytes (128.0MB) copied, 0.541025 seconds, 236.6MB/s after:134217728 bytes (128.0MB) copied, 0.520445 seconds, 245.9MB/s after:134217728 bytes (128.0MB) copied, 0.527846 seconds, 242.5MB/s after:134217728 bytes (128.0MB) copied, 0.519510 seconds, 246.4MB/s after:134217728 bytes (128.0MB) copied, 0.527231 seconds, 242.8MB/s after:134217728 bytes (128.0MB) copied, 0.525030 seconds, 243.8MB/s after:134217728 bytes (128.0MB) copied, 0.524236 seconds, 244.2MB/s after:134217728 bytes (128.0MB) copied, 0.523659 seconds, 244.4MB/s after:134217728 bytes (128.0MB) copied, 0.525018 seconds, 243.8MB/s after:134217728 bytes (128.0MB) copied, 0.519249 seconds, 246.5MB/s after:134217728 bytes (128.0MB) copied, 0.518527 seconds, 246.9MB/s Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> 
ARMv6+ processors do not use CONFIG_CPU_USE_DOMAINS and use privileged
ldr/str instructions in copy_{from/to}_user.  They are currently
unnecessarily using single ldr/str instructions and can use ldm/stm
instructions instead like memcpy does (but with appropriate fixup
tables).

This speeds up a "dd if=foo of=bar bs=32k" on a tmpfs filesystem by
about 4% on my Cortex-A9.

before:134217728 bytes (128.0MB) copied, 0.543848 seconds, 235.4MB/s
before:134217728 bytes (128.0MB) copied, 0.538610 seconds, 237.6MB/s
before:134217728 bytes (128.0MB) copied, 0.544356 seconds, 235.1MB/s
before:134217728 bytes (128.0MB) copied, 0.544364 seconds, 235.1MB/s
before:134217728 bytes (128.0MB) copied, 0.537130 seconds, 238.3MB/s
before:134217728 bytes (128.0MB) copied, 0.533443 seconds, 240.0MB/s
before:134217728 bytes (128.0MB) copied, 0.545691 seconds, 234.6MB/s
before:134217728 bytes (128.0MB) copied, 0.534695 seconds, 239.4MB/s
before:134217728 bytes (128.0MB) copied, 0.540561 seconds, 236.8MB/s
before:134217728 bytes (128.0MB) copied, 0.541025 seconds, 236.6MB/s

 after:134217728 bytes (128.0MB) copied, 0.520445 seconds, 245.9MB/s
 after:134217728 bytes (128.0MB) copied, 0.527846 seconds, 242.5MB/s
 after:134217728 bytes (128.0MB) copied, 0.519510 seconds, 246.4MB/s
 after:134217728 bytes (128.0MB) copied, 0.527231 seconds, 242.8MB/s
 after:134217728 bytes (128.0MB) copied, 0.525030 seconds, 243.8MB/s
 after:134217728 bytes (128.0MB) copied, 0.524236 seconds, 244.2MB/s
 after:134217728 bytes (128.0MB) copied, 0.523659 seconds, 244.4MB/s
 after:134217728 bytes (128.0MB) copied, 0.525018 seconds, 243.8MB/s
 after:134217728 bytes (128.0MB) copied, 0.519249 seconds, 246.5MB/s
 after:134217728 bytes (128.0MB) copied, 0.518527 seconds, 246.9MB/s

Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Merge branches 'fixes', 'misc' and 'spectre' into for-next 2018-10-10T12:53:33+00:00 Russell King rmk+kernel@armlinux.org.uk 2018-10-10T12:53:33+00:00 3e98d240981a33290afc9435d01ec248e5880354 






ARM: 8796/1: spectre-v1,v1.1: provide helpers for address sanitization
2018-10-05T09:51:15+00:00

Julien Thierry
julien.thierry@arm.com

2018-09-11T09:14:50+00:00

afaf6838f4bc896a711180b702b388b8cfa638fc

Introduce C and asm helpers to sanitize user address, taking the
address range they target into account.

Use asm helper for existing sanitization in __copy_from_user().

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>





Introduce C and asm helpers to sanitize user address, taking the
address range they target into account.

Use asm helper for existing sanitization in __copy_from_user().

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>