arm64: clean up symbol aliasing

Now that we have SYM_FUNC_ALIAS() and SYM_FUNC_ALIAS_WEAK(), use those
to simplify and more consistently define function aliases across
arch/arm64.

Aliases are now defined in terms of a canonical function name. For
position-independent functions I've made the __pi_<func> name the
canonical name, and defined other alises in terms of this.

The SYM_FUNC_{START,END}_PI(func) macros obscure the __pi_<func> name,
and make this hard to seatch for. The SYM_FUNC_START_WEAK_PI() macro
also obscures the fact that the __pi_<func> fymbol is global and the
<func> symbol is weak. For clarity, I have removed these macros and used
SYM_FUNC_{START,END}() directly with the __pi_<func> name.

For example:

SYM_FUNC_START_WEAK_PI(func)
... asm insns ...
SYM_FUNC_END_PI(func)
EXPORT_SYMBOL(func)

... becomes:

SYM_FUNC_START(__pi_func)
... asm insns ...
SYM_FUNC_END(__pi_func)

SYM_FUNC_ALIAS_WEAK(func, __pi_func)
EXPORT_SYMBOL(func)

For clarity, where there are multiple annotations such as
EXPORT_SYMBOL(), I've tried to keep annotations grouped by symbol. For
example, where a function has a name and an alias which are both
exported, this is organised as:

SYM_FUNC_START(func)
... asm insns ...
SYM_FUNC_END(func)
EXPORT_SYMBOL(func)

SYM_FUNC_ALIAS(alias, func)
EXPORT_SYMBOL(alias)

For consistency with the other string functions, I've defined strrchr as
a position-independent function, as it can safely be used as such even
though we have no users today.

As we no longer use SYM_FUNC_{START,END}_ALIAS(), our local copies are
removed. The common versions will be removed by a subsequent patch.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220216162229.1076788-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: fix strlen() with CONFIG_KASAN_HW_TAGS

When the kernel is built with CONFIG_KASAN_HW_TAGS and the CPU supports
MTE, memory accesses are checked at 16-byte granularity, and
out-of-bounds accesses can result in tag check faults. Our current
implementation of strlen() makes unaligned 16-byte accesses (within a
naturally aligned 4096-byte window), and can trigger tag check faults.

This can be seen at boot time, e.g.

| BUG: KASAN: invalid-access in __pi_strlen+0x14/0x150
| Read at addr f4ff0000c0028300 by task swapper/0/0
| Pointer tag: [f4], memory tag: [fe]
|
| CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-09550-g03c2813535a2-dirty #20
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0x0/0x1b0
| show_stack+0x1c/0x30
| dump_stack_lvl+0x68/0x84
| print_address_description+0x7c/0x2b4
| kasan_report+0x138/0x38c
| __do_kernel_fault+0x190/0x1c4
| do_tag_check_fault+0x78/0x90
| do_mem_abort+0x44/0xb4
| el1_abort+0x40/0x60
| el1h_64_sync_handler+0xb0/0xd0
| el1h_64_sync+0x78/0x7c
| __pi_strlen+0x14/0x150
| __register_sysctl_table+0x7c4/0x890
| register_leaf_sysctl_tables+0x1a4/0x210
| register_leaf_sysctl_tables+0xc8/0x210
| __register_sysctl_paths+0x22c/0x290
| register_sysctl_table+0x2c/0x40
| sysctl_init+0x20/0x30
| proc_sys_init+0x3c/0x48
| proc_root_init+0x80/0x9c
| start_kernel+0x640/0x69c
| __primary_switched+0xc0/0xc8

To fix this, we can reduce the (strlen-internal) MIN_PAGE_SIZE to 16
bytes when CONFIG_KASAN_HW_TAGS is selected. This will cause strlen() to
align the base pointer downwards to a 16-byte boundary, and to discard
the additional prefix bytes without counting them. All subsequent
accesses will be 16-byte aligned 16-byte LDPs. While the comments say
the body of the loop will access 32 bytes, this is performed as two
16-byte acceses, with the second made only if the first did not
encounter a NUL byte, so the body of the loop will not over-read across
a 16-byte boundary.

No other string routines are affected. The other str*() routines will
not make any access which straddles a 16-byte boundary, and the mem*()
routines will only make acceses which straddle a 16-byte boundary when
which is entirely within the bounds of the relevant base and size
arguments.

Fixes: 325a1de81287 ("arm64: Import updated version of Cortex Strings' strlen")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Potapenko <glider@google.com
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20210712090043.20847-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: update string routine copyrights and URLs

To make future archaeology easier, let's have the string routine comment
blocks encode the specific upstream commit ID they were imported from.
These are the same commit IDs as listed in the commits importing the
code, expanded to 16 characters. Note that the routines have different
commit IDs, each reprsenting the latest upstream commit which changed
the particular routine.

At the same time, let's consistently include 2021 in the copyright
dates.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210602151358.35571-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Import updated version of Cortex Strings' strlen

Import an updated version of the former Cortex Strings - now Arm
Optimized Routines - strcmp function. The latest version introduces
Advanced SIMD usage which rules it out for our purposes, but we can
still pick an intermediate improvement from the previous version,
namely string/aarch64/strlen.S at commit 98e4d6a from
https://github.com/ARM-software/optimized-routines

Note that for simplicity Arm have chosen to contribute this code
to Linux under GPLv2 rather than the original MIT license.

Signed-off-by: Sam Tebbs <sam.tebbs@arm.com>
[ rm: update attribution and commit message ]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/32e3489398a24b23ae6e996935ac4818f8fd9dfd.1622128527.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arm64: lib: Use modern annotations for assembly functions

In an effort to clarify and simplify the annotation of assembly functions
in the kernel new macros have been introduced. These replace ENTRY and
ENDPROC and also add a new annotation for static functions which previously
had no ENTRY equivalent. Update the annotations in the library code to the
new macros.

Signed-off-by: Mark Brown <broonie@kernel.org>
[will: Use SYM_FUNC_START_WEAK_PI]
Signed-off-by: Will Deacon <will@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

Based on 1 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
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arm64: string: use asm EXPORT_SYMBOL()

For a while now it's been possible to use EXPORT_SYMBOL() in assembly
files, which allows us to place exports immediately after assembly
functions, as we do for C functions.

As a step towards removing arm64ksyms.c, let's move the string routine
exports to the assembly files the functions are defined in. Routines
which should only be exported for !KASAN builds are exported using the
EXPORT_SYMBOL_NOKASAN() helper.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: lib: use C string functions with KASAN enabled

ARM64 has asm implementation of memchr(), memcmp(), str[r]chr(),
str[n]cmp(), str[n]len(). KASAN don't see memory accesses in asm code,
thus it can potentially miss many bugs.

Ifdef out __HAVE_ARCH_* defines of these functions when KASAN is enabled,
so the generic implementations from lib/string.c will be used.

We can't just remove the asm functions because efistub uses them. And we
can't have two non-weak functions either, so declare the asm functions as
weak.

Link: http://lkml.kernel.org/r/20180920135631.23833-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arm64: use ENDPIPROC() to annotate position independent assembler routines

For more control over which functions are called with the MMU off or
with the UEFI 1:1 mapping active, annotate some assembler routines as
position independent. This is done by introducing ENDPIPROC(), which
replaces the ENDPROC() declaration of those routines.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: lib: Implement optimized string length routines

This patch, based on Linaro's Cortex Strings library, adds
an assembly optimized strlen() and strnlen() functions.

Signed-off-by: Zhichang Yuan <zhichang.yuan@linaro.org>
Signed-off-by: Deepak Saxena <dsaxena@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>