2019-06-03 13:44:50 +08:00
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/* SPDX-License-Identifier: GPL-2.0-only */
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2014-04-28 13:11:34 +08:00
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/*
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2021-06-02 23:13:58 +08:00
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* Copyright (c) 2013-2021, Arm Limited.
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2014-04-28 13:11:34 +08:00
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*
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2021-05-27 23:34:43 +08:00
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* Adapted from the original at:
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2021-06-02 23:13:58 +08:00
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* https://github.com/ARM-software/optimized-routines/blob/98e4d6a5c13c8e54/string/aarch64/strlen.S
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2014-04-28 13:11:34 +08:00
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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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>
2021-07-12 17:00:43 +08:00
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#include <asm/mte-def.h>
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2014-04-28 13:11:34 +08:00
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2021-05-27 23:34:43 +08:00
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/* Assumptions:
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2014-04-28 13:11:34 +08:00
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*
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2021-05-27 23:34:43 +08:00
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* ARMv8-a, AArch64, unaligned accesses, min page size 4k.
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2014-04-28 13:11:34 +08:00
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*/
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2021-05-27 23:34:43 +08:00
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#define L(label) .L ## label
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2014-04-28 13:11:34 +08:00
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/* Arguments and results. */
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2021-05-27 23:34:43 +08:00
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#define srcin x0
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#define len x0
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2014-04-28 13:11:34 +08:00
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/* Locals and temporaries. */
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2021-05-27 23:34:43 +08:00
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#define src x1
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#define data1 x2
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#define data2 x3
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#define has_nul1 x4
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#define has_nul2 x5
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#define tmp1 x4
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#define tmp2 x5
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#define tmp3 x6
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#define tmp4 x7
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#define zeroones x8
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/* NUL detection works on the principle that (X - 1) & (~X) & 0x80
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(=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and
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can be done in parallel across the entire word. A faster check
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(X - 1) & 0x80 is zero for non-NUL ASCII characters, but gives
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false hits for characters 129..255. */
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2014-04-28 13:11:34 +08:00
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#define REP8_01 0x0101010101010101
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#define REP8_7f 0x7f7f7f7f7f7f7f7f
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#define REP8_80 0x8080808080808080
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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>
2021-07-12 17:00:43 +08:00
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/*
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* When KASAN_HW_TAGS is in use, memory is checked at MTE_GRANULE_SIZE
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* (16-byte) granularity, and we must ensure that no access straddles this
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* alignment boundary.
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*/
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#ifdef CONFIG_KASAN_HW_TAGS
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#define MIN_PAGE_SIZE MTE_GRANULE_SIZE
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#else
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2021-05-27 23:34:43 +08:00
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#define MIN_PAGE_SIZE 4096
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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>
2021-07-12 17:00:43 +08:00
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#endif
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2021-05-27 23:34:43 +08:00
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/* Since strings are short on average, we check the first 16 bytes
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of the string for a NUL character. In order to do an unaligned ldp
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safely we have to do a page cross check first. If there is a NUL
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byte we calculate the length from the 2 8-byte words using
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conditional select to reduce branch mispredictions (it is unlikely
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strlen will be repeatedly called on strings with the same length).
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If the string is longer than 16 bytes, we align src so don't need
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further page cross checks, and process 32 bytes per iteration
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using the fast NUL check. If we encounter non-ASCII characters,
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fallback to a second loop using the full NUL check.
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If the page cross check fails, we read 16 bytes from an aligned
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address, remove any characters before the string, and continue
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in the main loop using aligned loads. Since strings crossing a
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page in the first 16 bytes are rare (probability of
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16/MIN_PAGE_SIZE ~= 0.4%), this case does not need to be optimized.
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AArch64 systems have a minimum page size of 4k. We don't bother
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checking for larger page sizes - the cost of setting up the correct
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page size is just not worth the extra gain from a small reduction in
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the cases taking the slow path. Note that we only care about
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whether the first fetch, which may be misaligned, crosses a page
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boundary. */
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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>
2022-02-17 00:22:27 +08:00
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SYM_FUNC_START(__pi_strlen)
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2021-05-27 23:34:43 +08:00
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and tmp1, srcin, MIN_PAGE_SIZE - 1
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mov zeroones, REP8_01
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cmp tmp1, MIN_PAGE_SIZE - 16
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b.gt L(page_cross)
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ldp data1, data2, [srcin]
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#ifdef __AARCH64EB__
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/* For big-endian, carry propagation (if the final byte in the
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string is 0x01) means we cannot use has_nul1/2 directly.
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Since we expect strings to be small and early-exit,
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byte-swap the data now so has_null1/2 will be correct. */
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rev data1, data1
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rev data2, data2
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#endif
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2014-04-28 13:11:34 +08:00
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sub tmp1, data1, zeroones
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2021-05-27 23:34:43 +08:00
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orr tmp2, data1, REP8_7f
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2014-04-28 13:11:34 +08:00
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sub tmp3, data2, zeroones
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2021-05-27 23:34:43 +08:00
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orr tmp4, data2, REP8_7f
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bics has_nul1, tmp1, tmp2
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bic has_nul2, tmp3, tmp4
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ccmp has_nul2, 0, 0, eq
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beq L(main_loop_entry)
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/* Enter with C = has_nul1 == 0. */
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csel has_nul1, has_nul1, has_nul2, cc
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mov len, 8
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rev has_nul1, has_nul1
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clz tmp1, has_nul1
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csel len, xzr, len, cc
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add len, len, tmp1, lsr 3
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ret
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2014-04-28 13:11:34 +08:00
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2021-05-27 23:34:43 +08:00
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/* The inner loop processes 32 bytes per iteration and uses the fast
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NUL check. If we encounter non-ASCII characters, use a second
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loop with the accurate NUL check. */
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.p2align 4
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L(main_loop_entry):
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bic src, srcin, 15
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sub src, src, 16
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L(main_loop):
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ldp data1, data2, [src, 32]!
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L(page_cross_entry):
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sub tmp1, data1, zeroones
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sub tmp3, data2, zeroones
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orr tmp2, tmp1, tmp3
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tst tmp2, zeroones, lsl 7
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bne 1f
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ldp data1, data2, [src, 16]
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sub tmp1, data1, zeroones
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sub tmp3, data2, zeroones
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orr tmp2, tmp1, tmp3
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tst tmp2, zeroones, lsl 7
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beq L(main_loop)
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add src, src, 16
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1:
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/* The fast check failed, so do the slower, accurate NUL check. */
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orr tmp2, data1, REP8_7f
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orr tmp4, data2, REP8_7f
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bics has_nul1, tmp1, tmp2
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bic has_nul2, tmp3, tmp4
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ccmp has_nul2, 0, 0, eq
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beq L(nonascii_loop)
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|
|
|
|
/* Enter with C = has_nul1 == 0. */
|
|
|
|
L(tail):
|
|
|
|
#ifdef __AARCH64EB__
|
|
|
|
/* For big-endian, carry propagation (if the final byte in the
|
|
|
|
string is 0x01) means we cannot use has_nul1/2 directly. The
|
|
|
|
easiest way to get the correct byte is to byte-swap the data
|
|
|
|
and calculate the syndrome a second time. */
|
|
|
|
csel data1, data1, data2, cc
|
|
|
|
rev data1, data1
|
|
|
|
sub tmp1, data1, zeroones
|
|
|
|
orr tmp2, data1, REP8_7f
|
|
|
|
bic has_nul1, tmp1, tmp2
|
|
|
|
#else
|
|
|
|
csel has_nul1, has_nul1, has_nul2, cc
|
|
|
|
#endif
|
2014-04-28 13:11:34 +08:00
|
|
|
sub len, src, srcin
|
2021-05-27 23:34:43 +08:00
|
|
|
rev has_nul1, has_nul1
|
|
|
|
add tmp2, len, 8
|
|
|
|
clz tmp1, has_nul1
|
|
|
|
csel len, len, tmp2, cc
|
|
|
|
add len, len, tmp1, lsr 3
|
2014-04-28 13:11:34 +08:00
|
|
|
ret
|
|
|
|
|
2021-05-27 23:34:43 +08:00
|
|
|
L(nonascii_loop):
|
|
|
|
ldp data1, data2, [src, 16]!
|
|
|
|
sub tmp1, data1, zeroones
|
|
|
|
orr tmp2, data1, REP8_7f
|
|
|
|
sub tmp3, data2, zeroones
|
|
|
|
orr tmp4, data2, REP8_7f
|
|
|
|
bics has_nul1, tmp1, tmp2
|
|
|
|
bic has_nul2, tmp3, tmp4
|
|
|
|
ccmp has_nul2, 0, 0, eq
|
|
|
|
bne L(tail)
|
|
|
|
ldp data1, data2, [src, 16]!
|
|
|
|
sub tmp1, data1, zeroones
|
|
|
|
orr tmp2, data1, REP8_7f
|
|
|
|
sub tmp3, data2, zeroones
|
|
|
|
orr tmp4, data2, REP8_7f
|
|
|
|
bics has_nul1, tmp1, tmp2
|
|
|
|
bic has_nul2, tmp3, tmp4
|
|
|
|
ccmp has_nul2, 0, 0, eq
|
|
|
|
beq L(nonascii_loop)
|
|
|
|
b L(tail)
|
|
|
|
|
|
|
|
/* Load 16 bytes from [srcin & ~15] and force the bytes that precede
|
|
|
|
srcin to 0x7f, so we ignore any NUL bytes before the string.
|
|
|
|
Then continue in the aligned loop. */
|
|
|
|
L(page_cross):
|
|
|
|
bic src, srcin, 15
|
|
|
|
ldp data1, data2, [src]
|
|
|
|
lsl tmp1, srcin, 3
|
|
|
|
mov tmp4, -1
|
|
|
|
#ifdef __AARCH64EB__
|
|
|
|
/* Big-endian. Early bytes are at MSB. */
|
|
|
|
lsr tmp1, tmp4, tmp1 /* Shift (tmp1 & 63). */
|
|
|
|
#else
|
2014-04-28 13:11:34 +08:00
|
|
|
/* Little-endian. Early bytes are at LSB. */
|
2021-05-27 23:34:43 +08:00
|
|
|
lsl tmp1, tmp4, tmp1 /* Shift (tmp1 & 63). */
|
|
|
|
#endif
|
|
|
|
orr tmp1, tmp1, REP8_80
|
|
|
|
orn data1, data1, tmp1
|
|
|
|
orn tmp2, data2, tmp1
|
|
|
|
tst srcin, 8
|
|
|
|
csel data1, data1, tmp4, eq
|
|
|
|
csel data2, data2, tmp2, eq
|
|
|
|
b L(page_cross_entry)
|
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>
2022-02-17 00:22:27 +08:00
|
|
|
SYM_FUNC_END(__pi_strlen)
|
|
|
|
SYM_FUNC_ALIAS_WEAK(strlen, __pi_strlen)
|
2018-12-08 02:08:21 +08:00
|
|
|
EXPORT_SYMBOL_NOKASAN(strlen)
|