[PATCH v2 0/7] linkage: better symbol aliasing

Mark Rutland
2022-01-25T11:34:50Z

This series aims to make symbol aliasing simpler and more consistent.
The basic idea is to replace SYM_FUNC_START_ALIAS(alias) and
SYM_FUNC_END_ALIAS(alias) with a new SYM_FUNC_ALIAS(alias, name), so
that e.g.

SYM_FUNC_START(func)
SYM_FUNC_START_ALIAS(alias1)
SYM_FUNC_START_ALIAS(alias2)
... asm insns ...
SYM_FUNC_END(func)
SYM_FUNC_END_ALIAS(alias1)
SYM_FUNC_END_ALIAS(alias2)
EXPORT_SYMBOL(alias1)
EXPORT_SYMBOL(alias2)

... can become:

SYM_FUNC_START(name)
... asm insns ...
SYM_FUNC_END(name)

SYM_FUNC_ALIAS(alias1, func)
EXPORT_SYMBOL(alias1)

SYM_FUNC_ALIAS(alias2, func)
EXPORT_SYMBOL(alias2)

This avoids repetition and hopefully make it easier to ensure
consistency (e.g. so each function has a single canonical name and
associated metadata).

I've build+boot tested arm64 defconfig without issues, and also build
tested arm/i386/x86_64 defconfig without issues. I've pushed the series
to my `linkage/alias-rework` branch on git.kernel.org, atop v5.17-rc1:

git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git linkage/alias-rework
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=linkage/alias-rework

Since RFCv1 [1]:
* Drop arm64 dma alias removal (taken via arm64 for v5.17)
* Rename SYM_FUNC_LOCAL_ALIAS() -> SYM_FUNC_ALIAS_LOCAL()
* Update the tools/ copies of x86 routines
* Add preparatory fix for 32-bit arm
* Rebase to v5.17-rc1

[1] https://lore.kernel.org/r/20211206124715.4101571-1-mark.rutland@arm.com/

Thanks,
Mark.

Mark Rutland (7):
arm: lib: remove leading whitespace in bitop macro
linkage: add SYM_{ENTRY,START,END}_AT()
linkage: add SYM_FUNC_ALIAS{,_LOCAL,_WEAK}()
arm64: clean up symbol aliasing
x86: clean up symbol aliasing
linkage: remove SYM_FUNC_{START,END}_ALIAS()
tools: update x86 string routines

Documentation/asm-annotations.rst | 11 ++--
arch/arm/lib/bitops.h | 8 +--
arch/arm64/include/asm/linkage.h | 24 -------
arch/arm64/kvm/hyp/nvhe/cache.S | 5 +-
arch/arm64/lib/clear_page.S | 5 +-
arch/arm64/lib/copy_page.S | 5 +-
arch/arm64/lib/memchr.S | 5 +-
arch/arm64/lib/memcmp.S | 6 +-
arch/arm64/lib/memcpy.S | 21 +++---
arch/arm64/lib/memset.S | 12 ++--
arch/arm64/lib/strchr.S | 6 +-
arch/arm64/lib/strcmp.S | 6 +-
arch/arm64/lib/strlen.S | 6 +-
arch/arm64/lib/strncmp.S | 6 +-
arch/arm64/lib/strnlen.S | 6 +-
arch/arm64/lib/strrchr.S | 5 +-
arch/arm64/mm/cache.S | 35 ++++++----
arch/x86/boot/compressed/head_32.S | 3 +-
arch/x86/boot/compressed/head_64.S | 3 +-
arch/x86/crypto/aesni-intel_asm.S | 4 +-
arch/x86/lib/memcpy_64.S | 10 +--
arch/x86/lib/memmove_64.S | 4 +-
arch/x86/lib/memset_64.S | 6 +-
include/linux/linkage.h | 87 +++++++++++++++----------
tools/arch/x86/lib/memcpy_64.S | 10 +--
tools/arch/x86/lib/memset_64.S | 6 +-
tools/perf/util/include/linux/linkage.h | 80 +++++++++++++++--------
27 files changed, 209 insertions(+), 176 deletions(-)

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2.30.2