linux/include
Ard Biesheuvel 951bcae6c5 kallsyms: Avoid weak references for kallsyms symbols
kallsyms is a directory of all the symbols in the vmlinux binary, and so
creating it is somewhat of a chicken-and-egg problem, as its non-zero
size affects the layout of the binary, and therefore the values of the
symbols.

For this reason, the kernel is linked more than once, and the first pass
does not include any kallsyms data at all. For the linker to accept
this, the symbol declarations describing the kallsyms metadata are
emitted as having weak linkage, so they can remain unsatisfied. During
the subsequent passes, the weak references are satisfied by the kallsyms
metadata that was constructed based on information gathered from the
preceding passes.

Weak references lead to somewhat worse codegen, because taking their
address may need to produce NULL (if the reference was unsatisfied), and
this is not usually supported by RIP or PC relative symbol references.

Given that these references are ultimately always satisfied in the final
link, let's drop the weak annotation, and instead, provide fallback
definitions in the linker script that are only emitted if an unsatisfied
reference exists.

While at it, drop the FRV specific annotation that these symbols reside
in .rodata - FRV is long gone.

Tested-by: Nick Desaulniers <ndesaulniers@google.com> # Boot
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lkml.kernel.org/r/20230504174320.3930345-1-ardb%40kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-05-02 19:48:26 +09:00
..
acpi ACPI: bus: allow _UID matching for integer zero 2024-04-08 16:57:51 +02:00
asm-generic kallsyms: Avoid weak references for kallsyms symbols 2024-05-02 19:48:26 +09:00
clocksource
crypto This update includes the following changes: 2024-03-15 14:46:54 -07:00
drm drm fixes for 6.9-rc1 2024-03-21 19:04:31 -07:00
dt-bindings Char/Misc and other driver subsystem updates for 6.9-rc1 2024-03-21 13:21:31 -07:00
keys
kunit
kvm KVM: arm64: Fix host-programmed guest events in nVHE 2024-03-26 01:51:44 -07:00
linux Char/Misc driver fixes for 6.9-rc5 2024-04-21 10:32:58 -07:00
math-emu
media media updates for v6.9-rc1 2024-03-15 11:36:54 -07:00
memory
misc
net net/sched: Fix mirred deadlock on device recursion 2024-04-17 18:22:52 -07:00
pcmcia
ras
rdma
rv
scsi scsi: sd: Fix TCG OPAL unlock on system resume 2024-03-25 15:46:12 -04:00
soc Char/Misc and other driver subsystem updates for 6.9-rc1 2024-03-21 13:21:31 -07:00
sound ASoC: Fixes for v6.9 2024-04-05 08:48:12 +02:00
target
trace nfsd-6.9 fixes: 2024-04-15 14:09:47 -07:00
uapi vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE 2024-04-08 04:11:04 -04:00
ufs
vdso vdso: Use CONFIG_PAGE_SHIFT in vdso/datapage.h 2024-04-03 21:50:04 +02:00
video
xen