linux/include
Christophe Leroy 8fd4ddda2f static_call: Don't make __static_call_return0 static
System.map shows that vmlinux contains several instances of
__static_call_return0():

	c0004fc0 t __static_call_return0
	c0011518 t __static_call_return0
	c00d8160 t __static_call_return0

arch_static_call_transform() uses the middle one to check whether we are
setting a call to __static_call_return0 or not:

	c0011520 <arch_static_call_transform>:
	c0011520:       3d 20 c0 01     lis     r9,-16383	<== r9 =  0xc001 << 16
	c0011524:       39 29 15 18     addi    r9,r9,5400	<== r9 += 0x1518
	c0011528:       7c 05 48 00     cmpw    r5,r9		<== r9 has value 0xc0011518 here

So if static_call_update() is called with one of the other instances of
__static_call_return0(), arch_static_call_transform() won't recognise it.

In order to work properly, global single instance of __static_call_return0() is required.

Fixes: 3f2a8fc4b1 ("static_call/x86: Add __static_call_return0()")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/30821468a0e7d28251954b578e5051dc09300d04.1647258493.git.christophe.leroy@csgroup.eu
2022-04-05 09:59:38 +02:00
..
acpi Merge branches 'acpi-soc', 'acpi-video' and 'acpi-apei' 2022-03-18 17:48:55 +01:00
asm-generic ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
clocksource
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2022-03-21 16:02:36 -07:00
drm
dt-bindings RTC for 5.18 2022-04-01 09:37:18 -07:00
keys
kunit
kvm
linux static_call: Don't make __static_call_return0 static 2022-04-05 09:59:38 +02:00
math-emu
media
memory
misc
net Networking changes for 5.18. 2022-03-24 13:13:26 -07:00
pcmcia
ras mm/memory-failure.c: fix race with changing page compound again 2022-03-22 15:57:07 -07:00
rdma
scsi SCSI misc on 20220324 2022-03-24 19:37:53 -07:00
soc drm for 5.18-rc1 2022-03-24 16:19:43 -07:00
sound sound fixes for 5.18-rc1 2022-04-01 10:32:46 -07:00
target scsi: target: Add iscsi/cpus_allowed_list in configfs 2022-03-14 23:40:36 -04:00
trace Updates to Tracing: 2022-04-03 12:26:01 -07:00
uapi tracing: mark user_events as BROKEN 2022-04-02 10:32:14 -07:00
vdso
video
xen xen/grant-table: remove readonly parameter from functions 2022-03-15 20:34:40 -05:00