Linus Torvalds 4356e9f841 work around gcc bugs with 'asm goto' with outputs ... We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c323 ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. but the same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Andrew Pinski <quic_apinski@quicinc.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2024-02-09 15:57:48 -08:00
..
boot	powerpc/fsl: Fix fsl,tmu-calibration to match the schema	2023-12-19 21:53:56 +11:00
configs	Networking changes for 6.8.	2024-01-11 10:07:29 -08:00
crypto	crypto: p10-aes-gcm - Avoid -Wstringop-overflow warnings	2023-12-01 18:03:26 +08:00
include	work around gcc bugs with 'asm goto' with outputs	2024-02-09 15:57:48 -08:00
kernel	work around gcc bugs with 'asm goto' with outputs	2024-02-09 15:57:48 -08:00
kexec	Quite a lot of kexec work this time around. Many singleton patches in	2024-01-09 11:46:20 -08:00
kvm	Generic:	2024-01-17 13:03:37 -08:00
lib	powerpc/lib: Validate size for vector operations	2023-11-27 22:06:19 +11:00
math-emu
mm	Many singleton patches against the MM code. The patch series which	2024-01-09 11:18:47 -08:00
net	powerpc/bpf: use bpf_jit_binary_pack_[alloc|finalize|free]	2023-10-23 20:33:19 +11:00
perf	Performance events changes for v6.8 are:	2024-01-08 19:37:20 -08:00
platforms	TTY/Serial changes for 6.8-rc1	2024-01-18 11:37:24 -08:00
purgatory	powerpc/purgatory: remove PGO flags	2023-06-12 11:31:50 -07:00
sysdev	pci-v6.8-changes	2024-01-17 16:23:17 -08:00
tools	powerpc/tools: Pass -mabi=elfv2 to gcc-check-mprofile-kernel.sh	2023-10-20 17:46:33 +11:00
xmon	TTY/Serial driver changes for 6.6-rc1	2023-09-01 09:38:00 -07:00
Kbuild
Kconfig	powerpc fixes for 6.8 #2	2024-01-21 11:04:29 -08:00
Kconfig.debug	powerpc/ps3: move udbg_shutdown_ps3gelic prototype	2023-11-21 12:06:50 +11:00
Makefile	powerpc/Makefile: Auto detect cross compiler	2023-12-07 23:34:38 +11:00
Makefile.postlink	kbuild: remove ARCH_POSTLINK from module builds	2023-10-28 21:10:08 +09:00