kernel/linux.git/arch/xtensa/include/asm/jump_label.h, branch v6.19.5Linux kernel stable tree (mirror)https://git.radix-linux.su/kernel/linux.git/atom?h=v6.19.52025-06-06T08:03:35+00:00xtensa: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-uapi headers2025-06-06T08:03:35+00:00Thomas Huththuth@redhat.com2025-03-14T07:10:10+00:00urn:sha1:44a4ef59d5506c6dc7599d876a3a1014697ec480
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with uapi headers that
rather should use __ASSEMBLER__ instead. So let's standardize on
the __ASSEMBLER__ macro that is provided by the compilers now.
This is a completely mechanical patch (done with a simple "sed -i"
statement).
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20250314071013.1575167-40-thuth@redhat.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
work around gcc bugs with 'asm goto' with outputs2024-02-09T23:57:48+00:00Linus Torvaldstorvalds@linux-foundation.org2024-02-09T20:39:31+00:00urn:sha1:4356e9f841f7fbb945521cef3577ba394c65f3fc
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
3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f53 ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").
Then, much later, we ended up removing the workaround in commit
43c249ea0b1e ("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>
xtensa: implement jump_label support2018-12-20T22:44:38+00:00Max Filippovjcmvbkbc@gmail.com2018-12-20T03:48:37+00:00urn:sha1:64711f9a47d4defa90417f5e8db8ed0060bc3275
Use 3-byte 'nop' and 'j' instructions that are always present. Don't let
assembler mark a spot right after patchable 'j' instruction as
unreachable and later put literals or padding bytes there. Add separate
implementations of patch_text for SMP and UP cases, avoiding use of
atomics on UP.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>