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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>
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Commit a0a12c3ed057 ("asm goto: eradicate CC_HAS_ASM_GOTO") eradicates
CC_HAS_ASM_GOTO, and in the process also causes the perf tool on x86 to
use asm_volatile_goto when compiling __GEN_RMWcc.
However, asm_volatile_goto is not declared in the perf tool headers,
which causes a compilation error:
In file included from tools/arch/x86/include/asm/atomic.h:7,
from tools/include/asm/atomic.h:6,
from tools/include/linux/atomic.h:5,
from tools/include/linux/refcount.h:41,
from tools/lib/perf/include/internal/cpumap.h:5,
from tools/perf/util/cpumap.h:7,
from tools/perf/util/env.h:7,
from tools/perf/util/header.h:12,
from pmu-events/pmu-events.c:9:
tools/arch/x86/include/asm/atomic.h: In function ‘atomic_dec_and_test’:
tools/arch/x86/include/asm/rmwcc.h:7:2: error: implicit declaration of function ‘asm_volatile_goto’ [-Werror=implicit-function-declaration]
asm_volatile_goto (fullop "; j" cc " %l[cc_label]" \
^~~~~~~~~~~~~~~~~
Define asm_volatile_goto in compiler_types.h if not declared, like the
main kernel header files do.
Fixes: a0a12c3ed057 ("asm goto: eradicate CC_HAS_ASM_GOTO")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch copies sparse context/locking annotations from
include/compiler-types.h to tools/include/compiler-types.h.
Committer notes:
This will be used in the upcoming workqueue patchset.
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http //lore.kernel.org/lkml/58b2f161ce856ec8b499f4dcf60a10adc84651e0.1627657061.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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As it'll be used by the ctype.h sync with its kernel source original.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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We're cherry picking stuff from the kernel to allow for the other
headers that we keep in sync via tools/perf/check-headers.sh to work,
so introduce linux/compiler_types.h and from there get the compiler
specific stuff.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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