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233e667e1a
glibc-2.35 (upcoming release date 2022-02-01) exposes the rseq per-thread data in the TCB, accessible at an offset from the thread pointer, rather than through an actual Thread-Local Storage (TLS) variable, as the Linux kernel selftests initially expected. The __rseq_abi TLS and glibc-2.35's ABI for per-thread data cannot actively coexist in a process, because the kernel supports only a single rseq registration per thread. Here is the scheme introduced to ensure selftests can work both with an older glibc and with glibc-2.35+: - librseq exposes its own "rseq_offset, rseq_size, rseq_flags" ABI. - librseq queries for glibc rseq ABI (__rseq_offset, __rseq_size, __rseq_flags) using dlsym() in a librseq library constructor. If those are found, copy their values into rseq_offset, rseq_size, and rseq_flags. - Else, if those glibc symbols are not found, handle rseq registration from librseq and use its own IE-model TLS to implement the rseq ABI per-thread storage. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220124171253.22072-8-mathieu.desnoyers@efficios.com
39 lines
1.2 KiB
Makefile
39 lines
1.2 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0+ OR MIT
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ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
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CLANG_FLAGS += -no-integrated-as
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endif
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CFLAGS += -O2 -Wall -g -I./ -I../../../../usr/include/ -L$(OUTPUT) -Wl,-rpath=./ \
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$(CLANG_FLAGS)
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LDLIBS += -lpthread -ldl
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# Own dependencies because we only want to build against 1st prerequisite, but
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# still track changes to header files and depend on shared object.
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OVERRIDE_TARGETS = 1
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TEST_GEN_PROGS = basic_test basic_percpu_ops_test param_test \
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param_test_benchmark param_test_compare_twice
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TEST_GEN_PROGS_EXTENDED = librseq.so
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TEST_PROGS = run_param_test.sh
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TEST_FILES := settings
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include ../lib.mk
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$(OUTPUT)/librseq.so: rseq.c rseq.h rseq-*.h
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$(CC) $(CFLAGS) -shared -fPIC $< $(LDLIBS) -o $@
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$(OUTPUT)/%: %.c $(TEST_GEN_PROGS_EXTENDED) rseq.h rseq-*.h
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$(CC) $(CFLAGS) $< $(LDLIBS) -lrseq -o $@
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$(OUTPUT)/param_test_benchmark: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
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rseq.h rseq-*.h
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$(CC) $(CFLAGS) -DBENCHMARK $< $(LDLIBS) -lrseq -o $@
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$(OUTPUT)/param_test_compare_twice: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
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rseq.h rseq-*.h
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$(CC) $(CFLAGS) -DRSEQ_COMPARE_TWICE $< $(LDLIBS) -lrseq -o $@
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