Compiler and tooling-generated symbols are difficult to maintain across all supported architectures. Make the allowlist more robust by replacing the harcoded list with a mechanism that automatically detects these symbols.
This mechanism generates a C function designed to trigger common compiler-inserted symbols. Signed-off-by: Vincent Donnefort <[email protected]> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index beb15936829d..3b427b76434a 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -136,17 +136,37 @@ obj-$(CONFIG_TRACE_REMOTE_TEST) += remote_test.o # simple_ring_buffer is used by the pKVM hypervisor which does not have access # to all kernel symbols. Fail the build if forbidden symbols are found. # -UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __gcov __aeabi_unwind -UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer llvm_gcda llvm_gcov -UNDEFINED_ALLOWLIST += .TOC\. __clear_pages_unrolled __memmove copy_page warn_slowpath_fmt -UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory -UNDEFINED_ALLOWLIST += warn_bogus_irq_restore __stack_chk_guard -UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST)) +# undefsyms_base generates a set of compiler and tooling-generated symbols that can +# safely be ignored for simple_ring_buffer. +# +$(obj)/undefsyms_base.c: FORCE + $(Q)echo '#include <asm/page.h>' > $@ + $(Q)echo '#include <asm/local.h>' >> $@ + $(Q)echo 'static char page[PAGE_SIZE] __aligned(PAGE_SIZE);' >> $@ + $(Q)echo 'void undefsyms_base(int n);' >> $@ + $(Q)echo 'void undefsyms_base(int n) {' >> $@ + $(Q)echo ' char buffer[256] = { 0 };' >> $@ + $(Q)echo ' u32 u = 0;' >> $@ + $(Q)echo ' memset((char * volatile)page, 8, PAGE_SIZE);' >> $@ + $(Q)echo ' memset((char * volatile)buffer, 8, sizeof(buffer));' >> $@ + $(Q)echo ' cmpxchg((u32 * volatile)&u, 0, 8);' >> $@ + $(Q)echo ' WARN_ON(n == 0xdeadbeef);' >> $@ + $(Q)echo '}' >> $@ + +clean-files += undefsyms_base.c +targets += undefsyms_base.c + +$(obj)/undefsyms_base.o: $(obj)/undefsyms_base.c + +extra-y += undefsyms_base.o + +UNDEFINED_ALLOWLIST = __asan __gcov __kasan __kcsan __hwasan __sanitizer __tsan __ubsan __x86_indirect_thunk \ + $(shell $(NM) -u $(obj)/undefsyms_base.o 2>/dev/null | awk '{print $$2}') quiet_cmd_check_undefined = NM $< - cmd_check_undefined = test -z "`$(NM) -u $< | grep -v $(UNDEFINED_ALLOWLIST)`" + cmd_check_undefined = test -z "`$(NM) -u $< | grep -v $(addprefix -e ,$(UNDEFINED_ALLOWLIST))`" -$(obj)/%.o.checked: $(obj)/%.o FORCE +$(obj)/%.o.checked: $(obj)/%.o $(obj)/undefsyms_base.o FORCE $(call if_changed,check_undefined) always-$(CONFIG_SIMPLE_RING_BUFFER) += simple_ring_buffer.o.checked base-commit: 33f2e266515717c4b2df585dadefa0525557726c -- 2.53.0.851.ga537e3e6e9-goog
