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-rw-r--r--include/asm-generic/bug.h16
-rw-r--r--include/asm-generic/vmlinux.lds.h20
2 files changed, 35 insertions, 1 deletions
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 76a10e0dca9f..b402494883b6 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -241,6 +241,22 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
# define WARN_ON_SMP(x) ({0;})
#endif
+/*
+ * WARN_ON_FUNCTION_MISMATCH() warns if a value doesn't match a
+ * function address, and can be useful for catching issues with
+ * callback functions, for example.
+ *
+ * With CONFIG_CFI_CLANG, the warning is disabled because the
+ * compiler replaces function addresses taken in C code with
+ * local jump table addresses, which breaks cross-module function
+ * address equality.
+ */
+#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_MODULES)
+# define WARN_ON_FUNCTION_MISMATCH(x, fn) ({ 0; })
+#else
+# define WARN_ON_FUNCTION_MISMATCH(x, fn) WARN_ON_ONCE((x) != (fn))
+#endif
+
#endif /* __ASSEMBLY__ */
#endif
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 0331d5d49551..40a9c101565e 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -544,6 +544,22 @@
. = ALIGN((align)); \
__end_rodata = .;
+
+/*
+ * .text..L.cfi.jumptable.* contain Control-Flow Integrity (CFI)
+ * jump table entries.
+ */
+#ifdef CONFIG_CFI_CLANG
+#define TEXT_CFI_JT \
+ . = ALIGN(PMD_SIZE); \
+ __cfi_jt_start = .; \
+ *(.text..L.cfi.jumptable .text..L.cfi.jumptable.*) \
+ . = ALIGN(PMD_SIZE); \
+ __cfi_jt_end = .;
+#else
+#define TEXT_CFI_JT
+#endif
+
/*
* Non-instrumentable text section
*/
@@ -570,6 +586,7 @@
NOINSTR_TEXT \
*(.text..refcount) \
*(.ref.text) \
+ TEXT_CFI_JT \
MEM_KEEP(init.text*) \
MEM_KEEP(exit.text*) \
@@ -974,7 +991,8 @@
* keep any .init_array.* sections.
* https://bugs.llvm.org/show_bug.cgi?id=46478
*/
-#if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN)
+#if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN) || \
+ defined(CONFIG_CFI_CLANG)
# ifdef CONFIG_CONSTRUCTORS
# define SANITIZER_DISCARDS \
*(.eh_frame)

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