kallsyms: Drop CONFIG_CFI_CLANG workarounds

With -fsanitize=kcfi, the compiler no longer renames static
functions with CONFIG_CFI_CLANG + ThinLTO. Drop the code that cleans
up the ThinLTO hash from the function names.

Signed-off-by: Sami Tolvanen <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Tested-by: Kees Cook <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: samitolvanen

kernel/kallsyms.c

@@ -159,30 +159,13 @@ static bool cleanup_symbol_name(char *s)
 	 * character in an identifier in C. Suffixes observed:
 	 * - foo.llvm.[0-9a-f]+
 	 * - foo.[0-9a-f]+
-	 * - foo.[0-9a-f]+.cfi_jt
 	 */
 	res = strchr(s, '.');
 	if (res) {
 		*res = '\0';
 		return true;
 	}
 
-	if (!IS_ENABLED(CONFIG_CFI_CLANG) ||
-	    !IS_ENABLED(CONFIG_LTO_CLANG_THIN) ||
-	    CONFIG_CLANG_VERSION >= 130000)
-		return false;
-
-	/*
-	 * Prior to LLVM 13, the following suffixes were observed when thinLTO
-	 * and CFI are both enabled:
-	 * - foo$[0-9]+
-	 */
-	res = strrchr(s, '$');
-	if (res) {
-		*res = '\0';
-		return true;
-	}
-
 	return false;
 }