kpatch-build: Support Clang/LLVM kernel builds and fix a call padding issue

kpatch-build/create-diff-object.c

@@ -479,97 +479,6 @@ static bool is_special_static(struct symbol *sym)
 	return false;
 }
 
-static bool has_digit_tail(char *tail)
-{
-	if (*tail != '.')
-		return false;
-
-	while (isdigit(*++tail))
-		;
-
-	if (!*tail)
-		return true;
-
-	return false;
-}
-
-/*
- * Hack for __UNIQUE_ID().  The following should match:
- *
- *   __UNIQUE_ID_ddebug1131.186
- *   __UNIQUE_ID_ddebug1132.187
- */
-static int __kpatch_unique_id_strcmp(char *s1, char *s2)
-{
-	/* match '__UNIQUE_ID_ddebug' */
-	while (*s1 == *s2) {
-		if (!*s1)
-			return 0;
-		s1++;
-		s2++;
-	}
-
-	/* skip digits before '.' or EOL */
-	while (isdigit(*s1))
-		s1++;
-	while (isdigit(*s2))
-		s2++;
-
-	if ((!*s1 || has_digit_tail(s1)) &&
-	    (!*s2 || has_digit_tail(s2)))
-		return 0;
-
-	return 1;
-}
-
-/*
- * This is like strcmp, but for gcc-mangled symbols.  It skips the comparison
- * of any substring which consists of '.' followed by any number of digits.
- */
-static int kpatch_mangled_strcmp(char *s1, char *s2)
-{
-	/*
-	 * ELF string sections aren't mangled, though they look that way.  Just
-	 * compare them normally.
-	 */
-	if (strstr(s1, ".str1."))
-		return strcmp(s1, s2);
-
-	if (!strncmp(s1, "__UNIQUE_ID_", 12))
-		return __kpatch_unique_id_strcmp(s1, s2);
-
-	/*
-	 * With LLVM, dynamic debug unique id looks like
-	 *   <func_name>.__UNIQUE_ID_ddebug<number>.
-	 *
-	 * Use __kpatch_unique_id_strcmp to compare them.
-	 */
-	if (strstr(s1, "__UNIQUE_ID_ddebug"))
-		return __kpatch_unique_id_strcmp(s1, s2);
-
-	while (*s1 == *s2) {
-		if (!*s1)
-			return 0;
-		if (*s1 == '.' && isdigit(s1[1])) {
-			if (!isdigit(s2[1]))
-				return 1;
-			while (isdigit(*++s1))
-				;
-			while (isdigit(*++s2))
-				;
-		} else {
-			s1++;
-			s2++;
-		}
-	}
-
-	if ((!*s1 && has_digit_tail(s2)) ||
-	    (!*s2 && has_digit_tail(s1)))
-		return 0;
-
-	return 1;
-}
-
 static bool rela_equal(struct rela *rela1, struct rela *rela2)
 {
 	struct rela *rela_toc1, *rela_toc2;
@@ -1399,7 +1308,8 @@ static bool kpatch_is_normal_static_local(struct symbol *sym)
 	if (sym->type != STT_OBJECT || sym->bind != STB_LOCAL)
 		return false;
 
-	if (!strncmp(sym->name, ".L", 2))
+	if (!strncmp(sym->name, ".L", 2) ||
+	    !strncmp(sym->name, ".compoundliteral", 16))
 		return false;
 
 	if (!strchr(sym->name, '.'))
@@ -3890,7 +3800,7 @@ static void kpatch_create_intermediate_sections(struct kpatch_elf *kelf,
 			ALLOC_LINK(rela2, &ksym_sec->rela->relas);
 			rela2->sym = strsym;
 			rela2->type = absolute_rela_type(kelf);
-			rela2->addend = offset_of_string(&kelf->strings, rela->sym->name);
+			rela2->addend = offset_of_string(&kelf->strings, symbol.name);
 			rela2->offset = (unsigned int)(index * sizeof(*ksyms) + \
 					offsetof(struct kpatch_symbol, name));
 
@@ -4169,14 +4079,13 @@ static void kpatch_create_ftrace_callsite_sections(struct kpatch_elf *kelf)
 				ERROR("malloc");
 			memcpy(newdata, sym->sec->data->d_buf, sym->sec->data->d_size);
 			sym->sec->data->d_buf = newdata;
-			insn = newdata;
+			insn = newdata + insn_offset;
 
 			/*
 			 * Replace the NOP with a call to fentry.  The fentry
 			 * rela symbol is already there, just need to change
 			 * the relocation type accordingly.
 			 */
-			insn = sym->sec->data->d_buf;
 			if (insn[0] != 0xf)
 				ERROR("%s: unexpected instruction at the start of the function", sym->name);
 			insn[0] = 0xe8;

kpatch-build/kpatch-build

@@ -55,6 +55,7 @@ SKIPCLEANUP=0
 SKIPCOMPILERCHECK=0
 ARCH_KCFLAGS=""
 DEBUG_KCFLAGS=""
+USER_KCFLAGS="${KCFLAGS:-}"
 declare -a PATCH_LIST
 APPLIED_PATCHES=0
 OOT_MODULE=
@@ -1343,7 +1344,7 @@ if [[ "$ARCH" = "loongarch64" ]]; then
 fi
 
 export KCFLAGS="-I$DATADIR/patch -ffunction-sections -fdata-sections \
-		$ARCH_KCFLAGS $DEBUG_KCFLAGS"
+		$ARCH_KCFLAGS $DEBUG_KCFLAGS${USER_KCFLAGS:+ $USER_KCFLAGS}"
 
 echo "Reading special section data"
 find_special_section_data
@@ -1361,6 +1362,9 @@ declare -a MAKEVARS
 if [[ -n "$CONFIG_CC_IS_CLANG" ]]; then
 	MAKEVARS+=("CC=${KPATCH_CC_PREFIX}${CLANG}")
 	MAKEVARS+=("HOSTCC=clang")
+	if [[ -n "$CONFIG_LD_IS_LLD" && -n "$CONFIG_AS_IS_LLVM" ]] && command -v llvm-objcopy &>/dev/null; then
+		MAKEVARS+=("LLVM=${LLVM:-1}")
+	fi
 else
 	MAKEVARS+=("CC=${KPATCH_CC_PREFIX}${GCC}")
 fi
@@ -1549,7 +1553,7 @@ do
 done
 echo
 
-export KCFLAGS="-I$DATADIR/patch $ARCH_KCFLAGS"
+export KCFLAGS="-I$DATADIR/patch $ARCH_KCFLAGS${USER_KCFLAGS:+ $USER_KCFLAGS}"
 if [[ "$USE_KLP" -eq 0 ]]; then
 	export KCPPFLAGS="-D__KPATCH_MODULE__"
 fi

kpatch-build/kpatch-elf.c

@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <err.h>
@@ -769,6 +770,98 @@ bool is_ubsan_sec(const char *name) {
 		return false;
 }
 
+static bool has_digit_tail(char *tail)
+{
+	if (*tail != '.')
+		return false;
+
+	while (isdigit((unsigned char)*++tail))
+		;
+
+	if (!*tail)
+		return true;
+
+	return false;
+}
+
+/*
+ * Hack for __UNIQUE_ID().  The following should match:
+ *
+ *   __UNIQUE_ID_ddebug1131.186
+ *   __UNIQUE_ID_ddebug1132.187
+ */
+static int __kpatch_unique_id_strcmp(char *s1, char *s2)
+{
+	/* match '__UNIQUE_ID_ddebug' */
+	while (*s1 == *s2) {
+		if (!*s1)
+			return 0;
+		s1++;
+		s2++;
+	}
+
+	/* skip digits before '.' or EOL */
+	while (isdigit((unsigned char)*s1))
+		s1++;
+	while (isdigit((unsigned char)*s2))
+		s2++;
+
+	if ((!*s1 || has_digit_tail(s1)) &&
+	    (!*s2 || has_digit_tail(s2)))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * This is like strcmp, but for gcc/clang-mangled symbols.  It skips the
+ * comparison of any substring which consists of '.' followed by any number of
+ * digits.
+ */
+int kpatch_mangled_strcmp(char *s1, char *s2)
+{
+	/*
+	 * ELF string sections aren't mangled, though they look that way.  Just
+	 * compare them normally.
+	 */
+	if (strstr(s1, ".str1."))
+		return strcmp(s1, s2);
+
+	if (!strncmp(s1, "__UNIQUE_ID_", 12))
+		return __kpatch_unique_id_strcmp(s1, s2);
+
+	/*
+	 * With LLVM, dynamic debug unique id looks like
+	 *   <func_name>.__UNIQUE_ID_ddebug<number>.
+	 *
+	 * Use __kpatch_unique_id_strcmp to compare them.
+	 */
+	if (strstr(s1, "__UNIQUE_ID_ddebug"))
+		return __kpatch_unique_id_strcmp(s1, s2);
+
+	while (*s1 == *s2) {
+		if (!*s1)
+			return 0;
+		if (*s1 == '.' && isdigit((unsigned char)s1[1])) {
+			if (!isdigit((unsigned char)s2[1]))
+				return 1;
+			while (isdigit((unsigned char)*++s1))
+				;
+			while (isdigit((unsigned char)*++s2))
+				;
+		} else {
+			s1++;
+			s2++;
+		}
+	}
+
+	if ((!*s1 && has_digit_tail(s2)) ||
+	    (!*s2 && has_digit_tail(s1)))
+		return 0;
+
+	return 1;
+}
+
 void print_strtab(char *buf, size_t size)
 {
 	size_t i;

kpatch-build/kpatch-elf.h

@@ -186,6 +186,7 @@ bool is_file_sym(struct symbol *sym);
 bool is_local_func_sym(struct symbol *sym);
 bool is_local_sym(struct symbol *sym);
 bool is_ubsan_sec(const char *name);
+int kpatch_mangled_strcmp(char *s1, char *s2);
 
 void print_strtab(char *buf, size_t size);
 void kpatch_create_shstrtab(struct kpatch_elf *kelf);