sys: use globals for the ELF kernel and module type strings

Initialize the globals with macros so we can use the same values in the
loader.

Also remove unnecessary "elfN module" checks.

Reviewed by: imp, kib
Pull Request: https://github.com/freebsd/freebsd-src/pull/1394

sys/arm/arm/machdep_boot.c

@@ -356,12 +356,12 @@ fake_preload_metadata(struct arm_boot_params *abp __unused, void *dtb_ptr,
 
 	fake_preload[i++] = MODINFO_NAME;
 	fake_preload[i++] = strlen("kernel") + 1;
-	strcpy((char*)&fake_preload[i++], "kernel");
+	strcpy((char *)&fake_preload[i++], "kernel");
 	i += 1;
 	fake_preload[i++] = MODINFO_TYPE;
-	fake_preload[i++] = strlen("elf kernel") + 1;
-	strcpy((char*)&fake_preload[i++], "elf kernel");
-	i += 2;
+	fake_preload[i++] = strlen(preload_kerntype) + 1;
+	strcpy((char *)&fake_preload[i], preload_kerntype);
+	i += howmany(fake_preload[i - 1], sizeof(uint32_t));
 	fake_preload[i++] = MODINFO_ADDR;
 	fake_preload[i++] = sizeof(vm_offset_t);
 	fake_preload[i++] = KERNVIRTADDR;

sys/arm64/arm64/machdep_boot.c

@@ -98,7 +98,7 @@ fake_preload_metadata(void *dtb_ptr, size_t dtb_size)
 	PRELOAD_PUSH_STRING("kernel");
 
 	PRELOAD_PUSH_VALUE(uint32_t, MODINFO_TYPE);
-	PRELOAD_PUSH_STRING("elf kernel");
+	PRELOAD_PUSH_STRING(preload_kerntype);
 
 	PRELOAD_PUSH_VALUE(uint32_t, MODINFO_ADDR);
 	PRELOAD_PUSH_VALUE(uint32_t, sizeof(vm_offset_t));

sys/kern/link_elf.c

@@ -895,9 +895,7 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 	dynptr = preload_search_info(modptr,
 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
-	if (type == NULL ||
-	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
-	     strcmp(type, "elf module") != 0))
+	if (type == NULL || strcmp(type, preload_modtype) != 0)
 		return (EFTYPE);
 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
 		return (EINVAL);

sys/kern/link_elf_obj.c

@@ -365,11 +365,8 @@ link_elf_link_preload(linker_class_t cls, const char *filename,
 	    MODINFOMD_ELFHDR);
 	shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 	    MODINFOMD_SHDR);
-	if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
-	    " obj module") != 0 &&
-	    strcmp(type, "elf obj module") != 0)) {
+	if (type == NULL || strcmp(type, preload_modtype_obj) != 0)
 		return (EFTYPE);
-	}
 	if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 	    shdr == NULL)
 		return (EINVAL);

sys/kern/subr_module.c

@@ -46,10 +46,14 @@
 vm_offset_t preload_addr_relocate = 0;
 caddr_t preload_metadata, preload_kmdp;
 
+const char preload_modtype[] = MODTYPE;
+const char preload_kerntype[] = KERNTYPE;
+const char preload_modtype_obj[] = MODTYPE_OBJ;
+
 void
 preload_initkmdp(bool fatal)
 {
-	preload_kmdp = preload_search_by_type("elf kernel");
+	preload_kmdp = preload_search_by_type(preload_kerntype);
 
 	if (preload_kmdp == NULL && fatal)
 		panic("unable to find kernel metadata");

sys/powerpc/powerpc/machdep.c

@@ -644,15 +644,14 @@ fake_preload_metadata(void) {
 
 	fake_preload[i++] = MODINFO_NAME;
 	fake_preload[i++] = strlen("kernel") + 1;
-	strcpy((char*)&fake_preload[i], "kernel");
+	strcpy((char *)&fake_preload[i], "kernel");
 	/* ['k' 'e' 'r' 'n'] ['e' 'l' '\0' ..] */
 	i += 2;
 
 	fake_preload[i++] = MODINFO_TYPE;
-	fake_preload[i++] = strlen("elf kernel") + 1;
-	strcpy((char*)&fake_preload[i], "elf kernel");
-	/* ['e' 'l' 'f' ' '] ['k' 'e' 'r' 'n'] ['e' 'l' '\0' ..] */
-	i += 3;
+	fake_preload[i++] = strlen(preload_kerntype) + 1;
+	strcpy((char *)&fake_preload[i], preload_kerntype);
+	i += howmany(fake_preload[i - 1], sizeof(uint32_t));
 
 #ifdef __powerpc64__
 	/* Padding -- Fields start on u_long boundaries */

sys/riscv/riscv/machdep.c

@@ -365,7 +365,7 @@ fake_preload_metadata(struct riscv_bootparams *rvbp)
 	PRELOAD_PUSH_VALUE(uint32_t, MODINFO_NAME);
 	PRELOAD_PUSH_STRING("kernel");
 	PRELOAD_PUSH_VALUE(uint32_t, MODINFO_TYPE);
-	PRELOAD_PUSH_STRING("elf kernel");
+	PRELOAD_PUSH_STRING(preload_kerntype);
 
 	PRELOAD_PUSH_VALUE(uint32_t, MODINFO_ADDR);
 	PRELOAD_PUSH_VALUE(uint32_t, sizeof(vm_offset_t));

sys/sys/linker.h

@@ -220,6 +220,14 @@ void linker_kldload_unbusy(int flags);
 
 #endif	/* _KERNEL */
 
+/*
+ * ELF file types
+ */
+#define KERNTYPE_MB	"elf multiboot kernel"
+#define KERNTYPE	"elf kernel"
+#define MODTYPE_OBJ	"elf obj module"
+#define MODTYPE		"elf module"
+
 /*
  * Module information subtypes
  */
@@ -273,6 +281,9 @@ void linker_kldload_unbusy(int flags);
  */
 extern vm_offset_t	preload_addr_relocate;
 extern caddr_t		preload_metadata, preload_kmdp;
+extern const char	preload_modtype[];
+extern const char	preload_kerntype[];
+extern const char	preload_modtype_obj[];
 
 extern void *		preload_fetch_addr(caddr_t _mod);
 extern size_t		preload_fetch_size(caddr_t _mod);