scripts/sorttable: Convert Elf_Ehdr to union

In order to remove the double #include of sorttable.h for 64 and 32 bit
to create duplicate functions for both, replace the Elf_Ehdr macro with a
union that defines both Elf64_Ehdr and Elf32_Ehdr, with field e64 for the
64bit version, and e32 for the 32bit version.

Then a macro etype can be used instead to get to the proper value.

This will eventually be replaced with just single functions that can
handle both 32bit and 64bit ELF parsing.

Cc: bpf <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nicolas Schier <[email protected]>
Cc: Zheng Yejian <[email protected]>
Cc: Martin  Kelly <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Steven Rostedt (Google) <[email protected]>

Author: rostedt

scripts/sorttable.c

@@ -64,6 +64,11 @@
 #define EM_LOONGARCH	258
 #endif
 
+typedef union {
+	Elf32_Ehdr	e32;
+	Elf64_Ehdr	e64;
+} Elf_Ehdr;
+
 static uint32_t (*r)(const uint32_t *);
 static uint16_t (*r2)(const uint16_t *);
 static uint64_t (*r8)(const uint64_t *);
@@ -266,10 +271,10 @@ static void sort_relative_table_with_data(char *extab_image, int image_size)
 static int do_file(char const *const fname, void *addr)
 {
 	int rc = -1;
-	Elf32_Ehdr *ehdr = addr;
+	Elf_Ehdr *ehdr = addr;
 	table_sort_t custom_sort = NULL;
 
-	switch (ehdr->e_ident[EI_DATA]) {
+	switch (ehdr->e32.e_ident[EI_DATA]) {
 	case ELFDATA2LSB:
 		r	= rle;
 		r2	= r2le;
@@ -284,18 +289,18 @@ static int do_file(char const *const fname, void *addr)
 		break;
 	default:
 		fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
-			ehdr->e_ident[EI_DATA], fname);
+			ehdr->e32.e_ident[EI_DATA], fname);
 		return -1;
 	}
 
-	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 ||
-	    (r2(&ehdr->e_type) != ET_EXEC && r2(&ehdr->e_type) != ET_DYN) ||
-	    ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
+	if (memcmp(ELFMAG, ehdr->e32.e_ident, SELFMAG) != 0 ||
+	    (r2(&ehdr->e32.e_type) != ET_EXEC && r2(&ehdr->e32.e_type) != ET_DYN) ||
+	    ehdr->e32.e_ident[EI_VERSION] != EV_CURRENT) {
 		fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file %s\n", fname);
 		return -1;
 	}
 
-	switch (r2(&ehdr->e_machine)) {
+	switch (r2(&ehdr->e32.e_machine)) {
 	case EM_386:
 	case EM_AARCH64:
 	case EM_LOONGARCH:
@@ -318,14 +323,14 @@ static int do_file(char const *const fname, void *addr)
 		break;
 	default:
 		fprintf(stderr, "unrecognized e_machine %d %s\n",
-			r2(&ehdr->e_machine), fname);
+			r2(&ehdr->e32.e_machine), fname);
 		return -1;
 	}
 
-	switch (ehdr->e_ident[EI_CLASS]) {
+	switch (ehdr->e32.e_ident[EI_CLASS]) {
 	case ELFCLASS32:
-		if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr) ||
-		    r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
+		if (r2(&ehdr->e32.e_ehsize) != sizeof(Elf32_Ehdr) ||
+		    r2(&ehdr->e32.e_shentsize) != sizeof(Elf32_Shdr)) {
 			fprintf(stderr,
 				"unrecognized ET_EXEC/ET_DYN file: %s\n", fname);
 			break;
@@ -334,20 +339,19 @@ static int do_file(char const *const fname, void *addr)
 		break;
 	case ELFCLASS64:
 		{
-		Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
-		if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr) ||
-		    r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
+		if (r2(&ehdr->e64.e_ehsize) != sizeof(Elf64_Ehdr) ||
+		    r2(&ehdr->e64.e_shentsize) != sizeof(Elf64_Shdr)) {
 			fprintf(stderr,
 				"unrecognized ET_EXEC/ET_DYN file: %s\n",
 				fname);
 			break;
 		}
-		rc = do_sort_64(ghdr, fname, custom_sort);
+		rc = do_sort_64(ehdr, fname, custom_sort);
 		}
 		break;
 	default:
 		fprintf(stderr, "unrecognized ELF class %d %s\n",
-			ehdr->e_ident[EI_CLASS], fname);
+			ehdr->e32.e_ident[EI_CLASS], fname);
 		break;
 	}
 

scripts/sorttable.h

@@ -23,12 +23,12 @@
 #undef sort_mcount_loc
 #undef elf_mcount_loc
 #undef do_sort
-#undef Elf_Ehdr
 #undef Elf_Shdr
 #undef Elf_Sym
 #undef ELF_ST_TYPE
 #undef uint_t
 #undef _r
+#undef etype
 
 #ifdef SORTTABLE_64
 # define extable_ent_size	16
@@ -37,25 +37,25 @@
 # define sort_mcount_loc	sort_mcount_loc_64
 # define elf_mcount_loc		elf_mcount_loc_64
 # define do_sort		do_sort_64
-# define Elf_Ehdr		Elf64_Ehdr
 # define Elf_Shdr		Elf64_Shdr
 # define Elf_Sym		Elf64_Sym
 # define ELF_ST_TYPE		ELF64_ST_TYPE
 # define uint_t			uint64_t
 # define _r			r8
+# define etype			e64
 #else
 # define extable_ent_size	8
 # define compare_extable	compare_extable_32
 # define get_mcount_loc		get_mcount_loc_32
 # define sort_mcount_loc	sort_mcount_loc_32
 # define elf_mcount_loc		elf_mcount_loc_32
 # define do_sort		do_sort_32
-# define Elf_Ehdr		Elf32_Ehdr
 # define Elf_Shdr		Elf32_Shdr
 # define Elf_Sym		Elf32_Sym
 # define ELF_ST_TYPE		ELF32_ST_TYPE
 # define uint_t			uint32_t
 # define _r			r
+# define etype			e32
 #endif
 
 #if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
@@ -222,7 +222,7 @@ static int do_sort(Elf_Ehdr *ehdr,
 		   table_sort_t custom_sort)
 {
 	int rc = -1;
-	Elf_Shdr *s, *shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
+	Elf_Shdr *s, *shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->etype.e_shoff));
 	Elf_Shdr *strtab_sec = NULL;
 	Elf_Shdr *symtab_sec = NULL;
 	Elf_Shdr *extab_sec = NULL;
@@ -249,12 +249,12 @@ static int do_sort(Elf_Ehdr *ehdr,
 	unsigned int orc_num_entries = 0;
 #endif
 
-	shstrndx = r2(&ehdr->e_shstrndx);
+	shstrndx = r2(&ehdr->etype.e_shstrndx);
 	if (shstrndx == SHN_XINDEX)
 		shstrndx = r(&shdr[0].sh_link);
 	secstrings = (const char *)ehdr + _r(&shdr[shstrndx].sh_offset);
 
-	shnum = r2(&ehdr->e_shnum);
+	shnum = r2(&ehdr->etype.e_shnum);
 	if (shnum == SHN_UNDEF)
 		shnum = _r(&shdr[0].sh_size);