a.out: Remove the a.out implementation

In commit 19e8b701 ("a.out: Stop building a.out/osf1 support on
alpha and m68k") the last users of a.out were disabled.

As nothing has turned up to cause this change to be reverted, let's
remove the code implementing a.out support as well.

There may be userspace users of the uapi bits left so the uapi
headers have been left untouched.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> # arm defconfigs
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/871qrx3hq3.fsf@email.froward.int.ebiederm.org

MAINTAINERS

@@ -7685,7 +7685,6 @@ R:	Kees Cook <keescook@chromium.org>
 L:	linux-mm@kvack.org
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/execve
-F:	arch/alpha/kernel/binfmt_loader.c
 F:	fs/*binfmt_*.c
 F:	fs/exec.c
 F:	include/linux/binfmts.h

arch/alpha/include/asm/a.out.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __ALPHA_A_OUT_H__
-#define __ALPHA_A_OUT_H__
-
-#include <uapi/asm/a.out.h>
-
-
-/* Assume that start addresses below 4G belong to a TASO application.
-   Unfortunately, there is no proper bit in the exec header to check.
-   Worse, we have to notice the start address before swapping to use
-   /sbin/loader, which of course is _not_ a TASO application.  */
-#define SET_AOUT_PERSONALITY(BFPM, EX) \
-	set_personality (((BFPM->taso || EX.ah.entry < 0x100000000L \
-			   ? ADDR_LIMIT_32BIT : 0) | PER_OSF4))
-
-#endif /* __A_OUT_GNU_H__ */

arch/alpha/kernel/Makefile

@@ -47,10 +47,6 @@ else
 # Misc support
 obj-$(CONFIG_ALPHA_SRM)		+= srmcons.o
 
-ifdef CONFIG_BINFMT_AOUT
-obj-y	+= binfmt_loader.o
-endif
-
 # Core logic support
 obj-$(CONFIG_ALPHA_APECS)	+= core_apecs.o
 obj-$(CONFIG_ALPHA_CIA)		+= core_cia.o

arch/alpha/kernel/binfmt_loader.c

-// SPDX-License-Identifier: GPL-2.0
-#include <linux/init.h>
-#include <linux/fs.h>
-#include <linux/file.h>
-#include <linux/mm_types.h>
-#include <linux/binfmts.h>
-#include <linux/a.out.h>
-
-static int load_binary(struct linux_binprm *bprm)
-{
-	struct exec *eh = (struct exec *)bprm->buf;
-	unsigned long loader;
-	struct file *file;
-	int retval;
-
-	if (eh->fh.f_magic != 0x183 || (eh->fh.f_flags & 0x3000) != 0x3000)
-		return -ENOEXEC;
-
-	if (bprm->loader)
-		return -ENOEXEC;
-
-	loader = bprm->vma->vm_end - sizeof(void *);
-
-	file = open_exec("/sbin/loader");
-	retval = PTR_ERR(file);
-	if (IS_ERR(file))
-		return retval;
-
-	/* Remember if the application is TASO.  */
-	bprm->taso = eh->ah.entry < 0x100000000UL;
-
-	bprm->interpreter = file;
-	bprm->loader = loader;
-	return 0;
-}
-
-static struct linux_binfmt loader_format = {
-	.load_binary	= load_binary,
-};
-
-static int __init init_loader_binfmt(void)
-{
-	insert_binfmt(&loader_format);
-	return 0;
-}
-arch_initcall(init_loader_binfmt);

arch/alpha/kernel/osf_sys.c

@@ -1278,45 +1278,15 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	return addr;
 }
 
-#ifdef CONFIG_OSF4_COMPAT
-/* Clear top 32 bits of iov_len in the user's buffer for
-   compatibility with old versions of OSF/1 where iov_len
-   was defined as int. */
-static int
-osf_fix_iov_len(const struct iovec __user *iov, unsigned long count)
-{
-	unsigned long i;
-
-	for (i = 0 ; i < count ; i++) {
-		int __user *iov_len_high = (int __user *)&iov[i].iov_len + 1;
-
-		if (put_user(0, iov_len_high))
-			return -EFAULT;
-	}
-	return 0;
-}
-#endif
-
 SYSCALL_DEFINE3(osf_readv, unsigned long, fd,
 		const struct iovec __user *, vector, unsigned long, count)
 {
-#ifdef CONFIG_OSF4_COMPAT
-	if (unlikely(personality(current->personality) == PER_OSF4))
-		if (osf_fix_iov_len(vector, count))
-			return -EFAULT;
-#endif
-
 	return sys_readv(fd, vector, count);
 }
 
 SYSCALL_DEFINE3(osf_writev, unsigned long, fd,
 		const struct iovec __user *, vector, unsigned long, count)
 {
-#ifdef CONFIG_OSF4_COMPAT
-	if (unlikely(personality(current->personality) == PER_OSF4))
-		if (osf_fix_iov_len(vector, count))
-			return -EFAULT;
-#endif
 	return sys_writev(fd, vector, count);
 }
 

arch/arm/configs/badge4_defconfig

@@ -6,7 +6,6 @@ CONFIG_UNUSED_BOARD_FILES=y
 CONFIG_CMDLINE="init=/linuxrc root=/dev/mtdblock3"
 CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=m
 CONFIG_MODULES=y
 CONFIG_MODVERSIONS=y
 CONFIG_PARTITION_ADVANCED=y

arch/arm/configs/corgi_defconfig

@@ -16,7 +16,6 @@ CONFIG_MACH_HUSKY=y
 CONFIG_UNUSED_BOARD_FILES=y
 CONFIG_CMDLINE="console=ttyS0,115200n8 console=tty1 noinitrd root=/dev/mtdblock2 rootfstype=jffs2   debug"
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=m
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y

arch/arm/configs/ezx_defconfig

@@ -25,7 +25,6 @@ CONFIG_CPU_FREQ_GOV_ONDEMAND=m
 CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m
 CONFIG_CPU_IDLE=y
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=m
 CONFIG_PM=y
 CONFIG_APM_EMULATION=y
 CONFIG_MODULES=y

arch/arm/configs/footbridge_defconfig

@@ -9,7 +9,6 @@ CONFIG_ARCH_EBSA285_HOST=y
 CONFIG_ARCH_NETWINDER=y
 CONFIG_FPE_NWFPE=y
 CONFIG_FPE_NWFPE_XP=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_MODULES=y
 CONFIG_PARTITION_ADVANCED=y
 CONFIG_ACORN_PARTITION=y

arch/arm/configs/hackkit_defconfig

@@ -7,7 +7,6 @@ CONFIG_UNUSED_BOARD_FILES=y
 CONFIG_CMDLINE="console=ttySA0,115200 root=/dev/ram0 initrd=0xc0400000,8M init=/rootshell"
 CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_MODULES=y
 CONFIG_NET=y
 CONFIG_PACKET=y

arch/arm/configs/iop32x_defconfig

@@ -12,7 +12,6 @@ CONFIG_MACH_N2100=y
 CONFIG_UNUSED_BOARD_FILES=y
 CONFIG_CMDLINE="console=ttyS0,115200 root=/dev/nfs ip=bootp cachepolicy=writealloc"
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_PARTITION_ADVANCED=y

arch/arm/configs/jornada720_defconfig

@@ -6,7 +6,6 @@ CONFIG_SA1100_JORNADA720=y
 CONFIG_SA1100_JORNADA720_SSP=y
 CONFIG_UNUSED_BOARD_FILES=y
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_PM=y
 CONFIG_MODULES=y
 CONFIG_NET=y

arch/arm/configs/lart_defconfig

@@ -8,7 +8,6 @@ CONFIG_CMDLINE="console=ttySA0,9600 root=/dev/ram"
 CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
 CONFIG_CPU_FREQ_GOV_USERSPACE=y
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_PM=y
 CONFIG_MODULES=y
 CONFIG_NET=y

arch/arm/configs/neponset_defconfig

@@ -9,7 +9,6 @@ CONFIG_ZBOOT_ROM_BSS=0xc1000000
 CONFIG_ZBOOT_ROM=y
 CONFIG_CMDLINE="console=ttySA0,38400n8 cpufreq=221200 rw root=/dev/mtdblock2 mtdparts=sa1100:512K(boot),1M(kernel),2560K(initrd),4M(root) load_ramdisk=1 prompt_ramdisk=0 mem=32M noinitrd initrd=0xc0800000,3M"
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_PM=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y

arch/arm/configs/netwinder_defconfig

@@ -5,7 +5,6 @@ CONFIG_ARCH_NETWINDER=y
 CONFIG_DEPRECATED_PARAM_STRUCT=y
 CONFIG_CMDLINE="root=0x801"
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_PARTITION_ADVANCED=y
 CONFIG_NET=y
 CONFIG_PACKET=y

arch/arm/configs/rpc_defconfig

@@ -7,7 +7,6 @@ CONFIG_MODULE_UNLOAD=y
 CONFIG_ARCH_RPC=y
 CONFIG_CPU_SA110=y
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=y
 CONFIG_PARTITION_ADVANCED=y
 CONFIG_BSD_DISKLABEL=y
 CONFIG_SLAB=y

arch/arm/configs/spitz_defconfig

@@ -13,7 +13,6 @@ CONFIG_MACH_AKITA=y
 CONFIG_MACH_BORZOI=y
 CONFIG_CMDLINE="console=ttyS0,115200n8 console=tty1 noinitrd root=/dev/mtdblock2 rootfstype=jffs2   debug"
 CONFIG_FPE_NWFPE=y
-CONFIG_BINFMT_AOUT=m
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y

fs/Kconfig.binfmt

@@ -142,39 +142,6 @@ config BINFMT_ZFLAT
 	help
 	  Support FLAT format compressed binaries
 
-config HAVE_AOUT
-       def_bool n
-
-config BINFMT_AOUT
-	tristate "Kernel support for a.out and ECOFF binaries"
-	depends on HAVE_AOUT
-	help
-	  A.out (Assembler.OUTput) is a set of formats for libraries and
-	  executables used in the earliest versions of UNIX.  Linux used
-	  the a.out formats QMAGIC and ZMAGIC until they were replaced
-	  with the ELF format.
-
-	  The conversion to ELF started in 1995.  This option is primarily
-	  provided for historical interest and for the benefit of those
-	  who need to run binaries from that era.
-
-	  Most people should answer N here.  If you think you may have
-	  occasional use for this format, enable module support above
-	  and answer M here to compile this support as a module called
-	  binfmt_aout.
-
-	  If any crucial components of your system (such as /sbin/init
-	  or /lib/ld.so) are still in a.out format, you will have to
-	  say Y here.
-
-config OSF4_COMPAT
-	bool "OSF/1 v4 readv/writev compatibility"
-	depends on ALPHA && BINFMT_AOUT
-	help
-	  Say Y if you are using OSF/1 binaries (like Netscape and Acrobat)
-	  with v4 shared libraries freely available from Compaq. If you're
-	  going to use shared libraries from Tru64 version 5.0 or later, say N.
-
 config BINFMT_MISC
 	tristate "Kernel support for MISC binaries"
 	help

fs/Makefile

@@ -38,7 +38,6 @@ obj-$(CONFIG_FS_DAX)		+= dax.o
 obj-$(CONFIG_FS_ENCRYPTION)	+= crypto/
 obj-$(CONFIG_FS_VERITY)		+= verity/
 obj-$(CONFIG_FILE_LOCKING)      += locks.o
-obj-$(CONFIG_BINFMT_AOUT)	+= binfmt_aout.o
 obj-$(CONFIG_BINFMT_MISC)	+= binfmt_misc.o
 obj-$(CONFIG_BINFMT_SCRIPT)	+= binfmt_script.o
 obj-$(CONFIG_BINFMT_ELF)	+= binfmt_elf.o

fs/binfmt_aout.c

-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  linux/fs/binfmt_aout.c
- *
- *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
- */
-
-#include <linux/module.h>
-
-#include <linux/time.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/a.out.h>
-#include <linux/errno.h>
-#include <linux/signal.h>
-#include <linux/string.h>
-#include <linux/fs.h>
-#include <linux/file.h>
-#include <linux/stat.h>
-#include <linux/fcntl.h>
-#include <linux/ptrace.h>
-#include <linux/user.h>
-#include <linux/binfmts.h>
-#include <linux/personality.h>
-#include <linux/init.h>
-#include <linux/coredump.h>
-#include <linux/slab.h>
-#include <linux/sched/task_stack.h>
-
-#include <linux/uaccess.h>
-#include <asm/cacheflush.h>
-
-static int load_aout_binary(struct linux_binprm *);
-static int load_aout_library(struct file*);
-
-static struct linux_binfmt aout_format = {
-	.module		= THIS_MODULE,
-	.load_binary	= load_aout_binary,
-	.load_shlib	= load_aout_library,
-};
-
-#define BAD_ADDR(x)	((unsigned long)(x) >= TASK_SIZE)
-
-static int set_brk(unsigned long start, unsigned long end)
-{
-	start = PAGE_ALIGN(start);
-	end = PAGE_ALIGN(end);
-	if (end > start)
-		return vm_brk(start, end - start);
-	return 0;
-}
-
-/*
- * create_aout_tables() parses the env- and arg-strings in new user
- * memory and creates the pointer tables from them, and puts their
- * addresses on the "stack", returning the new stack pointer value.
- */
-static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
-{
-	char __user * __user *argv;
-	char __user * __user *envp;
-	unsigned long __user *sp;
-	int argc = bprm->argc;
-	int envc = bprm->envc;
-
-	sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
-#ifdef __alpha__
-/* whee.. test-programs are so much fun. */
-	put_user(0, --sp);
-	put_user(0, --sp);
-	if (bprm->loader) {
-		put_user(0, --sp);
-		put_user(1003, --sp);
-		put_user(bprm->loader, --sp);
-		put_user(1002, --sp);
-	}
-	put_user(bprm->exec, --sp);
-	put_user(1001, --sp);
-#endif
-	sp -= envc+1;
-	envp = (char __user * __user *) sp;
-	sp -= argc+1;
-	argv = (char __user * __user *) sp;
-#ifndef __alpha__
-	put_user((unsigned long) envp,--sp);
-	put_user((unsigned long) argv,--sp);
-#endif
-	put_user(argc,--sp);
-	current->mm->arg_start = (unsigned long) p;
-	while (argc-->0) {
-		char c;
-		put_user(p,argv++);
-		do {
-			get_user(c,p++);
-		} while (c);
-	}
-	put_user(NULL,argv);
-	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
-	while (envc-->0) {
-		char c;
-		put_user(p,envp++);
-		do {
-			get_user(c,p++);
-		} while (c);
-	}
-	put_user(NULL,envp);
-	current->mm->env_end = (unsigned long) p;
-	return sp;
-}
-
-/*
- * These are the functions used to load a.out style executables and shared
- * libraries.  There is no binary dependent code anywhere else.
- */
-
-static int load_aout_binary(struct linux_binprm * bprm)
-{
-	struct pt_regs *regs = current_pt_regs();
-	struct exec ex;
-	unsigned long error;
-	unsigned long fd_offset;
-	unsigned long rlim;
-	int retval;
-
-	ex = *((struct exec *) bprm->buf);		/* exec-header */
-	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
-	     N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
-	    N_TRSIZE(ex) || N_DRSIZE(ex) ||
-	    i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
-		return -ENOEXEC;
-	}
-
-	/*
-	 * Requires a mmap handler. This prevents people from using a.out
-	 * as part of an exploit attack against /proc-related vulnerabilities.
-	 */
-	if (!bprm->file->f_op->mmap)
-		return -ENOEXEC;
-
-	fd_offset = N_TXTOFF(ex);
-
-	/* Check initial limits. This avoids letting people circumvent
-	 * size limits imposed on them by creating programs with large
-	 * arrays in the data or bss.
-	 */
-	rlim = rlimit(RLIMIT_DATA);
-	if (rlim >= RLIM_INFINITY)
-		rlim = ~0;
-	if (ex.a_data + ex.a_bss > rlim)
-		return -ENOMEM;
-
-	/* Flush all traces of the currently running executable */
-	retval = begin_new_exec(bprm);
-	if (retval)
-		return retval;
-
-	/* OK, This is the point of no return */
-#ifdef __alpha__
-	SET_AOUT_PERSONALITY(bprm, ex);
-#else
-	set_personality(PER_LINUX);
-#endif
-	setup_new_exec(bprm);
-
-	current->mm->end_code = ex.a_text +
-		(current->mm->start_code = N_TXTADDR(ex));
-	current->mm->end_data = ex.a_data +
-		(current->mm->start_data = N_DATADDR(ex));
-	current->mm->brk = ex.a_bss +
-		(current->mm->start_brk = N_BSSADDR(ex));
-
-	retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
-	if (retval < 0)
-		return retval;
-
-
-	if (N_MAGIC(ex) == OMAGIC) {
-		unsigned long text_addr, map_size;
-		loff_t pos;
-
-		text_addr = N_TXTADDR(ex);
-
-#ifdef __alpha__
-		pos = fd_offset;
-		map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
-#else
-		pos = 32;
-		map_size = ex.a_text+ex.a_data;
-#endif
-		error = vm_brk(text_addr & PAGE_MASK, map_size);
-		if (error)
-			return error;
-
-		error = read_code(bprm->file, text_addr, pos,
-				  ex.a_text+ex.a_data);
-		if ((signed long)error < 0)
-			return error;
-	} else {
-		if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
-		    (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
-		{
-			printk(KERN_NOTICE "executable not page aligned\n");
-		}
-
-		if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
-		{
-			printk(KERN_WARNING 
-			       "fd_offset is not page aligned. Please convert program: %pD\n",
-			       bprm->file);
-		}
-
-		if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
-			error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
-			if (error)
-				return error;
-
-			read_code(bprm->file, N_TXTADDR(ex), fd_offset,
-				  ex.a_text + ex.a_data);
-			goto beyond_if;
-		}
-
-		error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
-			PROT_READ | PROT_EXEC, MAP_FIXED | MAP_PRIVATE,
-			fd_offset);
-
-		if (error != N_TXTADDR(ex))
-			return error;
-
-		error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
-				PROT_READ | PROT_WRITE | PROT_EXEC,
-				MAP_FIXED | MAP_PRIVATE,
-				fd_offset + ex.a_text);
-		if (error != N_DATADDR(ex))
-			return error;
-	}
-beyond_if:
-	set_binfmt(&aout_format);
-
-	retval = set_brk(current->mm->start_brk, current->mm->brk);
-	if (retval < 0)
-		return retval;
-
-	current->mm->start_stack =
-		(unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
-#ifdef __alpha__
-	regs->gp = ex.a_gpvalue;
-#endif
-	finalize_exec(bprm);
-	start_thread(regs, ex.a_entry, current->mm->start_stack);
-	return 0;
-}
-
-static int load_aout_library(struct file *file)
-{
-	struct inode * inode;
-	unsigned long bss, start_addr, len;
-	unsigned long error;
-	int retval;
-	struct exec ex;
-	loff_t pos = 0;
-
-	inode = file_inode(file);
-
-	retval = -ENOEXEC;
-	error = kernel_read(file, &ex, sizeof(ex), &pos);
-	if (error != sizeof(ex))
-		goto out;
-
-	/* We come in here for the regular a.out style of shared libraries */
-	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
-	    N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
-	    i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
-		goto out;
-	}
-
-	/*
-	 * Requires a mmap handler. This prevents people from using a.out
-	 * as part of an exploit attack against /proc-related vulnerabilities.
-	 */
-	if (!file->f_op->mmap)
-		goto out;
-
-	if (N_FLAGS(ex))
-		goto out;
-
-	/* For  QMAGIC, the starting address is 0x20 into the page.  We mask
-	   this off to get the starting address for the page */
-
-	start_addr =  ex.a_entry & 0xfffff000;
-
-	if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
-		if (printk_ratelimit())
-		{
-			printk(KERN_WARNING 
-			       "N_TXTOFF is not page aligned. Please convert library: %pD\n",
-			       file);
-		}
-		retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
-		if (retval)
-			goto out;
-
-		read_code(file, start_addr, N_TXTOFF(ex),
-			  ex.a_text + ex.a_data);
-		retval = 0;
-		goto out;
-	}
-	/* Now use mmap to map the library into memory. */
-	error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
-			PROT_READ | PROT_WRITE | PROT_EXEC,
-			MAP_FIXED | MAP_PRIVATE,
-			N_TXTOFF(ex));
-	retval = error;
-	if (error != start_addr)
-		goto out;
-
-	len = PAGE_ALIGN(ex.a_text + ex.a_data);
-	bss = ex.a_text + ex.a_data + ex.a_bss;
-	if (bss > len) {
-		retval = vm_brk(start_addr + len, bss - len);
-		if (retval)
-			goto out;
-	}
-	retval = 0;
-out:
-	return retval;
-}
-
-static int __init init_aout_binfmt(void)
-{
-	register_binfmt(&aout_format);
-	return 0;
-}
-
-static void __exit exit_aout_binfmt(void)
-{
-	unregister_binfmt(&aout_format);
-}
-
-core_initcall(init_aout_binfmt);
-module_exit(exit_aout_binfmt);
-MODULE_LICENSE("GPL");

fs/exec.c

@@ -957,8 +957,7 @@ struct file *open_exec(const char *name)
 }
 EXPORT_SYMBOL(open_exec);
 
-#if defined(CONFIG_HAVE_AOUT) || defined(CONFIG_BINFMT_FLAT) || \
-    defined(CONFIG_BINFMT_ELF_FDPIC)
+#if defined(CONFIG_BINFMT_FLAT) || defined(CONFIG_BINFMT_ELF_FDPIC)
 ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
 {
 	ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);

include/linux/a.out.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __A_OUT_GNU_H__
-#define __A_OUT_GNU_H__
-
-#include <uapi/linux/a.out.h>
-
-#ifndef __ASSEMBLY__
-#ifdef linux
-#include <asm/page.h>
-#if defined(__i386__) || defined(__mc68000__)
-#else
-#ifndef SEGMENT_SIZE
-#define SEGMENT_SIZE	PAGE_SIZE
-#endif
-#endif
-#endif
-#endif /*__ASSEMBLY__ */
-#endif /* __A_OUT_GNU_H__ */