Message-Id: <1305144843-5058-16-git-send-email-msalter@redhat.com>
Date:	Wed, 11 May 2011 16:14:02 -0400
From:	Mark Salter <msalter@...hat.com>
To:	linux-kernel@...r.kernel.org
Subject: [PATCH 15/16] Add new elf binfmt support for DSBT

This patch adds support for a new ELF-based binary format for systems without
an MMU. DSBT stands for Data Segment Base Table and supports shared text
segments while allowing for non-shared data. In this regard, it is similar to
FDPIC, but differs in approach. FDPIC ties data segment references to function
pointers and doubles the size of function pointers in doing so. DSBT handles
function pointers in the normal way, but data accesses are performed relative
to a dedicated register pointing to the correct data segment. FDPIC callers are
responsible for setting up the correct data reference before calling a function
in another DSO. With DSBT, the callee is responsible for setting up the correct
data segment pointer.

This format was developed by Texas Instruments for use by their C6X family of
DSPs. However, this patch is not specific to TI DSPs and could be supported
by other architectures.

Signed-off-by: Mark Salter <msalter@...hat.com>
---
 fs/Kconfig.binfmt        |   10 +
 fs/Makefile              |    1 +
 fs/binfmt_elf_dsbt.c     | 1035 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/elf-dsbt.h |   88 ++++
 4 files changed, 1134 insertions(+), 0 deletions(-)
 create mode 100644 fs/binfmt_elf_dsbt.c
 create mode 100644 include/linux/elf-dsbt.h

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 79e2ca7..8fc5337 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -40,6 +40,16 @@ config BINFMT_ELF_FDPIC
 
 	  It is also possible to run FDPIC ELF binaries on MMU linux also.
 
+config BINFMT_ELF_DSBT
+	bool "Kernel support for DSBT ELF binaries"
+	default y
+	depends on (TMS320C6X && !MMU)
+	help
+	  ELF DSBT binaries are based on ELF and are similar to FDPIC in that
+	  individual load segments can be placed independently of each other.
+	  Also like FDPIC, DSBT is designed to allow systems with no MMU to
+	  share text segments while data segments are not.
+
 config CORE_DUMP_DEFAULT_ELF_HEADERS
 	bool "Write ELF core dumps with partial segments"
 	default y
diff --git a/fs/Makefile b/fs/Makefile
index fb68c2b..95c500b 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -40,6 +40,7 @@ obj-y				+= binfmt_script.o
 obj-$(CONFIG_BINFMT_ELF)	+= binfmt_elf.o
 obj-$(CONFIG_COMPAT_BINFMT_ELF)	+= compat_binfmt_elf.o
 obj-$(CONFIG_BINFMT_ELF_FDPIC)	+= binfmt_elf_fdpic.o
+obj-$(CONFIG_BINFMT_ELF_DSBT)	+= binfmt_elf_dsbt.o
 obj-$(CONFIG_BINFMT_SOM)	+= binfmt_som.o
 obj-$(CONFIG_BINFMT_FLAT)	+= binfmt_flat.o
 
diff --git a/fs/binfmt_elf_dsbt.c b/fs/binfmt_elf_dsbt.c
new file mode 100644
index 0000000..24c2b7b
--- /dev/null
+++ b/fs/binfmt_elf_dsbt.c
@@ -0,0 +1,1035 @@
+/* binfmt_elf_dsbt.c: DSBT ELF binary format
+ *
+ * Copyright (C) 2010, 2011 Texas Instruments Incorporated
+ * Written by Mark Salter (msalter@...hat.com)
+ * Derived from binfmt_elf_fdpic.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/binfmts.h>
+#include <linux/string.h>
+#include <linux/file.h>
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/security.h>
+#include <linux/highmem.h>
+#include <linux/highuid.h>
+#include <linux/personality.h>
+#include <linux/ptrace.h>
+#include <linux/init.h>
+#include <linux/elf.h>
+#include <linux/elf-dsbt.h>
+#include <linux/elfcore.h>
+#include <linux/coredump.h>
+#include <linux/uaccess.h>
+#include <linux/param.h>
+#include <asm/pgalloc.h>
+
+typedef char *elf_caddr_t;
+
+#if 0
+#define kdebug(fmt, ...) printk(KERN_DEBUG "DSBT: "fmt"\n" , ##__VA_ARGS__)
+#else
+#define kdebug(fmt, ...) do {} while (0)
+#endif
+
+#if ELF_EXEC_PAGESIZE > PAGE_SIZE
+#define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
+#else
+#define ELF_MIN_ALIGN	PAGE_SIZE
+#endif
+
+#if ELF_CLASS == ELFCLASS32
+#define dt_tag_t Elf32_Sword
+#define elf_off  Elf32_Off
+#else
+#define dt_tag_t Elf64_Sxword
+#define elf_off  Elf64_Off
+#endif
+
+
+#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
+#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
+#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
+
+#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
+
+static int load_elf_dsbt_binary(struct linux_binprm *, struct pt_regs *);
+
+static struct linux_binfmt elf_dsbt_format = {
+	.module		= THIS_MODULE,
+	.load_binary	= load_elf_dsbt_binary,
+	.min_coredump	= ELF_EXEC_PAGESIZE,
+};
+
+static int is_elf_dsbt(struct elfhdr *hdr, struct file *file)
+{
+	if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
+		return 0;
+	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
+		return 0;
+	if (!elf_check_arch(hdr) || !elf_check_dsbt(hdr))
+		return 0;
+	if (!file->f_op || !file->f_op->mmap)
+		return 0;
+	return 1;
+}
+
+/*
+ * read the program headers table into memory
+ */
+static int elf_dsbt_fetch_phdrs(struct elf_dsbt_params *params,
+				 struct file *file)
+{
+	struct elf32_phdr *phdr;
+	unsigned long size;
+	int retval, loop;
+
+	if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
+		return -ENOMEM;
+	if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
+		return -ENOMEM;
+
+	size = params->hdr.e_phnum * sizeof(struct elf_phdr);
+	params->phdrs = kmalloc(size, GFP_KERNEL);
+	if (!params->phdrs)
+		return -ENOMEM;
+
+	retval = kernel_read(file, params->hdr.e_phoff,
+			     (char *) params->phdrs, size);
+	if (unlikely(retval != size))
+		return retval < 0 ? retval : -ENOEXEC;
+
+	/* determine stack size for this binary */
+	phdr = params->phdrs;
+	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
+		if (phdr->p_type != PT_GNU_STACK)
+			continue;
+
+		params->stack_size = phdr->p_memsz;
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * read the .dynamic section into memory
+ */
+static int elf_dsbt_fetch_dynamic(struct elf_dsbt_params *params,
+				  struct file *file)
+{
+	struct elf_shdr *shdrs, *shdr;
+	int i, retval;
+	unsigned long size;
+
+	if (params->hdr.e_shentsize != sizeof(struct elf_shdr))
+		return -EINVAL;
+	if (params->hdr.e_shnum > 65536U / sizeof(struct elf_shdr))
+		return -EINVAL;
+
+	size = params->hdr.e_shnum * sizeof(struct elf_shdr);
+	shdrs = kmalloc(size, GFP_KERNEL);
+	if (!shdrs)
+		return -ENOMEM;
+
+	retval = kernel_read(file, params->hdr.e_shoff,
+			     (char *) shdrs, size);
+	if (unlikely(retval != size)) {
+		kfree(shdrs);
+		return (retval < 0) ? retval : -EIO;
+	}
+
+	shdr = &shdrs[1];
+	for (i = 1; i < params->hdr.e_shnum; i++, shdr++) {
+		if (shdr->sh_type != SHT_DYNAMIC)
+			continue;
+
+		params->dynamic = kmalloc(shdr->sh_size, GFP_KERNEL);
+		if (!params->dynamic) {
+			kfree(shdrs);
+			return -ENOMEM;
+		}
+
+		retval = kernel_read(file, shdr->sh_offset,
+			     (char *) params->dynamic, shdr->sh_size);
+
+		if (unlikely(retval != shdr->sh_size)) {
+			kfree(shdrs);
+			return retval < 0 ? retval : -ENOEXEC;
+		}
+		break;
+	}
+	return 0;
+}
+
+/*
+ * search for dynamic section tag value
+ */
+static elf_dyn *find_dynamic_tag(struct elf_dsbt_params *params,
+				 dt_tag_t tag)
+{
+	elf_dyn *d = params->dynamic;
+
+	while (d->d_tag) {
+		if (d->d_tag == tag)
+			return d;
+		++d;
+	}
+	return NULL;
+}
+
+#ifndef ELF_BASE_PLATFORM
+/*
+ * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
+ * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
+ * will be copied to the user stack in the same manner as AT_PLATFORM.
+ */
+#define ELF_BASE_PLATFORM NULL
+#endif
+
+/*
+ * transfer the program arguments and environment from the holding pages onto
+ * the stack
+ */
+static int elf_dsbt_transfer_args_to_stack(struct linux_binprm *bprm,
+					    unsigned long *_sp)
+{
+	unsigned long index, stop, sp;
+	char *src;
+	int ret = 0;
+
+	stop = bprm->p >> PAGE_SHIFT;
+	sp = *_sp;
+
+	for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
+		src = kmap(bprm->page[index]);
+		sp -= PAGE_SIZE;
+		if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
+			ret = -EFAULT;
+		kunmap(bprm->page[index]);
+		if (ret < 0)
+			goto out;
+	}
+
+	*_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
+
+out:
+	return ret;
+}
+
+/*
+ * present useful information to the program by shovelling it onto the new
+ * process's stack
+ */
+static int create_elf_dsbt_tables(struct linux_binprm *bprm,
+				   struct mm_struct *mm,
+				   struct elf_dsbt_params *exec_params,
+				   struct elf_dsbt_params *interp_params)
+{
+	const struct cred *cred = current_cred();
+	unsigned long sp, csp, nitems;
+	elf_caddr_t __user *argv, *envp;
+	size_t platform_len = 0, len;
+	char *k_platform, *k_base_platform;
+	char __user *u_platform, *u_base_platform, *p;
+	long hwcap;
+	int loop;
+	int nr;	/* reset for each csp adjustment */
+
+	sp = mm->start_stack;
+
+	/* stack the program arguments and environment */
+	if (elf_dsbt_transfer_args_to_stack(bprm, &sp) < 0)
+		return -EFAULT;
+
+	hwcap = ELF_HWCAP;
+
+	/*
+	 * If this architecture has a platform capability string, copy it
+	 * to userspace.  In some cases (Sparc), this info is impossible
+	 * for userspace to get any other way, in others (i386) it is
+	 * merely difficult.
+	 */
+	k_platform = ELF_PLATFORM;
+	u_platform = NULL;
+
+	if (k_platform) {
+		platform_len = strlen(k_platform) + 1;
+		sp -= platform_len;
+		u_platform = (char __user *) sp;
+		if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
+			return -EFAULT;
+	}
+
+	/*
+	 * If this architecture has a "base" platform capability
+	 * string, copy it to userspace.
+	 */
+	k_base_platform = ELF_BASE_PLATFORM;
+	u_base_platform = NULL;
+
+	if (k_base_platform) {
+		platform_len = strlen(k_base_platform) + 1;
+		sp -= platform_len;
+		u_base_platform = (char __user *) sp;
+		if (__copy_to_user(u_base_platform, k_base_platform,
+				   platform_len) != 0)
+			return -EFAULT;
+	}
+
+	sp &= ~7UL;
+
+	/* stack the load map(s) */
+	len = sizeof(struct elf32_dsbt_loadmap);
+	len += sizeof(struct elf32_dsbt_loadseg) * exec_params->loadmap->nsegs;
+	sp = (sp - len) & ~7UL;
+	exec_params->map_addr = sp;
+	kdebug("exec_params->map_addr[%x]", sp);
+
+	if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
+		return -EFAULT;
+
+	current->mm->context.exec_dsbt_loadmap = (unsigned long) sp;
+
+	if (interp_params->loadmap) {
+		len = sizeof(struct elf32_dsbt_loadmap);
+		len += sizeof(struct elf32_dsbt_loadseg) *
+			interp_params->loadmap->nsegs;
+		sp = (sp - len) & ~7UL;
+		interp_params->map_addr = sp;
+		kdebug("interp_params->map_addr[%x]", sp);
+		if (copy_to_user((void __user *) sp, interp_params->loadmap,
+				 len) != 0)
+			return -EFAULT;
+
+		current->mm->context.interp_dsbt_loadmap = (unsigned long) sp;
+	}
+
+	/* force 16 byte _final_ alignment here for generality */
+#define DLINFO_ITEMS 15
+
+	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
+		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
+
+	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
+		nitems++;
+
+	csp = sp;
+	sp -= nitems * 2 * sizeof(unsigned long);
+	sp -= (bprm->envc + 1) * sizeof(char *);	/* envv[] */
+	sp -= (bprm->argc + 1) * sizeof(char *);	/* argv[] */
+	sp -= 1 * sizeof(unsigned long);		/* argc */
+
+	csp -= sp & 15UL;
+	sp -= sp & 15UL;
+
+	/* put the ELF interpreter info on the stack */
+#define NEW_AUX_ENT(id, val)						\
+	do {								\
+		struct { unsigned long _id, _val; } __user *ent;	\
+									\
+		ent = (void __user *) csp;				\
+		__put_user((id), &ent[nr]._id);				\
+		__put_user((val), &ent[nr]._val);			\
+		nr++;							\
+	} while (0)
+
+	nr = 0;
+	csp -= 2 * sizeof(unsigned long);
+	NEW_AUX_ENT(AT_NULL, 0);
+	if (k_platform) {
+		nr = 0;
+		csp -= 2 * sizeof(unsigned long);
+		NEW_AUX_ENT(AT_PLATFORM,
+			    (elf_addr_t) (unsigned long) u_platform);
+	}
+
+	if (k_base_platform) {
+		nr = 0;
+		csp -= 2 * sizeof(unsigned long);
+		NEW_AUX_ENT(AT_BASE_PLATFORM,
+			    (elf_addr_t) (unsigned long) u_base_platform);
+	}
+
+	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
+		nr = 0;
+		csp -= 2 * sizeof(unsigned long);
+		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
+	}
+
+	nr = 0;
+	csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
+	NEW_AUX_ENT(AT_HWCAP,	hwcap);
+	NEW_AUX_ENT(AT_PAGESZ,	PAGE_SIZE);
+	NEW_AUX_ENT(AT_CLKTCK,	CLOCKS_PER_SEC);
+	NEW_AUX_ENT(AT_PHDR,	exec_params->ph_addr);
+	NEW_AUX_ENT(AT_PHENT,	sizeof(struct elf_phdr));
+	NEW_AUX_ENT(AT_PHNUM,	exec_params->hdr.e_phnum);
+	NEW_AUX_ENT(AT_BASE,	interp_params->elfhdr_addr);
+	NEW_AUX_ENT(AT_FLAGS,	0);
+	NEW_AUX_ENT(AT_ENTRY,	exec_params->entry_addr);
+	NEW_AUX_ENT(AT_UID,	(elf_addr_t) cred->uid);
+	NEW_AUX_ENT(AT_EUID,	(elf_addr_t) cred->euid);
+	NEW_AUX_ENT(AT_GID,	(elf_addr_t) cred->gid);
+	NEW_AUX_ENT(AT_EGID,	(elf_addr_t) cred->egid);
+	NEW_AUX_ENT(AT_SECURE,	security_bprm_secureexec(bprm));
+	NEW_AUX_ENT(AT_EXECFN,	bprm->exec);
+
+	kdebug("AUX entry start: %x]", csp);
+#ifdef ARCH_DLINFO
+	nr = 0;
+	csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
+
+	/* ARCH_DLINFO must come last so platform specific code can enforce
+	 * special alignment requirements on the AUXV if necessary (eg. PPC).
+	 */
+	ARCH_DLINFO;
+#endif
+#undef NEW_AUX_ENT
+
+	/* allocate room for argv[] and envv[] */
+	csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
+	envp = (elf_caddr_t __user *) csp;
+	csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
+	argv = (elf_caddr_t __user *) csp;
+
+	kdebug("argv[%x] envp[%x]\n", argv, envp);
+
+	/* stack argc */
+	csp -= sizeof(unsigned long);
+	__put_user(bprm->argc, (unsigned long __user *) csp);
+
+	BUG_ON(csp != sp);
+
+	/* fill in the argv[] array */
+	current->mm->arg_start = current->mm->start_stack -
+		(MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
+
+	p = (char __user *) current->mm->arg_start;
+	for (loop = bprm->argc; loop > 0; loop--) {
+		__put_user((elf_caddr_t) p, argv++);
+		len = strnlen_user(p, MAX_ARG_STRLEN);
+		if (!len || len > MAX_ARG_STRLEN)
+			return -EINVAL;
+		p += len;
+	}
+	__put_user(NULL, argv);
+	current->mm->arg_end = (unsigned long) p;
+
+	/* fill in the envv[] array */
+	current->mm->env_start = (unsigned long) p;
+	for (loop = bprm->envc; loop > 0; loop--) {
+		__put_user((elf_caddr_t)(unsigned long) p, envp++);
+		len = strnlen_user(p, MAX_ARG_STRLEN);
+		if (!len || len > MAX_ARG_STRLEN)
+			return -EINVAL;
+		p += len;
+	}
+	__put_user(NULL, envp);
+	current->mm->env_end = (unsigned long) p;
+
+	mm->start_stack = (unsigned long) sp;
+	return 0;
+}
+
+/*
+ * map a single segment
+ */
+static unsigned long elf_dsbt_map(struct file *filep, unsigned long addr,
+		struct elf32_dsbt_seg *seg, int prot, int type)
+{
+	unsigned long map_addr;
+	unsigned long size = seg->p_memsz + ELF_PAGEOFFSET(seg->p_vaddr);
+	unsigned long off = seg->p_offset - ELF_PAGEOFFSET(seg->p_vaddr);
+	addr = ELF_PAGESTART(addr);
+	size = ELF_PAGEALIGN(size);
+
+	/* mmap() will return -EINVAL if given a zero size, but a
+	 * segment with zero filesize is perfectly valid */
+	if (!size)
+		return addr;
+
+	down_write(&current->mm->mmap_sem);
+	map_addr = do_mmap(filep, addr, size, prot, type, off);
+	up_write(&current->mm->mmap_sem);
+	return map_addr;
+}
+
+/*
+ * load the appropriate binary image (executable or interpreter) into memory
+ * - we assume no MMU is available
+ * - we assume that there is one LOADable segment with execute flags
+ * - we assume that there is one LOADable segment without execute flags
+ */
+static int elf_dsbt_map_file(struct elf_dsbt_params *params,
+			      struct file *file,
+			      struct mm_struct *mm,
+			      const char *what,
+			      const char *interp_name)
+{
+	struct elf32_phdr *phdr, *code_phdr = NULL;
+	struct elf32_phdr *data_phdr = NULL;
+	struct elf32_phdr *dyn_phdr = NULL;
+	struct elf32_dsbt_loadmap *loadmap;
+	struct elf32_dsbt_loadseg *seg;
+	elf_dyn *dyn;
+	unsigned long mapped_addr, bss_len;
+	int loop, ret, flags, ndseg, prot;
+
+	phdr = params->phdrs;
+	ndseg = 0;
+	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
+		if (phdr->p_type == PT_DYNAMIC)
+			dyn_phdr = phdr;
+
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		kdebug("elf_dsbt_map_file: [LOAD] va=%lx of=%lx "
+		       "fs=%lx ms=%lx flags=%lx",
+		       (unsigned long) phdr->p_vaddr,
+		       (unsigned long) phdr->p_offset,
+		       (unsigned long) phdr->p_filesz,
+		       (unsigned long) phdr->p_memsz,
+		       (unsigned long) phdr->p_flags);
+
+		if (ELF_PAGEOFFSET(phdr->p_offset) != ELF_PAGEOFFSET(phdr->p_vaddr)) {
+			kdebug("Bad ELF file!");
+			return -EINVAL;
+		}
+
+		/*
+		 * There should be only one executable segment and
+		 * one RW segment.
+		 */
+		if (phdr->p_flags & PF_X) {
+			if (code_phdr) {
+				kdebug("more than one executable segment!");
+				return -EINVAL;
+			}
+			code_phdr = phdr;
+		} else {
+			if (data_phdr) {
+				kdebug("more than one RW segment!");
+				return -EINVAL;
+			}
+			data_phdr = phdr;
+		}
+	}
+	if (!code_phdr) {
+		kdebug("no executable segment!");
+		return -EINVAL;
+	}
+	if (!data_phdr) {
+		kdebug("no RW segment!");
+		return -EINVAL;
+	}
+
+	params->code_seg.p_vaddr  = code_phdr->p_vaddr;
+	params->code_seg.p_offset = code_phdr->p_offset;
+	params->code_seg.p_memsz  = code_phdr->p_memsz;
+	params->code_seg.p_filesz = code_phdr->p_filesz;
+
+	params->data_seg.p_vaddr  = data_phdr->p_vaddr;
+	params->data_seg.p_offset = data_phdr->p_offset;
+	params->data_seg.p_memsz  = data_phdr->p_memsz;
+	params->data_seg.p_filesz = data_phdr->p_filesz;
+
+	/* map code segment */
+	flags = MAP_PRIVATE | MAP_DENYWRITE;
+	if (params->flags & ELF_DSBT_FLAG_EXECUTABLE)
+		flags |= MAP_EXECUTABLE;
+
+	prot = PROT_READ | PROT_EXEC;
+
+	mapped_addr = elf_dsbt_map(file, params->code_seg.p_vaddr,
+				   &params->code_seg, prot, flags);
+	if (BAD_ADDR(mapped_addr))
+		return (int) mapped_addr;
+
+	params->code_seg.addr = mapped_addr +
+		ELF_PAGEOFFSET(params->code_seg.p_vaddr);
+
+	kdebug("mapped code seg from %08x to %08x",
+	       params->code_seg.p_vaddr, params->code_seg.addr);
+
+	/* map data segment */
+	mapped_addr = elf_dsbt_map(file, params->data_seg.p_vaddr,
+				   &params->data_seg,
+				   PROT_READ | PROT_WRITE, MAP_PRIVATE);
+	if (BAD_ADDR(mapped_addr)) {
+		do_munmap(current->mm, mapped_addr,
+			  params->data_seg.p_memsz);
+		return (int) mapped_addr;
+	}
+	params->data_seg.addr = mapped_addr +
+		ELF_PAGEOFFSET(params->data_seg.p_vaddr);
+
+	kdebug("mapped data seg from %08x to %08x",
+	       params->data_seg.p_vaddr, params->data_seg.addr);
+
+	/* clear any bss area */
+	bss_len = params->data_seg.p_memsz - params->data_seg.p_filesz;
+	if (bss_len) {
+		unsigned long bss_start;
+
+		bss_start = params->data_seg.addr + params->data_seg.p_filesz;
+
+		kdebug("clearing %d bytes of bss at %08x", bss_len, bss_start);
+		ret = clear_user((void *)bss_start, bss_len);
+		if (ret)
+			return ret;
+	}
+
+	/* fetch dsbt info from dynamic section */
+	dyn = find_dynamic_tag(params, DT_ARCH_DSBT_BASE);
+	if (!dyn) {
+		kdebug("DSBT BASE not found");
+		return -EINVAL;
+	}
+	/* relocate it */
+	params->dsbt_base = (dyn->d_un.d_ptr - params->data_seg.p_vaddr) +
+		params->data_seg.addr;
+
+	dyn = find_dynamic_tag(params, DT_ARCH_DSBT_SIZE);
+	if (!dyn) {
+		kdebug("DSBT SIZE not found");
+		return -EINVAL;
+	}
+	params->dsbt_size = dyn->d_un.d_ptr;
+
+	dyn = find_dynamic_tag(params, DT_ARCH_DSBT_INDEX);
+	if (!dyn) {
+		kdebug("DSBT INDEX not found");
+		return -EINVAL;
+	}
+	params->dsbt_index = dyn->d_un.d_ptr;
+
+	/* determine where the elf header has wound up if mapped */
+	if (params->code_seg.p_offset == 0)
+		params->elfhdr_addr = params->code_seg.addr;
+	else if (params->data_seg.p_offset == 0)
+		params->elfhdr_addr = params->data_seg.addr;
+	else {
+		/* elf header has not been mapped */
+		kdebug("elf header not mapped!");
+		return -EINVAL;
+	}
+
+	/* determine where the program header table has wound up if mapped */
+	if (params->hdr.e_phoff >= params->code_seg.p_offset &&
+	    params->hdr.e_phoff < params->code_seg.p_offset + params->code_seg.p_memsz)
+		params->ph_addr = params->code_seg.addr +
+			(params->hdr.e_phoff - params->code_seg.p_offset);
+	else if (params->hdr.e_phoff >= params->data_seg.p_offset &&
+		 params->hdr.e_phoff < params->data_seg.p_offset + params->data_seg.p_memsz)
+		params->ph_addr = params->data_seg.addr +
+			(params->hdr.e_phoff - params->data_seg.p_offset);
+	else {
+		/* program header has not been mapped */
+		kdebug("program header not mapped!");
+		return -EINVAL;
+	}
+
+	/* determine where the dynamic section has wound up if there is one */
+	if (dyn_phdr) {
+		if (dyn_phdr->p_offset >= params->code_seg.p_offset &&
+		    dyn_phdr->p_offset < params->code_seg.p_offset + params->code_seg.p_memsz)
+			params->dynamic_addr = params->code_seg.addr +
+				(dyn_phdr->p_offset - params->code_seg.p_offset);
+		else if (dyn_phdr->p_offset >= params->data_seg.p_offset &&
+			 dyn_phdr->p_offset < params->data_seg.p_offset + params->data_seg.p_memsz)
+			params->dynamic_addr = params->data_seg.addr +
+				(dyn_phdr->p_offset - params->data_seg.p_offset);
+		else {
+			/* dynamic section has not been mapped */
+			kdebug("dynamic section not mapped!");
+			return -EINVAL;
+		}
+	}
+
+	loadmap = kmalloc(sizeof(*loadmap) +
+			  (2 * sizeof(struct elf32_dsbt_loadseg)), GFP_KERNEL);
+	if (!loadmap)
+		return -ENOMEM;
+
+	params->loadmap = loadmap;
+
+	loadmap->version = ELF_DSBT_LOADMAP_VERSION;
+	loadmap->dsbt_table = (unsigned *)params->dsbt_base;
+	loadmap->dsbt_size = params->dsbt_size;
+	loadmap->dsbt_index = params->dsbt_index;
+	loadmap->nsegs = 2;
+
+	seg = loadmap->segs;
+
+	seg->addr = params->code_seg.addr;
+	seg->p_vaddr = params->code_seg.p_vaddr;
+	seg->p_memsz = params->code_seg.p_memsz;
+	++seg;
+	seg->addr = params->data_seg.addr;
+	seg->p_vaddr = params->data_seg.p_vaddr;
+	seg->p_memsz = params->data_seg.p_memsz;
+	++seg;
+
+	/* map the entry point */
+	if (params->hdr.e_entry)
+		params->entry_addr = params->code_seg.addr +
+			(params->hdr.e_entry - params->code_seg.p_vaddr);
+
+	if (mm) {
+		if (!mm->start_code) {
+			mm->start_code = params->code_seg.addr;
+			mm->end_code = params->code_seg.addr +
+				params->code_seg.p_memsz;
+		}
+
+		if (!mm->start_data) {
+			mm->start_data = params->data_seg.addr;
+			mm->end_data = params->data_seg.addr +
+				params->data_seg.p_memsz;
+		}
+	}
+
+	kdebug("Mapped Object [%s]:", what);
+	kdebug("- elfhdr   : %lx", params->elfhdr_addr);
+	kdebug("- PHDR[]   : %lx", params->ph_addr);
+	kdebug("- entry    : %lx", params->entry_addr);
+	kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
+	kdebug("- CODE     : %lx", params->code_seg.addr);
+	kdebug("- DATA     : %lx", params->data_seg.addr);
+	kdebug("- DSBT TBL : %lx", loadmap->dsbt_table);
+	kdebug("- DSBT SZ  : %d", loadmap->dsbt_size);
+	kdebug("- DSBT IDX : %d", loadmap->dsbt_index);
+
+	return 0;
+}
+
+/*
+ * load a DSBT binary into various bits of memory
+ */
+static int load_elf_dsbt_binary(struct linux_binprm *bprm,
+				struct pt_regs *regs)
+{
+	struct elf_dsbt_params exec_params, interp_params;
+	struct elf_phdr *phdr;
+	unsigned long stack_size, entryaddr;
+#ifdef ELF_DSBT_PLAT_INIT
+	unsigned long dynaddr, dsbt_table;
+#endif
+	unsigned long stack_prot;
+	struct file *interpreter = NULL; /* to shut gcc up */
+	char *interpreter_name = NULL;
+	int executable_stack;
+	int retval, i;
+
+	kdebug("____ LOAD  pid[%d] ____", current->pid);
+
+	memset(&exec_params, 0, sizeof(exec_params));
+	memset(&interp_params, 0, sizeof(interp_params));
+
+	exec_params.hdr = *(struct elfhdr *) bprm->buf;
+	exec_params.flags = ELF_DSBT_FLAG_EXECUTABLE | ELF_DSBT_FLAG_PRESENT;
+
+	/* check that this is a binary we know how to deal with */
+	retval = -ENOEXEC;
+	if (!is_elf_dsbt(&exec_params.hdr, bprm->file)) {
+		kdebug("not DSBT binary!");
+		goto error;
+	}
+
+	/* read the program header table */
+	retval = elf_dsbt_fetch_phdrs(&exec_params, bprm->file);
+	if (retval < 0) {
+		kdebug("can't get phdrs!");
+		goto error;
+	}
+
+	/* read the dynamic section */
+	retval = elf_dsbt_fetch_dynamic(&exec_params, bprm->file);
+	if (retval < 0) {
+		kdebug("can't get dynamic section!");
+		goto error;
+	}
+
+	/* scan for a program header that specifies an interpreter */
+	phdr = exec_params.phdrs;
+
+	for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
+		switch (phdr->p_type) {
+		case PT_INTERP:
+			kdebug("found PT_INTERP");
+			retval = -ENOMEM;
+			if (phdr->p_filesz > PATH_MAX)
+				goto error;
+			retval = -ENOENT;
+			if (phdr->p_filesz < 2)
+				goto error;
+
+			/* read the name of the interpreter into memory */
+			interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
+			if (!interpreter_name)
+				goto error;
+
+			retval = kernel_read(bprm->file,
+					     phdr->p_offset,
+					     interpreter_name,
+					     phdr->p_filesz);
+			if (unlikely(retval != phdr->p_filesz)) {
+				if (retval >= 0)
+					retval = -ENOEXEC;
+				goto error;
+			}
+
+			retval = -ENOENT;
+			if (interpreter_name[phdr->p_filesz - 1] != '\0')
+				goto error;
+
+			kdebug("Using ELF interpreter %s", interpreter_name);
+
+			/* replace the program with the interpreter */
+			interpreter = open_exec(interpreter_name);
+			retval = PTR_ERR(interpreter);
+			if (IS_ERR(interpreter)) {
+				interpreter = NULL;
+				goto error;
+			}
+
+			/*
+			 * If the binary is not readable then enforce
+			 * mm->dumpable = 0 regardless of the interpreter's
+			 * permissions.
+			 */
+			if (file_permission(interpreter, MAY_READ) < 0)
+				bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
+
+			retval = kernel_read(interpreter, 0, bprm->buf,
+					     BINPRM_BUF_SIZE);
+			if (unlikely(retval != BINPRM_BUF_SIZE)) {
+				if (retval >= 0)
+					retval = -ENOEXEC;
+				goto error;
+			}
+
+			interp_params.hdr = *((struct elfhdr *) bprm->buf);
+			break;
+
+		case PT_LOAD:
+			kdebug("found PT_LOAD");
+			break;
+		}
+
+	}
+	/* perform insanity checks on the interpreter */
+	if (interpreter_name) {
+		retval = -ELIBBAD;
+		if (!is_elf_dsbt(&interp_params.hdr, interpreter))
+			goto error;
+
+		interp_params.flags = ELF_DSBT_FLAG_PRESENT;
+
+		/* read the interpreter's program header table */
+		retval = elf_dsbt_fetch_phdrs(&interp_params, interpreter);
+		if (retval < 0)
+			goto error;
+
+		/* read the interpreter's dynamic section */
+		retval = elf_dsbt_fetch_dynamic(&interp_params, interpreter);
+		if (retval < 0) {
+			kdebug("can't get dynamic section!");
+			goto error;
+		}
+	}
+
+	executable_stack = EXSTACK_DEFAULT;
+
+	stack_size = interp_params.stack_size;
+
+	retval = -ENOEXEC;
+	if (stack_size == 0) {
+#if 0
+		kdebug("zero stack size");
+		goto error;
+#else
+		stack_size = 0x8000;
+#endif
+	}
+
+	/* flush all traces of the currently running executable */
+	retval = flush_old_exec(bprm);
+	if (retval) {
+		kdebug("flush_old_exec returned: %d", retval);
+		goto error;
+	}
+
+	/* there's now no turning back... the old userspace image is dead,
+	 * defunct, deceased, etc. after this point we have to exit via
+	 * error_kill */
+	set_personality(PER_LINUX);
+	if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
+		current->personality |= READ_IMPLIES_EXEC;
+
+	setup_new_exec(bprm);
+
+	set_binfmt(&elf_dsbt_format);
+
+	current->mm->start_code = 0;
+	current->mm->end_code = 0;
+	current->mm->start_stack = 0;
+	current->mm->start_data = 0;
+	current->mm->end_data = 0;
+
+	current->flags &= ~PF_FORKNOEXEC;
+
+	/* load the executable and interpreter into memory */
+	retval = elf_dsbt_map_file(&exec_params, bprm->file, current->mm,
+				   "executable", interpreter_name);
+	if (retval < 0) {
+		kdebug("elf_dsbt_map_file: returned %d", retval);
+		goto error_kill;
+	}
+
+	if (interpreter_name) {
+		retval = elf_dsbt_map_file(&interp_params, interpreter,
+					   current->mm, "interpreter", NULL);
+		if (retval < 0) {
+			printk(KERN_ERR "Unable to load interpreter");
+			goto error_kill;
+		}
+
+		allow_write_access(interpreter);
+		fput(interpreter);
+		interpreter = NULL;
+	}
+
+	/* create a stack and brk area big enough for everyone
+	 * - the brk heap starts at the bottom and works up
+	 * - the stack starts at the top and works down
+	 */
+	stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
+	if (stack_size < PAGE_SIZE * 2)
+		stack_size = PAGE_SIZE * 2;
+
+	stack_prot = PROT_READ | PROT_WRITE;
+	if (executable_stack == EXSTACK_ENABLE_X ||
+	    (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
+		stack_prot |= PROT_EXEC;
+
+	down_write(&current->mm->mmap_sem);
+	current->mm->start_brk = do_mmap(NULL, 0, stack_size, stack_prot,
+					 MAP_PRIVATE | MAP_ANONYMOUS |
+					 MAP_UNINITIALIZED | MAP_GROWSDOWN,
+					 0);
+
+	if (IS_ERR_VALUE(current->mm->start_brk)) {
+		up_write(&current->mm->mmap_sem);
+		retval = current->mm->start_brk;
+		current->mm->start_brk = 0;
+		kdebug("do_mmap failed");
+		goto error_kill;
+	}
+
+	up_write(&current->mm->mmap_sem);
+
+	current->mm->brk = current->mm->start_brk;
+	current->mm->context.end_brk = current->mm->start_brk;
+	current->mm->context.end_brk +=
+		(stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
+	current->mm->start_stack = current->mm->start_brk + stack_size;
+
+	install_exec_creds(bprm);
+	current->flags &= ~PF_FORKNOEXEC;
+	if (create_elf_dsbt_tables(bprm, current->mm,
+				   &exec_params, &interp_params) < 0) {
+		kdebug("create_eld_dsbt_tables failed");
+		goto error_kill;
+	}
+
+	kdebug("- start_code  %lx", current->mm->start_code);
+	kdebug("- end_code    %lx", current->mm->end_code);
+	kdebug("- start_data  %lx", current->mm->start_data);
+	kdebug("- end_data    %lx", current->mm->end_data);
+	kdebug("- start_brk   %lx", current->mm->start_brk);
+	kdebug("- brk         %lx", current->mm->brk);
+	kdebug("- start_stack %lx", current->mm->start_stack);
+
+#ifdef ELF_DSBT_PLAT_INIT
+	/*
+	 * The ABI may specify that certain registers be set up in special
+	 * ways. This macro performs whatever initialization to the regs
+	 * structure is required.
+	 */
+	if (interp_params.dynamic_addr) {
+		dynaddr = interp_params.dynamic_addr;
+		dsbt_table = (unsigned long)interp_params.loadmap->dsbt_table;
+	} else {
+		dynaddr = exec_params.dynamic_addr;
+		dsbt_table = (unsigned long)exec_params.loadmap->dsbt_table;
+	}
+
+	kdebug("exec_params.map_addr[%x]", exec_params.map_addr);
+	kdebug("interp_params.map_addr[%x]", interp_params.map_addr);
+	ELF_DSBT_PLAT_INIT(regs,
+			   exec_params.map_addr,
+			   interp_params.map_addr,
+			   dynaddr, dsbt_table);
+#endif
+
+	/* everything is now ready... get the userspace context ready to roll */
+	if (interp_params.entry_addr)
+		entryaddr = interp_params.entry_addr;
+	else
+		entryaddr = exec_params.entry_addr;
+
+	start_thread(regs, entryaddr, current->mm->start_stack);
+
+	retval = 0;
+error:
+	kdebug("load returning: %d", retval);
+	if (interpreter) {
+		allow_write_access(interpreter);
+		fput(interpreter);
+	}
+	kfree(interpreter_name);
+	kfree(exec_params.phdrs);
+	kfree(interp_params.phdrs);
+	kfree(exec_params.dynamic);
+	kfree(interp_params.dynamic);
+	kfree(exec_params.loadmap);
+	kfree(interp_params.loadmap);
+	return retval;
+
+	/* unrecoverable error - kill the process */
+error_kill:
+	send_sig(SIGSEGV, current, 0);
+	goto error;
+
+}
+
+static int __init init_elf_dsbt_binfmt(void)
+{
+	return register_binfmt(&elf_dsbt_format);
+}
+
+static void __exit exit_elf_dsbt_binfmt(void)
+{
+	unregister_binfmt(&elf_dsbt_format);
+}
+
+core_initcall(init_elf_dsbt_binfmt);
+module_exit(exit_elf_dsbt_binfmt);
+MODULE_LICENSE("GPL");
diff --git a/include/linux/elf-dsbt.h b/include/linux/elf-dsbt.h
new file mode 100644
index 0000000..dadc400
--- /dev/null
+++ b/include/linux/elf-dsbt.h
@@ -0,0 +1,88 @@
+/* elf-dsbt.h: DSBT ELF load map
+ *
+ * Copyright (C) 2010, 2011 Texas Instruments Incorporated
+ * Written by Mark Salter <msalter@...hat.com>
+ * Based on elf-fdpic.h
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_ELF_DSBT_H
+#define _LINUX_ELF_DSBT_H
+
+#include <linux/elf.h>
+
+#if ELF_CLASS == ELFCLASS32
+#define elf_dyn Elf32_Dyn
+#else
+#define elf_dyn Elf64_Dyn
+#endif
+
+#define ELF_DSBT_LOADMAP_VERSION	0x0000
+
+/* This data structure represents a PT_LOAD segment.  */
+struct elf32_dsbt_loadseg {
+	/* Core address to which the segment is mapped.  */
+	Elf32_Addr addr;
+	/* VMA recorded in the program header.  */
+	Elf32_Addr p_vaddr;
+	/* Size of this segment in memory.  */
+	Elf32_Word p_memsz;
+};
+
+struct elf32_dsbt_loadmap {
+	/* Protocol version number, must be zero.  */
+	Elf32_Word version;
+
+	/* Pointer to DSBT */
+	unsigned   *dsbt_table;
+	unsigned   dsbt_size;
+	unsigned   dsbt_index;
+
+	/* number of segments */
+	Elf32_Word nsegs;
+
+	/* The actual memory map.  */
+	struct elf32_dsbt_loadseg segs[0];
+};
+
+/* internal segment mappings for ELF DSBT loader */
+struct elf32_dsbt_seg {
+	Elf32_Addr	addr;		/* core address to which mapped */
+	Elf32_Addr	p_vaddr;	/* VMA recorded in file */
+	Elf32_Off	p_offset;	/* file offset */
+	Elf32_Word	p_filesz;	/* initialized data in file */
+	Elf32_Word	p_memsz;	/* allocation size recorded in file */
+};
+
+/*
+ * binfmt binary parameters structure
+ */
+struct elf_dsbt_params {
+	struct elfhdr			hdr;		/* ref copy of ELF header */
+	struct elf_phdr			*phdrs;		/* ref copy of PT_PHDR table */
+	elf_dyn				*dynamic;	/* ref copy of .dynamic section */
+	struct elf32_dsbt_seg           code_seg;       /* mapping for code segment */
+	struct elf32_dsbt_seg           data_seg;       /* mapping for data segment */
+	struct elf32_dsbt_seg           *extra_segs;    /* mapping for extra segments */
+	struct elf32_dsbt_loadmap       *loadmap;       /* loadmap to be passed to userspace */
+	int				num_new;
+	unsigned long			elfhdr_addr;	/* mapped ELF header user address */
+	unsigned long			ph_addr;	/* mapped PT_PHDR user address */
+	unsigned long			map_addr;	/* mapped loadmap user address */
+	unsigned long			entry_addr;	/* mapped entry user address */
+	unsigned long			stack_size;	/* stack size requested (PT_GNU_STACK) */
+	unsigned long			dynamic_addr;	/* mapped PT_DYNAMIC user address */
+	unsigned long			flags;
+	unsigned long			dsbt_base;
+	unsigned int			dsbt_size;
+	unsigned int			dsbt_index;
+
+#define ELF_DSBT_FLAG_PRESENT		0x00000001	/* T if this object is present */
+#define ELF_DSBT_FLAG_EXECUTABLE	0x00000002	/* T if this object is the executable */
+};
+
+#endif /* _LINUX_ELF_DSBT_H */
-- 
1.6.2.5

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