elf.c
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/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/binfmts.h>
#include <linux/compat.h>
#include <linux/mman.h>
#include <linux/elf.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/vdso.h>
#include <arch/sim.h>
/* Notify a running simulator, if any, that an exec just occurred. */
static void sim_notify_exec(const char *binary_name)
{
unsigned char c;
do {
c = *binary_name++;
__insn_mtspr(SPR_SIM_CONTROL,
(SIM_CONTROL_OS_EXEC
| (c << _SIM_CONTROL_OPERATOR_BITS)));
} while (c);
}
static int notify_exec(struct mm_struct *mm)
{
char *buf, *path;
struct vm_area_struct *vma;
if (!sim_is_simulator())
return 1;
if (mm->exe_file == NULL)
return 0;
for (vma = current->mm->mmap; ; vma = vma->vm_next) {
if (vma == NULL)
return 0;
if (vma->vm_file == mm->exe_file)
break;
}
buf = (char *) __get_free_page(GFP_KERNEL);
if (buf == NULL)
return 0;
path = d_path(&mm->exe_file->f_path, buf, PAGE_SIZE);
if (IS_ERR(path)) {
free_page((unsigned long)buf);
return 0;
}
/*
* Notify simulator of an ET_DYN object so we know the load address.
* The somewhat cryptic overuse of SIM_CONTROL_DLOPEN allows us
* to be backward-compatible with older simulator releases.
*/
if (vma->vm_start == (ELF_ET_DYN_BASE & PAGE_MASK)) {
char buf[64];
int i;
snprintf(buf, sizeof(buf), "0x%lx:@", vma->vm_start);
for (i = 0; ; ++i) {
char c = buf[i];
__insn_mtspr(SPR_SIM_CONTROL,
(SIM_CONTROL_DLOPEN
| (c << _SIM_CONTROL_OPERATOR_BITS)));
if (c == '\0')
break;
}
}
sim_notify_exec(path);
free_page((unsigned long)buf);
return 1;
}
/* Notify a running simulator, if any, that we loaded an interpreter. */
static void sim_notify_interp(unsigned long load_addr)
{
size_t i;
for (i = 0; i < sizeof(load_addr); i++) {
unsigned char c = load_addr >> (i * 8);
__insn_mtspr(SPR_SIM_CONTROL,
(SIM_CONTROL_OS_INTERP
| (c << _SIM_CONTROL_OPERATOR_BITS)));
}
}
int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack)
{
struct mm_struct *mm = current->mm;
int retval = 0;
down_write(&mm->mmap_sem);
/*
* Notify the simulator that an exec just occurred.
* If we can't find the filename of the mapping, just use
* whatever was passed as the linux_binprm filename.
*/
if (!notify_exec(mm))
sim_notify_exec(bprm->filename);
retval = setup_vdso_pages();
#ifndef __tilegx__
/*
* Set up a user-interrupt mapping here; the user can't
* create one themselves since it is above TASK_SIZE.
* We make it unwritable by default, so the model for adding
* interrupt vectors always involves an mprotect.
*/
if (!retval) {
unsigned long addr = MEM_USER_INTRPT;
addr = mmap_region(NULL, addr, INTRPT_SIZE,
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
if (addr > (unsigned long) -PAGE_SIZE)
retval = (int) addr;
}
#endif
up_write(&mm->mmap_sem);
return retval;
}
void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
{
/* Zero all registers. */
memset(regs, 0, sizeof(*regs));
/* Report the interpreter's load address. */
sim_notify_interp(load_addr);
}