/* * This file is subject to the terms and conditions of the GNU General Public * License.  See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2009, 2010 Cavium Networks, Inc. */  #include <linux/kernel.h>#include <linux/err.h>#include <linux/sched.h>#include <linux/mm.h>#include <linux/init.h>#include <linux/binfmts.h>#include <linux/elf.h>#include <linux/vmalloc.h>#include <linux/unistd.h> #include <asm/vdso.h>#include <asm/uasm.h> /* * Including <asm/unistd.h> would give use the 64-bit syscall numbers ... */#define __NR_O32_sigreturn		4119#define __NR_O32_rt_sigreturn		4193#define __NR_N32_rt_sigreturn		6211 static struct page *vdso_page; static void __init install_trampoline(u32 *tramp, unsigned int sigreturn){	uasm_i_addiu(&tramp, 2, 0, sigreturn);	/* li v0, sigreturn */	uasm_i_syscall(&tramp, 0);} static int __init init_vdso(void){	struct mips_vdso *vdso; 	vdso_page = alloc_page(GFP_KERNEL);	if (!vdso_page)		panic("Cannot allocate vdso"); 	vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);	if (!vdso)		panic("Cannot map vdso");	clear_page(vdso); 	install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn);#ifdef CONFIG_32BIT	install_trampoline(vdso->signal_trampoline, __NR_sigreturn);#else	install_trampoline(vdso->n32_rt_signal_trampoline,			   __NR_N32_rt_sigreturn);	install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn);	install_trampoline(vdso->o32_rt_signal_trampoline,			   __NR_O32_rt_sigreturn);#endif 	vunmap(vdso); 	return 0;}subsys_initcall(init_vdso); static unsigned long vdso_addr(unsigned long start){	return STACK_TOP;} int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp){	int ret;	unsigned long addr;	struct mm_struct *mm = current->mm; 	down_write(&mm->mmap_sem); 	addr = vdso_addr(mm->start_stack); 	addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0);	if (IS_ERR_VALUE(addr)) {		ret = addr;		goto up_fail;	} 	ret = install_special_mapping(mm, addr, PAGE_SIZE,				      VM_READ|VM_EXEC|				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,				      &vdso_page); 	if (ret)		goto up_fail; 	mm->context.vdso = (void *)addr; up_fail:	up_write(&mm->mmap_sem);	return ret;} const char *arch_vma_name(struct vm_area_struct *vma){	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)		return "[vdso]";	return NULL;}