1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 2009, 2010 Cavium Networks, Inc. 7 */ 8 9 10 #include <linux/kernel.h> 11 #include <linux/err.h> 12 #include <linux/sched.h> 13 #include <linux/mm.h> 14 #include <linux/init.h> 15 #include <linux/binfmts.h> 16 #include <linux/elf.h> 17 #include <linux/vmalloc.h> 18 #include <linux/unistd.h> 19 20 #include <asm/vdso.h> 21 #include <asm/uasm.h> 22 23 /* 24 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ... 25 */ 26 #define __NR_O32_sigreturn 4119 27 #define __NR_O32_rt_sigreturn 4193 28 #define __NR_N32_rt_sigreturn 6211 29 30 static struct page *vdso_page; 31 32 static void __init install_trampoline(u32 *tramp, unsigned int sigreturn) 33 { 34 uasm_i_addiu(&tramp, 2, 0, sigreturn); /* li v0, sigreturn */ 35 uasm_i_syscall(&tramp, 0); 36 } 37 38 static int __init init_vdso(void) 39 { 40 struct mips_vdso *vdso; 41 42 vdso_page = alloc_page(GFP_KERNEL); 43 if (!vdso_page) 44 panic("Cannot allocate vdso"); 45 46 vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL); 47 if (!vdso) 48 panic("Cannot map vdso"); 49 clear_page(vdso); 50 51 install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn); 52 #ifdef CONFIG_32BIT 53 install_trampoline(vdso->signal_trampoline, __NR_sigreturn); 54 #else 55 install_trampoline(vdso->n32_rt_signal_trampoline, 56 __NR_N32_rt_sigreturn); 57 install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn); 58 install_trampoline(vdso->o32_rt_signal_trampoline, 59 __NR_O32_rt_sigreturn); 60 #endif 61 62 vunmap(vdso); 63 64 return 0; 65 } 66 subsys_initcall(init_vdso); 67 68 static unsigned long vdso_addr(unsigned long start) 69 { 70 return STACK_TOP; 71 } 72 73 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 74 { 75 int ret; 76 unsigned long addr; 77 struct mm_struct *mm = current->mm; 78 79 down_write(&mm->mmap_sem); 80 81 addr = vdso_addr(mm->start_stack); 82 83 addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0); 84 if (IS_ERR_VALUE(addr)) { 85 ret = addr; 86 goto up_fail; 87 } 88 89 ret = install_special_mapping(mm, addr, PAGE_SIZE, 90 VM_READ|VM_EXEC| 91 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 92 &vdso_page); 93 94 if (ret) 95 goto up_fail; 96 97 mm->context.vdso = (void *)addr; 98 99 up_fail: 100 up_write(&mm->mmap_sem); 101 return ret; 102 } 103 104 const char *arch_vma_name(struct vm_area_struct *vma) 105 { 106 if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) 107 return "[vdso]"; 108 return NULL; 109 } 110