1 files changed, 122 insertions, 0 deletions
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
new file mode 100644
index 000000000..ed2a27872
--- /dev/null
+++ b/arch/mips/kernel/vdso.c
@@ -0,0 +1,122 @@
+/*
+ * 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 <linux/random.h>
+
+#include <asm/vdso.h>
+#include <asm/uasm.h>
+#include <asm/processor.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)
+{
+	unsigned long offset = 0UL;
+
+	if (current->flags & PF_RANDOMIZE) {
+		offset = get_random_int();
+		offset <<= PAGE_SHIFT;
+		if (TASK_IS_32BIT_ADDR)
+			offset &= 0xfffffful;
+		else
+			offset &= 0xffffffful;
+	}
+
+	return STACK_TOP + offset;
+}
+
+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;
+}