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-rw-r--r--arch/loongarch/kernel/vdso.c143
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
new file mode 100644
index 000000000..8c9826062
--- /dev/null
+++ b/arch/loongarch/kernel/vdso.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author: Huacai Chen <chenhuacai@loongson.cn>
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#include <linux/binfmts.h>
+#include <linux/elf.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/timekeeper_internal.h>
+
+#include <asm/page.h>
+#include <asm/vdso.h>
+#include <vdso/helpers.h>
+#include <vdso/vsyscall.h>
+#include <generated/vdso-offsets.h>
+
+extern char vdso_start[], vdso_end[];
+
+/* Kernel-provided data used by the VDSO. */
+static union {
+ u8 page[VDSO_DATA_SIZE];
+ struct loongarch_vdso_data vdata;
+} loongarch_vdso_data __page_aligned_data;
+
+static struct page *vdso_pages[] = { NULL };
+struct vdso_data *vdso_data = loongarch_vdso_data.vdata.data;
+struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata;
+
+static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
+{
+ current->mm->context.vdso = (void *)(new_vma->vm_start);
+
+ return 0;
+}
+
+struct loongarch_vdso_info vdso_info = {
+ .vdso = vdso_start,
+ .size = PAGE_SIZE,
+ .code_mapping = {
+ .name = "[vdso]",
+ .pages = vdso_pages,
+ .mremap = vdso_mremap,
+ },
+ .data_mapping = {
+ .name = "[vvar]",
+ },
+ .offset_sigreturn = vdso_offset_sigreturn,
+};
+
+static int __init init_vdso(void)
+{
+ unsigned long i, cpu, pfn;
+
+ BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));
+ BUG_ON(!PAGE_ALIGNED(vdso_info.size));
+
+ for_each_possible_cpu(cpu)
+ vdso_pdata[cpu].node = cpu_to_node(cpu);
+
+ pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso));
+ for (i = 0; i < vdso_info.size / PAGE_SIZE; i++)
+ vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i);
+
+ return 0;
+}
+subsys_initcall(init_vdso);
+
+static unsigned long vdso_base(void)
+{
+ unsigned long base = STACK_TOP;
+
+ if (current->flags & PF_RANDOMIZE) {
+ base += prandom_u32_max(VDSO_RANDOMIZE_SIZE);
+ base = PAGE_ALIGN(base);
+ }
+
+ return base;
+}
+
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+ int ret;
+ unsigned long vvar_size, size, data_addr, vdso_addr;
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ struct loongarch_vdso_info *info = current->thread.vdso;
+
+ if (mmap_write_lock_killable(mm))
+ return -EINTR;
+
+ /*
+ * Determine total area size. This includes the VDSO data itself
+ * and the data pages.
+ */
+ vvar_size = VDSO_DATA_SIZE;
+ size = vvar_size + info->size;
+
+ data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
+ if (IS_ERR_VALUE(data_addr)) {
+ ret = data_addr;
+ goto out;
+ }
+ vdso_addr = data_addr + VDSO_DATA_SIZE;
+
+ vma = _install_special_mapping(mm, data_addr, vvar_size,
+ VM_READ | VM_MAYREAD,
+ &info->data_mapping);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto out;
+ }
+
+ /* Map VDSO data page. */
+ ret = remap_pfn_range(vma, data_addr,
+ virt_to_phys(&loongarch_vdso_data) >> PAGE_SHIFT,
+ vvar_size, PAGE_READONLY);
+ if (ret)
+ goto out;
+
+ /* Map VDSO code page. */
+ vma = _install_special_mapping(mm, vdso_addr, info->size,
+ VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+ &info->code_mapping);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto out;
+ }
+
+ mm->context.vdso = (void *)vdso_addr;
+ ret = 0;
+
+out:
+ mmap_write_unlock(mm);
+ return ret;
+}