[PATCH V4 19/22] LoongArch: Add VDSO and VSYSCALL support

From: Huacai Chen
Date: Mon Sep 27 2021 - 02:55:20 EST

This patch adds VDSO and VSYSCALL support (gettimeofday and its friends)
for LoongArch.

Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
arch/loongarch/include/asm/vdso.h | 38 +++++
arch/loongarch/include/asm/vdso/clocksource.h | 8 +
.../loongarch/include/asm/vdso/gettimeofday.h | 100 +++++++++++++
arch/loongarch/include/asm/vdso/processor.h | 14 ++
arch/loongarch/include/asm/vdso/vdso.h | 31 ++++
arch/loongarch/include/asm/vdso/vsyscall.h | 27 ++++
arch/loongarch/kernel/vdso.c | 138 ++++++++++++++++++
arch/loongarch/vdso/Makefile | 96 ++++++++++++
arch/loongarch/vdso/elf.S | 15 ++
arch/loongarch/vdso/gen_vdso_offsets.sh | 14 ++
arch/loongarch/vdso/sigreturn.S | 24 +++
arch/loongarch/vdso/vdso.S | 22 +++
arch/loongarch/vdso/vdso.lds.S | 72 +++++++++
arch/loongarch/vdso/vgettimeofday.c | 26 ++++
14 files changed, 625 insertions(+)
create mode 100644 arch/loongarch/include/asm/vdso.h
create mode 100644 arch/loongarch/include/asm/vdso/clocksource.h
create mode 100644 arch/loongarch/include/asm/vdso/gettimeofday.h
create mode 100644 arch/loongarch/include/asm/vdso/processor.h
create mode 100644 arch/loongarch/include/asm/vdso/vdso.h
create mode 100644 arch/loongarch/include/asm/vdso/vsyscall.h
create mode 100644 arch/loongarch/kernel/vdso.c
create mode 100644 arch/loongarch/vdso/Makefile
create mode 100644 arch/loongarch/vdso/elf.S
create mode 100755 arch/loongarch/vdso/gen_vdso_offsets.sh
create mode 100644 arch/loongarch/vdso/sigreturn.S
create mode 100644 arch/loongarch/vdso/vdso.S
create mode 100644 arch/loongarch/vdso/vdso.lds.S
create mode 100644 arch/loongarch/vdso/vgettimeofday.c

diff --git a/arch/loongarch/include/asm/vdso.h b/arch/loongarch/include/asm/vdso.h
new file mode 100644
index 000000000000..ed13a1342225
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+#ifndef __ASM_VDSO_H
+#define __ASM_VDSO_H
+
+#include <linux/mm_types.h>
+#include <vdso/datapage.h>
+
+#include <asm/barrier.h>
+
+/**
+ * struct loongarch_vdso_info - Details of a VDSO image.
+ * @vdso: Pointer to VDSO image (page-aligned).
+ * @size: Size of the VDSO image (page-aligned).
+ * @off_rt_sigreturn: Offset of the rt_sigreturn() trampoline.
+ * @code_mapping: Special mapping structure for vdso code.
+ * @code_mapping: Special mapping structure for vdso data.
+ *
+ * This structure contains details of a VDSO image, including the image data
+ * and offsets of certain symbols required by the kernel. It is generated as
+ * part of the VDSO build process, aside from the mapping page array, which is
+ * populated at runtime.
+ */
+struct loongarch_vdso_info {
+ void *vdso;
+ unsigned long size;
+ unsigned long offset_sigreturn;
+ struct vm_special_mapping code_mapping;
+ struct vm_special_mapping data_mapping;
+};
+
+extern struct loongarch_vdso_info vdso_info;
+
+#endif /* __ASM_VDSO_H */
diff --git a/arch/loongarch/include/asm/vdso/clocksource.h b/arch/loongarch/include/asm/vdso/clocksource.h
new file mode 100644
index 000000000000..13cd580d406d
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/clocksource.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __ASM_VDSOCLOCKSOURCE_H
+#define __ASM_VDSOCLOCKSOURCE_H
+
+#define VDSO_ARCH_CLOCKMODES \
+ VDSO_CLOCKMODE_CPU
+
+#endif /* __ASM_VDSOCLOCKSOURCE_H */
diff --git a/arch/loongarch/include/asm/vdso/gettimeofday.h b/arch/loongarch/include/asm/vdso/gettimeofday.h
new file mode 100644
index 000000000000..18ae4c9e2bdd
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/gettimeofday.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ *
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+#ifndef __ASM_VDSO_GETTIMEOFDAY_H
+#define __ASM_VDSO_GETTIMEOFDAY_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/barrier.h>
+#include <asm/unistd.h>
+#include <asm/vdso/vdso.h>
+
+#define VDSO_HAS_CLOCK_GETRES 1
+
+static __always_inline long gettimeofday_fallback(
+ struct __kernel_old_timeval *_tv,
+ struct timezone *_tz)
+{
+ register struct __kernel_old_timeval *tv asm("a0") = _tv;
+ register struct timezone *tz asm("a1") = _tz;
+ register long nr asm("a7") = __NR_gettimeofday;
+ register long ret asm("v0");
+
+ asm volatile(
+ " syscall 0\n"
+ : "=r" (ret)
+ : "r" (nr), "r" (tv), "r" (tz)
+ : "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
+ "$t8", "memory");
+
+ return ret;
+}
+
+static __always_inline long clock_gettime_fallback(
+ clockid_t _clkid,
+ struct __kernel_timespec *_ts)
+{
+ register clockid_t clkid asm("a0") = _clkid;
+ register struct __kernel_timespec *ts asm("a1") = _ts;
+ register long nr asm("a7") = __NR_clock_gettime;
+ register long ret asm("v0");
+
+ asm volatile(
+ " syscall 0\n"
+ : "=r" (ret)
+ : "r" (nr), "r" (clkid), "r" (ts)
+ : "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
+ "$t8", "memory");
+
+ return ret;
+}
+
+static __always_inline int clock_getres_fallback(
+ clockid_t _clkid,
+ struct __kernel_timespec *_ts)
+{
+ register clockid_t clkid asm("a0") = _clkid;
+ register struct __kernel_timespec *ts asm("a1") = _ts;
+ register long nr asm("a7") = __NR_clock_getres;
+ register long ret asm("v0");
+
+ asm volatile(
+ " syscall 0\n"
+ : "=r" (ret)
+ : "r" (nr), "r" (clkid), "r" (ts)
+ : "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
+ "$t8", "memory");
+
+ return ret;
+}
+
+static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
+ const struct vdso_data *vd)
+{
+ unsigned int count;
+
+ __asm__ __volatile__(
+ " rdtime.d %0, $zero\n"
+ : "=r" (count));
+
+ return count;
+}
+
+static inline bool loongarch_vdso_hres_capable(void)
+{
+ return true;
+}
+#define __arch_vdso_hres_capable loongarch_vdso_hres_capable
+
+static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
+{
+ return get_vdso_data();
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
diff --git a/arch/loongarch/include/asm/vdso/processor.h b/arch/loongarch/include/asm/vdso/processor.h
new file mode 100644
index 000000000000..7fb46fd66512
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/processor.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+#define cpu_relax() barrier()
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */
diff --git a/arch/loongarch/include/asm/vdso/vdso.h b/arch/loongarch/include/asm/vdso/vdso.h
new file mode 100644
index 000000000000..e878e12c233f
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/vdso.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+#ifndef __ASSEMBLY__
+
+#include <asm/asm.h>
+#include <asm/page.h>
+#include <asm/vdso.h>
+
+static inline unsigned long get_vdso_base(void)
+{
+ unsigned long addr;
+
+ __asm__(
+ " la.pcrel %0, _start\n"
+ : "=r" (addr)
+ :
+ :);
+
+ return addr;
+}
+
+static inline const struct vdso_data *get_vdso_data(void)
+{
+ return (const struct vdso_data *)(get_vdso_base() - PAGE_SIZE);
+}
+
+#endif /* __ASSEMBLY__ */
diff --git a/arch/loongarch/include/asm/vdso/vsyscall.h b/arch/loongarch/include/asm/vdso/vsyscall.h
new file mode 100644
index 000000000000..5de615383a22
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/vsyscall.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSO_VSYSCALL_H
+#define __ASM_VDSO_VSYSCALL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/timekeeper_internal.h>
+#include <vdso/datapage.h>
+
+extern struct vdso_data *vdso_data;
+
+/*
+ * Update the vDSO data page to keep in sync with kernel timekeeping.
+ */
+static __always_inline
+struct vdso_data *__loongarch_get_k_vdso_data(void)
+{
+ return vdso_data;
+}
+#define __arch_get_k_vdso_data __loongarch_get_k_vdso_data
+
+/* The asm-generic header needs to be included after the definitions above */
+#include <asm-generic/vdso/vsyscall.h>
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_VSYSCALL_H */
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
new file mode 100644
index 000000000000..b759d573d4d8
--- /dev/null
+++ b/arch/loongarch/kernel/vdso.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ * Copyright (C) 2020-2021 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 loongarch_vdso_data {
+ u8 page[PAGE_SIZE];
+ struct vdso_data data[CS_BASES];
+} loongarch_vdso_data __page_aligned_data;
+struct vdso_data *vdso_data = loongarch_vdso_data.data;
+static struct page *vdso_pages[] = { NULL };
+
+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, pfn;
+
+ BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));
+ BUG_ON(!PAGE_ALIGNED(vdso_info.size));
+
+ 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;
+
+ if (current->flags & PF_RANDOMIZE) {
+ base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
+ 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 page.
+ */
+ vvar_size = PAGE_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 + PAGE_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(vdso_data) >> PAGE_SHIFT,
+ PAGE_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;
+}
diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile
new file mode 100644
index 000000000000..7e4c5cba81d6
--- /dev/null
+++ b/arch/loongarch/vdso/Makefile
@@ -0,0 +1,96 @@
+# SPDX-License-Identifier: GPL-2.0
+# Objects to go into the VDSO.
+
+# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
+# the inclusion of generic Makefile.
+ARCH_REL_TYPE_ABS := R_LARCH_32|R_LARCH_64|R_LARCH_JUMP_SLOT
+include $(srctree)/lib/vdso/Makefile
+
+obj-vdso-y := elf.o vgettimeofday.o sigreturn.o
+
+# Common compiler flags between ABIs.
+ccflags-vdso := \
+ $(filter -I%,$(KBUILD_CFLAGS)) \
+ $(filter -E%,$(KBUILD_CFLAGS)) \
+ $(filter -march=%,$(KBUILD_CFLAGS)) \
+ $(filter -m%-float,$(KBUILD_CFLAGS)) \
+ -D__VDSO__
+
+ifeq ($(cc-name),clang)
+ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS))
+endif
+
+cflags-vdso := $(ccflags-vdso) \
+ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
+ -O2 -g -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
+ -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
+ $(call cc-option, -fno-asynchronous-unwind-tables) \
+ $(call cc-option, -fno-stack-protector)
+aflags-vdso := $(ccflags-vdso) \
+ -D__ASSEMBLY__ -Wa,-gdwarf-2
+
+ifneq ($(c-gettimeofday-y),)
+ CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
+endif
+
+# VDSO linker flags.
+ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
+ $(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \
+ --hash-style=sysv --build-id -T
+
+GCOV_PROFILE := n
+
+#
+# Shared build commands.
+#
+
+quiet_cmd_vdsold_and_vdso_check = LD $@
+ cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
+
+quiet_cmd_vdsoas_o_S = AS $@
+ cmd_vdsoas_o_S = $(CC) $(a_flags) -c -o $@ $<
+
+# Generate VDSO offsets using helper script
+gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
+quiet_cmd_vdsosym = VDSOSYM $@
+ cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
+
+include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
+ $(call if_changed,vdsosym)
+
+#
+# Build native VDSO.
+#
+
+native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
+
+targets += $(obj-vdso-y)
+targets += vdso.lds vdso.so.dbg vdso.so
+
+obj-vdso := $(obj-vdso-y:%.o=$(obj)/%.o)
+
+$(obj-vdso): KBUILD_CFLAGS := $(cflags-vdso) $(native-abi)
+$(obj-vdso): KBUILD_AFLAGS := $(aflags-vdso) $(native-abi)
+
+$(obj)/vdso.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) $(native-abi)
+
+$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
+ $(call if_changed,vdsold_and_vdso_check)
+
+$(obj)/vdso.so: OBJCOPYFLAGS := -S
+$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE
+ $(call if_changed,objcopy)
+
+obj-y += vdso.o
+
+$(obj)/vdso.o : $(obj)/vdso.so
+
+# install commands for the unstripped file
+quiet_cmd_vdso_install = INSTALL $@
+ cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
+
+vdso.so: $(obj)/vdso.so.dbg
+ @mkdir -p $(MODLIB)/vdso
+ $(call cmd,vdso_install)
+
+vdso_install: vdso.so
diff --git a/arch/loongarch/vdso/elf.S b/arch/loongarch/vdso/elf.S
new file mode 100644
index 000000000000..a6d50bf863ff
--- /dev/null
+++ b/arch/loongarch/vdso/elf.S
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ *
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+#include <asm/vdso/vdso.h>
+
+#include <linux/elfnote.h>
+#include <linux/version.h>
+
+ELFNOTE_START(Linux, 0, "a")
+ .long LINUX_VERSION_CODE
+ELFNOTE_END
diff --git a/arch/loongarch/vdso/gen_vdso_offsets.sh b/arch/loongarch/vdso/gen_vdso_offsets.sh
new file mode 100755
index 000000000000..7da255fea213
--- /dev/null
+++ b/arch/loongarch/vdso/gen_vdso_offsets.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+#
+# Derived from RISC-V and ARM64:
+# Author: Will Deacon <will.deacon@xxxxxxx>
+#
+# Match symbols in the DSO that look like VDSO_*; produce a header file
+# of constant offsets into the shared object.
+#
+
+LC_ALL=C
+sed -n -e 's/^00*/0/' -e \
+'s/^\([0-9a-fA-F]*\) . VDSO_\([a-zA-Z0-9_]*\)$/\#define vdso_offset_\2\t0x\1/p'
diff --git a/arch/loongarch/vdso/sigreturn.S b/arch/loongarch/vdso/sigreturn.S
new file mode 100644
index 000000000000..38ce55577510
--- /dev/null
+++ b/arch/loongarch/vdso/sigreturn.S
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ *
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+#include <asm/vdso/vdso.h>
+
+#include <linux/linkage.h>
+#include <uapi/asm/unistd.h>
+
+#include <asm/regdef.h>
+#include <asm/asm.h>
+
+ .section .text
+ .cfi_sections .debug_frame
+
+SYM_FUNC_START(__vdso_rt_sigreturn)
+
+ li.w a7, __NR_rt_sigreturn
+ syscall 0
+
+SYM_FUNC_END(__vdso_rt_sigreturn)
diff --git a/arch/loongarch/vdso/vdso.S b/arch/loongarch/vdso/vdso.S
new file mode 100644
index 000000000000..41951232ef45
--- /dev/null
+++ b/arch/loongarch/vdso/vdso.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ *
+ * Derived from RISC-V:
+ * Copyright (C) 2014 Regents of the University of California
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/page.h>
+
+ __PAGE_ALIGNED_DATA
+
+ .globl vdso_start, vdso_end
+ .balign PAGE_SIZE
+vdso_start:
+ .incbin "arch/loongarch/vdso/vdso.so"
+ .balign PAGE_SIZE
+vdso_end:
+
+ .previous
diff --git a/arch/loongarch/vdso/vdso.lds.S b/arch/loongarch/vdso/vdso.lds.S
new file mode 100644
index 000000000000..ac576420d662
--- /dev/null
+++ b/arch/loongarch/vdso/vdso.lds.S
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+OUTPUT_FORMAT("elf64-loongarch", "elf64-loongarch", "elf64-loongarch")
+
+OUTPUT_ARCH(loongarch)
+
+SECTIONS
+{
+ PROVIDE(_start = .);
+ . = SIZEOF_HEADERS;
+
+ .hash : { *(.hash) } :text
+ .gnu.hash : { *(.gnu.hash) }
+ .dynsym : { *(.dynsym) }
+ .dynstr : { *(.dynstr) }
+ .gnu.version : { *(.gnu.version) }
+ .gnu.version_d : { *(.gnu.version_d) }
+ .gnu.version_r : { *(.gnu.version_r) }
+
+ .note : { *(.note.*) } :text :note
+
+ .text : { *(.text*) } :text
+ PROVIDE (__etext = .);
+ PROVIDE (_etext = .);
+ PROVIDE (etext = .);
+
+ .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
+ .eh_frame : { KEEP (*(.eh_frame)) } :text
+
+ .dynamic : { *(.dynamic) } :text :dynamic
+
+ .rodata : { *(.rodata*) } :text
+
+ _end = .;
+ PROVIDE(end = .);
+
+ /DISCARD/ : {
+ *(.gnu.attributes)
+ *(.note.GNU-stack)
+ *(.data .data.* .gnu.linkonce.d.* .sdata*)
+ *(.bss .sbss .dynbss .dynsbss)
+ }
+}
+
+PHDRS
+{
+ text PT_LOAD FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
+ dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
+ note PT_NOTE FLAGS(4); /* PF_R */
+ eh_frame_hdr PT_GNU_EH_FRAME;
+}
+
+VERSION
+{
+ LINUX_4.17 {
+ global:
+ __vdso_clock_getres;
+ __vdso_clock_gettime;
+ __vdso_gettimeofday;
+ __vdso_rt_sigreturn;
+ local: *;
+ };
+}
+
+/*
+ * Make the sigreturn code visible to the kernel.
+ */
+VDSO_sigreturn = __vdso_rt_sigreturn;
diff --git a/arch/loongarch/vdso/vgettimeofday.c b/arch/loongarch/vdso/vgettimeofday.c
new file mode 100644
index 000000000000..ba5d3cab7a5f
--- /dev/null
+++ b/arch/loongarch/vdso/vgettimeofday.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LoongArch userspace implementations of gettimeofday() and similar.
+ *
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+#include <linux/time.h>
+#include <linux/types.h>
+
+int __vdso_clock_gettime(clockid_t clock,
+ struct __kernel_timespec *ts)
+{
+ return __cvdso_clock_gettime(clock, ts);
+}
+
+int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
+ struct timezone *tz)
+{
+ return __cvdso_gettimeofday(tv, tz);
+}
+
+int __vdso_clock_getres(clockid_t clock_id,
+ struct __kernel_timespec *res)
+{
+ return __cvdso_clock_getres(clock_id, res);
+}
--
2.27.0