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 | 50 +++
arch/loongarch/include/asm/vdso/clocksource.h | 8 +
.../loongarch/include/asm/vdso/gettimeofday.h | 101 ++++++
arch/loongarch/include/asm/vdso/processor.h | 14 +
arch/loongarch/include/asm/vdso/vdso.h | 42 +++
arch/loongarch/include/asm/vdso/vsyscall.h | 27 ++
arch/loongarch/kernel/vdso.c | 132 ++++++++
arch/loongarch/vdso/Makefile | 97 ++++++
arch/loongarch/vdso/elf.S | 15 +
arch/loongarch/vdso/genvdso.c | 311 ++++++++++++++++++
arch/loongarch/vdso/genvdso.h | 122 +++++++
arch/loongarch/vdso/sigreturn.S | 24 ++
arch/loongarch/vdso/vdso.lds.S | 65 ++++
arch/loongarch/vdso/vgettimeofday.c | 26 ++
14 files changed, 1034 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 100644 arch/loongarch/vdso/genvdso.c
create mode 100644 arch/loongarch/vdso/genvdso.h
create mode 100644 arch/loongarch/vdso/sigreturn.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..d137ee9b217a
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso.h
@@ -0,0 +1,50 @@
+/* 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_image - Details of a VDSO image.
+ * @data: Pointer to VDSO image data (page-aligned).
+ * @size: Size of the VDSO image data (page-aligned).
+ * @off_sigreturn: Offset of the sigreturn() trampoline.
+ * @off_rt_sigreturn: Offset of the rt_sigreturn() trampoline.
+ * @mapping: Special mapping structure.
+ *
+ * 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_image {
+ void *data;
+ unsigned long size;
+
+ unsigned long off_sigreturn;
+ unsigned long off_rt_sigreturn;
+
+ struct vm_special_mapping mapping;
+};
+
+/*
+ * The following structures are auto-generated as part of the build for each
+ * ABI by genvdso, see arch/loongarch/vdso/Makefile.
+ */
+
+extern struct loongarch_vdso_image vdso_image;
+
+union loongarch_vdso_data {
+ struct vdso_data data[CS_BASES];
+ u8 page[PAGE_SIZE];
+};
+
+#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..d86bfd3a890e
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/gettimeofday.h
@@ -0,0 +1,101 @@
+/* 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/vdso/vdso.h>
+#include <asm/clocksource.h>
+#include <asm/unistd.h>
+#include <asm/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..873a983614ac
--- /dev/null
+++ b/arch/loongarch/include/asm/vdso/vdso.h
@@ -0,0 +1,42 @@
+/* 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;
+
+ /*
+ * Get the base load address of the VDSO. We have to avoid generating
+ * relocations and references to the GOT because ld.so does not peform
+ * relocations on the VDSO. We use the current offset from the VDSO base
+ * and perform a PC-relative branch which gives the absolute address in
+ * ra, and take the difference. The assembler chokes on
+ * "li.w %0, _start - .", so embed the offset as a word and branch over
+ * it.
+ *
+ */
+
+ __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..82635c3a4d74
--- /dev/null
+++ b/arch/loongarch/kernel/vdso.c
@@ -0,0 +1,132 @@
+// 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/abi.h>
+#include <asm/page.h>
+#include <asm/vdso.h>
+#include <vdso/helpers.h>
+#include <vdso/vsyscall.h>
+
+/* Kernel-provided data used by the VDSO. */
+static union loongarch_vdso_data loongarch_vdso_data __page_aligned_data;
+struct vdso_data *vdso_data = loongarch_vdso_data.data;
+
+/*
+ * Mapping for the VDSO data pages. The real pages are mapped manually, as
+ * what we map and where within the area they are mapped is determined at
+ * runtime.
+ */
+static struct page *no_pages[] = { NULL };
+static struct vm_special_mapping vdso_vvar_mapping = {
+ .name = "[vvar]",
+ .pages = no_pages,
+};
+
+static void __init init_vdso_image(struct loongarch_vdso_image *image)
+{
+ unsigned long num_pages, i;
+ unsigned long data_pfn;
+
+ BUG_ON(!PAGE_ALIGNED(image->data));
+ BUG_ON(!PAGE_ALIGNED(image->size));
+
+ num_pages = image->size / PAGE_SIZE;
+
+ data_pfn = __phys_to_pfn(__pa_symbol(image->data));
+ for (i = 0; i < num_pages; i++)
+ image->mapping.pages[i] = pfn_to_page(data_pfn + i);
+}
+
+static int __init init_vdso(void)
+{
+ init_vdso_image(&vdso_image);
+ 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)
+{
+ struct loongarch_vdso_image *image = current->thread.abi->vdso;
+ struct mm_struct *mm = current->mm;
+ unsigned long vvar_size, size, base, data_addr, vdso_addr;
+ struct vm_area_struct *vma;
+ int ret;
+
+ 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 + image->size;
+
+ base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
+ if (IS_ERR_VALUE(base)) {
+ ret = base;
+ goto out;
+ }
+
+ data_addr = base;
+ vdso_addr = data_addr + PAGE_SIZE;
+
+ vma = _install_special_mapping(mm, base, vvar_size,
+ VM_READ | VM_MAYREAD,
+ &vdso_vvar_mapping);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto out;
+ }
+
+ /* Map 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 image. */
+ vma = _install_special_mapping(mm, vdso_addr, image->size,
+ VM_READ | VM_EXEC |
+ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+ &image->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..99810605c6fa
--- /dev/null
+++ b/arch/loongarch/vdso/Makefile
@@ -0,0 +1,97 @@
+# 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 $@ $<
+
+# Strip rule for the raw .so files
+$(obj)/%.so.raw: OBJCOPYFLAGS := -S
+$(obj)/%.so.raw: $(obj)/%.so.dbg.raw FORCE
+ $(call if_changed,objcopy)
+
+hostprogs := genvdso
+
+quiet_cmd_genvdso = GENVDSO $@
+define cmd_genvdso
+ $(foreach file,$(filter %.raw,$^),cp $(file) $(file:%.raw=%) &&) \
+ $(obj)/genvdso $(<:%.raw=%) $(<:%.dbg.raw=%) $@ $(VDSO_NAME)
+endef
+
+#
+# Build native VDSO.
+#
+
+native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
+
+targets += $(obj-vdso-y)
+targets += vdso.lds
+targets += vdso.so.dbg.raw vdso.so.raw
+targets += vdso.so.dbg vdso.so
+targets += vdso-image.c
+
+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.raw: $(obj)/vdso.lds $(obj-vdso) FORCE
+ $(call if_changed,vdsold_and_vdso_check)
+
+$(obj)/vdso-image.c: $(obj)/vdso.so.dbg.raw $(obj)/vdso.so.raw \
+ $(obj)/genvdso FORCE
+ $(call if_changed,genvdso)
+
+obj-y += vdso-image.o
+
+
+
+# FIXME: Need install rule for debug.
+# Needs to deal with dependency for generation of dbg by cmd_genvdso...
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/genvdso.c b/arch/loongarch/vdso/genvdso.c
new file mode 100644
index 000000000000..3a3d5f776a2f
--- /dev/null
+++ b/arch/loongarch/vdso/genvdso.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ *
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+/*
+ * This tool is used to generate the real VDSO images from the raw image. It
+ * first patches up the LoongArch ABI flags and GNU attributes sections defined in
+ * elf.S to have the correct name and type. It then generates a C source file
+ * to be compiled into the kernel containing the VDSO image data and a
+ * loongarch_vdso_image struct for it, including symbol offsets extracted from the
+ * image.
+ *
+ * We need to be passed both a stripped and unstripped VDSO image. The stripped
+ * image is compiled into the kernel, but we must also patch up the unstripped
+ * image's ABI flags sections so that it can be installed and used for
+ * debugging.
+ */
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <byteswap.h>
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Define these in case the system elf.h is not new enough to have them. */
+#ifndef EM_LOONGARCH
+#define EM_LOONGARCH 258
+#endif
+
+#ifndef EF_LARCH_ABI_LP32
+#define EF_LARCH_ABI_LP32 0x00000001 /* LP32 ABI. */
+#endif
+
+#ifndef EF_LARCH_ABI_LPX32
+#define EF_LARCH_ABI_LPX32 0x00000002 /* LPX32 ABI */
+#endif
+
+#ifndef EF_LARCH_ABI_LP64
+#define EF_LARCH_ABI_LP64 0x00000003 /* LP64 ABI */
+#endif
+
+enum {
+ ABI_LP32 = (1 << 0),
+ ABI_LPX32 = (1 << 1),
+ ABI_LP64 = (1 << 2),
+
+ ABI_ALL = ABI_LP32 | ABI_LPX32 | ABI_LP64,
+};
+
+/* Symbols the kernel requires offsets for. */
+static struct {
+ const char *name;
+ const char *offset_name;
+ unsigned int abis;
+} vdso_symbols[] = {
+ { "__vdso_rt_sigreturn", "off_rt_sigreturn", ABI_ALL },
+ {}
+};
+
+static const char *program_name;
+static const char *vdso_name;
+static unsigned char elf_class;
+static unsigned int elf_abi;
+static bool need_swap;
+static FILE *out_file;
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define HOST_ORDER ELFDATA2LSB
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define HOST_ORDER ELFDATA2MSB
+#endif
+
+#define BUILD_SWAP(bits) \
+ static uint##bits##_t swap_uint##bits(uint##bits##_t val) \
+ { \
+ return need_swap ? bswap_##bits(val) : val; \
+ }
+
+BUILD_SWAP(16)
+BUILD_SWAP(32)
+BUILD_SWAP(64)
+
+#define __FUNC(name, bits) name##bits
+#define _FUNC(name, bits) __FUNC(name, bits)
+#define FUNC(name) _FUNC(name, ELF_BITS)
+
+#define __ELF(x, bits) Elf##bits##_##x
+#define _ELF(x, bits) __ELF(x, bits)
+#define ELF(x) _ELF(x, ELF_BITS)
+
+/*
+ * Include genvdso.h twice with ELF_BITS defined differently to get functions
+ * for both ELF32 and ELF64.
+ */
+
+#define ELF_BITS 32
+#include "genvdso.h"
+#undef ELF_BITS
+
+#define ELF_BITS 64
+#include "genvdso.h"
+#undef ELF_BITS
+
+static void *map_vdso(const char *path, size_t *_size)
+{
+ int fd;
+ struct stat stat;
+ void *addr;
+ const Elf32_Ehdr *ehdr;
+
+ fd = open(path, O_RDWR);
+ if (fd < 0) {
+ fprintf(stderr, "%s: Failed to open '%s': %s\n", program_name,
+ path, strerror(errno));
+ return NULL;
+ }
+
+ if (fstat(fd, &stat) != 0) {
+ fprintf(stderr, "%s: Failed to stat '%s': %s\n", program_name,
+ path, strerror(errno));
+ return NULL;
+ }
+
+ addr = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
+ 0);
+ if (addr == MAP_FAILED) {
+ fprintf(stderr, "%s: Failed to map '%s': %s\n", program_name,
+ path, strerror(errno));
+ return NULL;
+ }
+
+ /* ELF32/64 header formats are the same for the bits we're checking. */
+ ehdr = addr;
+
+ if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) {
+ fprintf(stderr, "%s: '%s' is not an ELF file\n", program_name,
+ path);
+ return NULL;
+ }
+
+ elf_class = ehdr->e_ident[EI_CLASS];
+ switch (elf_class) {
+ case ELFCLASS32:
+ case ELFCLASS64:
+ break;
+ default:
+ fprintf(stderr, "%s: '%s' has invalid ELF class\n",
+ program_name, path);
+ return NULL;
+ }
+
+ switch (ehdr->e_ident[EI_DATA]) {
+ case ELFDATA2LSB:
+ case ELFDATA2MSB:
+ need_swap = ehdr->e_ident[EI_DATA] != HOST_ORDER;
+ break;
+ default:
+ fprintf(stderr, "%s: '%s' has invalid ELF data order\n",
+ program_name, path);
+ return NULL;
+ }
+
+ if (swap_uint16(ehdr->e_machine) != EM_LOONGARCH) {
+ fprintf(stderr,
+ "%s: '%s' has invalid ELF machine (expected EM_LOONGARCH)\n",
+ program_name, path);
+ return NULL;
+ } else if (swap_uint16(ehdr->e_type) != ET_DYN) {
+ fprintf(stderr,
+ "%s: '%s' has invalid ELF type (expected ET_DYN)\n",
+ program_name, path);
+ return NULL;
+ }
+
+ *_size = stat.st_size;
+ return addr;
+}
+
+static bool patch_vdso(const char *path, void *vdso)
+{
+ if (elf_class == ELFCLASS64)
+ return patch_vdso64(path, vdso);
+ else
+ return patch_vdso32(path, vdso);
+}
+
+static bool get_symbols(const char *path, void *vdso)
+{
+ if (elf_class == ELFCLASS64)
+ return get_symbols64(path, vdso);
+ else
+ return get_symbols32(path, vdso);
+}
+
+int main(int argc, char **argv)
+{
+ const char *dbg_vdso_path, *vdso_path, *out_path;
+ void *dbg_vdso, *vdso;
+ size_t dbg_vdso_size, vdso_size, i;
+
+ program_name = argv[0];
+
+ if (argc < 4 || argc > 5) {
+ fprintf(stderr,
+ "Usage: %s <debug VDSO> <stripped VDSO> <output file> [<name>]\n",
+ program_name);
+ return EXIT_FAILURE;
+ }
+
+ dbg_vdso_path = argv[1];
+ vdso_path = argv[2];
+ out_path = argv[3];
+ vdso_name = (argc > 4) ? argv[4] : "";
+
+ dbg_vdso = map_vdso(dbg_vdso_path, &dbg_vdso_size);
+ if (!dbg_vdso)
+ return EXIT_FAILURE;
+
+ vdso = map_vdso(vdso_path, &vdso_size);
+ if (!vdso)
+ return EXIT_FAILURE;
+
+ /* Patch both the VDSOs' ABI flags sections. */
+ if (!patch_vdso(dbg_vdso_path, dbg_vdso))
+ return EXIT_FAILURE;
+ if (!patch_vdso(vdso_path, vdso))
+ return EXIT_FAILURE;
+
+ if (msync(dbg_vdso, dbg_vdso_size, MS_SYNC) != 0) {
+ fprintf(stderr, "%s: Failed to sync '%s': %s\n", program_name,
+ dbg_vdso_path, strerror(errno));
+ return EXIT_FAILURE;
+ } else if (msync(vdso, vdso_size, MS_SYNC) != 0) {
+ fprintf(stderr, "%s: Failed to sync '%s': %s\n", program_name,
+ vdso_path, strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ out_file = fopen(out_path, "w");
+ if (!out_file) {
+ fprintf(stderr, "%s: Failed to open '%s': %s\n", program_name,
+ out_path, strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ fprintf(out_file, "/* Automatically generated - do not edit */\n");
+ fprintf(out_file, "#include <linux/linkage.h>\n");
+ fprintf(out_file, "#include <linux/mm.h>\n");
+ fprintf(out_file, "#include <asm/vdso.h>\n");
+ fprintf(out_file, "static int vdso_mremap(\n");
+ fprintf(out_file, " const struct vm_special_mapping *sm,\n");
+ fprintf(out_file, " struct vm_area_struct *new_vma)\n");
+ fprintf(out_file, "{\n");
+ fprintf(out_file, " unsigned long new_size =\n");
+ fprintf(out_file, " new_vma->vm_end - new_vma->vm_start;\n");
+ fprintf(out_file, " if (vdso_image.size != new_size)\n");
+ fprintf(out_file, " return -EINVAL;\n");
+ fprintf(out_file, " current->mm->context.vdso =\n");
+ fprintf(out_file, " (void *)(new_vma->vm_start);\n");
+ fprintf(out_file, " return 0;\n");
+ fprintf(out_file, "}\n");
+
+ /* Write out the stripped VDSO data. */
+ fprintf(out_file,
+ "static unsigned char vdso_data[PAGE_ALIGN(%zu)] __page_aligned_data = {\n\t",
+ vdso_size);
+ for (i = 0; i < vdso_size; i++) {
+ if (!(i % 10))
+ fprintf(out_file, "\n\t");
+ fprintf(out_file, "0x%02x, ", ((unsigned char *)vdso)[i]);
+ }
+ fprintf(out_file, "\n};\n");
+
+ /* Preallocate a page array. */
+ fprintf(out_file,
+ "static struct page *vdso_pages[PAGE_ALIGN(%zu) / PAGE_SIZE];\n",
+ vdso_size);
+
+ fprintf(out_file, "struct loongarch_vdso_image vdso_image%s%s = {\n",
+ (vdso_name[0]) ? "_" : "", vdso_name);
+ fprintf(out_file, "\t.data = vdso_data,\n");
+ fprintf(out_file, "\t.size = PAGE_ALIGN(%zu),\n", vdso_size);
+ fprintf(out_file, "\t.mapping = {\n");
+ fprintf(out_file, "\t\t.name = \"[vdso]\",\n");
+ fprintf(out_file, "\t\t.pages = vdso_pages,\n");
+ fprintf(out_file, "\t\t.mremap = vdso_mremap,\n");
+ fprintf(out_file, "\t},\n");
+
+ /* Calculate and write symbol offsets to <output file> */
+ if (!get_symbols(dbg_vdso_path, dbg_vdso)) {
+ unlink(out_path);
+ return EXIT_FAILURE;
+ }
+
+ fprintf(out_file, "};\n");
+
+ return EXIT_SUCCESS;
+}
diff --git a/arch/loongarch/vdso/genvdso.h b/arch/loongarch/vdso/genvdso.h
new file mode 100644
index 000000000000..4cc83e996607
--- /dev/null
+++ b/arch/loongarch/vdso/genvdso.h
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
+ *
+ * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
+ */
+
+static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
+{
+ const ELF(Ehdr) *ehdr = vdso;
+ void *shdrs;
+ ELF(Shdr) *shdr;
+ uint16_t sh_count, sh_entsize, i;
+
+ shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
+ sh_count = swap_uint16(ehdr->e_shnum);
+ sh_entsize = swap_uint16(ehdr->e_shentsize);
+
+ shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx));
+
+ for (i = 0; i < sh_count; i++) {
+ shdr = shdrs + (i * sh_entsize);
+
+ /*
+ * Ensure there are no relocation sections - ld.so does not
+ * relocate the VDSO so if there are relocations things will
+ * break.
+ */
+ switch (swap_uint32(shdr->sh_type)) {
+ case SHT_REL:
+ case SHT_RELA:
+ fprintf(stderr,
+ "%s: '%s' contains relocation sections\n",
+ program_name, path);
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static inline bool FUNC(get_symbols)(const char *path, void *vdso)
+{
+ const ELF(Ehdr) *ehdr = vdso;
+ void *shdrs, *symtab;
+ ELF(Shdr) *shdr;
+ const ELF(Sym) *sym;
+ char *strtab, *name;
+ uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j;
+ uint64_t offset;
+ uint32_t flags;
+
+ shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
+ sh_count = swap_uint16(ehdr->e_shnum);
+ sh_entsize = swap_uint16(ehdr->e_shentsize);
+
+ for (i = 0; i < sh_count; i++) {
+ shdr = shdrs + (i * sh_entsize);
+
+ if (swap_uint32(shdr->sh_type) == SHT_SYMTAB)
+ break;
+ }
+
+ if (i == sh_count) {
+ fprintf(stderr, "%s: '%s' has no symbol table\n", program_name,
+ path);
+ return false;
+ }
+
+ /* Get flags */
+ flags = swap_uint32(ehdr->e_flags);
+ switch (flags) {
+ case EF_LARCH_ABI_LP32:
+ elf_abi = ABI_LP32;
+ break;
+ case EF_LARCH_ABI_LPX32:
+ elf_abi = ABI_LPX32;
+ break;
+ case EF_LARCH_ABI_LP64:
+ default:
+ elf_abi = ABI_LP64;
+ break;
+ }
+
+ /* Get symbol table. */
+ symtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+ st_entsize = FUNC(swap_uint)(shdr->sh_entsize);
+ st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize;
+
+ /* Get string table. */
+ shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize);
+ strtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+
+ /* Write offsets for symbols needed by the kernel. */
+ for (i = 0; vdso_symbols[i].name; i++) {
+ if (!(vdso_symbols[i].abis & elf_abi))
+ continue;
+
+ for (j = 0; j < st_count; j++) {
+ sym = symtab + (j * st_entsize);
+ name = strtab + swap_uint32(sym->st_name);
+
+ if (!strcmp(name, vdso_symbols[i].name)) {
+ offset = FUNC(swap_uint)(sym->st_value);
+
+ fprintf(out_file,
+ "\t.%s = 0x%" PRIx64 ",\n",
+ vdso_symbols[i].offset_name, offset);
+ break;
+ }
+ }
+
+ if (j == st_count) {
+ fprintf(stderr,
+ "%s: '%s' is missing required symbol '%s'\n",
+ program_name, path, vdso_symbols[i].name);
+ return false;
+ }
+ }
+
+ return true;
+}
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.lds.S b/arch/loongarch/vdso/vdso.lds.S
new file mode 100644
index 000000000000..57736ff67a4d
--- /dev/null
+++ b/arch/loongarch/vdso/vdso.lds.S
@@ -0,0 +1,65 @@
+/* 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_2.6 {
+ global:
+ __vdso_clock_gettime;
+ __vdso_gettimeofday;
+ local: *;
+ };
+}
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
