Messages in this thread | | | Date | Sun, 15 May 2022 22:47:16 +0800 | Subject | Re: [PATCH V10 19/22] LoongArch: Add VDSO and VSYSCALL support | From | WANG Xuerui <> |
| |
Hi,
On 5/14/22 16:03, Huacai Chen wrote: > Add VDSO and VSYSCALL support (sigreturn, gettimeofday and its friends) > for LoongArch. > > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> > --- > arch/loongarch/include/asm/vdso.h | 38 +++++ > arch/loongarch/include/asm/vdso/clocksource.h | 8 + > .../loongarch/include/asm/vdso/gettimeofday.h | 99 +++++++++++++ > arch/loongarch/include/asm/vdso/processor.h | 14 ++ > arch/loongarch/include/asm/vdso/vdso.h | 30 ++++ > 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 | 13 ++ > arch/loongarch/vdso/sigreturn.S | 24 +++ > arch/loongarch/vdso/vdso.S | 22 +++ > arch/loongarch/vdso/vdso.lds.S | 72 +++++++++ > arch/loongarch/vdso/vgettimeofday.c | 25 ++++ > 14 files changed, 621 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..996bddae12dc > --- /dev/null > +++ b/arch/loongarch/include/asm/vdso.h > @@ -0,0 +1,38 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Author: Huacai Chen <chenhuacai@loongson.cn> > + * Copyright (C) 2020-2022 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..5fc5a746b1c4 > --- /dev/null > +++ b/arch/loongarch/include/asm/vdso/gettimeofday.h > @@ -0,0 +1,99 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Author: Huacai Chen <chenhuacai@loongson.cn> > + * > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited > + */ > +#ifndef __ASM_VDSO_GETTIMEOFDAY_H > +#define __ASM_VDSO_GETTIMEOFDAY_H > + > +#ifndef __ASSEMBLY__ > + > +#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"); Here ret is being hinted to register $v0, which is in fact the same register as $a0; so I'm afraid the "=r" constraint wouldn't prevent the $a0 from being clobbered before the syscall insn? Changing "v0" to "a0", then "=r" to "+r", could do it, although I cannot build-test it (due to the boot protocol being incompatible with existing shipped systems). Please check this for me... > + > + return ret; > +} > + > +static __always_inline long clock_gettime_fallback( > + clockid_t _clkid, > + struct __kernel_timespec *_ts) > +{ > + register clockid_t clkid asm("a0") = _clkid; > + register struct __kernel_timespec *ts asm("a1") = _ts; > + register long nr asm("a7") = __NR_clock_gettime; > + register long ret asm("v0"); > + > + asm volatile( > + " syscall 0\n" > + : "=r" (ret) > + : "r" (nr), "r" (clkid), "r" (ts) > + : "$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..ef5770b343a0 > --- /dev/null > +++ b/arch/loongarch/include/asm/vdso/processor.h > @@ -0,0 +1,14 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2020-2022 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..5a01643a65b3 > --- /dev/null > +++ b/arch/loongarch/include/asm/vdso/vdso.h > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0-or-later */ > +/* > + * Author: Huacai Chen <chenhuacai@loongson.cn> > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited > + */ > + > +#ifndef __ASSEMBLY__ > + > +#include <asm/asm.h> > +#include <asm/page.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..e20c8ca87473 > --- /dev/null > +++ b/arch/loongarch/kernel/vdso.c > @@ -0,0 +1,138 @@ > +// 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 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 = STACK_TOP; > + > + 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..6b6e16732c60 > --- /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_MARK_LA|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 -G0 \ > + -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..9bb21b9f9583 > --- /dev/null > +++ b/arch/loongarch/vdso/elf.S > @@ -0,0 +1,15 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Author: Huacai Chen <chenhuacai@loongson.cn> > + * > + * Copyright (C) 2020-2022 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..1bb4e12642ff > --- /dev/null > +++ b/arch/loongarch/vdso/gen_vdso_offsets.sh > @@ -0,0 +1,13 @@ > +#!/bin/sh > +# SPDX-License-Identifier: GPL-2.0 > + > +# > +# Derived from RISC-V and ARM64: > +# Author: Will Deacon <will.deacon@arm.com> > +# > +# 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..9cb3c58fad03 > --- /dev/null > +++ b/arch/loongarch/vdso/sigreturn.S > @@ -0,0 +1,24 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Author: Huacai Chen <chenhuacai@loongson.cn> > + * > + * Copyright (C) 2020-2022 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..46789bade6ff > --- /dev/null > +++ b/arch/loongarch/vdso/vdso.S > @@ -0,0 +1,22 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2020-2022 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..955f02de4a2d > --- /dev/null > +++ b/arch/loongarch/vdso/vdso.lds.S > @@ -0,0 +1,72 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Author: Huacai Chen <chenhuacai@loongson.cn> > + * Copyright (C) 2020-2022 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_5.10 { > + 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..b1f4548dae92 > --- /dev/null > +++ b/arch/loongarch/vdso/vgettimeofday.c > @@ -0,0 +1,25 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * LoongArch userspace implementations of gettimeofday() and similar. > + * > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited > + */ > +#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); > +}
Other bits look familiar (it's generic vDSO but shows MIPS heritage too); from my experience with the MIPS vDSO this feels correct as well. Also I think an earlier version of the code is already deployed on my system and obviously working.
The only minor nit is, the proper capitalization "VDSO" should be "vDSO" -- it's short for "virtual DSO" after all. But the all-caps "VDSO" also has many occurrences so I guess it's down to preferences. Either would be okay for me, although I'd personally prefer "vDSO".
With the *other* bit (regarding asm constraints) addressed:
Reviewed-by: WANG Xuerui <git@xen0n.name>
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