x32: Add x32 VDSO support (1a21d4e0) · Commits · 戴 / test

arch/x86/vdso/.gitignore

+2 −0

Original line number	Diff line number	Diff line
		vdso.lds
		vdso-syms.lds
		vdsox32.lds
		vdsox32-syms.lds
		vdso32-syms.lds
		vdso32-syscall-syms.lds
		vdso32-sysenter-syms.lds

arch/x86/vdso/Makefile

+45 −1

Original line number	Diff line number	Diff line
		@@ -3,21 +3,29 @@
		#

		VDSO64-$(CONFIG_X86_64) := y
		VDSOX32-$(CONFIG_X86_X32_ABI) := y
		VDSO32-$(CONFIG_X86_32) := y
		VDSO32-$(CONFIG_COMPAT) := y

		vdso-install-$(VDSO64-y) += vdso.so
		vdso-install-$(VDSOX32-y) += vdsox32.so
		vdso-install-$(VDSO32-y) += $(vdso32-images)


		# files to link into the vdso
		vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o

		vobjs-$(VDSOX32-y) += $(vobjx32s-compat)

		# Filter out x32 objects.
		vobj64s := $(filter-out $(vobjx32s-compat),$(vobjs-y))

		# files to link into kernel
		obj-$(VDSO64-y) += vma.o vdso.o
		obj-$(VDSOX32-y) += vdsox32.o
		obj-$(VDSO32-y) += vdso32.o vdso32-setup.o

		vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
		vobjs := $(foreach F,$(vobj64s),$(obj)/$F)

		$(obj)/vdso.o: $(obj)/vdso.so

		@@ -72,6 +80,42 @@ endef
		$(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
		$(call if_changed,vdsosym)

		#
		# X32 processes use x32 vDSO to access 64bit kernel data.
		#
		# Build x32 vDSO image:
		# 1. Compile x32 vDSO as 64bit.
		# 2. Convert object files to x32.
		# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
		# so that it can reach 64bit address space with 64bit pointers.
		#

		targets += vdsox32-syms.lds
		obj-$(VDSOX32-y) += vdsox32-syms.lds

		CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
		VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
		-Wl,-soname=linux-vdso.so.1 \
		-Wl,-z,max-page-size=4096 \
		-Wl,-z,common-page-size=4096

		vobjx32s-y := $(vobj64s:.o=-x32.o)
		vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)

		# Convert 64bit object file to x32 for x32 vDSO.
		quiet_cmd_x32 = X32 $@
		cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@

		$(obj)/%-x32.o: $(obj)/%.o FORCE
		$(call if_changed,x32)

		targets += vdsox32.so vdsox32.so.dbg vdsox32.lds $(vobjx32s-y)

		$(obj)/vdsox32.o: $(src)/vdsox32.S $(obj)/vdsox32.so

		$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
		$(call if_changed,vdso)

		#
		# Build multiple 32-bit vDSO images to choose from at boot time.
		#

arch/x86/vdso/vdso32-setup.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -317,6 +317,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
		int ret = 0;
		bool compat;

		#ifdef CONFIG_X86_X32_ABI
		extern int x32_setup_additional_pages(struct linux_binprm *, int);
		if (test_thread_flag(TIF_X32))
		return x32_setup_additional_pages (bprm, uses_interp);
		#endif

		if (vdso_enabled == VDSO_DISABLED)
		return 0;

arch/x86/vdso/vdsox32.S

0 → 100644

+22 −0

Original line number	Diff line number	Diff line
		#include <asm/page_types.h>
		#include <linux/linkage.h>
		#include <linux/init.h>

		__PAGE_ALIGNED_DATA

		.globl vdsox32_start, vdsox32_end
		.align PAGE_SIZE
		vdsox32_start:
		.incbin "arch/x86/vdso/vdsox32.so"
		vdsox32_end:
		.align PAGE_SIZE /* extra data here leaks to userspace. */

		.previous

		.globl vdsox32_pages
		.bss
		.align 8
		.type vdsox32_pages, @object
		vdsox32_pages:
		.zero (vdsox32_end - vdsox32_start + PAGE_SIZE - 1) / PAGE_SIZE * 8
		.size vdsox32_pages, .-vdsox32_pages

arch/x86/vdso/vdsox32.lds.S

0 → 100644

+32 −0

Original line number	Diff line number	Diff line
		/*
		* Linker script for x32 vDSO.
		* We #include the file to define the layout details.
		* Here we only choose the prelinked virtual address.
		*
		* This file defines the version script giving the user-exported symbols in
		* the DSO. We can define local symbols here called VDSO* to make their
		* values visible using the asm-x86/vdso.h macros from the kernel proper.
		*/

		#define VDSO_PRELINK 0
		#include "vdso-layout.lds.S"

		/*
		* This controls what userland symbols we export from the vDSO.
		*/
		VERSION {
		LINUX_2.6 {
		global:
		clock_gettime;
		__vdso_clock_gettime;
		gettimeofday;
		__vdso_gettimeofday;
		getcpu;
		__vdso_getcpu;
		time;
		__vdso_time;
		local: *;
		};
		}

		VDSOX32_PRELINK = VDSO_PRELINK;

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