arm64: compat: Add vDSO

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2018 ARM Limited

 */

#ifndef __COMPAT_BARRIER_H

#define __COMPAT_BARRIER_H

#ifndef __ASSEMBLY__

/*

 * Warning: This code is meant to be used with

 * ENABLE_COMPAT_VDSO only.

 */

#ifndef ENABLE_COMPAT_VDSO

#error This header is meant to be used with ENABLE_COMPAT_VDSO only

#endif

#ifdef dmb

#undef dmb

#endif

#if __LINUX_ARM_ARCH__ >= 7

#define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory")

#elif __LINUX_ARM_ARCH__ == 6

#define dmb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \

				    : : "r" (0) : "memory")

#else

#define dmb(x) __asm__ __volatile__ ("" : : : "memory")

#endif

#if __LINUX_ARM_ARCH__ >= 8

#define aarch32_smp_mb()	dmb(ish)

#define aarch32_smp_rmb()	dmb(ishld)

#define aarch32_smp_wmb()	dmb(ishst)

#else

#define aarch32_smp_mb()	dmb(ish)

#define aarch32_smp_rmb()	aarch32_smp_mb()

#define aarch32_smp_wmb()	dmb(ishst)

#endif

#undef smp_mb

#undef smp_rmb

#undef smp_wmb

#define smp_mb()	aarch32_smp_mb()

#define smp_rmb()	aarch32_smp_rmb()

#define smp_wmb()	aarch32_smp_wmb()

#endif /* !__ASSEMBLY__ */

#endif /* __COMPAT_BARRIER_H */

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2018 ARM Limited

 */

#ifndef __ASM_VDSO_GETTIMEOFDAY_H

#define __ASM_VDSO_GETTIMEOFDAY_H

#ifndef __ASSEMBLY__

#include <asm/unistd.h>

#include <uapi/linux/time.h>

#include <asm/vdso/compat_barrier.h>

#define VDSO_HAS_CLOCK_GETRES		1

static __always_inline

int gettimeofday_fallback(struct __kernel_old_timeval *_tv,

			  struct timezone *_tz)

{

	register struct timezone *tz asm("r1") = _tz;

	register struct __kernel_old_timeval *tv asm("r0") = _tv;

	register long ret asm ("r0");

	register long nr asm("r7") = __NR_compat_gettimeofday;

	asm volatile(

	"	swi #0\n"

	: "=r" (ret)

	: "r" (tv), "r" (tz), "r" (nr)

	: "memory");

	return ret;

}

static __always_inline

long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)

{

	register struct __kernel_timespec *ts asm("r1") = _ts;

	register clockid_t clkid asm("r0") = _clkid;

	register long ret asm ("r0");

	register long nr asm("r7") = __NR_compat_clock_gettime64;

	asm volatile(

	"	swi #0\n"

	: "=r" (ret)

	: "r" (clkid), "r" (ts), "r" (nr)

	: "memory");

	return ret;

}

static __always_inline

int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)

{

	register struct __kernel_timespec *ts asm("r1") = _ts;

	register clockid_t clkid asm("r0") = _clkid;

	register long ret asm ("r0");

	register long nr asm("r7") = __NR_compat_clock_getres_time64;

	/* The checks below are required for ABI consistency with arm */

	if ((_clkid >= MAX_CLOCKS) && (_ts == NULL))

		return -EINVAL;

	asm volatile(

	"       swi #0\n"

	: "=r" (ret)

	: "r" (clkid), "r" (ts), "r" (nr)

	: "memory");

	return ret;

}

static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)

{

	u64 res;

	isb();

	asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (res));

	return res;

}

static __always_inline const struct vdso_data *__arch_get_vdso_data(void)

{

	const struct vdso_data *ret;

	/*

	 * This simply puts &_vdso_data into ret. The reason why we don't use

	 * `ret = _vdso_data` is that the compiler tends to optimise this in a

	 * very suboptimal way: instead of keeping &_vdso_data in a register,

	 * it goes through a relocation almost every time _vdso_data must be

	 * accessed (even in subfunctions). This is both time and space

	 * consuming: each relocation uses a word in the code section, and it

	 * has to be loaded at runtime.

	 *

	 * This trick hides the assignment from the compiler. Since it cannot

	 * track where the pointer comes from, it will only use one relocation

	 * where __arch_get_vdso_data() is called, and then keep the result in

	 * a register.

	 */

	asm volatile("mov %0, %1" : "=r"(ret) : "r"(_vdso_data));

	return ret;

}

#endif /* !__ASSEMBLY__ */

#endif /* __ASM_VDSO_GETTIMEOFDAY_H */

vdso.lds

vdso.so.raw

# SPDX-License-Identifier: GPL-2.0

#

# Makefile for vdso32

#

# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before

# the inclusion of generic Makefile.

ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32

include $(srctree)/lib/vdso/Makefile

COMPATCC := $(CROSS_COMPILE_COMPAT)gcc

# Same as cc-*option, but using COMPATCC instead of CC

cc32-option = $(call try-run,\

        $(COMPATCC) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))

cc32-disable-warning = $(call try-run,\

	$(COMPATCC) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))

cc32-ldoption = $(call try-run,\

        $(COMPATCC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))

# We cannot use the global flags to compile the vDSO files, the main reason

# being that the 32-bit compiler may be older than the main (64-bit) compiler

# and therefore may not understand flags set using $(cc-option ...). Besides,

# arch-specific options should be taken from the arm Makefile instead of the

# arm64 one.

# As a result we set our own flags here.

# From top-level Makefile

# NOSTDINC_FLAGS

VDSO_CPPFLAGS := -nostdinc -isystem $(shell $(COMPATCC) -print-file-name=include)

VDSO_CPPFLAGS += $(LINUXINCLUDE)

VDSO_CPPFLAGS += $(KBUILD_CPPFLAGS)

# Common C and assembly flags

# From top-level Makefile

VDSO_CAFLAGS := $(VDSO_CPPFLAGS)

VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)

ifdef CONFIG_DEBUG_INFO

VDSO_CAFLAGS += -g

endif

ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(COMPATCC)), y)

VDSO_CAFLAGS += -DCC_HAVE_ASM_GOTO

endif

# From arm Makefile

VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)

VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft

ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)

VDSO_CAFLAGS += -mbig-endian

else

VDSO_CAFLAGS += -mlittle-endian

endif

# From arm vDSO Makefile

VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector

VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING

# Try to compile for ARMv8. If the compiler is too old and doesn't support it,

# fall back to v7. There is no easy way to check for what architecture the code

# is being compiled, so define a macro specifying that (see arch/arm/Makefile).

VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\

                                   -march=armv7-a -D__LINUX_ARM_ARCH__=7)

VDSO_CFLAGS := $(VDSO_CAFLAGS)

VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1

# KBUILD_CFLAGS from top-level Makefile

VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \

               -fno-strict-aliasing -fno-common \

               -Werror-implicit-function-declaration \

               -Wno-format-security \

               -std=gnu89

VDSO_CFLAGS  += -O2

# Some useful compiler-dependent flags from top-level Makefile

VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,)

VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)

VDSO_CFLAGS += $(call cc32-option,-fno-strict-overflow)

VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes)

VDSO_CFLAGS += $(call cc32-option,-Werror=date-time)

VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types)

# The 32-bit compiler does not provide 128-bit integers, which are used in

# some headers that are indirectly included from the vDSO code.

# This hack makes the compiler happy and should trigger a warning/error if

# variables of such type are referenced.

VDSO_CFLAGS += -D__uint128_t='void*'

# Silence some warnings coming from headers that operate on long's

# (on GCC 4.8 or older, there is unfortunately no way to silence this warning)

VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow)

VDSO_CFLAGS += -Wno-int-to-pointer-cast

VDSO_AFLAGS := $(VDSO_CAFLAGS)

VDSO_AFLAGS += -D__ASSEMBLY__

VDSO_LDFLAGS := $(VDSO_CPPFLAGS)

# From arm vDSO Makefile

VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1

VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096

VDSO_LDFLAGS += -nostdlib -shared -mfloat-abi=soft

VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--hash-style=sysv)

VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--build-id)

VDSO_LDFLAGS += $(call cc32-ldoption,-fuse-ld=bfd)

# Borrow vdsomunge.c from the arm vDSO

# We have to use a relative path because scripts/Makefile.host prefixes

# $(hostprogs-y) with $(obj)

munge := ../../../arm/vdso/vdsomunge

hostprogs-y := $(munge)

c-obj-vdso := note.o

c-obj-vdso-gettimeofday := vgettimeofday.o

asm-obj-vdso := sigreturn.o

ifneq ($(c-gettimeofday-y),)

VDSO_CFLAGS_gettimeofday_o += -include $(c-gettimeofday-y)

endif

VDSO_CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os

# Build rules

targets := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw

c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso))

c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday))

asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso))

obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso)

obj-y += vdso.o

extra-y += vdso.lds

CPPFLAGS_vdso.lds += -P -C -U$(ARCH)

# Force dependency (vdso.s includes vdso.so through incbin)

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

include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE

	$(call if_changed,vdsosym)

# Strip rule for vdso.so

$(obj)/vdso.so: OBJCOPYFLAGS := -S

$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE

	$(call if_changed,objcopy)

$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE

	$(call if_changed,vdsomunge)

# Link rule for the .so file, .lds has to be first

$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE

	$(call if_changed,vdsold)

	$(call if_changed,vdso_check)

# Compilation rules for the vDSO sources

$(c-obj-vdso): %.o: %.c FORCE

	$(call if_changed_dep,vdsocc)

$(c-obj-vdso-gettimeofday): %.o: %.c FORCE

	$(call if_changed_dep,vdsocc_gettimeofday)

$(asm-obj-vdso): %.o: %.S FORCE

	$(call if_changed_dep,vdsoas)

# Actual build commands

quiet_cmd_vdsold = VDSOL   $@

      cmd_vdsold = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \

                   -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@

quiet_cmd_vdsocc = VDSOC   $@

      cmd_vdsocc = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<

quiet_cmd_vdsocc_gettimeofday = VDSOC_GTD   $@

      cmd_vdsocc_gettimeofday = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $<

quiet_cmd_vdsoas = VDSOA   $@

      cmd_vdsoas = $(COMPATCC) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $<

quiet_cmd_vdsomunge = MUNGE   $@

      cmd_vdsomunge = $(obj)/$(munge) $< $@

# Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO)

gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh

quiet_cmd_vdsosym = VDSOSYM $@

# The AArch64 nm should be able to read an AArch32 binary

      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@

# Install commands for the unstripped file

quiet_cmd_vdso_install = INSTALL $@

      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so

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

	@mkdir -p $(MODLIB)/vdso

	$(call cmd,vdso_install)

vdso_install: vdso.so

// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) 2012-2018 ARM Limited

 *

 * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.

 * Here we can supply some information useful to userland.

 */

#include <linux/uts.h>

#include <linux/version.h>

#include <linux/elfnote.h>

#include <linux/build-salt.h>

ELFNOTE32("Linux", 0, LINUX_VERSION_CODE);

BUILD_SALT;