FROMLIST: [PATCH 4/6] arm64: compat: Add a 32-bit vDSO

vdso.lds

vdso.so.raw

#

# Building a vDSO image for AArch32.

#

# Author: Kevin Brodsky <kevin.brodsky@arm.com>

# A mix between the arm64 and arm vDSO Makefiles.

ifeq ($(cc-name),clang)

  CC_ARM32 := $(cc-name) $(CLANG_TARGET_ARM32) -no-integrated-as

else

  CC_ARM32 := $(CROSS_COMPILE_ARM32)$(cc-name)

endif

# Same as cc-*option, but using CC_ARM32 instead of CC

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

        $(CC_ARM32) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))

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

	$(CC_ARM32) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))

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

        $(CC_ARM32) $(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 $(CC_ARM32) -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 $(CC_ARM32)), 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)

# 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 := vgettimeofday.o

asm-obj-vdso := sigreturn.o

# Build rules

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

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

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

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

# Compilation rules for the vDSO sources

$(filter-out vgettimeofday.o, $(c-obj-vdso)): %.o: %.c FORCE

	$(call if_changed_dep,vdsocc)

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

	$(call if_changed_dep,vdsoas)

# Actual build commands

quiet_cmd_vdsold = VDSOL32   $@

      cmd_vdsold = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \

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

quiet_cmd_vdsocc = VDSOC32   $@

      cmd_vdsocc = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<

quiet_cmd_vdsoas = VDSOA32   $@

      cmd_vdsoas = $(CC_ARM32) -Wp,-MD,$(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

/*

 * Userspace implementations of fallback calls

 *

 * Copyright (C) 2017 Cavium, Inc.

 * Copyright (C) 2012 ARM Limited

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * Author: Will Deacon <will.deacon@arm.com>

 * Rewriten into C by: Andrew Pinski <apinski@cavium.com>

 */

#ifndef __VDSO_COMPILER_H

#define __VDSO_COMPILER_H

#include <asm/barrier.h>	/* for isb() & dmb()	*/

#include <asm/param.h>		/* for HZ		*/

#include <asm/unistd32.h>

#include <linux/compiler.h>

#ifdef CONFIG_ARM_ARCH_TIMER

#define ARCH_PROVIDES_TIMER

#endif

/* can not include linux/time.h because of too much architectural cruft */

#ifndef NSEC_PER_SEC

#define NSEC_PER_SEC    1000000000L

#endif

/* can not include linux/jiffies.h because of too much architectural cruft */

#ifndef TICK_NSEC

#define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ)

#endif

/* can not include linux/hrtimer.h because of too much architectural cruft */

#ifndef LOW_RES_NSEC

#define LOW_RES_NSEC        TICK_NSEC

#ifdef ARCH_PROVIDES_TIMER

#ifdef CONFIG_HIGH_RES_TIMERS

# define HIGH_RES_NSEC        1

# define MONOTONIC_RES_NSEC    HIGH_RES_NSEC

#else

# define MONOTONIC_RES_NSEC    LOW_RES_NSEC

#endif

#endif

#endif

#define DEFINE_FALLBACK(name, type_arg1, name_arg1, type_arg2, name_arg2) \

static notrace long name##_fallback(type_arg1 _##name_arg1,		  \

				    type_arg2 _##name_arg2)		  \

{									  \

	register type_arg1 name_arg1 asm("r0") = _##name_arg1;		  \

	register type_arg2 name_arg2 asm("r1") = _##name_arg2;		  \

	register long ret asm ("r0");					  \

	register long nr asm("r7") = __NR_##name;			  \

									  \

	asm volatile(							  \

	"	swi #0\n"						  \

	: "=r" (ret)							  \

	: "r" (name_arg1), "r" (name_arg2), "r" (nr)			  \

	: "memory");							  \

									  \

	return ret;							  \

}

/*

 * AArch32 implementation of arch_counter_get_cntvct() suitable for vdso

 */

static __always_inline notrace u64 arch_vdso_read_counter(void)

{

	u64 res;

	/* Read the virtual counter. */

	isb();

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

	return res;

}

/*

 * Can not include asm/processor.h to pick this up because of all the

 * architectural components also included, so we open code a copy.

 */

static inline void cpu_relax(void)

{

	asm volatile("yield" ::: "memory");

}

#undef smp_rmb

#if __LINUX_ARM_ARCH__ >= 8

#define	smp_rmb()	dmb(ishld) /* ok on ARMv8 */

#else

#define	smp_rmb()	dmb(ish) /* ishld does not exist on ARMv7 */

#endif

/* Avoid unresolved references emitted by GCC */

void __aeabi_unwind_cpp_pr0(void)

{

}

void __aeabi_unwind_cpp_pr1(void)

{

}

void __aeabi_unwind_cpp_pr2(void)

{

}

#endif /* __VDSO_COMPILER_H */

#include "../vdso/datapage.h"

/*

 * Sigreturn trampolines for returning from a signal when the SA_RESTORER

 * flag is not set.

 *

 * Copyright (C) 2016 ARM Limited

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * Based on glibc's arm sa_restorer. While this is not strictly necessary, we

 * provide both A32 and T32 versions, in accordance with the arm sigreturn

 * code.

 */

#include <linux/linkage.h>

#include <asm/asm-offsets.h>

#include <asm/unistd32.h>

.macro sigreturn_trampoline name, syscall, regs_offset

	/*

	 * We provide directives for enabling stack unwinding through the

	 * trampoline. On arm, CFI directives are only used for debugging (and

	 * the vDSO is stripped of debug information), so only the arm-specific

	 * unwinding directives are useful here.

	 */

	.fnstart

	.save {r0-r15}

	.pad #\regs_offset

	/*

	 * It is necessary to start the unwind tables at least one instruction

	 * before the trampoline, as the unwinder will assume that the signal

	 * handler has been called from the trampoline, that is just before

	 * where the signal handler returns (mov r7, ...).

	 */

	nop

ENTRY(\name)

	mov	r7, #\syscall

	svc	#0

	.fnend

	/*

	 * We would like to use ENDPROC, but the macro uses @ which is a

	 * comment symbol for arm assemblers, so directly use .type with %

	 * instead.

	 */

	.type \name, %function

END(\name)

.endm

	.text

	.arm

	sigreturn_trampoline __kernel_sigreturn_arm, \

			     __NR_sigreturn, \

			     COMPAT_SIGFRAME_REGS_OFFSET

	sigreturn_trampoline __kernel_rt_sigreturn_arm, \

			     __NR_rt_sigreturn, \

			     COMPAT_RT_SIGFRAME_REGS_OFFSET

	.thumb

	sigreturn_trampoline __kernel_sigreturn_thumb, \

			     __NR_sigreturn, \

			     COMPAT_SIGFRAME_REGS_OFFSET

	sigreturn_trampoline __kernel_rt_sigreturn_thumb, \

			     __NR_rt_sigreturn, \

			     COMPAT_RT_SIGFRAME_REGS_OFFSET