vdso for ia32 on amd64

Reviewed by:	emaste
Discussed with:	jrtc27
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 month
Differential revision:	https://reviews.freebsd.org/D32960

sys/amd64/ia32/ia32_signal.c

@@ -81,6 +81,12 @@ __FBSDID("$FreeBSD$");
 #include <machine/cpufunc.h>
 #include <machine/trap.h>
 
+#include "vdso_ia32_offsets.h"
+
+extern const char _binary_elf_vdso32_so_1_start[];
+extern const char _binary_elf_vdso32_so_1_end[];
+extern char _binary_elf_vdso32_so_1_size;
+
 #ifdef COMPAT_FREEBSD4
 static void freebsd4_ia32_sendsig(sig_t, ksiginfo_t *, sigset_t *);
 #endif
@@ -416,7 +422,9 @@ ia32_osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	}
 
 	regs->tf_rsp = (uintptr_t)fp;
-	regs->tf_rip = p->p_sysent->sv_psstrings - sz_ia32_osigcode;
+	regs->tf_rip = p->p_sysent->sv_psstrings -
+	    (_binary_elf_vdso32_so_1_end - _binary_elf_vdso32_so_1_start) +
+	    VDSO_IA32_OSIGCODE_OFFSET;
 	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ds = _udatasel;
@@ -527,8 +535,8 @@ freebsd4_ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	}
 
 	regs->tf_rsp = (uintptr_t)sfp;
-	regs->tf_rip = p->p_sysent->sv_sigcode_base + sz_ia32_sigcode -
-	    sz_freebsd4_ia32_sigcode;
+	regs->tf_rip = p->p_sysent->sv_sigcode_base +
+	    VDSO_FREEBSD4_IA32_SIGCODE_OFFSET - VDSO_IA32_SIGCODE_OFFSET;
 	regs->tf_rflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucode32sel;
 	regs->tf_ss = _udatasel;

sys/amd64/ia32/ia32_sigtramp.S

@@ -32,14 +32,13 @@
 #include "ia32_assym.h"
 
 	.text
-	.code32
 /*
- * Signal trampoline, copied to top of user stack
- * XXX may need to be MD to match backend sendsig handoff protocol
+ * Signal trampoline, mapped as vdso into shared page, or copied to
+ * top of user stack for old binaries.
  */
 	ALIGN_TEXT
-	.globl	ia32_sigcode
-ia32_sigcode:
+	.globl	__vdso_ia32_sigcode
+__vdso_ia32_sigcode:
 	calll	*IA32_SIGF_HANDLER(%esp)
 	leal	IA32_SIGF_UC(%esp),%eax	/* get ucontext */
 	pushl	%eax
@@ -52,7 +51,8 @@ ia32_sigcode:
 
 #ifdef COMPAT_FREEBSD4
 	ALIGN_TEXT
-freebsd4_ia32_sigcode:
+	.globl	__vdso_freebsd4_ia32_sigcode
+__vdso_freebsd4_ia32_sigcode:
 	calll	*IA32_SIGF_HANDLER(%esp)
 	leal	IA32_SIGF_UC4(%esp),%eax/* get ucontext */
 	pushl	%eax
@@ -66,7 +66,8 @@ freebsd4_ia32_sigcode:
 
 #ifdef COMPAT_43
 	ALIGN_TEXT
-ia32_osigcode:
+	.globl	__vdso_ia32_osigcode
+__vdso_ia32_osigcode:
 	calll	*IA32_SIGF_HANDLER(%esp)/* call signal handler */
 	leal	IA32_SIGF_SC(%esp),%eax	/* get sigcontext */
 	pushl	%eax
@@ -90,28 +91,9 @@ ia32_osigcode:
  * vfork() and harder for other syscalls.
  */
 	ALIGN_TEXT
-lcall_tramp:
+	.globl	__vdso_lcall_tramp
+__vdso_lcall_tramp:
 	int	$0x80
 1:	jmp	1b
 #endif
-
-	ALIGN_TEXT
-esigcode:
-
-	.data
-	.globl	sz_ia32_sigcode
-sz_ia32_sigcode:
-	.long	esigcode-ia32_sigcode
-#ifdef COMPAT_FREEBSD4
-	.globl	sz_freebsd4_ia32_sigcode
-sz_freebsd4_ia32_sigcode:
-	.long	esigcode-freebsd4_ia32_sigcode
-#endif
-#ifdef COMPAT_43
-	.globl	sz_ia32_osigcode
-sz_ia32_osigcode:
-	.long	esigcode-ia32_osigcode
-	.globl	sz_lcall_tramp
-sz_lcall_tramp:
-	.long	esigcode-lcall_tramp
-#endif
+	.p2align 1

sys/amd64/ia32/ia32_syscall.c

@@ -92,6 +92,12 @@ __FBSDID("$FreeBSD$");
 #include <machine/pcb.h>
 #include <machine/cpufunc.h>
 
+#include "vdso_ia32_offsets.h"
+
+extern const char _binary_elf_vdso32_so_1_start[];
+extern const char _binary_elf_vdso32_so_1_end[];
+extern char _binary_elf_vdso32_so_1_size;
+
 #define	IDTVEC(name)	__CONCAT(X,name)
 
 extern inthand_t IDTVEC(int0x80_syscall), IDTVEC(int0x80_syscall_pti),
@@ -264,7 +270,9 @@ setup_lcall_gate(void)
 	bzero(&uap, sizeof(uap));
 	uap.start = 0;
 	uap.num = 1;
-	lcall_addr = curproc->p_sysent->sv_psstrings - sz_lcall_tramp;
+	lcall_addr = curproc->p_sysent->sv_psstrings -
+	    (_binary_elf_vdso32_so_1_end - _binary_elf_vdso32_so_1_start) +
+	    VDSO_LCALL_TRAMP_OFFSET;
 	bzero(&desc, sizeof(desc));
 	desc.sd_type = SDT_MEMERA;
 	desc.sd_dpl = SEL_UPL;

sys/compat/ia32/ia32_signal.h

@@ -195,14 +195,6 @@ struct ia32_sigframe3 {
 
 struct ksiginfo;
 struct image_params;
-extern char ia32_sigcode[];
-extern char freebsd4_ia32_sigcode[];
-extern char ia32_osigcode[];
-extern char lcall_tramp;
-extern int sz_ia32_sigcode;
-extern int sz_freebsd4_ia32_sigcode;
-extern int sz_ia32_osigcode;
-extern int sz_lcall_tramp;
 void ia32_sendsig(sig_t, struct ksiginfo *, sigset_t *);
 void ia32_setregs(struct thread *td, struct image_params *imgp,
     uintptr_t stack);

sys/compat/ia32/ia32_sysvec.c

@@ -83,6 +83,12 @@ CTASSERT(sizeof(struct ia32_ucontext4) == 324);
 CTASSERT(sizeof(struct ia32_sigframe4) == 408);
 #endif
 
+#include "vdso_ia32_offsets.h"
+
+extern const char _binary_elf_vdso32_so_1_start[];
+extern const char _binary_elf_vdso32_so_1_end[];
+extern char _binary_elf_vdso32_so_1_size;
+
 extern const char *freebsd32_syscallnames[];
 
 static SYSCTL_NODE(_compat, OID_AUTO, ia32, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
@@ -101,8 +107,9 @@ struct sysentvec ia32_freebsd_sysvec = {
 	.sv_transtrap	= NULL,
 	.sv_fixup	= elf32_freebsd_fixup,
 	.sv_sendsig	= ia32_sendsig,
-	.sv_sigcode	= ia32_sigcode,
-	.sv_szsigcode	= &sz_ia32_sigcode,
+	.sv_sigcode	= _binary_elf_vdso32_so_1_start,
+	.sv_szsigcode	= (int *)&_binary_elf_vdso32_so_1_size,
+	.sv_sigcodeoff	= VDSO_IA32_SIGCODE_OFFSET,
 	.sv_name	= "FreeBSD ELF32",
 	.sv_coredump	= elf32_coredump,
 	.sv_elf_core_osabi = ELFOSABI_FREEBSD,
@@ -121,7 +128,7 @@ struct sysentvec ia32_freebsd_sysvec = {
 	.sv_fixlimit	= ia32_fixlimit,
 	.sv_maxssiz	= &ia32_maxssiz,
 	.sv_flags	= SV_ABI_FREEBSD | SV_ASLR | SV_IA32 | SV_ILP32 |
-			    SV_SHP | SV_TIMEKEEP | SV_RNG_SEED_VER,
+			    SV_SHP | SV_TIMEKEEP | SV_RNG_SEED_VER | SV_DSO_SIG,
 	.sv_set_syscall_retval = ia32_set_syscall_retval,
 	.sv_fetch_syscall_args = ia32_fetch_syscall_args,
 	.sv_syscallnames = freebsd32_syscallnames,

sys/conf/files.amd64

@@ -18,6 +18,12 @@ elf-vdso.so.o			standard				\
 	no-implicit-rule before-depend	\
 	clean		"elf-vdso.so.o elf-vdso.so.1 vdso_offsets.h sigtramp.pico"
 #
+elf-vdso32.so.o			optional	compat_freebsd32		\
+	dependency	"$S/amd64/ia32/ia32_sigtramp.S ia32_assym.h $S/tools/amd64_ia32_vdso.sh" \
+	compile-with	"env AWK='${AWK}' NM='${NM}' LD='${LD}' CC='${CC}' OBJCOPY='${OBJCOPY}' S='${S}' sh $S/tools/amd64_ia32_vdso.sh" \
+	no-implicit-rule before-depend	\
+	clean		"elf-vdso32.so.o elf-vdso32.so.1 vdso_ia32_offsets.h ia32_sigtramp.pico"
+#
 ia32_genassym.o			standard				\
 	dependency 	"$S/compat/ia32/ia32_genassym.c offset.inc"		\
 	compile-with	"${CC} ${CFLAGS:N-flto:N-fno-common} -fcommon -c ${.IMPSRC}" \
@@ -368,7 +374,6 @@ kern/link_elf_obj.c		standard
 #amd64/ia32/ia32_exception.S	optional	compat_freebsd32
 amd64/ia32/ia32_reg.c		optional	compat_freebsd32
 amd64/ia32/ia32_signal.c	optional	compat_freebsd32
-amd64/ia32/ia32_sigtramp.S	optional	compat_freebsd32
 amd64/ia32/ia32_syscall.c	optional	compat_freebsd32
 amd64/ia32/ia32_misc.c		optional	compat_freebsd32
 compat/ia32/ia32_sysvec.c	optional	compat_freebsd32

sys/conf/vdso_amd64_ia32.ldscript

@@ -0,0 +1,94 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2021 The FreeBSD Foundation
+ *
+ * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Linker script for ia32 (32bit) vdso on amd64.
+ */
+
+OUTPUT_ARCH(i386)
+
+PHDRS
+{
+	text		PT_LOAD		FILEHDR PHDRS FLAGS(5); /* PF_R|PF_X */
+	dynamic		PT_DYNAMIC	FLAGS(5);
+	eh_frame_hdr	PT_GNU_EH_FRAME FLAGS(5);
+}
+
+SECTIONS
+{
+	. = . + SIZEOF_HEADERS;
+
+	.hash		: { *(.hash) }			:text
+	.gnu.hash	: { *(.gnu.hash) }		:text
+	.dynsym		: { *(.dynsym) }		:text
+	.dynstr		: { *(.dynstr) }		:text
+	.gnu.version	: { *(.gnu.version) }		:text
+	.gnu.version_d	: { *(.gnu.version_d) }		:text
+	.gnu.version_r	: { *(.gnu.version_r) }		:text
+	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
+	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
+	.dynamic	: { *(.dynamic) }		:text	:dynamic
+	.rodata		: { *(.rodata*) }		:text
+	.data : {
+	      *(.got.plt) *(.got)
+	} :text
+	/DISCARD/ /* .data */: {
+	      *(.data*)
+	      *(.sdata*)
+	      *(.gnu.linkonce.d.*)
+	      *(.bss*)
+	      *(.dynbss*)
+	      *(.gnu.linkonce.b.*)
+	      *(.ctors)
+	      *(.dtors)
+	      *(.jcr)
+	      *(.init_array)
+	      *(.init)
+	      *(.fini)
+	      *(.debug*)
+	      *(.comment)
+	}
+
+	. = ALIGN(0x10);
+	.text		: { *(.text .text*) }		:text	=0x90909090
+}
+
+VERSION
+{
+	FBSD_1.7 {
+		global:
+			__vdso_ia32_sigcode;
+			__vdso_freebsd4_ia32_sigcode;
+			__vdso_ia32_osigcode;
+			__vdso_lcall_tramp;
+		local:
+			*;
+	};
+}

sys/kern/imgact_aout.c

@@ -108,6 +108,12 @@ struct sysentvec aout_sysvec = {
 
 #elif defined(__amd64__)
 
+#include "vdso_ia32_offsets.h"
+
+extern const char _binary_elf_vdso32_so_1_start[];
+extern const char _binary_elf_vdso32_so_1_end[];
+extern char _binary_elf_vdso32_so_1_size;
+
 #define	AOUT32_PS_STRINGS \
     (AOUT32_USRSTACK - sizeof(struct freebsd32_ps_strings))
 #define	AOUT32_MINUSER		FREEBSD32_MINUSER
@@ -115,14 +121,16 @@ struct sysentvec aout_sysvec = {
 extern const char *freebsd32_syscallnames[];
 extern u_long ia32_maxssiz;
 
+static int aout_szsigcode;
+
 struct sysentvec aout_sysvec = {
 	.sv_size	= FREEBSD32_SYS_MAXSYSCALL,
 	.sv_table	= freebsd32_sysent,
 	.sv_transtrap	= NULL,
 	.sv_fixup	= aout_fixup,
 	.sv_sendsig	= ia32_sendsig,
-	.sv_sigcode	= ia32_sigcode,
-	.sv_szsigcode	= &sz_ia32_sigcode,
+	.sv_sigcode	= _binary_elf_vdso32_so_1_start,
+	.sv_szsigcode	= &aout_szsigcode,
 	.sv_name	= "FreeBSD a.out",
 	.sv_coredump	= NULL,
 	.sv_imgact_try	= NULL,
@@ -144,6 +152,13 @@ struct sysentvec aout_sysvec = {
 	.sv_onexit	= exit_onexit,
 	.sv_set_fork_retval = x86_set_fork_retval,
 };
+
+static void
+aout_sysent(void *arg __unused)
+{
+	aout_szsigcode = (int)(uintptr_t)&_binary_elf_vdso32_so_1_size;
+}
+SYSINIT(aout_sysent, SI_SUB_EXEC, SI_ORDER_ANY, aout_sysent, NULL);
 #else
 #error "Only ia32 arch is supported"
 #endif

sys/tools/amd64_ia32_vdso.sh

@@ -0,0 +1,53 @@
+#!/bin/sh
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2021 The FreeBSD Foundation
+# All rights reserved.
+#
+# This software was developed by Konstantin Belousov <kib@FreeBSD.org>
+# under sponsorship from the FreeBSD Foundation.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+set -e
+
+${CC} -x assembler-with-cpp -DLOCORE -fPIC -nostdinc -c -m32 \
+   -o ia32_sigtramp.pico -I. -I"${S}" -include opt_global.h \
+   "${S}"/amd64/ia32/ia32_sigtramp.S
+
+${LD} --shared -Bsymbolic -soname="elf-vdso32.so.1" \
+   -T "${S}"/conf/vdso_amd64_ia32.ldscript \
+   --eh-frame-hdr --no-undefined -z rodynamic -z norelro -nmagic \
+   --hash-style=sysv --fatal-warnings --strip-all \
+   -o elf-vdso32.so.1 ia32_sigtramp.pico
+
+${CC} -x assembler-with-cpp -DLOCORE -fPIC -nostdinc -c \
+   -o elf-vdso32.so.o -I. -I"${S}" -include opt_global.h \
+   -DVDSO_NAME=elf_vdso32_so_1 -DVDSO_FILE=elf-vdso32.so.1 \
+   "${S}"/tools/vdso_wrap.S
+
+${NM} -D elf-vdso32.so.1 | ${AWK} \
+   '/__vdso_ia32_sigcode/{printf "#define VDSO_IA32_SIGCODE_OFFSET 0x%s\n",$1}
+    /__vdso_freebsd4_ia32_sigcode/{printf "#define VDSO_FREEBSD4_IA32_SIGCODE_OFFSET 0x%s\n",$1}
+    /__vdso_ia32_osigcode/{printf "#define VDSO_IA32_OSIGCODE_OFFSET 0x%s\n",$1}
+    /__vdso_lcall_tramp/{printf "#define VDSO_LCALL_TRAMP_OFFSET 0x%s\n",$1}' \
+   >vdso_ia32_offsets.h