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Date:      Fri, 15 Nov 2019 18:42:13 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r354741 - in head/sys: amd64/amd64 arm/arm arm64/arm64 compat/freebsd32 compat/ia32 i386/i386 kern mips/mips powerpc/powerpc riscv/riscv sparc64/sparc64 sys
Message-ID:  <201911151842.xAFIgDrJ093716@repo.freebsd.org>

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Author: jhb
Date: Fri Nov 15 18:42:13 2019
New Revision: 354741
URL: https://svnweb.freebsd.org/changeset/base/354741

Log:
  Add a sv_copyout_auxargs() hook in sysentvec.
  
  Change the FreeBSD ELF ABIs to use this new hook to copyout ELF auxv
  instead of doing it in the sv_fixup hook.  In particular, this new
  hook allows the stack space to be allocated at the same time the auxv
  values are copied out to userland.  This allows us to avoid wasting
  space for unused auxv entries as well as not having to recalculate
  where the auxv vector is by walking back up over the argv and
  environment vectors.
  
  Reviewed by:	brooks, emaste
  Tested on:	amd64 (amd64 and i386 binaries), i386, mips, mips64
  Sponsored by:	DARPA
  Differential Revision:	https://reviews.freebsd.org/D22355

Modified:
  head/sys/amd64/amd64/elf_machdep.c
  head/sys/arm/arm/elf_machdep.c
  head/sys/arm64/arm64/elf32_machdep.c
  head/sys/arm64/arm64/elf_machdep.c
  head/sys/compat/freebsd32/freebsd32_misc.c
  head/sys/compat/ia32/ia32_sysvec.c
  head/sys/i386/i386/elf_machdep.c
  head/sys/kern/imgact_elf.c
  head/sys/kern/kern_exec.c
  head/sys/mips/mips/elf_machdep.c
  head/sys/mips/mips/freebsd32_machdep.c
  head/sys/powerpc/powerpc/elf32_machdep.c
  head/sys/powerpc/powerpc/elf64_machdep.c
  head/sys/riscv/riscv/elf_machdep.c
  head/sys/sparc64/sparc64/elf_machdep.c
  head/sys/sys/imgact_elf.h
  head/sys/sys/sysent.h

Modified: head/sys/amd64/amd64/elf_machdep.c
==============================================================================
--- head/sys/amd64/amd64/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/amd64/amd64/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -68,6 +68,7 @@ struct sysentvec elf64_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings	= exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/arm/arm/elf_machdep.c
==============================================================================
--- head/sys/arm/arm/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/arm/arm/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -75,6 +75,7 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/arm64/arm64/elf32_machdep.c
==============================================================================
--- head/sys/arm64/arm64/elf32_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/arm64/arm64/elf32_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -92,6 +92,7 @@ static struct sysentvec elf32_freebsd_sysvec = {
 	.sv_usrstack	= FREEBSD32_USRSTACK,
 	.sv_psstrings	= FREEBSD32_PS_STRINGS,
 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
+	.sv_copyout_auxargs = elf32_freebsd_copyout_auxargs,
 	.sv_copyout_strings = freebsd32_copyout_strings,
 	.sv_setregs	= freebsd32_setregs,
 	.sv_fixlimit	= NULL, // XXX

Modified: head/sys/arm64/arm64/elf_machdep.c
==============================================================================
--- head/sys/arm64/arm64/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/arm64/arm64/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -76,6 +76,7 @@ static struct sysentvec elf64_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/compat/freebsd32/freebsd32_misc.c
==============================================================================
--- head/sys/compat/freebsd32/freebsd32_misc.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/compat/freebsd32/freebsd32_misc.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -3195,14 +3195,8 @@ freebsd32_copyout_strings(struct image_params *imgp)
 	if (imgp->sysent->sv_stackgap != NULL)
 		imgp->sysent->sv_stackgap(imgp, (u_long *)&vectp);
 
-	if (imgp->auxargs) {
-		/*
-		 * Allocate room on the stack for the ELF auxargs
-		 * array.  It has up to AT_COUNT entries.
-		 */
-		vectp -= howmany(AT_COUNT * sizeof(Elf32_Auxinfo),
-		    sizeof(*vectp));
-	}
+	if (imgp->auxargs)
+		imgp->sysent->sv_copyout_auxargs(imgp, (u_long *)&vectp);
 
 	/*
 	 * Allocate room for the argv[] and env vectors including the

Modified: head/sys/compat/ia32/ia32_sysvec.c
==============================================================================
--- head/sys/compat/ia32/ia32_sysvec.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/compat/ia32/ia32_sysvec.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -114,6 +114,7 @@ struct sysentvec ia32_freebsd_sysvec = {
 	.sv_usrstack	= FREEBSD32_USRSTACK,
 	.sv_psstrings	= FREEBSD32_PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs	= elf32_freebsd_copyout_auxargs,
 	.sv_copyout_strings	= freebsd32_copyout_strings,
 	.sv_setregs	= ia32_setregs,
 	.sv_fixlimit	= ia32_fixlimit,

Modified: head/sys/i386/i386/elf_machdep.c
==============================================================================
--- head/sys/i386/i386/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/i386/i386/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -70,6 +70,7 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings	= exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/kern/imgact_elf.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -1289,7 +1289,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *i
 		addr = et_dyn_addr;
 
 	/*
-	 * Construct auxargs table (used by the fixup routine)
+	 * Construct auxargs table (used by the copyout_auxargs routine)
 	 */
 	elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_NOWAIT);
 	if (elf_auxargs == NULL) {
@@ -1323,16 +1323,13 @@ ret:
 
 #define	suword __CONCAT(suword, __ELF_WORD_SIZE)
 
-int
-__elfN(freebsd_fixup)(register_t **stack_base, struct image_params *imgp)
+void
+__elfN(freebsd_copyout_auxargs)(struct image_params *imgp, u_long *base)
 {
 	Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
 	Elf_Auxinfo *argarray, *pos;
-	Elf_Addr *base, *auxbase;
-	int error;
+	u_long auxlen;
 
-	base = (Elf_Addr *)*stack_base;
-	auxbase = base + imgp->args->argc + 1 + imgp->args->envc + 1;
 	argarray = pos = malloc(AT_COUNT * sizeof(*pos), M_TEMP,
 	    M_WAITOK | M_ZERO);
 
@@ -1376,11 +1373,18 @@ __elfN(freebsd_fixup)(register_t **stack_base, struct 
 	imgp->auxargs = NULL;
 	KASSERT(pos - argarray <= AT_COUNT, ("Too many auxargs"));
 
-	error = copyout(argarray, auxbase, sizeof(*argarray) * AT_COUNT);
+	auxlen = sizeof(*argarray) * (pos - argarray);
+	*base -= auxlen;
+	copyout(argarray, (void *)*base, auxlen);
 	free(argarray, M_TEMP);
-	if (error != 0)
-		return (error);
+}
 
+int
+__elfN(freebsd_fixup)(register_t **stack_base, struct image_params *imgp)
+{
+	Elf_Addr *base;
+
+	base = (Elf_Addr *)*stack_base;
 	base--;
 	if (suword(base, imgp->args->argc) == -1)
 		return (EFAULT);

Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/kern/kern_exec.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -1637,14 +1637,8 @@ exec_copyout_strings(struct image_params *imgp)
 	if (imgp->sysent->sv_stackgap != NULL)
 		imgp->sysent->sv_stackgap(imgp, (u_long *)&vectp);
 
-	if (imgp->auxargs) {
-		/*
-		 * Allocate room on the stack for the ELF auxargs
-		 * array.  It has up to AT_COUNT entries.
-		 */
-		vectp -= howmany(AT_COUNT * sizeof(Elf_Auxinfo),
-		    sizeof(*vectp));
-	}
+	if (imgp->auxargs)
+		imgp->sysent->sv_copyout_auxargs(imgp, (u_long *)&vectp);
 
 	/*
 	 * Allocate room for the argv[] and env vectors including the

Modified: head/sys/mips/mips/elf_machdep.c
==============================================================================
--- head/sys/mips/mips/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/mips/mips/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -71,6 +71,7 @@ struct sysentvec elf64_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
@@ -125,6 +126,7 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/mips/mips/freebsd32_machdep.c
==============================================================================
--- head/sys/mips/mips/freebsd32_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/mips/mips/freebsd32_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -94,6 +94,7 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_usrstack	= FREEBSD32_USRSTACK,
 	.sv_psstrings	= FREEBSD32_PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = freebsd32_copyout_strings,
 	.sv_setregs	= freebsd32_exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/powerpc/powerpc/elf32_machdep.c
==============================================================================
--- head/sys/powerpc/powerpc/elf32_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/powerpc/powerpc/elf32_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -87,6 +87,7 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_errtbl	= NULL,
 	.sv_transtrap	= NULL,
 	.sv_fixup	= __elfN(freebsd_fixup),
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_sendsig	= sendsig,
 	.sv_sigcode	= sigcode32,
 	.sv_szsigcode	= &szsigcode32,

Modified: head/sys/powerpc/powerpc/elf64_machdep.c
==============================================================================
--- head/sys/powerpc/powerpc/elf64_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/powerpc/powerpc/elf64_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -74,6 +74,7 @@ struct sysentvec elf64_freebsd_sysvec_v1 = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs_funcdesc,
 	.sv_fixlimit	= NULL,
@@ -111,6 +112,7 @@ struct sysentvec elf64_freebsd_sysvec_v2 = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_ALL,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/riscv/riscv/elf_machdep.c
==============================================================================
--- head/sys/riscv/riscv/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/riscv/riscv/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -79,6 +79,7 @@ struct sysentvec elf64_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings	= exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/sparc64/sparc64/elf_machdep.c
==============================================================================
--- head/sys/sparc64/sparc64/elf_machdep.c	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/sparc64/sparc64/elf_machdep.c	Fri Nov 15 18:42:13 2019	(r354741)
@@ -75,6 +75,7 @@ static struct sysentvec elf64_freebsd_sysvec = {
 	.sv_usrstack	= USRSTACK,
 	.sv_psstrings	= PS_STRINGS,
 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
+	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,

Modified: head/sys/sys/imgact_elf.h
==============================================================================
--- head/sys/sys/imgact_elf.h	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/sys/imgact_elf.h	Fri Nov 15 18:42:13 2019	(r354741)
@@ -99,6 +99,7 @@ int	__elfN(freebsd_fixup)(register_t **, struct image_
 int	__elfN(coredump)(struct thread *, struct vnode *, off_t, int);
 size_t	__elfN(populate_note)(int, void *, void *, size_t, void **);
 void	__elfN(stackgap)(struct image_params *, u_long *);
+void	__elfN(freebsd_copyout_auxargs)(struct image_params *, u_long *);
 
 /* Machine specific function to dump per-thread information. */
 void	__elfN(dump_thread)(struct thread *, void *, size_t *);

Modified: head/sys/sys/sysent.h
==============================================================================
--- head/sys/sys/sysent.h	Fri Nov 15 18:34:36 2019	(r354740)
+++ head/sys/sys/sysent.h	Fri Nov 15 18:42:13 2019	(r354741)
@@ -110,6 +110,7 @@ struct sysentvec {
 					/* function to dump core, or NULL */
 	int		(*sv_imgact_try)(struct image_params *);
 	void		(*sv_stackgap)(struct image_params *, u_long *);
+	void		(*sv_copyout_auxargs)(struct image_params *, u_long *);
 	int		sv_minsigstksz;	/* minimum signal stack size */
 	vm_offset_t	sv_minuser;	/* VM_MIN_ADDRESS */
 	vm_offset_t	sv_maxuser;	/* VM_MAXUSER_ADDRESS */



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