[src/trunk]: src/sys/rump Translate return values for emulations, e.g. Linux....

[pooka <pooka%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4641ebd3ea1c
branches:  trunk
changeset: 325277:4641ebd3ea1c
user:      pooka <pooka%NetBSD.org@localhost>
date:      Mon Dec 16 15:36:29 2013 +0000

description:
Translate return values for emulations, e.g. Linux.  For ports without
__HAVE_MINIMAL_EMUL, we simply look up the values from p->p_emul->e_errno.
For ports which cannot afford to keep an extra pointer per emul structure
around, we hope there is __HAVE_SYSCALL_INTERN support and thread the
errno values through p_emuldata.  Notably, we cannot alter the syscall
method like most ports do with syscall_intern, since they do it via
p_mdproc, so MI code is not possible there.

diffstat:

 sys/rump/kern/lib/libsys_linux/component.c |  16 ++++++++++++++--
 sys/rump/librump/rumpkern/emul.c           |   6 +++---
 sys/rump/librump/rumpkern/lwproc.c         |   7 +++++--
 sys/rump/librump/rumpkern/rump.c           |  30 ++++++++++++++++++++++++++++--
 4 files changed, 50 insertions(+), 9 deletions(-)

diffs (162 lines):

diff -r 57a0e8434804 -r 4641ebd3ea1c sys/rump/kern/lib/libsys_linux/component.c
--- a/sys/rump/kern/lib/libsys_linux/component.c        Mon Dec 16 12:08:14 2013 +0000
+++ b/sys/rump/kern/lib/libsys_linux/component.c        Mon Dec 16 15:36:29 2013 +0000
@@ -1,8 +1,10 @@
-/*     $NetBSD: component.c,v 1.8 2013/04/03 23:51:20 pooka Exp $      */
+/*     $NetBSD: component.c,v 1.9 2013/12/16 15:36:30 pooka Exp $      */
 
 #include <sys/param.h>
 #include <sys/proc.h>
 
+#include <compat/linux/common/linux_errno.h>
+
 #include <uvm/uvm_extern.h>
 
 #include "rump_private.h"
@@ -11,15 +13,25 @@
 
 extern struct sysent rump_linux_sysent[];
 
+#ifdef __HAVE_SYSCALL_INTERN
+static void
+rumplinux_syscall_intern(struct proc *p)
+{
+
+       p->p_emuldata = __UNCONST(native_to_linux_errno);
+}
+#endif
+
 struct emul emul_rump_sys_linux = {
        .e_name = "linux-rump",
        .e_sysent = rump_linux_sysent,
 #ifndef __HAVE_MINIMAL_EMUL
        .e_nsysent = RUMP_LINUX_SYS_NSYSENT,
+       .e_errno = native_to_linux_errno;
 #endif
        .e_vm_default_addr = uvm_default_mapaddr,
 #ifdef __HAVE_SYSCALL_INTERN
-       .e_syscall_intern = syscall_intern,
+       .e_syscall_intern = rumplinux_syscall_intern,
 #endif
 };
 
diff -r 57a0e8434804 -r 4641ebd3ea1c sys/rump/librump/rumpkern/emul.c
--- a/sys/rump/librump/rumpkern/emul.c  Mon Dec 16 12:08:14 2013 +0000
+++ b/sys/rump/librump/rumpkern/emul.c  Mon Dec 16 15:36:29 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: emul.c,v 1.159 2013/12/09 16:54:20 pooka Exp $ */
+/*     $NetBSD: emul.c,v 1.160 2013/12/16 15:36:29 pooka Exp $ */
 
 /*
  * Copyright (c) 2007-2011 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: emul.c,v 1.159 2013/12/09 16:54:20 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: emul.c,v 1.160 2013/12/16 15:36:29 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/null.h>
@@ -277,7 +277,7 @@
 syscall_intern(struct proc *p)
 {
 
-       /* no you don't */
+       p->p_emuldata = NULL;
 }
 #endif
 
diff -r 57a0e8434804 -r 4641ebd3ea1c sys/rump/librump/rumpkern/lwproc.c
--- a/sys/rump/librump/rumpkern/lwproc.c        Mon Dec 16 12:08:14 2013 +0000
+++ b/sys/rump/librump/rumpkern/lwproc.c        Mon Dec 16 15:36:29 2013 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: lwproc.c,v 1.25 2013/12/09 16:21:15 pooka Exp $       */
+/*      $NetBSD: lwproc.c,v 1.26 2013/12/16 15:36:29 pooka Exp $       */
 
 /*
  * Copyright (c) 2010, 2011 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.25 2013/12/09 16:21:15 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.26 2013/12/16 15:36:29 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -137,6 +137,9 @@
 
        p->p_vmspace = vmspace_kernel();
        p->p_emul = emul_default;
+#ifdef __HAVE_SYSCALL_INTERN
+       p->p_emul->e_syscall_intern(p);
+#endif
        if (*parent->p_comm)
                strcpy(p->p_comm, parent->p_comm);
        else
diff -r 57a0e8434804 -r 4641ebd3ea1c sys/rump/librump/rumpkern/rump.c
--- a/sys/rump/librump/rumpkern/rump.c  Mon Dec 16 12:08:14 2013 +0000
+++ b/sys/rump/librump/rumpkern/rump.c  Mon Dec 16 15:36:29 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rump.c,v 1.280 2013/12/09 17:57:11 pooka Exp $ */
+/*     $NetBSD: rump.c,v 1.281 2013/12/16 15:36:30 pooka Exp $ */
 
 /*
  * Copyright (c) 2007-2011 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rump.c,v 1.280 2013/12/09 17:57:11 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rump.c,v 1.281 2013/12/16 15:36:30 pooka Exp $");
 
 #include <sys/systm.h>
 #define ELFSIZE ARCH_ELFSIZE
@@ -837,6 +837,7 @@
        if (__predict_false(num >= SYS_NSYSENT))
                return ENOSYS;
 
+       /* XXX: always uses native syscall vector */
        callp = rump_sysent + num;
        l = curlwp;
        rv = sy_invoke(callp, l, (void *)arg, regrv, num);
@@ -1016,6 +1017,7 @@
        struct proc *p;
        struct emul *e;
        struct sysent *callp;
+       const int *etrans = NULL;
        int rv;
 
        rump_schedule();
@@ -1027,6 +1029,30 @@
        callp = e->e_sysent + num;
 
        rv = sy_invoke(callp, curlwp, data, retval, num);
+
+       /*
+        * I hope that (!__HAVE_MINIMAL_EMUL || __HAVE_SYSCALL_INTERN) is
+        * an invariant ...
+        */
+#if !defined(__HAVE_MINIMAL_EMUL)
+       etrans = e->e_errno;
+#elif defined(__HAVE_SYSCALL_INTERN)
+       etrans = p->p_emuldata;
+#endif
+
+       if (etrans) {
+               rv = etrans[rv];
+               /*
+                * XXX: small hack since Linux etrans vectors on some
+                * archs contain negative errnos, but rump_syscalls
+                * uses the -1 + errno ABI.  Note that these
+                * negative values are always the result of translation,
+                * otherwise the above translation method would not
+                * work very well.
+                */
+               if (rv < 0)
+                       rv = -rv;
+       }
        rump_unschedule();
 
        return rv;