[src/trunk]: src/sys/compat/irix Fixes the problem with libX11.so mapping by ...

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

details:   https://anonhg.NetBSD.org/src/rev/4be59a62ab39
branches:  trunk
changeset: 520921:4be59a62ab39
user:      manu <manu%NetBSD.org@localhost>
date:      Sat Jan 19 14:56:02 2002 +0000

description:
Fixes the problem with libX11.so mapping by syssgi(MAPELF): the load address
for the text section of libx11.so was overlapping with other ELF sections
aloready loaded, and this resulted into an ENOMEM error.

syssgi(MAPELF) uses elf32_load_psection() from syssrc/sys/kern/exec_subr.c
The problem was never experienced with load_psection() because it only has
to load one section, hence the requested address are not already allocated.

The fix is done when the initial mapping at the default address fails by
finding a free location in the VM space using uvm_map_findspace(), and then
retrying to load the section.

Other details:
- once the ELF section has been relocated, the ELF program header must be
updated with the new address and copied back to userland. For now we always
do it, maybe we could copy it only when it was modified.
- We are able to emulate the exact address where IRIX loads libX11.so instead
of the default location

diffstat:

 sys/compat/irix/irix_syssgi.c |  62 ++++++++++++++++++++++++++++++++++++------
 sys/compat/irix/irix_syssgi.h |   4 ++-
 2 files changed, 56 insertions(+), 10 deletions(-)

diffs (128 lines):

diff -r 5c06836cb032 -r 4be59a62ab39 sys/compat/irix/irix_syssgi.c
--- a/sys/compat/irix/irix_syssgi.c     Sat Jan 19 14:49:18 2002 +0000
+++ b/sys/compat/irix/irix_syssgi.c     Sat Jan 19 14:56:02 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: irix_syssgi.c,v 1.11 2001/12/27 09:31:09 manu Exp $ */
+/*     $NetBSD: irix_syssgi.c,v 1.12 2002/01/19 14:56:02 manu Exp $ */
 
 /*-
  * Copyright (c) 2001 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: irix_syssgi.c,v 1.11 2001/12/27 09:31:09 manu Exp $");
+__KERNEL_RCSID(0, "$NetBSD: irix_syssgi.c,v 1.12 2002/01/19 14:56:02 manu Exp $");
 
 #include "opt_ddb.h"
 
@@ -214,12 +214,15 @@
        struct exec_vmcmd_set vcset;
        struct exec_vmcmd *base_vcp = NULL;
        struct vnode *vp;
+       vaddr_t new_addr;
+       struct vm_map_entry *ret;
+       struct exec_vmcmd *vcp;
 
        vcset.evs_cnt = 0;
        vcset.evs_used = 0;
 
-       /* Check that the program header array is readable by the process */
-       if (!uvm_useracc((caddr_t)ph, sizeof(Elf_Phdr) * count, B_READ))
+       /* Check that the program header array is writable by the process */
+       if (!uvm_useracc((caddr_t)ph, sizeof(Elf_Phdr) * count, B_WRITE))
                return EACCES;
 
        kph = (Elf_Phdr *)malloc(sizeof(Elf_Phdr) * count,
@@ -265,27 +268,68 @@
        /* 
         * Run the vmcmds
         */
+       pht = kph;
        for (j = 0; j < vcset.evs_used && !error; j++) {
-               struct exec_vmcmd *vcp;
                vcp = &vcset.evs_cmds[j];
                if (vcp->ev_flags & VMCMD_RELATIVE) {
                        if (base_vcp == NULL)
-                               panic("irix_syssgi_mapelf: bad vmcmd base\n");
+                               panic("irix_syssgi_mapelf(): bad vmcmd base\n");
                                   
                        vcp->ev_addr += base_vcp->ev_addr;
                }
 #ifdef DEBUG_IRIX
-       printf("irix_syssgi_mapelf(): mapping j = %d\n", j);
-       printf("uaddr = 0x%08lx, size = 0x%08lx, prot = 0x%08x ", 
-           (unsigned long)uaddr, size, prot);
+               printf("irix_syssgi_mapelf(): mapping section j = %d \n", j);
+               printf("addr = 0x%08lx, size = 0x%08lx\n", 
+                   vcp->ev_addr, vcp->ev_len);
 #endif
                error = (*vcp->ev_proc)(p, vcp);
+               if (error) {
+                       /* 
+                        * We failed because the address where the default 
+                        * section proposes is already used. This happens
+                        * because there is already something at the default
+                        * load address for this ELF section. This happens
+                        * with the libX11.so text segment, which overlaps
+                        * with libXt.so sections.
+                        *
+                        * The fix is finding a free space and retrying.
+                        * IRIX maps libX11 at IRIX_MAPELF_RELOCATE, we
+                        * try to emulate this behavior.
+                        */
+                       ret = uvm_map_findspace(&p->p_vmspace->vm_map, 
+                           IRIX_MAPELF_RELOCATE, vcp->ev_len, &new_addr, 
+                           NULL, 0, pht->p_align , 0);
+                       if (ret) {
+#ifdef DEBUG_IRIX
+                               printf("irix_syssgi_mapelf(): ");
+                               printf("relocating from %p to %p\n",
+                                   (void *)vcp->ev_addr, (void *)new_addr);
+#endif
+                               vcp->ev_addr = new_addr;
+                               error = (*vcp->ev_proc)(p, vcp);
+                               /* 
+                                * Adjsut the virtual address in the ELF
+                                * program header
+                                */
+                               if (!error)
+                                       pht->p_vaddr = new_addr;
+                       }
+               }
                if (vcp->ev_flags & VMCMD_BASE)
                        base_vcp = vcp;
+               pht++;
        }
 
        FILE_UNUSE(fp, p);
        
+       /*
+        * Copy back the program header table in case we had to
+        * adjust some load virtual addresses 
+        */
+       error = copyout(kph, ph, sizeof(Elf_Phdr) * count);
+       if (error)
+               goto bad;
+       
        *retval = (register_t)kph->p_vaddr;     
 bad:
        free(kph, M_TEMP);
diff -r 5c06836cb032 -r 4be59a62ab39 sys/compat/irix/irix_syssgi.h
--- a/sys/compat/irix/irix_syssgi.h     Sat Jan 19 14:49:18 2002 +0000
+++ b/sys/compat/irix/irix_syssgi.h     Sat Jan 19 14:56:02 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: irix_syssgi.h,v 1.2 2001/12/08 11:17:37 manu Exp $ */
+/*     $NetBSD: irix_syssgi.h,v 1.3 2002/01/19 14:56:03 manu Exp $ */
 
 /*-
  * Copyright (c) 2001 The NetBSD Foundation, Inc.
@@ -39,6 +39,8 @@
 #ifndef _IRIX_SYSSGI_H_
 #define _IRIX_SYSSGI_H_
 
+#define IRIX_MAPELF_RELOCATE           0x4000000
+
 /* From IRIX's <sys/syssgi.h> */
 
 #define        IRIX_SGI_SYSID                  1