Fix some libdwfl bias calculations.

3 files changed, 38 insertions, 9 deletions

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 019dd1c0..347ebcf4 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,12 @@
+2010-05-20  Roland McGrath  <roland@redhat.com>
+
+	* linux-proc-maps.c (find_sysinfo_ehdr): Renamed to ...
+	(grovel_auxv): ... this.  Take DWFL argument.
+	(dwfl_linux_proc_report): Update caller.
+
+	* dwfl_module_getdwarf.c (open_elf): Calculate alignment for bias
+	based on dwfl->segment_align or manifest alignment of MOD->low_addr.
+
 2010-05-19  Roland McGrath  <roland@redhat.com>
 
 	* linux-kernel-modules.c (intuit_kernel_bounds): Rewritten.
diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index 6065257d..41ed0730 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -112,8 +112,16 @@ open_elf (Dwfl_Module *mod, struct dwfl_file *file)
 	    goto elf_error;
 	  if (ph->p_type == PT_LOAD)
 	    {
-	      file->bias = ((mod->low_addr & -ph->p_align)
-			    - (ph->p_vaddr & -ph->p_align));
+	      GElf_Addr align = mod->dwfl->segment_align;
+	      if (align <= 1)
+		{
+		  if ((mod->low_addr & (ph->p_align - 1)) == 0)
+		    align = ph->p_align;
+		  else
+		    align = ((GElf_Addr) 1 << ffsll (mod->low_addr)) >> 1;
+		}
+
+	      file->bias = ((mod->low_addr & -align) - (ph->p_vaddr & -align));
 	      break;
 	    }
 	}
diff --git a/libdwfl/linux-proc-maps.c b/libdwfl/linux-proc-maps.c
index 2206f63c..8504a5f3 100644
--- a/libdwfl/linux-proc-maps.c
+++ b/libdwfl/linux-proc-maps.c
@@ -1,5 +1,5 @@
 /* Standard libdwfl callbacks for debugging a live Linux process.
-   Copyright (C) 2005, 2007, 2008 Red Hat, Inc.
+   Copyright (C) 2005-2010 Red Hat, Inc.
    This file is part of Red Hat elfutils.
 
    Red Hat elfutils is free software; you can redistribute it and/or modify
@@ -70,7 +70,7 @@
 /* Search /proc/PID/auxv for the AT_SYSINFO_EHDR tag.  */
 
 static int
-find_sysinfo_ehdr (pid_t pid, GElf_Addr *sysinfo_ehdr)
+grovel_auxv (pid_t pid, Dwfl *dwfl, GElf_Addr *sysinfo_ehdr)
 {
   char *fname;
   if (asprintf (&fname, PROCAUXVFMT, pid) < 0)
@@ -100,18 +100,30 @@ find_sysinfo_ehdr (pid_t pid, GElf_Addr *sysinfo_ehdr)
 		if (d.a32[i].a_type == AT_SYSINFO_EHDR)
 		  {
 		    *sysinfo_ehdr = d.a32[i].a_un.a_val;
-		    nread = 0;
-		    break;
+		    if (dwfl->segment_align > 1)
+		      {
+			nread = 0;
+			break;
+		      }
 		  }
+		else if (d.a32[i].a_type == AT_PAGESZ
+			 && dwfl->segment_align <= 1)
+		  dwfl->segment_align = d.a32[i].a_un.a_val;
 	      break;
 	    case 8:
 	      for (size_t i = 0; (char *) &d.a64[i] < &d.buffer[nread]; ++i)
 		if (d.a64[i].a_type == AT_SYSINFO_EHDR)
 		  {
 		    *sysinfo_ehdr = d.a64[i].a_un.a_val;
-		    nread = 0;
-		    break;
+		    if (dwfl->segment_align > 1)
+		      {
+			nread = 0;
+			break;
+		      }
 		  }
+		else if (d.a64[i].a_type == AT_PAGESZ
+			 && dwfl->segment_align <= 1)
+		  dwfl->segment_align = d.a64[i].a_un.a_val;
 	      break;
 	    default:
 	      abort ();
@@ -238,7 +250,7 @@ dwfl_linux_proc_report (Dwfl *dwfl, pid_t pid)
 
   /* We'll notice the AT_SYSINFO_EHDR address specially when we hit it.  */
   GElf_Addr sysinfo_ehdr = 0;
-  int result = find_sysinfo_ehdr (pid, &sysinfo_ehdr);
+  int result = grovel_auxv (pid, dwfl, &sysinfo_ehdr);
   if (result != 0)
     return result;