commit 3bce9544deab0261c7c55ccdc46ce1f36e468040

Author: Mark Wielaard <mark@klomp.org>

Date:   Thu Jul 12 13:56:00 2018 +0200

    Accept read-only PT_LOAD segments and .rodata.

    The new binutils ld -z separate-code option creates multiple read-only

    PT_LOAD segments and might place .rodata in a non-executable segment.

    Allow and keep track of separate read-only segments and allow a readonly

    page with .rodata section.

    Based on patches from Tom Hughes <tom@compton.nu> and

    H.J. Lu <hjl.tools@gmail.com>.

    https://bugs.kde.org/show_bug.cgi?id=395682

index 13991b6..c36d498 100644

--- a/coregrind/m_debuginfo/debuginfo.c

+++ b/coregrind/m_debuginfo/debuginfo.c

@@ -1126,9 +1126,7 @@ ULong VG_(di_notify_mmap)( Addr a, Bool allow_SkFileV, Int use_fd )

 #    error "Unknown platform"

 #  endif

-#  if defined(VGP_x86_darwin) && DARWIN_VERS >= DARWIN_10_7

    is_ro_map = seg->hasR && !seg->hasW && !seg->hasX;

-#  endif

 #  if defined(VGO_solaris)

    is_rx_map = seg->hasR && seg->hasX && !seg->hasW;

diff --git a/coregrind/m_debuginfo/readelf.c b/coregrind/m_debuginfo/readelf.c

index 62192f0..95b97d6 100644

--- a/coregrind/m_debuginfo/readelf.c

+++ b/coregrind/m_debuginfo/readelf.c

@@ -1881,7 +1881,7 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di )

                Bool loaded = False;

                for (j = 0; j < VG_(sizeXA)(di->fsm.maps); j++) {

                   const DebugInfoMapping* map = VG_(indexXA)(di->fsm.maps, j);

-                  if (   (map->rx || map->rw)

+                  if (   (map->rx || map->rw || map->ro)

                       && map->size > 0 /* stay sane */

                       && a_phdr.p_offset >= map->foff

                       && a_phdr.p_offset <  map->foff + map->size

@@ -1912,6 +1912,16 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di )

                            i, (UWord)item.bias);

                         loaded = True;

                      }

+                     if (map->ro

+                         && (a_phdr.p_flags & (PF_R | PF_W | PF_X))

+                            == PF_R) {

+                        item.exec = False;

+                        VG_(addToXA)(svma_ranges, &item);

+                        TRACE_SYMTAB(

+                           "PT_LOAD[%ld]:   acquired as ro, bias 0x%lx\n",

+                           i, (UWord)item.bias);

+                        loaded = True;

+                     }

                   }

                }

                if (!loaded) {

@@ -2179,17 +2189,25 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di )

          }

       }

-      /* Accept .rodata where mapped as rx (data), even if zero-sized */

+      /* Accept .rodata where mapped as rx or rw (data), even if zero-sized */

       if (0 == VG_(strcmp)(name, ".rodata")) {

-         if (inrx && !di->rodata_present) {

-            di->rodata_present = True;

+         if (!di->rodata_present) {

             di->rodata_svma = svma;

-            di->rodata_avma = svma + inrx->bias;

+            di->rodata_avma = svma;

             di->rodata_size = size;

-            di->rodata_bias = inrx->bias;

             di->rodata_debug_svma = svma;

-            di->rodata_debug_bias = inrx->bias;

-                                    /* NB was 'inrw' prior to r11794 */

+            if (inrx) {

+               di->rodata_avma += inrx->bias;

+               di->rodata_bias = inrx->bias;

+               di->rodata_debug_bias = inrx->bias;

+            } else if (inrw) {

+               di->rodata_avma += inrw->bias;

+               di->rodata_bias = inrw->bias;

+               di->rodata_debug_bias = inrw->bias;

+            } else {

+               BAD(".rodata");

+            }

+            di->rodata_present = True;

             TRACE_SYMTAB("acquiring .rodata svma = %#lx .. %#lx\n",

                          di->rodata_svma,

                          di->rodata_svma + di->rodata_size - 1);