tile: support simulator notification for ET_DYN objects

The tile code notifies the simulator of new ET_EXEC objects starting
to execute so that tracing code can properly annotate the objects.
However, we didn't support ET_DYN executables like ld.so, so we
didn't properly load symbols, etc.  This change enables that support;
we use a variant of the SIM_CONTROL_DLOPEN simulator notification
that newer simulators will recognize and use to set the base address
for the next SIM_CONTROL_OS_EXEC notification.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c
index 743c951c61b061b516e1bb3ea06b397e42700d91..1691b81b2b0c2a5f135e286f80f87ca4c54d00d0 100644 (file)
--- a/arch/tile/mm/elf.c
+++ b/arch/tile/mm/elf.c
@@ -21,7 +21,7 @@
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
-#include <arch/sim_def.h>
+#include <arch/sim.h>
 
 /* Notify a running simulator, if any, that an exec just occurred. */
 static void sim_notify_exec(const char *binary_name)
@@ -38,21 +38,55 @@ static void sim_notify_exec(const char *binary_name)
 
 static int notify_exec(struct mm_struct *mm)
 {
-       int retval = 0;  /* failure */
-
-       if (mm->exe_file) {
-               char *buf = (char *) __get_free_page(GFP_KERNEL);
-               if (buf) {
-                       char *path = d_path(&mm->exe_file->f_path,
-                                           buf, PAGE_SIZE);
-                       if (!IS_ERR(path)) {
-                               sim_notify_exec(path);
-                               retval = 1;
-                       }
-                       free_page((unsigned long)buf);
+       char *buf, *path;
+       struct vm_area_struct *vma;
+
+       if (!sim_is_simulator())
+               return 1;
+
+       if (mm->exe_file == NULL)
+               return 0;
+
+       for (vma = current->mm->mmap; ; vma = vma->vm_next) {
+               if (vma == NULL)
+                       return 0;
+               if (vma->vm_file == mm->exe_file)
+                       break;
+       }
+
+       buf = (char *) __get_free_page(GFP_KERNEL);
+       if (buf == NULL)
+               return 0;
+
+       path = d_path(&mm->exe_file->f_path, buf, PAGE_SIZE);
+       if (IS_ERR(path)) {
+               free_page((unsigned long)buf);
+               return 0;
+       }
+
+       /*
+        * Notify simulator of an ET_DYN object so we know the load address.
+        * The somewhat cryptic overuse of SIM_CONTROL_DLOPEN allows us
+        * to be backward-compatible with older simulator releases.
+        */
+       if (vma->vm_start == (ELF_ET_DYN_BASE & PAGE_MASK)) {
+               char buf[64];
+               int i;
+
+               snprintf(buf, sizeof(buf), "0x%lx:@", vma->vm_start);
+               for (i = 0; ; ++i) {
+                       char c = buf[i];
+                       __insn_mtspr(SPR_SIM_CONTROL,
+                                    (SIM_CONTROL_DLOPEN
+                                     | (c << _SIM_CONTROL_OPERATOR_BITS)));
+                       if (c == '\0')
+                               break;
                }
        }
-       return retval;
+
+       sim_notify_exec(path);
+       free_page((unsigned long)buf);
+       return 1;
 }
 
 /* Notify a running simulator, if any, that we loaded an interpreter. */