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>

1 files changed, 48 insertions, 14 deletions

diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c
index 743c951c61b0..1691b81b2b0c 100644
--- 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. */