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Subject[PATCH] 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>
---
arch/tile/mm/elf.c | 62 ++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 48 insertions(+), 14 deletions(-)

diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c
index 743c951..1691b81 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. */
--
1.8.3.1


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