powerpc: ELF2 binaries launched directly.
No function descriptor, but we set r12 up and set TIF_RESTOREALL as it
normally isn't restored on return from syscall.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 75c2d10..0650e18 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1086,25 +1086,45 @@
regs->msr = MSR_USER;
#else
if (!is_32bit_task()) {
- unsigned long entry, toc;
+ unsigned long entry;
- /* start is a relocated pointer to the function descriptor for
- * the elf _start routine. The first entry in the function
- * descriptor is the entry address of _start and the second
- * entry is the TOC value we need to use.
- */
- __get_user(entry, (unsigned long __user *)start);
- __get_user(toc, (unsigned long __user *)start+1);
+ if (is_elf2_task()) {
+ /* Look ma, no function descriptors! */
+ entry = start;
- /* Check whether the e_entry function descriptor entries
- * need to be relocated before we can use them.
- */
- if (load_addr != 0) {
- entry += load_addr;
- toc += load_addr;
+ /*
+ * Ulrich says:
+ * The latest iteration of the ABI requires that when
+ * calling a function (at its global entry point),
+ * the caller must ensure r12 holds the entry point
+ * address (so that the function can quickly
+ * establish addressability).
+ */
+ regs->gpr[12] = start;
+ /* Make sure that's restored on entry to userspace. */
+ set_thread_flag(TIF_RESTOREALL);
+ } else {
+ unsigned long toc;
+
+ /* start is a relocated pointer to the function
+ * descriptor for the elf _start routine. The first
+ * entry in the function descriptor is the entry
+ * address of _start and the second entry is the TOC
+ * value we need to use.
+ */
+ __get_user(entry, (unsigned long __user *)start);
+ __get_user(toc, (unsigned long __user *)start+1);
+
+ /* Check whether the e_entry function descriptor entries
+ * need to be relocated before we can use them.
+ */
+ if (load_addr != 0) {
+ entry += load_addr;
+ toc += load_addr;
+ }
+ regs->gpr[2] = toc;
}
regs->nip = entry;
- regs->gpr[2] = toc;
regs->msr = MSR_USER64;
} else {
regs->nip = start;
