sh: Initial ELF FDPIC support.

This adds initial support for ELF FDPIC on MMU-less SH, as per version
0.2 of the ABI definition at:

	http://www.codesourcery.com/public/docs/sh-fdpic/sh-fdpic-abi.txt

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 23 insertions, 2 deletions

diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index f311551d9a05..46170a9a7221 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -33,6 +33,11 @@
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
+struct fdpic_func_descriptor {
+        unsigned long   text;
+        unsigned long   GOT;
+};
+
 /*
  * Atomically swap in the new signal mask, and wait for a signal.
  */
@@ -378,7 +383,15 @@ static int setup_frame(int sig, struct k_sigaction *ka,
         regs->regs[4] = signal; /* Arg for signal handler */
         regs->regs[5] = 0;
         regs->regs[6] = (unsigned long) &frame->sc;
-        regs->pc = (unsigned long) ka->sa.sa_handler;
+
+        if (current->personality & FDPIC_FUNCPTRS) {
+                struct fdpic_func_descriptor __user *funcptr =
+                        (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
+
+                __get_user(regs->pc, &funcptr->text);
+                __get_user(regs->regs[12], &funcptr->GOT);
+        } else
+                regs->pc = (unsigned long)ka->sa.sa_handler;
 
         set_fs(USER_DS);
 
@@ -458,7 +471,15 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         regs->regs[4] = signal; /* Arg for signal handler */
         regs->regs[5] = (unsigned long) &frame->info;
         regs->regs[6] = (unsigned long) &frame->uc;
-        regs->pc = (unsigned long) ka->sa.sa_handler;
+
+        if (current->personality & FDPIC_FUNCPTRS) {
+                struct fdpic_func_descriptor __user *funcptr =
+                        (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
+
+                __get_user(regs->pc, &funcptr->text);
+                __get_user(regs->regs[12], &funcptr->GOT);
+        } else
+                regs->pc = (unsigned long)ka->sa.sa_handler;
 
         set_fs(USER_DS);