1 files changed, 22 insertions, 27 deletions

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 8807ba2cf262..abd756315cb5 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -41,6 +41,8 @@
 struct rt_sigframe {
         struct siginfo info;
         struct ucontext uc;
+        u64 fp;
+        u64 lr;
 };
 
 static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
@@ -175,6 +177,10 @@ static int setup_sigframe(struct rt_sigframe __user *sf,
         struct aux_context __user *aux =
                 (struct aux_context __user *)sf->uc.uc_mcontext.__reserved;
 
+        /* set up the stack frame for unwinding */
+        __put_user_error(regs->regs[29], &sf->fp, err);
+        __put_user_error(regs->regs[30], &sf->lr, err);
+
         for (i = 0; i < 31; i++)
                 __put_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
                                  err);
@@ -196,11 +202,11 @@ static int setup_sigframe(struct rt_sigframe __user *sf,
         return err;
 }
 
-static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
-                                 int framesize)
+static struct rt_sigframe __user *get_sigframe(struct k_sigaction *ka,
+                                               struct pt_regs *regs)
 {
         unsigned long sp, sp_top;
-        void __user *frame;
+        struct rt_sigframe __user *frame;
 
         sp = sp_top = regs->sp;
 
@@ -210,11 +216,8 @@ static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
                 sp = sp_top = current->sas_ss_sp + current->sas_ss_size;
 
-        /* room for stack frame (FP, LR) */
-        sp -= 16;
-
-        sp = (sp - framesize) & ~15;
-        frame = (void __user *)sp;
+        sp = (sp - sizeof(struct rt_sigframe)) & ~15;
+        frame = (struct rt_sigframe __user *)sp;
 
         /*
          * Check that we can actually write to the signal frame.
@@ -225,20 +228,14 @@ static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
         return frame;
 }
 
-static int setup_return(struct pt_regs *regs, struct k_sigaction *ka,
-                        void __user *frame, int usig)
+static void setup_return(struct pt_regs *regs, struct k_sigaction *ka,
+                         void __user *frame, int usig)
 {
-        int err = 0;
         __sigrestore_t sigtramp;
-        unsigned long __user *sp = (unsigned long __user *)regs->sp;
-
-        /* set up the stack frame */
-        __put_user_error(regs->regs[29], sp - 2, err);
-        __put_user_error(regs->regs[30], sp - 1, err);
 
         regs->regs[0] = usig;
-        regs->regs[29] = regs->sp - 16;
         regs->sp = (unsigned long)frame;
+        regs->regs[29] = regs->sp + offsetof(struct rt_sigframe, fp);
         regs->pc = (unsigned long)ka->sa.sa_handler;
 
         if (ka->sa.sa_flags & SA_RESTORER)
@@ -247,8 +244,6 @@ static int setup_return(struct pt_regs *regs, struct k_sigaction *ka,
                 sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
 
         regs->regs[30] = (unsigned long)sigtramp;
-
-        return err;
 }
 
 static int setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
@@ -258,7 +253,7 @@ static int setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
         stack_t stack;
         int err = 0;
 
-        frame = get_sigframe(ka, regs, sizeof(*frame));
+        frame = get_sigframe(ka, regs);
         if (!frame)
                 return 1;
 
@@ -272,13 +267,13 @@ static int setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
         err |= __copy_to_user(&frame->uc.uc_stack, &stack, sizeof(stack));
 
         err |= setup_sigframe(frame, regs, set);
-        if (err == 0)
-                err = setup_return(regs, ka, frame, usig);
-
-        if (err == 0 && ka->sa.sa_flags & SA_SIGINFO) {
-                err |= copy_siginfo_to_user(&frame->info, info);
-                regs->regs[1] = (unsigned long)&frame->info;
-                regs->regs[2] = (unsigned long)&frame->uc;
+        if (err == 0) {
+                setup_return(regs, ka, frame, usig);
+                if (ka->sa.sa_flags & SA_SIGINFO) {
+                        err |= copy_siginfo_to_user(&frame->info, info);
+                        regs->regs[1] = (unsigned long)&frame->info;
+                        regs->regs[2] = (unsigned long)&frame->uc;
+                }
         }
 
         return err;