[ARM] 3664/1: crunch: add signal frame save/restore
Patch from Lennert Buytenhek
This patch makes the kernel save Crunch state in userland signal frames,
so that any userland signal handler can safely use the Crunch coprocessor
without corrupting the Crunch state of the code it preempted.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 1ce05ec..83a8d3c 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -132,6 +132,37 @@
return ret;
}
+#ifdef CONFIG_CRUNCH
+static int preserve_crunch_context(struct crunch_sigframe *frame)
+{
+ char kbuf[sizeof(*frame) + 8];
+ struct crunch_sigframe *kframe;
+
+ /* the crunch context must be 64 bit aligned */
+ kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
+ kframe->magic = CRUNCH_MAGIC;
+ kframe->size = CRUNCH_STORAGE_SIZE;
+ crunch_task_copy(current_thread_info(), &kframe->storage);
+ return __copy_to_user(frame, kframe, sizeof(*frame));
+}
+
+static int restore_crunch_context(struct crunch_sigframe *frame)
+{
+ char kbuf[sizeof(*frame) + 8];
+ struct crunch_sigframe *kframe;
+
+ /* the crunch context must be 64 bit aligned */
+ kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
+ if (__copy_from_user(kframe, frame, sizeof(*frame)))
+ return -1;
+ if (kframe->magic != CRUNCH_MAGIC ||
+ kframe->size != CRUNCH_STORAGE_SIZE)
+ return -1;
+ crunch_task_restore(current_thread_info(), &kframe->storage);
+ return 0;
+}
+#endif
+
#ifdef CONFIG_IWMMXT
static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
@@ -214,6 +245,10 @@
err |= !valid_user_regs(regs);
aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
+#ifdef CONFIG_CRUNCH
+ if (err == 0)
+ err |= restore_crunch_context(&aux->crunch);
+#endif
#ifdef CONFIG_IWMMXT
if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
err |= restore_iwmmxt_context(&aux->iwmmxt);
@@ -333,6 +368,10 @@
err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
+#ifdef CONFIG_CRUNCH
+ if (err == 0)
+ err |= preserve_crunch_context(&aux->crunch);
+#endif
#ifdef CONFIG_IWMMXT
if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
err |= preserve_iwmmxt_context(&aux->iwmmxt);