[PATCH] uml: skas0 - separate kernel address space on stock hosts

[pandora-kernel.git] / arch / um / sys-x86_64 / stub_segv.c

diff --git a/arch/um/sys-x86_64/stub_segv.c b/arch/um/sys-x86_64/stub_segv.c
new file mode 100644 (file)
index 0000000..161d1fe
--- /dev/null
+++ b/arch/um/sys-x86_64/stub_segv.c
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL
+ */
+
+#include <signal.h>
+#include <linux/compiler.h>
+#include <asm/unistd.h>
+#include "uml-config.h"
+#include "sysdep/sigcontext.h"
+#include "sysdep/faultinfo.h"
+
+void __attribute__ ((__section__ (".__syscall_stub")))
+stub_segv_handler(int sig)
+{
+       struct ucontext *uc;
+
+       __asm__("movq %%rdx, %0" : "=g" (uc) :);
+        GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
+                              &uc->uc_mcontext);
+
+       __asm__("movq %0, %%rax ; syscall": : "g" (__NR_getpid));
+       __asm__("movq %%rax, %%rdi ; movq %0, %%rax ; movq %1, %%rsi ;"
+               "syscall": : "g" (__NR_kill), "g" (SIGUSR1));
+       /* Two popqs to restore the stack to the state just before entering
+        * the handler, one pops the return address, the other pops the frame
+        * pointer.
+        */
+       __asm__("popq %%rax ; popq %%rax ; movq %0, %%rax ; syscall" : : "g"
+               (__NR_rt_sigreturn));
+}