[PATCH] uml: Fix sysrq-r support for skas mode

The old code had the IP and SP coming from the registers in the thread
struct, which are completely wrong since those are the userspace
registers.  This fixes that by pulling the correct values from the
jmp_buf in which the kernel state of each thread is stored.

Signed-off-by: Allan Graves <allan.graves@oracle.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 10 deletions

diff --git a/arch/um/os-Linux/sys-x86_64/registers.c b/arch/um/os-Linux/sys-x86_64/registers.c
index 44438d15c3d6..4b638dfb52b0 100644
--- a/arch/um/os-Linux/sys-x86_64/registers.c
+++ b/arch/um/os-Linux/sys-x86_64/registers.c
@@ -5,6 +5,7 @@
 
 #include <errno.h>
 #include <string.h>
+#include <setjmp.h>
 #include "ptrace_user.h"
 #include "uml-config.h"
 #include "skas_ptregs.h"
@@ -74,13 +75,11 @@ void get_safe_registers(unsigned long *regs)
         memcpy(regs, exec_regs, HOST_FRAME_SIZE * sizeof(unsigned long));
 }
 
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
+void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer)
+{
+        struct __jmp_buf_tag *jmpbuf = buffer;
+
+        UPT_SET(uml_regs, RIP, jmpbuf->__jmpbuf[JB_PC]);
+        UPT_SET(uml_regs, RSP, jmpbuf->__jmpbuf[JB_RSP]);
+        UPT_SET(uml_regs, RBP, jmpbuf->__jmpbuf[JB_RBP]);
+}