Merge branch 'devel'

[palacios.git] / kitten / arch / x86_64 / kernel / sys_arch_prctl.c

diff --git a/kitten/arch/x86_64/kernel/sys_arch_prctl.c b/kitten/arch/x86_64/kernel/sys_arch_prctl.c
new file mode 100644 (file)
index 0000000..5243162
--- /dev/null
+++ b/kitten/arch/x86_64/kernel/sys_arch_prctl.c
@@ -0,0 +1,84 @@
+#include <lwk/kernel.h>
+#include <lwk/task.h>
+#include <arch/prctl.h>
+#include <arch/uaccess.h>
+
+
+long
+do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
+{
+       int ret = 0; 
+       int doit = task == current;
+
+       switch (code) { 
+       case ARCH_SET_GS:
+               if (addr >= task->arch.addr_limit)
+                       return -EPERM; 
+
+               task->arch.thread.gsindex = 0;
+               task->arch.thread.gs = addr;
+               if (doit) {
+                       /* The kernel's %gs is currently loaded, so this
+                          call is needed to set the user version. */
+                       load_gs_index(0);
+                       ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr);
+               } 
+
+               break;
+       case ARCH_SET_FS:
+               /* Not strictly needed for fs, but do it for symmetry
+                  with gs */
+               if (addr >= task->arch.addr_limit)
+                       return -EPERM; 
+
+               task->arch.thread.fsindex = 0;
+               task->arch.thread.fs = addr;
+               if (doit) {
+                       /* The kernel doesn't use %fs so we can set it
+                          directly.  set the selector to 0 to not confuse
+                          __switch_to */
+                       asm volatile("movl %0,%%fs" :: "r" (0));
+                       ret = checking_wrmsrl(MSR_FS_BASE, addr);
+               }
+
+               break;
+       case ARCH_GET_FS: { 
+               unsigned long base; 
+               if (doit)
+                       rdmsrl(MSR_FS_BASE, base);
+               else
+                       base = task->arch.thread.fs;
+               ret = put_user(base, (unsigned long __user *)addr); 
+               break; 
+       }
+       case ARCH_GET_GS: { 
+               unsigned long base;
+               unsigned gsindex;
+               if (doit) {
+                       asm("movl %%gs,%0" : "=r" (gsindex));
+                       if (gsindex)
+                               rdmsrl(MSR_KERNEL_GS_BASE, base);
+                       else
+                               base = task->arch.thread.gs;
+               }
+               else
+                       base = task->arch.thread.gs;
+               ret = put_user(base, (unsigned long __user *)addr); 
+               break;
+       }
+
+       default:
+               ret = -EINVAL;
+               break;
+       } 
+
+       return ret;     
+}
+
+
+long
+sys_arch_prctl(int code, unsigned long addr)
+{
+       return do_arch_prctl(current, code, addr);
+}
+