ARM: virt: allow the kernel to be entered in HYP mode

[cascardo/linux.git] / arch / arm / include / asm / assembler.h

diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 03fb936..658a15d 100644 (file)
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -22,6 +22,7 @@
 
 #include <asm/ptrace.h>
 #include <asm/domain.h>
+#include <asm/opcodes-virt.h>
 
 #define IOMEM(x)       (x)
 
@@ -239,6 +240,33 @@
        .endm
 #endif
 
+/*
+ * Helper macro to enter SVC mode cleanly and mask interrupts. reg is
+ * a scratch register for the macro to overwrite.
+ *
+ * This macro is intended for forcing the CPU into SVC mode at boot time.
+ * you cannot return to the original mode.
+ *
+ * Beware, it also clobers LR.
+ */
+.macro safe_svcmode_maskall reg:req
+       mrs     \reg , cpsr
+       mov     lr , \reg
+       and     lr , lr , #MODE_MASK
+       cmp     lr , #HYP_MODE
+       orr     \reg , \reg , #PSR_A_BIT | PSR_I_BIT | PSR_F_BIT
+       bic     \reg , \reg , #MODE_MASK
+       orr     \reg , \reg , #SVC_MODE
+THUMB( orr     \reg , \reg , #PSR_T_BIT        )
+       msr     spsr_cxsf, \reg
+       adr     lr, BSYM(2f)
+       bne     1f
+       __MSR_ELR_HYP(14)
+       __ERET
+1:     movs    pc, lr
+2:
+.endm
+
 /*
  * STRT/LDRT access macros with ARM and Thumb-2 variants
  */