xen: arm: separate guest user regs from internal guest state.

struct cpu_user_regs is currently used as both internal state
(specifically at the base of the stack) and a guest/toolstack
visible API (via struct vcpu_guest_context used by
XEN_DOMCTL_{g,s}etvcpucontext and VCPUOP_initialise).

This causes problems when we want to make the API 64-bit clean since
we don't really want to change the size of the on-stack struct.

So split into vcpu_guest_core_regs which is the API facing struct
and keep cpu_user_regs purely internal, translate between the two.

In the user API arrange for both 64- and 32-bit registers to be
included in a layout which does not differ depending on toolstack
architecture. Also switch to using the more formal banked register
names (e.g. with the _usr suffix) for clarity.

This is an ABI change. Note that the kernel doesn't currently use
this data structure so it affects the tools interface only.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 7f6d7ce6aa..041832e68e 100644
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -107,17 +107,17 @@ static int vcpu_arm(struct xc_dom_image *dom, void *ptr)
     /* clear everything */
     memset(ctxt, 0, sizeof(*ctxt));
 
-    ctxt->user_regs.pc = dom->parms.virt_entry;
+    ctxt->user_regs.pc32 = dom->parms.virt_entry;
 
     /* Linux boot protocol. See linux.Documentation/arm/Booting. */
-    ctxt->user_regs.r0 = 0; /* SBZ */
+    ctxt->user_regs.r0_usr = 0; /* SBZ */
     /* Machine ID: We use DTB therefore no machine id */
-    ctxt->user_regs.r1 = 0xffffffff;
+    ctxt->user_regs.r1_usr = 0xffffffff;
     /* ATAGS/DTB: We currently require that the guest kernel to be
      * using CONFIG_ARM_APPENDED_DTB. Ensure that r2 does not look
      * like a valid pointer to a set of ATAGS or a DTB.
      */
-    ctxt->user_regs.r2 = 0xffffffff;
+    ctxt->user_regs.r2_usr = 0xffffffff;
 
     ctxt->sctlr = /* #define SCTLR_BASE */0x00c50078;
 
@@ -130,7 +130,7 @@ static int vcpu_arm(struct xc_dom_image *dom, void *ptr)
     ctxt->flags = VGCF_online;
 
     DOMPRINTF("Initial state CPSR %#"PRIx32" PC %#"PRIx32,
-           ctxt->user_regs.cpsr, ctxt->user_regs.pc);
+           ctxt->user_regs.cpsr, ctxt->user_regs.pc32);
 
     return 0;
 }