x86/entry: Adjust restore_all_xen to hold stack_end in %r14

All other SPEC_CTRL_{ENTRY,EXIT}_* helpers hold stack_end in %r14.  Adjust it
for consistency.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 7aa28849a1155d856e214e9a80a7e65fffdc3e58)

diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index e82b4581cff0953adf1beb99b6db5771536813e3..3cec072f814558c0db9ecf02cb312fa429caf371 100644 (file)
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -599,15 +599,15 @@ restore_all_xen:
          * Check whether we need to switch to the per-CPU page tables, in
          * case we return to late PV exit code (from an NMI or #MC).
          */
-        GET_STACK_END(bx)
-        cmpb  $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%rbx)
+        GET_STACK_END(14)
+        cmpb  $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%r14)
 UNLIKELY_START(ne, exit_cr3)
-        mov   STACK_CPUINFO_FIELD(pv_cr3)(%rbx), %rax
+        mov   STACK_CPUINFO_FIELD(pv_cr3)(%r14), %rax
         mov   %rax, %cr3
 UNLIKELY_END(exit_cr3)
 
         /* WARNING! `ret`, `call *`, `jmp *` not safe beyond this point. */
-        SPEC_CTRL_EXIT_TO_XEN     /* Req: %rbx=end, Clob: acd */
+        SPEC_CTRL_EXIT_TO_XEN     /* Req: %r14=end, Clob: acd */
 
         RESTORE_ALL adj=8
         iretq

diff --git a/xen/include/asm-x86/spec_ctrl_asm.h b/xen/include/asm-x86/spec_ctrl_asm.h
index f8cd76fe9e3509f91e053750b2c5040d380dc61a..fa82f0a13cac149ff56f61015e291e6c46c2eaa0 100644 (file)
--- a/xen/include/asm-x86/spec_ctrl_asm.h
+++ b/xen/include/asm-x86/spec_ctrl_asm.h
@@ -357,10 +357,10 @@ UNLIKELY_DISPATCH_LABEL(\@_serialise):
  */
 .macro SPEC_CTRL_EXIT_TO_XEN
 /*
- * Requires %rbx=stack_end
+ * Requires %r14=stack_end
  * Clobbers %rax, %rcx, %rdx
  */
-    testb $SCF_ist_sc_msr, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%rbx)
+    testb $SCF_ist_sc_msr, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%r14)
     jz .L\@_skip_sc_msr
 
     /*
@@ -371,10 +371,10 @@ UNLIKELY_DISPATCH_LABEL(\@_serialise):
      */
     xor %edx, %edx
 
-    testb $SCF_use_shadow, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%rbx)
+    testb $SCF_use_shadow, STACK_CPUINFO_FIELD(spec_ctrl_flags)(%r14)
     jz .L\@_skip_sc_msr
 
-    mov STACK_CPUINFO_FIELD(shadow_spec_ctrl)(%rbx), %eax
+    mov STACK_CPUINFO_FIELD(shadow_spec_ctrl)(%r14), %eax
     mov $MSR_SPEC_CTRL, %ecx
     wrmsr