From 5f7efd47c8273fde972637d0360851802f76eca9 Mon Sep 17 00:00:00 2001
Message-ID: <5f7efd47c8273fde972637d0360851802f76eca9.1695733540.git.m.a.young@durham.ac.uk>
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From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Wed, 13 Sep 2023 13:48:16 +0100
Subject: [XEN PATCH 06/10] 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)
---
 xen/arch/x86/include/asm/spec_ctrl_asm.h | 8 ++++----
 xen/arch/x86/x86_64/entry.S              | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/include/asm/spec_ctrl_asm.h b/xen/arch/x86/include/asm/spec_ctrl_asm.h
index 97c4db31cd..66c706496f 100644
--- a/xen/arch/x86/include/asm/spec_ctrl_asm.h
+++ b/xen/arch/x86/include/asm/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
 
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index b45a09823a..92279a225d 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -665,15 +665,15 @@ 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
-- 
2.41.0