[xen stable-4.16] x86/spec-ctrl: Turn the remaining SPEC_CTRL_{ENTRY,EXIT}_* into asm macros

[patchbot@xxxxxxx]

commit 353e876a9dd5a93d0bf8819e77613c33db0de97b
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Sep 1 11:38:44 2023 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Sep 19 19:38:04 2023 +0100

    x86/spec-ctrl: Turn the remaining SPEC_CTRL_{ENTRY,EXIT}_* into asm macros
    
    These have grown more complex over time, with some already having been
    converted.
    
    Provide full Requires/Clobbers comments, otherwise missing at this level of
    indirection.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    (cherry picked from commit 7125429aafb9e3c9c88fc93001fc2300e0ac2cc8)
---
 xen/include/asm-x86/spec_ctrl_asm.h | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/xen/include/asm-x86/spec_ctrl_asm.h 
b/xen/include/asm-x86/spec_ctrl_asm.h
index 251c30eee5..94ed5dc880 100644
--- a/xen/include/asm-x86/spec_ctrl_asm.h
+++ b/xen/include/asm-x86/spec_ctrl_asm.h
@@ -236,26 +236,45 @@
 .endm
 
 /* Use after an entry from PV context (syscall/sysenter/int80/int82/etc). */
-#define SPEC_CTRL_ENTRY_FROM_PV                                         \
+.macro SPEC_CTRL_ENTRY_FROM_PV
+/*
+ * Requires %rsp=regs/cpuinfo, %rdx=0
+ * Clobbers %rax, %rcx, %rdx
+ */
     ALTERNATIVE "", __stringify(DO_SPEC_CTRL_COND_IBPB maybexen=0),     \
-        X86_FEATURE_IBPB_ENTRY_PV;                                      \
-    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV;            \
+        X86_FEATURE_IBPB_ENTRY_PV
+
+    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV
+
     ALTERNATIVE "", __stringify(DO_SPEC_CTRL_ENTRY maybexen=0),         \
         X86_FEATURE_SC_MSR_PV
+.endm
 
 /* Use in interrupt/exception context.  May interrupt Xen or PV context. */
-#define SPEC_CTRL_ENTRY_FROM_INTR                                       \
+.macro SPEC_CTRL_ENTRY_FROM_INTR
+/*
+ * Requires %rsp=regs, %r14=stack_end, %rdx=0
+ * Clobbers %rax, %rcx, %rdx
+ */
     ALTERNATIVE "", __stringify(DO_SPEC_CTRL_COND_IBPB maybexen=1),     \
-        X86_FEATURE_IBPB_ENTRY_PV;                                      \
-    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV;            \
+        X86_FEATURE_IBPB_ENTRY_PV
+
+    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV
+
     ALTERNATIVE "", __stringify(DO_SPEC_CTRL_ENTRY maybexen=1),         \
         X86_FEATURE_SC_MSR_PV
+.endm
 
 /* Use when exiting to PV guest context. */
-#define SPEC_CTRL_EXIT_TO_PV                                            \
-    ALTERNATIVE "",                                                     \
-        DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR_PV;              \
+.macro SPEC_CTRL_EXIT_TO_PV
+/*
+ * Requires %rax=spec_ctrl, %rsp=regs/info
+ * Clobbers %rcx, %rdx
+ */
+    ALTERNATIVE "", DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR_PV
+
     DO_SPEC_CTRL_COND_VERW
+.endm
 
 /*
  * Use in IST interrupt/exception context.  May interrupt Xen or PV context.
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16