[PATCH 1/3] x86/entry: Adjustments to "reduce assembly code size of entry points"

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Some retroactive review, for if I'd got to the patch in time.

 * The new ASM-friendly BUILD_BUG_ON() should be in a header file.
 * entry_int82() wants the movl->movb treatment too.

Fixes: c144b9e32427 ("x86: Reduce assembly code size of entry points")
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>

Fixes just to link the two patches.
---
 xen/arch/x86/include/asm/asm_defns.h | 12 ++++++++++++
 xen/arch/x86/x86_64/compat/entry.S   |  2 +-
 xen/arch/x86/x86_64/entry.S          |  8 --------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/include/asm/asm_defns.h 
b/xen/arch/x86/include/asm/asm_defns.h
index a9a6c21c76cd..f18a11b36198 100644
--- a/xen/arch/x86/include/asm/asm_defns.h
+++ b/xen/arch/x86/include/asm/asm_defns.h
@@ -56,6 +56,18 @@ register unsigned long current_stack_pointer asm("rsp");
 #define ASSERT_INTERRUPTS_DISABLED \
     ASSERT_INTERRUPT_STATUS(z, "INTERRUPTS DISABLED")
 
+#ifdef __ASSEMBLY__
+
+.macro BUILD_BUG_ON condstr cond:vararg
+        .if \cond
+        .error "Condition \"\condstr\" not satisfied"
+        .endif
+.endm
+/* preprocessor macro to make error message more user friendly */
+#define BUILD_BUG_ON(cond) BUILD_BUG_ON #cond cond
+
+#endif /* __ASSEMBLY__ */
+
 #ifdef __ASSEMBLY__
 # define _ASM_EX(p) p-.
 #else
diff --git a/xen/arch/x86/x86_64/compat/entry.S 
b/xen/arch/x86/x86_64/compat/entry.S
index d4f0e4804090..93fbbeb4ae18 100644
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -15,7 +15,7 @@ FUNC(entry_int82)
         ENDBR64
         ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
         pushq $0
-        movl  $HYPERCALL_VECTOR, 4(%rsp)
+        movb  $HYPERCALL_VECTOR, 4(%rsp)
         SAVE_ALL compat=1 /* DPL1 gate, restricted to 32bit PV guests only. */
 
         SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index a7bd8f0ca5b1..f8938b0b42fd 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -22,14 +22,6 @@
 #endif
 .endm
 
-.macro BUILD_BUG_ON condstr cond:vararg
-        .if \cond
-        .error "Condition \"\condstr\" not satisfied"
-        .endif
-.endm
-/* preprocessor macro to make error message more user friendly */
-#define BUILD_BUG_ON(cond) BUILD_BUG_ON #cond cond
-
 #ifdef CONFIG_PV
 /* %rbx: struct vcpu */
 FUNC_LOCAL(switch_to_kernel)
-- 
2.30.2