[PATCH] x86/boot: Introduce boot-helpers.h

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Eclair complains that neither reloc_trampoline{32,64}() can see their
declarations.

reloc_trampoline32() needs to become asmlinkage, while reloc_trampoline64()
needs declaring properly in a way that both efi-boot.h and reloc-trampoline.c
can see.

Introduce boot-helpers.h for the purpose.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Frediano Ziglio <frediano.ziglio@xxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>

https://gitlab.com/xen-project/people/andyhhp/xen/-/pipelines/1549438881
---
 xen/arch/x86/boot/reloc-trampoline.c    |  4 +++-
 xen/arch/x86/efi/efi-boot.h             |  4 ++--
 xen/arch/x86/include/asm/boot-helpers.h | 13 +++++++++++++
 3 files changed, 18 insertions(+), 3 deletions(-)
 create mode 100644 xen/arch/x86/include/asm/boot-helpers.h

diff --git a/xen/arch/x86/boot/reloc-trampoline.c 
b/xen/arch/x86/boot/reloc-trampoline.c
index d5548eb08f85..e35e7c78aa86 100644
--- a/xen/arch/x86/boot/reloc-trampoline.c
+++ b/xen/arch/x86/boot/reloc-trampoline.c
@@ -2,13 +2,15 @@
 
 #include <xen/compiler.h>
 #include <xen/stdint.h>
+
+#include <asm/boot-helpers.h>
 #include <asm/trampoline.h>
 
 extern const int32_t __trampoline_rel_start[], __trampoline_rel_stop[];
 extern const int32_t __trampoline_seg_start[], __trampoline_seg_stop[];
 
 #if defined(__i386__)
-void reloc_trampoline32(void)
+void asmlinkage reloc_trampoline32(void)
 #elif defined (__x86_64__)
 void reloc_trampoline64(void)
 #else
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 9d3f2b71447e..1d8902a9a724 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -4,6 +4,8 @@
  * therefore can define arch specific global variables.
  */
 #include <xen/vga.h>
+
+#include <asm/boot-helpers.h>
 #include <asm/e820.h>
 #include <asm/edd.h>
 #include <asm/microcode.h>
@@ -103,8 +105,6 @@ static void __init efi_arch_relocate_image(unsigned long 
delta)
     }
 }
 
-void reloc_trampoline64(void);
-
 static void __init relocate_trampoline(unsigned long phys)
 {
     trampoline_phys = phys;
diff --git a/xen/arch/x86/include/asm/boot-helpers.h 
b/xen/arch/x86/include/asm/boot-helpers.h
new file mode 100644
index 000000000000..166f49b4da01
--- /dev/null
+++ b/xen/arch/x86/include/asm/boot-helpers.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Declarations for helper functions compiled for both 32bit and 64bit.
+ *
+ * The 32bit forms are called only from assembly, so no declaration is provide
+ * here.
+ */
+#ifndef X86_BOOT_HELPERS_H
+#define X86_BOOT_HELPERS_H
+
+void reloc_trampoline64(void);
+
+#endif /* X86_BOOT_HELPERS_H */
-- 
2.39.5