[PATCH v3 11/52] xen/arm: mmu: fold FIXMAP into MMU system

[Penny Zheng <Penny.Zheng@xxxxxxx>]

FIXMAP in MMU system is used to do special-purpose 4K mapping, like
mapping early UART, temporarily mapping source codes for copy and paste
(copy_from_paddr), etc.

As FIXMAP feature is highly dependent on virtual address translation, we
introduce a new Kconfig CONFIG_HAS_FIXMAP to wrap all releated codes, then
we fold it into MMU system.
Since PMAP relies on FIXMAP, so we fold it too into MMU system.

Under !CONFIG_HAS_FIXMAP, we provide empty stubbers for not breaking
compilation.

Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v1 -> v2
- new patch
---
v3:
- fold CONFIG_HAS_FIXMAP into CONFIG_HAS_MMU
- change CONFIG_HAS_FIXMAP to an Arm-specific Kconfig
---
 xen/arch/arm/Kconfig              |  7 ++++++-
 xen/arch/arm/include/asm/fixmap.h | 31 ++++++++++++++++++++++++++++---
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index fb77392b82..22b28b8ba2 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -15,7 +15,6 @@ config ARM
        select HAS_DEVICE_TREE
        select HAS_PASSTHROUGH
        select HAS_PDX
-       select HAS_PMAP
        select IOMMU_FORCE_PT_SHARE
 
 config ARCH_DEFCONFIG
@@ -63,11 +62,17 @@ source "arch/Kconfig"
 config HAS_MMU
        bool "Memory Management Unit support in a VMSA system"
        default y
+       select HAS_PMAP
        help
          In a VMSA system, a Memory Management Unit (MMU) provides 
fine-grained control of
          a memory system through a set of virtual to physical address mappings 
and associated memory
          properties held in memory-mapped tables known as translation tables.
 
+config HAS_FIXMAP
+       bool "Provide special-purpose 4K mapping slots in a VMSA"
+       depends on HAS_MMU
+       default y
+
 config ACPI
        bool "ACPI (Advanced Configuration and Power Interface) Support 
(UNSUPPORTED)" if UNSUPPORTED
        depends on ARM_64
diff --git a/xen/arch/arm/include/asm/fixmap.h 
b/xen/arch/arm/include/asm/fixmap.h
index d0c9a52c8c..1b5b62866b 100644
--- a/xen/arch/arm/include/asm/fixmap.h
+++ b/xen/arch/arm/include/asm/fixmap.h
@@ -4,9 +4,6 @@
 #ifndef __ASM_FIXMAP_H
 #define __ASM_FIXMAP_H
 
-#include <xen/acpi.h>
-#include <xen/pmap.h>
-
 /* Fixmap slots */
 #define FIXMAP_CONSOLE  0  /* The primary UART */
 #define FIXMAP_MISC     1  /* Ephemeral mappings of hardware */
@@ -22,6 +19,11 @@
 
 #ifndef __ASSEMBLY__
 
+#ifdef CONFIG_HAS_FIXMAP
+
+#include <xen/acpi.h>
+#include <xen/pmap.h>
+
 /*
  * Direct access to xen_fixmap[] should only happen when {set,
  * clear}_fixmap() is unusable (e.g. where we would end up to
@@ -43,6 +45,29 @@ static inline unsigned int virt_to_fix(vaddr_t vaddr)
     return ((vaddr - FIXADDR_START) >> PAGE_SHIFT);
 }
 
+#else /* !CONFIG_HAS_FIXMAP */
+
+#include <xen/mm-frame.h>
+#include <xen/errno.h>
+
+static inline void set_fixmap(unsigned int map, mfn_t mfn,
+                              unsigned int attributes)
+{
+    ASSERT_UNREACHABLE();
+}
+
+static inline void clear_fixmap(unsigned int map)
+{
+    ASSERT_UNREACHABLE();
+}
+
+static inline unsigned int virt_to_fix(vaddr_t vaddr)
+{
+    ASSERT_UNREACHABLE();
+    return -EINVAL;
+}
+#endif /* !CONFIG_HAS_FIXMAP */
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_FIXMAP_H */
-- 
2.25.1