[PATCH v1 2/4] xen: arm: make VMAP only support in MMU system

[Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>]

From: Penny Zheng <penny.zheng@xxxxxxx>

VMAP is widely used in ALTERNATIVE feature, CPUERRATA feature, etc to
remap a range of memory with new memory attributes. Since this is
highly dependent on virtual address translation, we choose to fold VMAP
in MMU system.

In this patch, we introduce a new Kconfig CONFIG_HAS_VMAP, and make it
only support in MMU system on ARM architecture. And we make features
like ALTERNATIVE, CPUERRATA, etc, now depend on VMAP.

Split 
"https://patchwork.kernel.org/project/xen-devel/patch/20230626033443.2943270-16-Penny.Zheng@xxxxxxx/";
into Arm specific

Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
---
 xen/arch/arm/Kconfig   | 6 +++++-
 xen/arch/arm/Makefile  | 2 +-
 xen/arch/arm/setup.c   | 4 ++++
 xen/arch/arm/smpboot.c | 2 ++
 xen/include/xen/vmap.h | 6 ++++++
 5 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 21d03d9f44..c8d417298c 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -12,7 +12,7 @@ config ARM_64
 config ARM
        def_bool y
        select FUNCTION_ALIGNMENT_4B
-       select HAS_ALTERNATIVE
+       select HAS_ALTERNATIVE if HAS_VMAP
        select HAS_DEVICE_TREE
        select HAS_PASSTHROUGH
        select HAS_UBSAN
@@ -58,9 +58,13 @@ config PADDR_BITS
        default 40 if ARM_PA_BITS_40
        default 48 if ARM_64
 
+config HAS_VMAP
+       def_bool y
+
 config MMU
        def_bool y
        select HAS_PMAP
+       select HAS_VMAP
 
 source "arch/Kconfig"
 
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 45dc29ea53..6882814d38 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -11,7 +11,7 @@ obj-$(CONFIG_HAS_VPCI) += vpci.o
 
 obj-$(CONFIG_HAS_ALTERNATIVE) += alternative.o
 obj-y += bootfdt.init.o
-obj-y += cpuerrata.o
+obj-$(CONFIG_HAS_VMAP) += cpuerrata.o
 obj-y += cpufeature.o
 obj-y += decode.o
 obj-y += device.o
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 0c2fdaceaf..9d34ac7f64 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -804,11 +804,13 @@ void asmlinkage __init start_xen(unsigned long 
boot_phys_offset,
     nr_cpu_ids = smp_get_max_cpus();
     printk(XENLOG_INFO "SMP: Allowing %u CPUs\n", nr_cpu_ids);
 
+#ifdef CONFIG_HAS_VMAP
     /*
      * Some errata relies on SMCCC version which is detected by psci_init()
      * (called from smp_init_cpus()).
      */
     check_local_cpu_errata();
+#endif
 
     check_local_cpu_features();
 
@@ -879,8 +881,10 @@ void asmlinkage __init start_xen(unsigned long 
boot_phys_offset,
      * It needs to be called after do_initcalls to be able to use
      * stop_machine (tasklets initialized via an initcall).
      */
+#ifdef CONFIG_HAS_VMAP
     apply_alternatives_all();
     enable_errata_workarounds();
+#endif
     enable_cpu_features();
 
     /* Create initial domain 0. */
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 04e363088d..999afc028e 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -406,7 +406,9 @@ void asmlinkage start_secondary(void)
 
     local_abort_enable();
 
+#ifdef CONFIG_HAS_VMAP
     check_local_cpu_errata();
+#endif
     check_local_cpu_features();
 
     printk(XENLOG_DEBUG "CPU %u booted.\n", smp_processor_id());
diff --git a/xen/include/xen/vmap.h b/xen/include/xen/vmap.h
index fdae37e950..84797acfc0 100644
--- a/xen/include/xen/vmap.h
+++ b/xen/include/xen/vmap.h
@@ -138,10 +138,16 @@ static inline void iounmap(void __iomem *va)
 /* Pointer to 1 octet past the end of the VMAP_DEFAULT virtual area */
 void *arch_vmap_virt_end(void);
 
+#ifdef CONFIG_MMU
 /* Initialises the VMAP_DEFAULT virtual range */
 static inline void vm_init(void)
 {
     vm_init_type(VMAP_DEFAULT, (void *)VMAP_VIRT_START, arch_vmap_virt_end());
 }
+#else
+static inline void vm_init(void)
+{
+}
+#endif
 
 #endif /* __XEN_VMAP_H__ */
-- 
2.25.1