[PATCH v2 04/16] xen/riscv: add ioremap_*() variants using ioremap_attr()

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Introduce ioremap_attr() as a shared helper to implement architecture-specific
ioremap variants:
- ioremap_nocache()
- ioremap_cache()
- ioremap_wc()

These functions use __vmap() internally and apply appropriate memory attributes
for RISC-V.

These functions are implemned not as static inline function or macros as it will
require to include asm/page.h into asm/io.h what will lead to compilation
issue.

Also, remove the unused ioremap_wt() macro from asm/io.h, as write-through
mappings are not expected to be used on RISC-V.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in v2:
 - Update the commit subject + message.  
 - move out Svpbmt changes to separate patch.
 - Drop #ifdef SVPBMT for ioremap().
 - Redefine ioremap_* in io.h.
 - Introduce ioremap_attr().
---
 xen/arch/riscv/include/asm/io.h | 11 +++--------
 xen/arch/riscv/mm.c             | 34 +++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/xen/arch/riscv/include/asm/io.h b/xen/arch/riscv/include/asm/io.h
index 8bab4ffa03..921e334ce1 100644
--- a/xen/arch/riscv/include/asm/io.h
+++ b/xen/arch/riscv/include/asm/io.h
@@ -41,14 +41,9 @@
 #include <xen/macros.h>
 #include <xen/types.h>
 
-/*
- * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
- * change the properties of memory regions.  This should be fixed by the
- * upcoming platform spec.
- */
-#define ioremap_nocache(addr, size) ioremap(addr, size)
-#define ioremap_wc(addr, size) ioremap(addr, size)
-#define ioremap_wt(addr, size) ioremap(addr, size)
+void __iomem *ioremap_nocache(paddr_t start, size_t len);
+void __iomem *ioremap_cache(paddr_t start, size_t len);
+void __iomem *ioremap_wc(paddr_t start, size_t len);
 
 /* Generic IO read/write.  These perform native-endian accesses. */
 static inline void __raw_writeb(uint8_t val, volatile void __iomem *addr)
diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c
index d3ece9f132..c8526dd2ef 100644
--- a/xen/arch/riscv/mm.c
+++ b/xen/arch/riscv/mm.c
@@ -11,6 +11,7 @@
 #include <xen/pfn.h>
 #include <xen/sections.h>
 #include <xen/sizes.h>
+#include <xen/vmap.h>
 
 #include <asm/early_printk.h>
 #include <asm/csr.h>
@@ -583,3 +584,36 @@ void *__init arch_vmap_virt_end(void)
 {
     return (void *)(VMAP_VIRT_START + VMAP_VIRT_SIZE);
 }
+
+static void *ioremap_attr(paddr_t start, size_t len, pte_attr_t attributes)
+{
+    mfn_t mfn = _mfn(PFN_DOWN(start));
+    unsigned int offs = start & (PAGE_SIZE - 1);
+    unsigned int nr = PFN_UP(offs + len);
+    void *ptr = __vmap(&mfn, nr, 1, 1, attributes, VMAP_DEFAULT);
+
+    if ( ptr == NULL )
+        return NULL;
+
+    return ptr + offs;
+}
+
+void __iomem *ioremap_nocache(paddr_t start, size_t len)
+{
+    return ioremap_attr(start, len, PAGE_HYPERVISOR_NOCACHE);
+}
+
+void __iomem *ioremap_cache(paddr_t start, size_t len)
+{
+    return ioremap_attr(start, len, PAGE_HYPERVISOR);
+}
+
+void __iomem *ioremap_wc(paddr_t start, size_t len)
+{
+    return ioremap_attr(start, len, PAGE_HYPERVISOR_WC);
+}
+
+void *ioremap(paddr_t pa, size_t len)
+{
+    return ioremap_attr(pa, len, PAGE_HYPERVISOR_NOCACHE);
+}
-- 
2.49.0