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[Xen-devel] [PATCH v4 01/10] xen/arm: page: Use ARMv8 naming to improve readability



This is based on the Linux ARMv8 naming scheme (see arch/arm64/mm/proc.S). Each
type will contain "NORMAL" or "DEVICE" to make clear whether each attribute
targets device or normal memory.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

---

    Changes in v3:
        - The ai '000' is named MT_DEVICE_nGnRnE and not
        MT_DEVICE_nGnRE. The definition is still valid.
        - Expand the comment to point to "Device Memory" section in the
        ARM ARM.

    Changes in v2:
        * Move the patch before "xen/arm: page: Clean-up the definition
        of MAIRVAL"
---
 xen/arch/arm/kernel.c             |  2 +-
 xen/arch/arm/mm.c                 | 28 ++++++++++++++--------------
 xen/arch/arm/platforms/vexpress.c |  2 +-
 xen/drivers/video/arm_hdlcd.c     |  2 +-
 xen/include/asm-arm/page.h        | 35 +++++++++++++++++++----------------
 5 files changed, 36 insertions(+), 33 deletions(-)

diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
index 9c183f96da..a12baa86e7 100644
--- a/xen/arch/arm/kernel.c
+++ b/xen/arch/arm/kernel.c
@@ -54,7 +54,7 @@ void copy_from_paddr(void *dst, paddr_t paddr, unsigned long 
len)
         s = paddr & (PAGE_SIZE-1);
         l = min(PAGE_SIZE - s, len);
 
-        set_fixmap(FIXMAP_MISC, maddr_to_mfn(paddr), MT_BUFFERABLE);
+        set_fixmap(FIXMAP_MISC, maddr_to_mfn(paddr), MT_NORMAL_NC);
         memcpy(dst, src + s, l);
         clean_dcache_va_range(dst, l);
 
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 9a37f29ce6..f41c6ce6f1 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -290,7 +290,7 @@ static inline lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned 
attr)
 
     switch ( attr )
     {
-    case MT_BUFFERABLE:
+    case MT_NORMAL_NC:
         /*
          * ARM ARM: Overlaying the shareability attribute (DDI
          * 0406C.b B3-1376 to 1377)
@@ -305,8 +305,8 @@ static inline lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned 
attr)
          */
         e.pt.sh = LPAE_SH_OUTER;
         break;
-    case MT_UNCACHED:
-    case MT_DEV_SHARED:
+    case MT_DEVICE_nGnRnE:
+    case MT_DEVICE_nGnRE:
         /*
          * Shareability is ignored for non-Normal memory, Outer is as
          * good as anything.
@@ -369,7 +369,7 @@ static void __init create_mappings(lpae_t *second,
 
     count = nr_mfns / LPAE_ENTRIES;
     p = second + second_linear_offset(virt_offset);
-    pte = mfn_to_xen_entry(_mfn(base_mfn), MT_WRITEALLOC);
+    pte = mfn_to_xen_entry(_mfn(base_mfn), MT_NORMAL);
     if ( granularity == 16 * LPAE_ENTRIES )
         pte.pt.contig = 1;  /* These maps are in 16-entry contiguous chunks. */
     for ( i = 0; i < count; i++ )
@@ -422,7 +422,7 @@ void *map_domain_page(mfn_t mfn)
         else if ( map[slot].pt.avail == 0 )
         {
             /* Commandeer this 2MB slot */
-            pte = mfn_to_xen_entry(_mfn(slot_mfn), MT_WRITEALLOC);
+            pte = mfn_to_xen_entry(_mfn(slot_mfn), MT_NORMAL);
             pte.pt.avail = 1;
             write_pte(map + slot, pte);
             break;
@@ -543,7 +543,7 @@ static inline lpae_t pte_of_xenaddr(vaddr_t va)
 {
     paddr_t ma = va + phys_offset;
 
-    return mfn_to_xen_entry(maddr_to_mfn(ma), MT_WRITEALLOC);
+    return mfn_to_xen_entry(maddr_to_mfn(ma), MT_NORMAL);
 }
 
 /* Map the FDT in the early boot page table */
@@ -652,7 +652,7 @@ void __init setup_pagetables(unsigned long 
boot_phys_offset, paddr_t xen_paddr)
     /* Initialise xen second level entries ... */
     /* ... Xen's text etc */
 
-    pte = mfn_to_xen_entry(maddr_to_mfn(xen_paddr), MT_WRITEALLOC);
+    pte = mfn_to_xen_entry(maddr_to_mfn(xen_paddr), MT_NORMAL);
     pte.pt.xn = 0;/* Contains our text mapping! */
     xen_second[second_table_offset(XEN_VIRT_START)] = pte;
 
@@ -669,7 +669,7 @@ void __init setup_pagetables(unsigned long 
boot_phys_offset, paddr_t xen_paddr)
 
     /* ... Boot Misc area for xen relocation */
     dest_va = BOOT_RELOC_VIRT_START;
-    pte = mfn_to_xen_entry(maddr_to_mfn(xen_paddr), MT_WRITEALLOC);
+    pte = mfn_to_xen_entry(maddr_to_mfn(xen_paddr), MT_NORMAL);
     /* Map the destination in xen_second. */
     xen_second[second_table_offset(dest_va)] = pte;
     /* Map the destination in boot_second. */
@@ -700,7 +700,7 @@ void __init setup_pagetables(unsigned long 
boot_phys_offset, paddr_t xen_paddr)
         unsigned long va = XEN_VIRT_START + (i << PAGE_SHIFT);
         if ( !is_kernel(va) )
             break;
-        pte = mfn_to_xen_entry(mfn, MT_WRITEALLOC);
+        pte = mfn_to_xen_entry(mfn, MT_NORMAL);
         pte.pt.table = 1; /* 4k mappings always have this bit set */
         if ( is_kernel_text(va) || is_kernel_inittext(va) )
         {
@@ -771,7 +771,7 @@ int init_secondary_pagetables(int cpu)
     for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
     {
         pte = mfn_to_xen_entry(virt_to_mfn(domheap+i*LPAE_ENTRIES),
-                               MT_WRITEALLOC);
+                               MT_NORMAL);
         pte.pt.table = 1;
         write_pte(&first[first_table_offset(DOMHEAP_VIRT_START+i*FIRST_SIZE)], 
pte);
     }
@@ -869,13 +869,13 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
             mfn_t first_mfn = alloc_boot_pages(1, 1);
 
             clear_page(mfn_to_virt(first_mfn));
-            pte = mfn_to_xen_entry(first_mfn, MT_WRITEALLOC);
+            pte = mfn_to_xen_entry(first_mfn, MT_NORMAL);
             pte.pt.table = 1;
             write_pte(p, pte);
             first = mfn_to_virt(first_mfn);
         }
 
-        pte = mfn_to_xen_entry(_mfn(mfn), MT_WRITEALLOC);
+        pte = mfn_to_xen_entry(_mfn(mfn), MT_NORMAL);
         /* TODO: Set pte.pt.contig when appropriate. */
         write_pte(&first[first_table_offset(vaddr)], pte);
 
@@ -915,7 +915,7 @@ void __init setup_frametable_mappings(paddr_t ps, paddr_t 
pe)
     for ( i = 0; i < nr_second; i++ )
     {
         clear_page(mfn_to_virt(mfn_add(second_base, i)));
-        pte = mfn_to_xen_entry(mfn_add(second_base, i), MT_WRITEALLOC);
+        pte = mfn_to_xen_entry(mfn_add(second_base, i), MT_NORMAL);
         pte.pt.table = 1;
         write_pte(&xen_first[first_table_offset(FRAMETABLE_VIRT_START)+i], 
pte);
     }
@@ -969,7 +969,7 @@ static int create_xen_table(lpae_t *entry)
     if ( p == NULL )
         return -ENOMEM;
     clear_page(p);
-    pte = mfn_to_xen_entry(virt_to_mfn(p), MT_WRITEALLOC);
+    pte = mfn_to_xen_entry(virt_to_mfn(p), MT_NORMAL);
     pte.pt.table = 1;
     write_pte(entry, pte);
     return 0;
diff --git a/xen/arch/arm/platforms/vexpress.c 
b/xen/arch/arm/platforms/vexpress.c
index 9badbc079d..df2c4b5bec 100644
--- a/xen/arch/arm/platforms/vexpress.c
+++ b/xen/arch/arm/platforms/vexpress.c
@@ -65,7 +65,7 @@ int vexpress_syscfg(int write, int function, int device, 
uint32_t *data)
     uint32_t *syscfg = (uint32_t *) FIXMAP_ADDR(FIXMAP_MISC);
     int ret = -1;
 
-    set_fixmap(FIXMAP_MISC, maddr_to_mfn(V2M_SYS_MMIO_BASE), MT_DEV_SHARED);
+    set_fixmap(FIXMAP_MISC, maddr_to_mfn(V2M_SYS_MMIO_BASE), MT_DEVICE_nGnRE);
 
     if ( syscfg[V2M_SYS_CFGCTRL/4] & V2M_SYS_CFG_START )
         goto out;
diff --git a/xen/drivers/video/arm_hdlcd.c b/xen/drivers/video/arm_hdlcd.c
index 5fa7f518b1..1175399dbc 100644
--- a/xen/drivers/video/arm_hdlcd.c
+++ b/xen/drivers/video/arm_hdlcd.c
@@ -227,7 +227,7 @@ void __init video_init(void)
     /* uses FIXMAP_MISC */
     set_pixclock(videomode->pixclock);
 
-    set_fixmap(FIXMAP_MISC, maddr_to_mfn(hdlcd_start), MT_DEV_SHARED);
+    set_fixmap(FIXMAP_MISC, maddr_to_mfn(hdlcd_start), MT_DEVICE_nGnRE);
     HDLCD[HDLCD_COMMAND] = 0;
 
     HDLCD[HDLCD_LINELENGTH] = videomode->xres * bytes_per_pixel;
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 30fcfa0778..3d0bc6db81 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -25,15 +25,18 @@
  * LPAE Memory region attributes. Indexed by the AttrIndex bits of a
  * LPAE entry; the 8-bit fields are packed little-endian into MAIR0 and MAIR1.
  *
+ * See section "Device memory" B2.7.2 in ARM DDI 0487B.a for more
+ * details about the meaning of *G*R*E.
+ *
  *                    ai    encoding
- *   MT_UNCACHED      000   0000 0000  -- Strongly Ordered
- *   MT_BUFFERABLE    001   0100 0100  -- Non-Cacheable
- *   MT_WRITETHROUGH  010   1010 1010  -- Write-through
- *   MT_WRITEBACK     011   1110 1110  -- Write-back
- *   MT_DEV_SHARED    100   0000 0100  -- Device
+ *   MT_DEVICE_nGnRnE 000   0000 0000  -- Strongly Ordered/Device nGnRnE
+ *   MT_NORMAL_NC     001   0100 0100  -- Non-Cacheable
+ *   MT_NORMAL_WT     010   1010 1010  -- Write-through
+ *   MT_NORMAL_WB     011   1110 1110  -- Write-back
+ *   MT_DEVICE_nGnRE  100   0000 0100  -- Device nGnRE
  *   ??               101
  *   reserved         110
- *   MT_WRITEALLOC    111   1111 1111  -- Write-back write-allocate
+ *   MT_NORMAL        111   1111 1111  -- Write-back write-allocate
  */
 #define MAIR0VAL 0xeeaa4400
 #define MAIR1VAL 0xff000004
@@ -47,16 +50,16 @@
  * registers, as defined above.
  *
  */
-#define MT_UNCACHED      0x0
-#define MT_BUFFERABLE    0x1
-#define MT_WRITETHROUGH  0x2
-#define MT_WRITEBACK     0x3
-#define MT_DEV_SHARED    0x4
-#define MT_WRITEALLOC    0x7
-
-#define PAGE_HYPERVISOR         (MT_WRITEALLOC)
-#define PAGE_HYPERVISOR_NOCACHE (MT_DEV_SHARED)
-#define PAGE_HYPERVISOR_WC      (MT_BUFFERABLE)
+#define MT_DEVICE_nGnRnE 0x0
+#define MT_NORMAL_NC     0x1
+#define MT_NORMAL_WT     0x2
+#define MT_NORMAL_WB     0x3
+#define MT_DEVICE_nGnRE  0x4
+#define MT_NORMAL        0x7
+
+#define PAGE_HYPERVISOR         (MT_NORMAL)
+#define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE)
+#define PAGE_HYPERVISOR_WC      (MT_NORMAL_NC)
 
 /*
  * Defines for changing the hypervisor PTE .ro and .nx bits. This is only to be
-- 
2.11.0


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