From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Sat, 26 Mar 2016 18:19:20 +0000 (+0000)
Subject: Improve the legibility of the pagetable generation code
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=2664b843c34f0d05e15888ac43c30d909ba3baa3;p=people%2Froyger%2Fxen-test-framework.git

Improve the legibility of the pagetable generation code

Factor the common _PAGE_xxx attributes out into PAGE_COMMON, and introduce a
macro for the index calculation.

Add _ACCESSED and _DIRTY to the common attributes, to avoid the processor
needing to set the bits.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/arch/x86/hvm_pagetables.S b/arch/x86/hvm_pagetables.S
index 509a3bc..2e0bd5a 100644
--- a/arch/x86/hvm_pagetables.S
+++ b/arch/x86/hvm_pagetables.S
@@ -2,6 +2,10 @@
 
 #include <arch/x86/page.h>
 
+#define PAGE_COMMON _PAGE_DIRTY + _PAGE_ACCESSED + _PAGE_USER + _PAGE_RW + _PAGE_PRESENT
+
+#define PAE_IDX(sym) ((. - (sym)) / PAE_PTE_SZ)
+
         .data
         .p2align PAGE_SHIFT
 
@@ -9,19 +13,17 @@
 GLOBAL(pae_l1_identmap)
         .long 0, 0 /* Unmap page at 0 to catch errors with NULL pointers. */
         .rept PAE_L1_PT_ENTRIES - 1
-        .long (((. - pae_l1_identmap) / 8) << PAE_L1_PT_SHIFT) + \
-              _PAGE_USER + _PAGE_RW + _PAGE_PRESENT
+        .long (PAE_IDX(pae_l1_identmap) << PAE_L1_PT_SHIFT) + PAGE_COMMON
         .long 0
         .endr
 SIZE(pae_l1_identmap)
 
 /* PAE mappings up to 4G, mostly in 2M superpages. Uses 4x 4k pages. */
 GLOBAL(pae_l2_identmap)
-        .long pae_l1_identmap + _PAGE_USER + _PAGE_RW + _PAGE_PRESENT
+        .long pae_l1_identmap + PAGE_COMMON
         .long 0
         .rept (4 * PAE_L2_PT_ENTRIES) - 1
-        .long (((. - pae_l2_identmap) / 8) << PAE_L2_PT_SHIFT) + \
-              _PAGE_PSE + _PAGE_USER + _PAGE_RW + _PAGE_PRESENT
+        .long (PAE_IDX(pae_l2_identmap) << PAE_L2_PT_SHIFT) + _PAGE_PSE + PAGE_COMMON
         .long 0
         .endr
 SIZE(pae_l2_identmap)
@@ -29,8 +31,7 @@ SIZE(pae_l2_identmap)
 /* PAE l3 pagetable.  Maps 4x l2 tables. */
 GLOBAL(pae_l3_identmap)
         .rept 4
-        .long pae_l2_identmap + (((. - pae_l3_identmap) / 8 ) << PAGE_SHIFT) + \
-              _PAGE_USER + _PAGE_RW + _PAGE_PRESENT
+        .long pae_l2_identmap + (PAE_IDX(pae_l3_identmap) << PAGE_SHIFT) + PAGE_COMMON
         .long 0
         .endr
         .fill PAE_L3_PT_ENTRIES - 4, 8, 0
@@ -38,7 +39,7 @@ SIZE(pae_l3_identmap)
 
 /* PAE l4 pagetable.  Maps 1x l3 table. */
 GLOBAL(pae_l4_identmap)
-        .long pae_l3_identmap + _PAGE_USER + _PAGE_RW + _PAGE_PRESENT
+        .long pae_l3_identmap + PAGE_COMMON
         .long 0
         .fill PAE_L4_PT_ENTRIES - 1, 8, 0
 SIZE(pae_l4_identmap)
@@ -46,7 +47,7 @@ SIZE(pae_l4_identmap)
 /* PAE l3 32bit quad.  Contains 4 64bit entries. */
 GLOBAL(pae32_l3_identmap)
         .rept PAE32_L3_ENTRIES
-        .long pae_l2_identmap + (((. - pae32_l3_identmap) / 8 ) << PAGE_SHIFT) + _PAGE_PRESENT
+        .long pae_l2_identmap + (PAE_IDX(pae32_l3_identmap) << PAGE_SHIFT) + _PAGE_PRESENT
         .long 0
         .endr
 SIZE(pae32_l3_identmap)
diff --git a/include/arch/x86/page.h b/include/arch/x86/page.h
index f12931f..171d93b 100644
--- a/include/arch/x86/page.h
+++ b/include/arch/x86/page.h
@@ -20,6 +20,8 @@
 #define _PAGE_PRESENT           0x001
 #define _PAGE_RW                0x002
 #define _PAGE_USER              0x004
+#define _PAGE_ACCESSED          0x020
+#define _PAGE_DIRTY             0x040
 #define _PAGE_PSE               0x080
 
 #if CONFIG_PAGING_LEVELS >= 3 /* PAE Paging */