Changeset d242cb6 in mainline for kernel/arch/amd64

Timestamp:

2013-05-13T22:34:28Z (13 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

6e8ed225

Parents:

959d2ec

Message:

make sure we configure two distinct segment descriptors and set the read bit on the code segment before switching back to real-mode for VESA/VBE
this fixes execution on the latest (3.9.1) Linux KVM with real-mode x86 code emulation that is particularly picky about the code segment permission bits

Location:

kernel/arch/amd64

Files:

• include/arch/pm.h (modified) (1 diff)
• src/pm.c (modified) (1 diff)

kernel/arch/amd64/include/arch/pm.h

@@ -57 +57 @@
 #ifdef CONFIG_FB
 
-#define VESA_INIT_DES      8
 #define VESA_INIT_SEGMENT  0x8000
+#define VESA_INIT_CODE_DES      8
+#define VESA_INIT_DATA_DES      9
 
 #undef GDT_ITEMS
-#define GDT_ITEMS  9
+#define GDT_ITEMS  10
 
 #endif /* CONFIG_FB */

kernel/arch/amd64/src/pm.c

@@ -112 +112 @@
         /* VESA Init descriptor */
 #ifdef CONFIG_FB
-        {
-                0xffff, 0, VESA_INIT_SEGMENT >> 12, AR_PRESENT | AR_CODE | DPL_KERNEL,
-                    0xf, 0, 0, 0, 0, 0
-        }
+        { 0xffff, 0, VESA_INIT_SEGMENT >> 12, AR_PRESENT | AR_CODE | AR_READABLE | DPL_KERNEL, 0xf, 0, 0, 0, 0, 0 },
+        { 0xffff, 0, VESA_INIT_SEGMENT >> 12, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL, 0xf, 0, 0, 0, 0, 0 }
 #endif
 };