Changeset f4946de in mainline

Timestamp:

2010-07-12T16:00:33Z (14 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

efbd094

Parents:

4e91239

Message:

Use trap gate instead of interrupt gate for the syscall int handler.

Location:

kernel/arch/ia32

Files:

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

kernel/arch/ia32/include/pm.h

@@ -67 +67 @@
 #define AR_CODE       (3 << 3)
 #define AR_WRITABLE   (1 << 1)
-#define AR_INTERRUPT  (0x0e)
-#define AR_TSS        (0x09)
+#define AR_INTERRUPT  (0xe)
+#define AR_TRAP       (0xf)
+#define AR_TSS        (0x9)
 
 #define DPL_KERNEL  (PL_KERNEL << 5)

kernel/arch/ia32/src/asm.S

@@ -313 +313 @@
                 
         cld
-        sti
                 
         /* Call syscall_handler(edx, ecx, ebx, esi, edi, ebp, eax) */

kernel/arch/ia32/src/pm.c

@@ -130 +130 @@
                 d->selector = gdtselector(KTEXT_DES);
 
-                d->access = AR_PRESENT | AR_INTERRUPT;  /* masking interrupt */
-
                 if (i == VECTOR_SYSCALL) {
                         /*
-                         * The syscall interrupt gate must be calleable from
-                         * userland.
+                         * The syscall trap gate must be callable from
+                         * userland. Interrupts will remain enabled.
                          */
-                        d->access |= DPL_USER;
+                        d->access = AR_PRESENT | AR_TRAP | DPL_USER;
+                } else {
+                        /*
+                         * Other interrupts use interrupt gates which
+                         * disable interrupts.
+                         */
+                        d->access = AR_PRESENT | AR_INTERRUPT;
                 }
         }