Changeset c8cd9a8 in mainline

Timestamp:

2010-07-14T12:29:35Z (14 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

864e272

Parents:

a7220de

Message:

Preallocate space for the istate structure on the stack for the use by the
SYSENTER instruction.

Location:

kernel/arch/ia32/src

Files:

• asm.S (modified) (3 diffs)
• proc/scheduler.c (modified) (2 diffs)

kernel/arch/ia32/src/asm.S

@@ -175 +175 @@
 
 /*
- * Size of the entire istate structure including the error word and the
- * hardware-saved part.
- */
-#define ISTATE_REAL_SIZE  (ISTATE_SOFT_SIZE + 24)
-
-/*
  * The SYSENTER syscall mechanism can be used for syscalls with
  * four or fewer arguments. To pass these four arguments, we
@@ -191 +185 @@
 .global sysenter_handler
 sysenter_handler:
-        subl $(ISTATE_REAL_SIZE), %esp
+
+        /*
+         * Note that the space needed for the istate structure has been
+         * preallocated on the stack by before_thread_runs_arch().
+         */
 
         /*
@@ -260 +258 @@
         movl ISTATE_OFFSET_ESP(%esp), %ecx
 
-        addl $(ISTATE_REAL_SIZE), %esp
-        
         sysexit   /* return to userspace */
 

kernel/arch/ia32/src/proc/scheduler.c

@@ -39 +39 @@
 #include <arch.h>
 #include <arch/context.h>  /* SP_DELTA */
+#include <arch/interrupt.h>
 #include <arch/pm.h>
 #include <arch/asm.h>
@@ -63 +64 @@
         if (CPU->arch.fi.bits.sep) {
                 /* Set kernel stack for CP3 -> CPL0 switch via SYSENTER */
-                write_msr(IA32_MSR_SYSENTER_ESP, kstk);
+                write_msr(IA32_MSR_SYSENTER_ESP, kstk - sizeof(istate_t));
         }