SMP - Force TLB flush before scheduling a process

- this makes sure that each process always run with updated TLB

- this is the simplest way how to achieve the consistency. As it means
  significant performace degradation when not require, this is nto the
  final solution and will be refined

diff --git a/kernel/arch/i386/include/arch_proto.h b/kernel/arch/i386/include/arch_proto.h
index 0d923899989491ad592b95ade7d3c6d9386a47e7..89c57bc82d2efb4f33f9049ede459ec5bf40b58d 100644 (file)
--- a/kernel/arch/i386/include/arch_proto.h
+++ b/kernel/arch/i386/include/arch_proto.h
@@ -109,6 +109,8 @@ _PROTOTYPE(void __switch_address_space, (struct proc * p,
 #define switch_address_space(proc)     \
        __switch_address_space(proc, get_cpulocal_var_ptr(ptproc))
 
+_PROTOTYPE(void refresh_tlb, (void));
+
 /* protect.c */
 struct tss_s {
   reg_t backlink;

diff --git a/kernel/arch/i386/klib.S b/kernel/arch/i386/klib.S
index decb55a7d01d20187905be704b90e145ace8d39a..e7e7feb89ab5dc912846bb0fcbc41706b2b32ee2 100644 (file)
--- a/kernel/arch/i386/klib.S
+++ b/kernel/arch/i386/klib.S
@@ -803,9 +803,11 @@ ENTRY(__switch_address_space)
         * test if the cr3 is loaded with the current value to avoid unnecessary
         * TLB flushes
         */
+#if 0
        mov     %cr3, %ecx
        cmp     %ecx, %eax
        je      0f
+#endif
        mov     %eax, %cr3
        /* get ptproc */
        mov     8(%esp), %eax
@@ -872,10 +874,12 @@ ENTRY(eoi_8259_slave)
        outb    $INT2_CTL
        ret
        
-.data
-idt_ptr:
-       .short 0x3ff
-       .long 0x0
+/* in some cases we need to force TLB update, reloading cr3 does the trick */
+ENTRY(refresh_tlb)
+       mov     %cr3, %eax
+       mov     %eax, %cr3
+       ret
+
 #ifdef CONFIG_SMP
 
 /*===========================================================================*/
@@ -1043,3 +1047,8 @@ ENTRY(switch_k_stack)
 
        /* NOT_REACHABLE */
 0:     jmp     0b
+
+.data
+idt_ptr:
+       .short 0x3ff
+       .long 0x0

diff --git a/kernel/proc.c b/kernel/proc.c
index 7f36fc728bf097a9ebb4316fed164993eb26dc71..3728a3c554fe4d802286c277c16d35c0df4174d1 100644 (file)
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -356,6 +356,8 @@ check_misc_flags:
         */
        p->p_misc_flags &= ~MF_CONTEXT_SET;
 
+       assert(!(p->p_misc_flags & MF_FULLVM) || p->p_seg.p_cr3 != 0);
+       refresh_tlb();
        /*
         * restore_user_context() carries out the actual mode switch from kernel
         * to userspace. This function does not return