From e0603719902c282f98dd60ecffdf1dc9c7b1a738 Mon Sep 17 00:00:00 2001
From: AlmuHS <almuhs@github.com>
Date: Thu, 27 Jun 2019 18:47:47 +0200
Subject: experiment: get rid of temporary direct mapping after start AP

---
 i386/i386/mp_desc.c     | 8 ++++++++
 i386/i386at/model_dep.c | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/i386/i386/mp_desc.c b/i386/i386/mp_desc.c
index c1dac103..e55b7500 100644
--- a/i386/i386/mp_desc.c
+++ b/i386/i386/mp_desc.c
@@ -529,6 +529,9 @@ start_other_cpus(void)
     int cpu;
     vm_offset_t	stack_start;
     int apic_id = lapic->apic_id.r >>24;
+    extern pt_entry_t *kernel_page_dir;
+    extern int nb_direct_value;
+    int i = 0;
 
     printf("found %d cpus\n", ncpu);
     printf("The current cpu is: %d\n", cpu_number());
@@ -563,6 +566,11 @@ start_other_cpus(void)
                     stack_start += STACK_SIZE;
                 }
         }
+
+    /* Get rid of the temporary direct mapping and flush it out of the TLB.  */
+    for (i = 0 ; i < nb_direct_value; i++){
+        kernel_page_dir[lin2pdenum_cont(INIT_VM_MIN_KERNEL_ADDRESS) + i] = 0;
+    }
 }
 
 #endif	/* NCPUS > 1 */
diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c
index 49a81054..015f5abe 100644
--- a/i386/i386at/model_dep.c
+++ b/i386/i386at/model_dep.c
@@ -143,6 +143,7 @@ extern void linux_init(void);
 
 unsigned kernel_page_dir_addr = 0;
 unsigned pdpbase_addr = 0;
+int nb_direct_value = 0;
 
 /*
  * Find devices.  The system is alive.
@@ -461,6 +462,7 @@ i386at_init(void)
     if ((vm_offset_t)(-delta) < delta)
         delta = (vm_offset_t)(-delta);
     nb_direct = delta >> PDESHIFT;
+    nb_direct_value = nb_direct;
     for (i = 0; i < nb_direct; i++)
         kernel_page_dir[lin2pdenum_cont(INIT_VM_MIN_KERNEL_ADDRESS) + i] =
             kernel_page_dir[lin2pdenum_cont(LINEAR_MIN_KERNEL_ADDRESS) + i];
-- 
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