mm,pmm: map percpu, idt and frames arrays in KERNEL_MAP area

If there is not enough early frames (or for whatever reason the frame physical address is big enough), it might be the case that such frame mapping does not fit into the relatively small KERNEL_BASE area. It is better to always map in the large enough KERNEL_MAP area. The early frames arrays (before the final page tables are created) have to be mapped into the KERNEL_BASE area as this is the only space covered by boot time page tables (see EARLY_VIRT_MEM settings). Signed-off-by: Pawel Wieczorkiewicz <[email protected]>
KernelTestFramework · Nov 24, 2023 · 60d2f0d · 60d2f0d
1 parent 10d37ef
commit 60d2f0d
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Showing 3 changed files with 6 additions and 4 deletions.
diff --git a/arch/x86/traps.c b/arch/x86/traps.c
@@ -130,7 +130,7 @@ void init_traps(const cpu_t *cpu) {
 
     BUG_ON(!percpu);
 
-    percpu->idt = get_free_page(GFP_KERNEL | GFP_USER);
+    percpu->idt = get_free_page(GFP_KERNEL_MAP | GFP_USER);
     BUG_ON(!percpu->idt);
 
     percpu->idt_ptr.size = (sizeof(idt_entry_t) * MAX_INT) - 1;

diff --git a/common/percpu.c b/common/percpu.c
@@ -50,7 +50,7 @@ percpu_t *get_percpu_page(unsigned int cpu) {
     /* Per CPU page must be identity mapped,
      * because GDT descriptor has 32-bit base.
      */
-    percpu = get_free_page(GFP_IDENT | GFP_KERNEL | GFP_USER);
+    percpu = get_free_page(GFP_IDENT | GFP_KERNEL_MAP | GFP_USER);
     BUG_ON(!percpu);
     memset(percpu, 0, PAGE_SIZE);
 

diff --git a/mm/pmm.c b/mm/pmm.c
@@ -107,7 +107,7 @@ static frames_array_t *new_frames_array(void) {
     if (!boot_flags.virt)
         array = (frames_array_t *) mfn_to_virt_kern(frame->mfn);
     else {
-        array = vmap_kern_4k(mfn_to_virt_kern(frame->mfn), frame->mfn, L1_PROT);
+        array = vmap_kern_4k(mfn_to_virt_map(frame->mfn), frame->mfn, L1_PROT);
         if (!array)
             goto error;
     }
@@ -645,7 +645,9 @@ void map_frames_array(void) {
 
     list_for_each_entry (array, &frames, list) {
         mfn_t mfn = virt_to_mfn(array);
+        void *va = IS_ADDR_SPACE_VA(array, VIRT_KERNEL_BASE) ? mfn_to_virt_kern(mfn)
+                                                             : mfn_to_virt_map(mfn);
 
-        BUG_ON(!vmap_kern_4k(mfn_to_virt_kern(mfn), mfn, L1_PROT));
+        BUG_ON(!vmap_kern_4k(va, mfn, L1_PROT));
     }
 }