Changeset 17af882 in mainline for kernel/genarch/src/mm/page_pt.c

Timestamp:

2014-06-16T11:32:05Z (10 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

2cb32f9

Parents:

334bf28

Message:

Switch the amd64 kernel (back) from 'large' to 'kernel' memory model.

• This makes the amd64 kernel 6% smaller and more comfortable to debug.
• Unlike in the original 'kernel' memory model implementation, KA2PA(PA2KA(x)) == x; for x from kernel identity.
• Memory outside of the kernel identity region continues to be available by the standard means.

File:

• kernel/genarch/src/mm/page_pt.c (modified) (1 diff)

kernel/genarch/src/mm/page_pt.c

@@ -384 +384 @@
             addr - 1 < base + size - 1;
             addr += ptl0_step) {
+                if (GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(addr))) {
+                        ASSERT(overlaps(addr, ptl0_step,
+                            config.identity_base, config.identity_size));
+
+                        /*
+                         * This PTL0 entry also maps the kernel identity region,
+                         * so it is already global and initialized.
+                         */
+                        continue;
+                }
+
                 uintptr_t l1 = PA2KA(frame_alloc(frames, FRAME_LOWMEM, 0));
                 memsetb((void *) l1, FRAMES2SIZE(frames), 0);