Changeset 5e761f3 in mainline

Timestamp:

2013-01-24T20:21:18Z (11 years ago)

Author:

Maurizio Lombardi <m.lombardi85@…>

Branches:

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

Children:

b1011dae

Parents:

b7e41ac

Message:

boot mm.c fixes:

• disable the MMU before starting changing the page table content.
• invalidate the TLB entries before turning the MMU on.
• remove dead code.

File:

• boot/arch/arm32/src/mm.c (modified) (5 diffs)

boot/arch/arm32/src/mm.c

@@ -37 +37 @@
 #include <arch/asm.h>
 #include <arch/mm.h>
+
+/** Disable the MMU */
+static void disable_paging(void)
+{
+        asm volatile (
+                "mrc p15, 0, r0, c1, c0, 0\n"
+                "bic r0, r0, #1\n"
+                "mcr p15, 0, r0, c1, c0, 0\n"
+        );
+}
 
 /** Check if caching can be enabled for a given memory section.
@@ -100 +110 @@
                 init_ptl0_section(&boot_pt[page], page);
         
-        /*
-         * Create 1:1 virtual-physical mapping in kernel space
-         * (upper 2 GB), physical addresses start from 0.
-         */
-        /* BeagleBoard-xM (DM37x) memory starts at 2GB border,
-         * thus mapping only lower 2GB is not not enough.
-         * Map entire AS 1:1 instead and hope it works. */
-        for (page = split_page; page < PTL0_ENTRIES; page++)
-#ifndef MACHINE_beagleboardxm
-                init_ptl0_section(&boot_pt[page], page - split_page);
-#else
-                init_ptl0_section(&boot_pt[page], page);
-#endif
-        
         asm volatile (
                 "mcr p15, 0, %[pt], c2, c0, 0\n"
@@ -129 +125 @@
                 "ldr r0, =0x55555555\n"
                 "mcr p15, 0, r0, c3, c0, 0\n"
-                
-#ifdef PROCESSOR_armv7_a
-                /* Read Auxiliary control register */
-                "mrc p15, 0, r0, c1, c0, 1\n"
-                /* Mask to enable L2 cache */
-                "ldr r1, =0x00000002\n"
-                "orr r0, r0, r1\n"
-                /* Store Auxiliary control register */
-                "mrc p15, 0, r0, c1, c0, 1\n"
-#endif
+
                 /* Current settings */
                 "mrc p15, 0, r0, c1, c0, 0\n"
@@ -156 +143 @@
 #endif
                 "orr r0, r0, r1\n"
+
+                /* Flush the TLB */
+                "mcr p15, 0, r0, c8, c7, 0\n"
                 
-                /* Store settings */
+                /* Store settings, enable the MMU */
                 "mcr p15, 0, r0, c1, c0, 0\n"
                 ::: "r0", "r1"
@@ -165 +155 @@
 /** Start the MMU - initialize page table and enable paging. */
 void mmu_start() {
+        disable_paging();
         init_boot_pt();
         enable_paging();