885
edits
Changes
→KernelLdr_MapInitialIdentityMapping
attribute = 0x60000000000708;
attribute = 0x60000000000708;
ttbr0_page_table.Map(page_tables_base, page_tables_size, page_tables_base, &attribute, allocator);
ttbr0_page_table.Map(page_tables_base, page_tables_size, page_tables_base, &attribute, allocator);
</pre>
Next, this sets some system registers.
<pre>
// Set TTBR0/TTBR1 with initial page tables.
TTBR0_EL1 = ttbr0_page_table.GetL1Table();
TTBR1_EL1 = ttbr1_page_table.GetL1Table();
// Configure MAIR, TCR. TODO: Document here what bits these are.
MAIR_EL1 = 0x44FF0400;
TCR_EL1 = 0x11B5193519;
// Check what CPU we're running on to configure CPUECTLR, CPUACTLR appropriately.
manufacture_id = MIDR_EL1;
implemeter = manufacturer_id >> 24) & 0xFF;
if (implementer == 0x41) {
// Implementer ID is 0x41 (ARM Limited).
architecture = (manufacture_id >> 4) & 0x0FFF;
hw_variant = (manufacture_id >> 20) & 0xF;
hw_revision = (manufacture_id >> 0) & 0xF;
if (architecture == 0xD07) {
// Architecture is 0xD07 (Cortex-A57).
cpuactlr_value = 0x1000000; // Non-cacheable load forwarding enabled
cpuectlr_value = 0x1B00000040; // TODO: What is this?
if (hw_variant == 0 || (hw_variant == 1 && hw_revision <= 1)) {
// If supported, disable load-pass DMB.
cpuactlr_value |= 0x800000000000000;
}
CPUACTLR_EL1 = cpuactlr_value;
if (CPUECTLR_EL1 != cpuectlr_value) {
CPUECTLR_EL1 = cpuectlr_value;
}
}
}
</pre>
</pre>