x86-32, mm: Add an initial page table for core bootstrapping

This patch adds an initial page table with low mappings used exclusively
for booting APs/resuming after ACPI suspend/machine restart. After this,
there's no need to add low mappings to swapper_pg_dir and zap them later
or create own swsusp PGD page solely for ACPI sleep needs - we have
initial_page_table for that.

Signed-off-by: Borislav Petkov <bp@alien8.de>
LKML-Reference: <20101020070526.GA9588@liondog.tnic>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 322b24fbeafd..af6cf2bfceee 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -728,6 +728,17 @@ void __init setup_arch(char **cmdline_p)
 #ifdef CONFIG_X86_32
         memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
         visws_early_detect();
+
+        /*
+         * copy kernel address range established so far and switch
+         * to the proper swapper page table
+         */
+        clone_pgd_range(swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
+                        initial_page_table + KERNEL_PGD_BOUNDARY,
+                        KERNEL_PGD_PTRS);
+
+        load_cr3(swapper_pg_dir);
+        __flush_tlb_all();
 #else
         printk(KERN_INFO "Command line: %s\n", boot_command_line);
 #endif
@@ -1009,7 +1020,12 @@ void __init setup_arch(char **cmdline_p)
         paging_init();
         x86_init.paging.pagetable_setup_done(swapper_pg_dir);
 
-        setup_trampoline_page_table();
+#ifdef CONFIG_X86_32
+        /* sync back kernel address range */
+        clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
+                        swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
+                        KERNEL_PGD_PTRS);
+#endif
 
         tboot_probe();