6 files changed, 44 insertions, 20 deletions

diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
index 2984a25ff383..f686f49e8b7b 100644
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -26,6 +26,7 @@ struct mm_struct;
 struct vm_area_struct;
 
 extern pgd_t swapper_pg_dir[1024];
+extern pgd_t trampoline_pg_dir[1024];
 
 static inline void pgtable_cache_init(void) { }
 static inline void check_pgt_cache(void) { }
diff --git a/arch/x86/include/asm/trampoline.h b/arch/x86/include/asm/trampoline.h
index cb507bb05d79..8f78fdf3f178 100644
--- a/arch/x86/include/asm/trampoline.h
+++ b/arch/x86/include/asm/trampoline.h
@@ -13,14 +13,17 @@ extern unsigned char *trampoline_base;
 
 extern unsigned long init_rsp;
 extern unsigned long initial_code;
+extern unsigned long initial_page_table;
 extern unsigned long initial_gs;
 
 #define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data, PAGE_SIZE)
 
 extern unsigned long setup_trampoline(void);
+extern void __init setup_trampoline_page_table(void);
 extern void __init reserve_trampoline_memory(void);
 #else
 static inline void reserve_trampoline_memory(void) {};
+extern void __init setup_trampoline_page_table(void) {};
 #endif /* CONFIG_X86_TRAMPOLINE */
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index ff4c453e13f3..fa8c1b8e09fb 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -334,7 +334,7 @@ ENTRY(startup_32_smp)
 /*
  * Enable paging
  */
-        movl $pa(swapper_pg_dir),%eax
+        movl pa(initial_page_table), %eax
         movl %eax,%cr3          /* set the page table pointer.. */
         movl %cr0,%eax
         orl  $X86_CR0_PG,%eax
@@ -614,6 +614,8 @@ ignore_int:
 .align 4
 ENTRY(initial_code)
         .long i386_start_kernel
+ENTRY(initial_page_table)
+        .long pa(swapper_pg_dir)
 
 /*
  * BSS section
@@ -629,6 +631,10 @@ ENTRY(swapper_pg_dir)
 #endif
 swapper_pg_fixmap:
         .fill 1024,4,0
+#ifdef CONFIG_X86_TRAMPOLINE
+ENTRY(trampoline_pg_dir)
+        .fill 1024,4,0
+#endif
 ENTRY(empty_zero_page)
         .fill 4096,1,0
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index b008e7883207..c3a4fbb2b996 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1014,6 +1014,8 @@ void __init setup_arch(char **cmdline_p)
         paging_init();
         x86_init.paging.pagetable_setup_done(swapper_pg_dir);
 
+        setup_trampoline_page_table();
+
         tboot_probe();
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a5e928b0cb5f..abf4a86ffc54 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -73,7 +73,6 @@
 
 #ifdef CONFIG_X86_32
 u8 apicid_2_node[MAX_APICID];
-static int low_mappings;
 #endif
 
 /* State of each CPU */
@@ -281,6 +280,18 @@ notrace static void __cpuinit start_secondary(void *unused)
          * fragile that we want to limit the things done here to the
          * most necessary things.
          */
+
+#ifdef CONFIG_X86_32
+        /*
+         * Switch away from the trampoline page-table
+         *
+         * Do this before cpu_init() because it needs to access per-cpu
+         * data which may not be mapped in the trampoline page-table.
+         */
+        load_cr3(swapper_pg_dir);
+        __flush_tlb_all();
+#endif
+
         vmi_bringup();
         cpu_init();
         preempt_disable();
@@ -299,12 +310,6 @@ notrace static void __cpuinit start_secondary(void *unused)
                 legacy_pic->chip->unmask(0);
         }
 
-#ifdef CONFIG_X86_32
-        while (low_mappings)
-                cpu_relax();
-        __flush_tlb_all();
-#endif
-
         /* This must be done before setting cpu_online_mask */
         set_cpu_sibling_map(raw_smp_processor_id());
         wmb();
@@ -750,6 +755,7 @@ do_rest:
 #ifdef CONFIG_X86_32
         /* Stack for startup_32 can be just as for start_secondary onwards */
         irq_ctx_init(cpu);
+        initial_page_table = __pa(&trampoline_pg_dir);
 #else
         clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
         initial_gs = per_cpu_offset(cpu);
@@ -897,20 +903,8 @@ int __cpuinit native_cpu_up(unsigned int cpu)
 
         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 
-#ifdef CONFIG_X86_32
-        /* init low mem mapping */
-        clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
-                min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
-        flush_tlb_all();
-        low_mappings = 1;
-
         err = do_boot_cpu(apicid, cpu);
 
-        zap_low_mappings(false);
-        low_mappings = 0;
-#else
-        err = do_boot_cpu(apicid, cpu);
-#endif
         if (err) {
                 pr_debug("do_boot_cpu failed %d\n", err);
                 return -EIO;
diff --git a/arch/x86/kernel/trampoline.c b/arch/x86/kernel/trampoline.c
index c652ef62742d..a874495b3673 100644
--- a/arch/x86/kernel/trampoline.c
+++ b/arch/x86/kernel/trampoline.c
@@ -1,6 +1,7 @@
 #include <linux/io.h>
 
 #include <asm/trampoline.h>
+#include <asm/pgtable.h>
 #include <asm/e820.h>
 
 #if defined(CONFIG_X86_64) && defined(CONFIG_ACPI_SLEEP)
@@ -37,3 +38,20 @@ unsigned long __trampinit setup_trampoline(void)
         memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
         return virt_to_phys(trampoline_base);
 }
+
+void __init setup_trampoline_page_table(void)
+{
+#ifdef CONFIG_X86_32
+        /* Copy kernel address range */
+        clone_pgd_range(trampoline_pg_dir + KERNEL_PGD_BOUNDARY,
+                        swapper_pg_dir + KERNEL_PGD_BOUNDARY,
+                        min_t(unsigned long, KERNEL_PGD_PTRS,
+                              KERNEL_PGD_BOUNDARY));
+
+        /* Initialize low mappings */
+        clone_pgd_range(trampoline_pg_dir,
+                        swapper_pg_dir + KERNEL_PGD_BOUNDARY,
+                        min_t(unsigned long, KERNEL_PGD_PTRS,
+                              KERNEL_PGD_BOUNDARY));
+#endif
+}