x86: ioremap mptable

Impact: fix boot with mptable above max_low_mapped

Try to use early_ioremap() to map MPC to make sure it works even it is
at the end of ram.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <49AE4901.3090801@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reported-and-tested-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 20 insertions, 1 deletions

diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 37cb1bda1baf..ae9060cb4481 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -558,6 +558,19 @@ static inline void __init construct_default_ISA_mptable(int mpc_default_type)
 
 static struct mpf_intel *mpf_found;
 
+static unsigned long __init get_mpc_size(unsigned long physptr)
+{
+        struct mpc_table *mpc;
+        unsigned long size;
+
+        mpc = early_ioremap(physptr, PAGE_SIZE);
+        size = mpc->length;
+        early_iounmap(mpc, PAGE_SIZE);
+        apic_printk(APIC_VERBOSE, "  mpc: %lx-%lx\n", physptr, physptr + size);
+
+        return size;
+}
+
 /*
  * Scan the memory blocks for an SMP configuration block.
  */
@@ -611,12 +624,16 @@ static void __init __get_smp_config(unsigned int early)
                 construct_default_ISA_mptable(mpf->feature1);
 
         } else if (mpf->physptr) {
+                struct mpc_table *mpc;
+                unsigned long size;
 
+                size = get_mpc_size(mpf->physptr);
+                mpc = early_ioremap(mpf->physptr, size);
                 /*
                  * Read the physical hardware table.  Anything here will
                  * override the defaults.
                  */
-                if (!smp_read_mpc(phys_to_virt(mpf->physptr), early)) {
+                if (!smp_read_mpc(mpc, early)) {
 #ifdef CONFIG_X86_LOCAL_APIC
                         smp_found_config = 0;
 #endif
@@ -624,8 +641,10 @@ static void __init __get_smp_config(unsigned int early)
                                "BIOS bug, MP table errors detected!...\n");
                         printk(KERN_ERR "... disabling SMP support. "
                                "(tell your hw vendor)\n");
+                        early_iounmap(mpc, size);
                         return;
                 }
+                early_iounmap(mpc, size);
 
                 if (early)
                         return;