x86/platform/UV: Remove EFI memmap quirk for UV2+

Commit a5d90c9 ("x86/efi: Quirk out SGI UV") added a quirk
to efi_apply_memmap_quirks to force SGI UV systems to fall back
to the old EFI memmap mechanism.  We have a BIOS fix for this
issue on all systems except for UV1.  This commit fixes up the
EFI quirk/MMR mapping code so that we only apply the special
case to UV1 hardware.

Signed-off-by: Alex Thorlton <[email protected]>
Reviewed-by: Matt Fleming <[email protected]>
Cc: Dimitri Sivanich <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hedi Berriche <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Travis <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: Alex Thorlton

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -889,7 +889,10 @@ void __init uv_system_init(void)
 		return;
 	}
 	pr_info("UV: Found %s hub\n", hub);
-	map_low_mmrs();
+
+	/* We now only need to map the MMRs on UV1 */
+	if (is_uv1_hub())
+		map_low_mmrs();
 
 	m_n_config.v = uv_read_local_mmr(UVH_RH_GAM_CONFIG_MMR );
 	m_val = m_n_config.s.m_skt;

arch/x86/platform/efi/quirks.c

@@ -8,6 +8,7 @@
 #include <linux/memblock.h>
 #include <linux/bootmem.h>
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include <asm/efi.h>
 #include <asm/uv/uv.h>
 
@@ -248,6 +249,16 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
 	return ret;
 }
 
+static const struct dmi_system_id sgi_uv1_dmi[] = {
+	{ NULL, "SGI UV1",
+		{	DMI_MATCH(DMI_PRODUCT_NAME,	"Stoutland Platform"),
+			DMI_MATCH(DMI_PRODUCT_VERSION,	"1.0"),
+			DMI_MATCH(DMI_BIOS_VENDOR,	"SGI.COM"),
+		}
+	},
+	{ } /* NULL entry stops DMI scanning */
+};
+
 void __init efi_apply_memmap_quirks(void)
 {
 	/*
@@ -260,10 +271,8 @@ void __init efi_apply_memmap_quirks(void)
 		efi_unmap_memmap();
 	}
 
-	/*
-	 * UV doesn't support the new EFI pagetable mapping yet.
-	 */
-	if (is_uv_system())
+	/* UV2+ BIOS has a fix for this issue.  UV1 still needs the quirk. */
+	if (dmi_check_system(sgi_uv1_dmi))
 		set_bit(EFI_OLD_MEMMAP, &efi.flags);
 }