[PATCH v3] x86: UV SGI, Don't track GRU space in PAT

[Jack Steiner <steiner@sgi.com>]

GRU space is always mapped as WB in the page table. There is
no need to track the mappings in the PAT. This also eliminates
the "freeing invalid memtype" messages when the GRU space is unmapped.

Signed-off-by: Jack Steiner <steiner@sgi.com>

---
Version 2 with changes suggested by Ingo (at least I think I understood what
he wanted).

Version 3 with changes suggested by Peter to make the new function
a member of the x86_platform structure.



 arch/x86/include/asm/pat.h         |    2 ++
 arch/x86/include/asm/x86_init.h    |    1 +
 arch/x86/kernel/apic/x2apic_uv_x.c |   19 ++++++++++++++++++-
 arch/x86/kernel/x86_init.c         |    2 ++
 arch/x86/mm/pat.c                  |   11 ++++++++---
 5 files changed, 31 insertions(+), 4 deletions(-)

Index: linux/arch/x86/include/asm/pat.h
===================================================================
--- linux.orig/arch/x86/include/asm/pat.h	2009-11-19 01:39:52.000000000 -0600
+++ linux/arch/x86/include/asm/pat.h	2009-11-19 11:13:35.000000000 -0600
@@ -24,4 +24,6 @@ int io_reserve_memtype(resource_size_t s
 
 void io_free_memtype(resource_size_t start, resource_size_t end);
 
+int default_is_untracked_pat_range(u64 start, u64 end);
+
 #endif /* _ASM_X86_PAT_H */
Index: linux/arch/x86/include/asm/x86_init.h
===================================================================
--- linux.orig/arch/x86/include/asm/x86_init.h	2009-11-19 01:39:52.000000000 -0600
+++ linux/arch/x86/include/asm/x86_init.h	2009-11-19 11:19:38.000000000 -0600
@@ -131,6 +131,7 @@ struct x86_platform_ops {
 	unsigned long (*get_wallclock)(void);
 	int (*set_wallclock)(unsigned long nowtime);
 	void (*iommu_shutdown)(void);
+	int (*is_untracked_pat_range)(u64 start, u64 end);
 };
 
 extern struct x86_init_ops x86_init;
Index: linux/arch/x86/kernel/apic/x2apic_uv_x.c
===================================================================
--- linux.orig/arch/x86/kernel/apic/x2apic_uv_x.c	2009-11-19 11:09:47.000000000 -0600
+++ linux/arch/x86/kernel/apic/x2apic_uv_x.c	2009-11-19 11:21:09.000000000 -0600
@@ -30,10 +30,22 @@
 #include <asm/apic.h>
 #include <asm/ipi.h>
 #include <asm/smp.h>
+#include <asm/x86_init.h>
 
 DEFINE_PER_CPU(int, x2apic_extra_bits);
 
 static enum uv_system_type uv_system_type;
+static u64 gru_start_paddr, gru_end_paddr;
+
+static int is_GRU_range(u64 start, u64 end)
+{
+	return start >= gru_start_paddr && end < gru_end_paddr;
+}
+
+static int uv_is_untracked_pat_range(u64 start, u64 end)
+{
+	return is_ISA_range(start, end) || is_GRU_range(start, end);
+}
 
 static int early_get_nodeid(void)
 {
@@ -49,6 +61,7 @@ static int early_get_nodeid(void)
 static int __init uv_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
 	if (!strcmp(oem_id, "SGI")) {
+		x86_platform.is_untracked_pat_range =  uv_is_untracked_pat_range;
 		if (!strcmp(oem_table_id, "UVL"))
 			uv_system_type = UV_LEGACY_APIC;
 		else if (!strcmp(oem_table_id, "UVX"))
@@ -386,8 +399,12 @@ static __init void map_gru_high(int max_
 	int shift = UVH_RH_GAM_GRU_OVERLAY_CONFIG_MMR_BASE_SHFT;
 
 	gru.v = uv_read_local_mmr(UVH_RH_GAM_GRU_OVERLAY_CONFIG_MMR);
-	if (gru.s.enable)
+	if (gru.s.enable) {
 		map_high("GRU", gru.s.base, shift, max_pnode, map_wb);
+		gru_start_paddr = ((u64)gru.s.base << shift);
+		gru_end_paddr = gru_start_paddr + (1UL << shift) * (max_pnode + 1);
+
+	}
 }
 
 static __init void map_mmr_high(int max_pnode)
Index: linux/arch/x86/kernel/x86_init.c
===================================================================
--- linux.orig/arch/x86/kernel/x86_init.c	2009-11-19 01:39:52.000000000 -0600
+++ linux/arch/x86/kernel/x86_init.c	2009-11-19 11:12:45.000000000 -0600
@@ -15,6 +15,7 @@
 #include <asm/irq.h>
 #include <asm/tsc.h>
 #include <asm/iommu.h>
+#include <asm/pat.h>
 
 void __cpuinit x86_init_noop(void) { }
 void __init x86_init_uint_noop(unsigned int unused) { }
@@ -80,4 +81,5 @@ struct x86_platform_ops x86_platform = {
 	.get_wallclock			= mach_get_cmos_time,
 	.set_wallclock			= mach_set_rtc_mmss,
 	.iommu_shutdown			= iommu_shutdown_noop,
+	.is_untracked_pat_range		= default_is_untracked_pat_range,
 };
Index: linux/arch/x86/mm/pat.c
===================================================================
--- linux.orig/arch/x86/mm/pat.c	2009-11-19 11:09:47.000000000 -0600
+++ linux/arch/x86/mm/pat.c	2009-11-19 11:20:26.000000000 -0600
@@ -348,6 +348,11 @@ static int free_ram_pages_type(u64 start
 	return 0;
 }
 
+int default_is_untracked_pat_range(u64 start, u64 end)
+{
+	return is_ISA_range(start, end);
+}
+
 /*
  * req_type typically has one of the:
  * - _PAGE_CACHE_WB
@@ -383,7 +388,7 @@ int reserve_memtype(u64 start, u64 end, 
 	}
 
 	/* Low ISA region is always mapped WB in page table. No need to track */
-	if (is_ISA_range(start, end - 1)) {
+	if (x86_platform.is_untracked_pat_range(start, end - 1)) {
 		if (new_type)
 			*new_type = _PAGE_CACHE_WB;
 		return 0;
@@ -494,7 +499,7 @@ int free_memtype(u64 start, u64 end)
 		return 0;
 
 	/* Low ISA region is always mapped WB. No need to track */
-	if (is_ISA_range(start, end - 1))
+	if (x86_platform.is_untracked_pat_range(start, end - 1))
 		return 0;
 
 	is_range_ram = pat_pagerange_is_ram(start, end);
@@ -577,7 +582,7 @@ static unsigned long lookup_memtype(u64 
 	int rettype = _PAGE_CACHE_WB;
 	struct memtype *entry;
 
-	if (is_ISA_range(paddr, paddr + PAGE_SIZE - 1))
+	if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE - 1))
 		return rettype;
 
 	if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {