x86: introduce max_low_pfn_mapped for 64-bit

when more than 4g memory is installed, don't map the big hole below 4g.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

5 files changed, 47 insertions, 12 deletions

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index a31a579a47c..9c981c4a364 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -130,7 +130,7 @@ char *__init __acpi_map_table(unsigned long phys, unsigned long size)
 	if (!phys || !size)
 		return NULL;
 
-	if (phys+size <= (max_pfn_mapped << PAGE_SHIFT))
+	if (phys+size <= (max_low_pfn_mapped << PAGE_SHIFT))
 		return __va(phys);
 
 	offset = phys & (PAGE_SIZE - 1);
diff --git a/arch/x86/kernel/cpu/amd_64.c b/arch/x86/kernel/cpu/amd_64.c
index 958526d6a74..bd182b7616e 100644
--- a/arch/x86/kernel/cpu/amd_64.c
+++ b/arch/x86/kernel/cpu/amd_64.c
@@ -199,10 +199,14 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 		 * Don't do it for gbpages because there seems very little
 		 * benefit in doing so.
 		 */
-		if (!rdmsrl_safe(MSR_K8_TSEG_ADDR, &tseg) &&
-		    (tseg >> PMD_SHIFT) <
-			(max_pfn_mapped >> (PMD_SHIFT-PAGE_SHIFT)))
+		if (!rdmsrl_safe(MSR_K8_TSEG_ADDR, &tseg)) {
+		    if ((tseg>>PMD_SHIFT) <
+				(max_low_pfn_mapped>>(PMD_SHIFT-PAGE_SHIFT)) ||
+			((tseg>>PMD_SHIFT) <
+				(max_pfn_mapped>>(PMD_SHIFT-PAGE_SHIFT)) &&
+			 (tseg>>PMD_SHIFT) >= (1ULL<<(32 - PMD_SHIFT))))
 			set_memory_4k((unsigned long)__va(tseg), 1);
+		}
 	}
 }
 
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 3451e0b3f32..9f5002e0b35 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1056,7 +1056,7 @@ unsigned long __initdata end_user_pfn = MAX_ARCH_PFN;
 /*
  * Find the highest page frame number we have available
  */
-unsigned long __init e820_end(void)
+static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
 {
 	int i;
 	unsigned long last_pfn = 0;
@@ -1064,12 +1064,21 @@ unsigned long __init e820_end(void)
 
 	for (i = 0; i < e820.nr_map; i++) {
 		struct e820entry *ei = &e820.map[i];
+		unsigned long start_pfn;
 		unsigned long end_pfn;
 
-		if (ei->type != E820_RAM)
+		if (ei->type != type)
 			continue;
 
+		start_pfn = ei->addr >> PAGE_SHIFT;
 		end_pfn = (ei->addr + ei->size) >> PAGE_SHIFT;
+
+		if (start_pfn >= limit_pfn)
+			continue;
+		if (end_pfn > limit_pfn) {
+			last_pfn = limit_pfn;
+			break;
+		}
 		if (end_pfn > last_pfn)
 			last_pfn = end_pfn;
 	}
@@ -1083,7 +1092,15 @@ unsigned long __init e820_end(void)
 			 last_pfn, max_arch_pfn);
 	return last_pfn;
 }
+unsigned long __init e820_end_of_ram_pfn(void)
+{
+	return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
+}
 
+unsigned long __init e820_end_of_low_ram_pfn(void)
+{
+	return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
+}
 /*
  * Finds an active region in the address range from start_pfn to last_pfn and
  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
@@ -1206,7 +1223,7 @@ static int __init parse_memmap_opt(char *p)
 		 * the real mem size before original memory map is
 		 * reset.
 		 */
-		saved_max_pfn = e820_end();
+		saved_max_pfn = e820_end_of_ram_pfn();
 #endif
 		e820.nr_map = 0;
 		userdef = 1;
diff --git a/arch/x86/kernel/efi.c b/arch/x86/kernel/efi.c
index 94382faeadb..06cc8d4254b 100644
--- a/arch/x86/kernel/efi.c
+++ b/arch/x86/kernel/efi.c
@@ -473,7 +473,7 @@ void __init efi_enter_virtual_mode(void)
 		size = md->num_pages << EFI_PAGE_SHIFT;
 		end = md->phys_addr + size;
 
-		if (PFN_UP(end) <= max_pfn_mapped)
+		if (PFN_UP(end) <= max_low_pfn_mapped)
 			va = __va(md->phys_addr);
 		else
 			va = efi_ioremap(md->phys_addr, size);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a7c3471ea17..86fc2d62427 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -713,14 +713,14 @@ void __init setup_arch(char **cmdline_p)
 	 * partially used pages are not usable - thus
 	 * we are rounding upwards:
 	 */
-	max_pfn = e820_end();
+	max_pfn = e820_end_of_ram_pfn();
 
 	/* preallocate 4k for mptable mpc */
 	early_reserve_e820_mpc_new();
 	/* update e820 for memory not covered by WB MTRRs */
 	mtrr_bp_init();
 	if (mtrr_trim_uncached_memory(max_pfn))
-		max_pfn = e820_end();
+		max_pfn = e820_end_of_ram_pfn();
 
 #ifdef CONFIG_X86_32
 	/* max_low_pfn get updated here */
@@ -732,12 +732,26 @@ void __init setup_arch(char **cmdline_p)
 
 	/* How many end-of-memory variables you have, grandma! */
 	/* need this before calling reserve_initrd */
-	max_low_pfn = max_pfn;
+	if (max_pfn > (1UL<<(32 - PAGE_SHIFT)))
+		max_low_pfn = e820_end_of_low_ram_pfn();
+	else
+		max_low_pfn = max_pfn;
+
 	high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
 #endif
 
 	/* max_pfn_mapped is updated here */
-	max_pfn_mapped = init_memory_mapping(0, (max_low_pfn << PAGE_SHIFT));
+	max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
+	max_pfn_mapped = max_low_pfn_mapped;
+
+#ifdef CONFIG_X86_64
+	if (max_pfn > max_low_pfn) {
+		max_pfn_mapped = init_memory_mapping(1UL<<32,
+						     max_pfn<<PAGE_SHIFT);
+		/* can we preseve max_low_pfn ?*/
+		max_low_pfn = max_pfn;
+	}
+#endif
 
 	/*
 	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.