From 5a8765bcd2ceef21b677a7d60f9071a040e84e18 Mon Sep 17 00:00:00 2001
From: Yinghai Lu <yinghai@kernel.org>
Date: Sat, 15 Dec 2012 20:59:08 -0800
Subject: [PATCH v7 09/29] x86, 64bit: Print init kernel lowmap correctly

When we get end of x86_64_start_kernel.

We have
1. kernel highmap 512M (KERNEL_IMAGE_SIZE) from kernel loaded address.
2. kernel lowmap: [0, 2M), and size (_end - _text) from kernel
   loaded address.

for example, if the kernel bzImage is loaded high from 8G, will get:
1. kernel highmap:  [8G, 8G+512M)
2. kernel lowmap: [0, 2M), and  [8G, 8G +_end - _text)

So max_pfn_mapped that is for low map pfn recording is not that
simple to 512M for 64 bit.

Try to print out two ranges, when kernel is loaded high.

Also need to use KERNEL_IMAGE_SIZE directly for highmap cleanup.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/kernel/head64.c |    3 ---
 arch/x86/kernel/setup.c  |   20 ++++++++++++++++++--
 arch/x86/mm/init_64.c    |    6 +++++-
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 014b48d..2775666 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -158,9 +158,6 @@ void __init x86_64_start_kernel(char * real_mode_data)
 	/* clear bss before set_intr_gate with early_idt_handler */
 	clear_bss();
 
-	/* XXX - this is wrong... we need to build page tables from scratch */
-	max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;
-
 	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
 #ifdef CONFIG_EARLY_PRINTK
 		set_intr_gate(i, &early_idt_handlers[i]);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 81ea5a5..d321b9b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -646,6 +646,23 @@ static int __init parse_reservelow(char *p)
 
 early_param("reservelow", parse_reservelow);
 
+static __init void print_init_mem_mapped(void)
+{
+#ifdef CONFIG_X86_32
+	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
+			(max_pfn_mapped<<PAGE_SHIFT) - 1);
+#else
+	unsigned long text = __pa_symbol(&_text);
+	unsigned long end = round_up(__pa_symbol(_end) - 1, PMD_SIZE);
+
+	if (text <= PMD_SIZE)
+		printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
+			end - 1);
+	else
+		printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx] [mem %#010lx-%#010lx]\n",
+			PMD_SIZE - 1, text, end - 1);
+#endif
+}
 /*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
@@ -910,8 +927,7 @@ void __init setup_arch(char **cmdline_p)
 	setup_bios_corruption_check();
 #endif
 
-	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
-			(max_pfn_mapped<<PAGE_SHIFT) - 1);
+	print_init_mem_mapped();
 
 	setup_real_mode();
 
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 4f5f9f7..1a88012 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -381,10 +381,14 @@ void __init init_extra_mapping_uc(unsigned long phys, unsigned long size)
 void __init cleanup_highmap(void)
 {
 	unsigned long vaddr = __START_KERNEL_map;
-	unsigned long vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT);
+	unsigned long vaddr_end = __START_KERNEL_map + KERNEL_IMAGE_SIZE;
 	unsigned long end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
 	pmd_t *pmd = level2_kernel_pgt;
 
+	/* Xen has its own end somehow with abused max_pfn_mapped */
+	if (max_pfn_mapped)
+		vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT);
+
 	for (; vaddr + PMD_SIZE - 1 < vaddr_end; pmd++, vaddr += PMD_SIZE) {
 		if (pmd_none(*pmd))
 			continue;
-- 
1.7.10.4