[PATCH v9 14/46] x86, mm: use pfn_range_is_mapped() with reserve_initrd

[Yinghai Lu <yinghai@kernel.org>]

We are going to map ram only in patch:
        x86, mm: Only direct map addresses that are marked as E820_RAM

so range under max_low_pfn_mapped, ranges between 4g and max_pfn_mapped
could have holes in them and the holes will not be mapped.

Use pfn_range_is_mapped() to check if range is mapped for initrd.

That could happen if the bootloader put initrd in range but user used
"memmap=" to carve some of ranges out.

Also during copying need to use early_memmap to map original initrd
for accessing.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kernel/setup.c |   52 +++++++++++++++++++++++++---------------------
 1 files changed, 28 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d85cbd9..bd52f9d 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -317,20 +317,19 @@ static void __init relocate_initrd(void)
 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
 	u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
 	u64 area_size     = PAGE_ALIGN(ramdisk_size);
-	u64 end_of_lowmem = max_low_pfn_mapped << PAGE_SHIFT;
 	u64 ramdisk_here;
 	unsigned long slop, clen, mapaddr;
 	char *p, *q;
 
-	/* We need to move the initrd down into lowmem */
-	ramdisk_here = memblock_find_in_range(0, end_of_lowmem, area_size,
-					 PAGE_SIZE);
+	/* We need to move the initrd down into directly mapped mem */
+	ramdisk_here = memblock_find_in_range(0, PFN_PHYS(max_low_pfn_mapped),
+						 area_size, PAGE_SIZE);
 
 	if (!ramdisk_here)
 		panic("Cannot find place for new RAMDISK of size %lld\n",
 			 ramdisk_size);
 
-	/* Note: this includes all the lowmem currently occupied by
+	/* Note: this includes all the mem currently occupied by
 	   the initrd, we rely on that fact to keep the data intact. */
 	memblock_reserve(ramdisk_here, area_size);
 	initrd_start = ramdisk_here + PAGE_OFFSET;
@@ -340,17 +339,7 @@ static void __init relocate_initrd(void)
 
 	q = (char *)initrd_start;
 
-	/* Copy any lowmem portion of the initrd */
-	if (ramdisk_image < end_of_lowmem) {
-		clen = end_of_lowmem - ramdisk_image;
-		p = (char *)__va(ramdisk_image);
-		memcpy(q, p, clen);
-		q += clen;
-		ramdisk_image += clen;
-		ramdisk_size  -= clen;
-	}
-
-	/* Copy the highmem portion of the initrd */
+	/* Copy the initrd */
 	while (ramdisk_size) {
 		slop = ramdisk_image & ~PAGE_MASK;
 		clen = ramdisk_size;
@@ -364,7 +353,7 @@ static void __init relocate_initrd(void)
 		ramdisk_image += clen;
 		ramdisk_size  -= clen;
 	}
-	/* high pages is not converted by early_res_to_bootmem */
+
 	ramdisk_image = boot_params.hdr.ramdisk_image;
 	ramdisk_size  = boot_params.hdr.ramdisk_size;
 	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
@@ -373,13 +362,27 @@ static void __init relocate_initrd(void)
 		ramdisk_here, ramdisk_here + ramdisk_size - 1);
 }
 
+static u64 __init get_mem_size(unsigned long limit_pfn)
+{
+	int i;
+	u64 mapped_pages = 0;
+	unsigned long start_pfn, end_pfn;
+
+	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
+		start_pfn = min_t(unsigned long, start_pfn, limit_pfn);
+		end_pfn = min_t(unsigned long, end_pfn, limit_pfn);
+		mapped_pages += end_pfn - start_pfn;
+	}
+
+	return mapped_pages << PAGE_SHIFT;
+}
 static void __init reserve_initrd(void)
 {
 	/* Assume only end is not page aligned */
 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
 	u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
-	u64 end_of_lowmem = max_low_pfn_mapped << PAGE_SHIFT;
+	u64 mapped_size;
 
 	if (!boot_params.hdr.type_of_loader ||
 	    !ramdisk_image || !ramdisk_size)
@@ -387,18 +390,19 @@ static void __init reserve_initrd(void)
 
 	initrd_start = 0;
 
-	if (ramdisk_size >= (end_of_lowmem>>1)) {
+	mapped_size = get_mem_size(max_low_pfn_mapped);
+	if (ramdisk_size >= (mapped_size>>1))
 		panic("initrd too large to handle, "
 		       "disabling initrd (%lld needed, %lld available)\n",
-		       ramdisk_size, end_of_lowmem>>1);
-	}
+		       ramdisk_size, mapped_size>>1);
 
 	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
 			ramdisk_end - 1);
 
-
-	if (ramdisk_end <= end_of_lowmem) {
-		/* All in lowmem, easy case */
+	if (ramdisk_end <= (max_low_pfn_mapped<<PAGE_SHIFT) &&
+	    pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
+				PFN_DOWN(ramdisk_end))) {
+		/* All are mapped, easy case */
 		/*
 		 * don't need to reserve again, already reserved early
 		 * in i386_start_kernel
-- 
1.7.7