Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

3 files changed, 28 insertions, 50 deletions

diff --git a/kernel/arch/x86/xen/enlighten.c b/kernel/arch/x86/xen/enlighten.c
index b7de78bdc..ffa41591b 100644
--- a/kernel/arch/x86/xen/enlighten.c
+++ b/kernel/arch/x86/xen/enlighten.c
@@ -74,7 +74,6 @@
 #include <asm/mach_traps.h>
 #include <asm/mwait.h>
 #include <asm/pci_x86.h>
-#include <asm/pat.h>
 #include <asm/cpu.h>
 
 #ifdef CONFIG_ACPI
@@ -961,7 +960,7 @@ static void xen_load_sp0(struct tss_struct *tss,
 	tss->x86_tss.sp0 = thread->sp0;
 }
 
-static void xen_set_iopl_mask(unsigned mask)
+void xen_set_iopl_mask(unsigned mask)
 {
 	struct physdev_set_iopl set_iopl;
 
@@ -1519,7 +1518,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 {
 	struct physdev_set_iopl set_iopl;
 	unsigned long initrd_start = 0;
-	u64 pat;
 	int rc;
 
 	if (!xen_start_info)
@@ -1627,13 +1625,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 				   xen_start_info->nr_pages);
 	xen_reserve_special_pages();
 
-	/*
-	 * Modify the cache mode translation tables to match Xen's PAT
-	 * configuration.
-	 */
-	rdmsrl(MSR_IA32_CR_PAT, pat);
-	pat_init_cache_modes(pat);
-
 	/* keep using Xen gdt for now; no urgent need to change it */
 
 #ifdef CONFIG_X86_32
diff --git a/kernel/arch/x86/xen/mmu.c b/kernel/arch/x86/xen/mmu.c
index cb5e266a8..1e56ff583 100644
--- a/kernel/arch/x86/xen/mmu.c
+++ b/kernel/arch/x86/xen/mmu.c
@@ -1113,7 +1113,7 @@ static void __init xen_cleanhighmap(unsigned long vaddr,
 
 	/* NOTE: The loop is more greedy than the cleanup_highmap variant.
 	 * We include the PMD passed in on _both_ boundaries. */
-	for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE));
+	for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
 			pmd++, vaddr += PMD_SIZE) {
 		if (pmd_none(*pmd))
 			continue;
diff --git a/kernel/arch/x86/xen/setup.c b/kernel/arch/x86/xen/setup.c
index 7ab29518a..e34589145 100644
--- a/kernel/arch/x86/xen/setup.c
+++ b/kernel/arch/x86/xen/setup.c
@@ -393,6 +393,9 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 	unsigned long i = 0;
 	unsigned long n = end_pfn - start_pfn;
 
+	if (remap_pfn == 0)
+		remap_pfn = nr_pages;
+
 	while (i < n) {
 		unsigned long cur_pfn = start_pfn + i;
 		unsigned long left = n - i;
@@ -438,17 +441,29 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 	return remap_pfn;
 }
 
-static void __init xen_set_identity_and_remap(unsigned long nr_pages)
+static unsigned long __init xen_count_remap_pages(
+	unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
+	unsigned long remap_pages)
+{
+	if (start_pfn >= nr_pages)
+		return remap_pages;
+
+	return remap_pages + min(end_pfn, nr_pages) - start_pfn;
+}
+
+static unsigned long __init xen_foreach_remap_area(unsigned long nr_pages,
+	unsigned long (*func)(unsigned long start_pfn, unsigned long end_pfn,
+			      unsigned long nr_pages, unsigned long last_val))
 {
 	phys_addr_t start = 0;
-	unsigned long last_pfn = nr_pages;
+	unsigned long ret_val = 0;
 	const struct e820entry *entry = xen_e820_map;
 	int i;
 
 	/*
 	 * Combine non-RAM regions and gaps until a RAM region (or the
-	 * end of the map) is reached, then set the 1:1 map and
-	 * remap the memory in those non-RAM regions.
+	 * end of the map) is reached, then call the provided function
+	 * to perform its duty on the non-RAM region.
 	 *
 	 * The combined non-RAM regions are rounded to a whole number
 	 * of pages so any partial pages are accessible via the 1:1
@@ -466,14 +481,13 @@ static void __init xen_set_identity_and_remap(unsigned long nr_pages)
 				end_pfn = PFN_UP(entry->addr);
 
 			if (start_pfn < end_pfn)
-				last_pfn = xen_set_identity_and_remap_chunk(
-						start_pfn, end_pfn, nr_pages,
-						last_pfn);
+				ret_val = func(start_pfn, end_pfn, nr_pages,
+					       ret_val);
 			start = end;
 		}
 	}
 
-	pr_info("Released %ld page(s)\n", xen_released_pages);
+	return ret_val;
 }
 
 /*
@@ -596,35 +610,6 @@ static void __init xen_ignore_unusable(void)
 	}
 }
 
-static unsigned long __init xen_count_remap_pages(unsigned long max_pfn)
-{
-	unsigned long extra = 0;
-	unsigned long start_pfn, end_pfn;
-	const struct e820entry *entry = xen_e820_map;
-	int i;
-
-	end_pfn = 0;
-	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
-		start_pfn = PFN_DOWN(entry->addr);
-		/* Adjacent regions on non-page boundaries handling! */
-		end_pfn = min(end_pfn, start_pfn);
-
-		if (start_pfn >= max_pfn)
-			return extra + max_pfn - end_pfn;
-
-		/* Add any holes in map to result. */
-		extra += start_pfn - end_pfn;
-
-		end_pfn = PFN_UP(entry->addr + entry->size);
-		end_pfn = min(end_pfn, max_pfn);
-
-		if (entry->type != E820_RAM)
-			extra += end_pfn - start_pfn;
-	}
-
-	return extra;
-}
-
 bool __init xen_is_e820_reserved(phys_addr_t start, phys_addr_t size)
 {
 	struct e820entry *entry;
@@ -804,7 +789,7 @@ char * __init xen_memory_setup(void)
 	max_pages = xen_get_max_pages();
 
 	/* How many extra pages do we need due to remapping? */
-	max_pages += xen_count_remap_pages(max_pfn);
+	max_pages += xen_foreach_remap_area(max_pfn, xen_count_remap_pages);
 
 	if (max_pages > max_pfn)
 		extra_pages += max_pages - max_pfn;
@@ -922,7 +907,9 @@ char * __init xen_memory_setup(void)
 	 * Set identity map on non-RAM pages and prepare remapping the
 	 * underlying RAM.
 	 */
-	xen_set_identity_and_remap(max_pfn);
+	xen_foreach_remap_area(max_pfn, xen_set_identity_and_remap_chunk);
+
+	pr_info("Released %ld page(s)\n", xen_released_pages);
 
 	return "Xen";
 }