[PATCH V4 3/4] s390/mm: Define arch_get_mappable_range()

From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org, hca@linux.ibm.com,
	catalin.marinas@arm.com
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
	Oscar Salvador <osalvador@suse.de>,
	Vasily Gorbik <gor@linux.ibm.com>, Will Deacon <will@kernel.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	David Hildenbrand <david@redhat.com>,
	linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH V4 3/4] s390/mm: Define arch_get_mappable_range()
Date: Mon, 25 Jan 2021 08:28:51 +0530	[thread overview]
Message-ID: <1611543532-18698-4-git-send-email-anshuman.khandual@arm.com> (raw)
In-Reply-To: <1611543532-18698-1-git-send-email-anshuman.khandual@arm.com>

This overrides arch_get_mappabble_range() on s390 platform which will be
used with recently added generic framework. It modifies the existing range
check in vmem_add_mapping() using arch_get_mappable_range(). It also adds a
VM_BUG_ON() check that would ensure that mhp_range_allowed() has already
been called on the hotplug path.

Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: linux-s390@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/s390/mm/init.c |  1 +
 arch/s390/mm/vmem.c | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 73a163065b95..0e76b2127dc6 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -297,6 +297,7 @@ int arch_add_memory(int nid, u64 start, u64 size,
 	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
 		return -EINVAL;
 
+	VM_BUG_ON(!mhp_range_allowed(start, size, true));
 	rc = vmem_add_mapping(start, size);
 	if (rc)
 		return rc;
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 01f3a5f58e64..82dbf9450105 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -4,6 +4,7 @@
  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
  */
 
+#include <linux/memory_hotplug.h>
 #include <linux/memblock.h>
 #include <linux/pfn.h>
 #include <linux/mm.h>
@@ -532,11 +533,22 @@ void vmem_remove_mapping(unsigned long start, unsigned long size)
 	mutex_unlock(&vmem_mutex);
 }
 
+struct range arch_get_mappable_range(void)
+{
+	struct range mhp_range;
+
+	mhp_range.start = 0;
+	mhp_range.end =  VMEM_MAX_PHYS - 1;
+	return mhp_range;
+}
+
 int vmem_add_mapping(unsigned long start, unsigned long size)
 {
+	struct range range = arch_get_mappable_range();
 	int ret;
 
-	if (start + size > VMEM_MAX_PHYS ||
+	if (start < range.start ||
+	    start + size > range.end + 1 ||
 	    start + size < start)
 		return -ERANGE;
 
-- 
2.20.1

