From 8cc33a134681892a71a4f67397bb13a541bb463e Mon Sep 17 00:00:00 2001
Message-Id: <8cc33a134681892a71a4f67397bb13a541bb463e.1566225007.git.aquini@redhat.com>
In-Reply-To: <d42f467a923dfc09309acb7a83b42e3285fbd8f4.1566225007.git.aquini@redhat.com>
References: <d42f467a923dfc09309acb7a83b42e3285fbd8f4.1566225007.git.aquini@redhat.com>
From: Sandipan Das <sandipan@linux.ibm.com>
Date: Thu, 15 Aug 2019 13:08:38 +0530
Subject: [RHEL7 PATCH 11/31] hugeutils: Add utility to check if slices are
 supported

This adds an utility to check if the current processor
architecture supports slices. Slices are used to divide
up a virtual address space and put certain restrictions
like on powerpc64 with Hash MMU where one can have only
one page size per slice.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Rafael Aquini <aquini@redhat.com>
---
 hugeutils.c              | 21 +++++++++++++++++++++
 libhugetlbfs_privutils.h |  3 +++
 2 files changed, 24 insertions(+)

diff --git a/hugeutils.c b/hugeutils.c
index fc64946..e573622 100644
--- a/hugeutils.c
+++ b/hugeutils.c
@@ -800,6 +800,27 @@ int hpool_sizes(struct hpage_pool *pools, int pcnt)
 	return (which < pcnt) ? which : -1;
 }
 
+int arch_has_slice_support(void)
+{
+#ifdef __powerpc64__
+	char mmu_type[16];
+	FILE *fp;
+
+	fp = popen("cat /proc/cpuinfo | grep MMU | awk '{ print $3}'", "r");
+	if (!fp || fscanf(fp, "%s", mmu_type) < 0) {
+		ERROR("Failed to determine MMU type\n");
+		abort();
+	}
+
+	pclose(fp);
+	return strcmp(mmu_type, "Hash") == 0;
+#elif defined(__powerpc__) && !defined(PPC_NO_SEGMENTS)
+	return 1;
+#else
+	return 0;
+#endif
+}
+
 /*
  * If we have a default page size then we support hugepages.
  */
diff --git a/libhugetlbfs_privutils.h b/libhugetlbfs_privutils.h
index 149e42f..8b12fed 100644
--- a/libhugetlbfs_privutils.h
+++ b/libhugetlbfs_privutils.h
@@ -53,6 +53,9 @@ int set_nr_hugepages(long pagesize, unsigned long val);
 #define set_nr_overcommit_hugepages __pu_set_nr_overcommit_hugepages
 int set_nr_overcommit_hugepages(long pagesize, unsigned long val);
 
+#define arch_has_slice_support __pu_arch_has_slice_support
+int arch_has_slice_support(void);
+
 #define kernel_has_hugepages __pu_kernel_has_hugepages
 int kernel_has_hugepages(void);
 
-- 
1.8.3.1