From 9f1e6d707cc4df1a0a6ad5d4496cd2dcc6db6000 Mon Sep 17 00:00:00 2001
From: Ken Sato <ken.sato.ty@hitachi-solutions.com>
Date: Mon, 30 Nov 2020 14:23:51 +0900
Subject: [PATCH] get_mempolicy: Support (MPOL_F_NODE | MPOL_F_ADDR) specified

If flags specifies both MPOL_F_NODE and MPOL_F_ADDR,
get_mempolicy() will return the node ID of the node on
which the address addr is allocated into the location pointed to by mode.

Change-Id: Id485e3f4838e3679d877a95e53b21e3421cac88a
---
 kernel/mem.c         | 41 +++++++++++++++++++++++++++++++++++++++++
 kernel/syscall.c     | 14 ++++++++++++++
 lib/include/memory.h |  2 ++
 3 files changed, 57 insertions(+)

diff --git a/kernel/mem.c b/kernel/mem.c
index 62562cf4..fdd29db6 100644
--- a/kernel/mem.c
+++ b/kernel/mem.c
@@ -2931,3 +2931,44 @@ retry:
 
 	return ptep;
 }
+
+int phys_to_nid(unsigned long p)
+{
+   int i, numa_id = -1, _numa_id;
+   unsigned long _start, _end;
+
+   for (i = 0; i < ihk_mc_get_nr_memory_chunks(); i++) {
+	   ihk_mc_get_memory_chunk(i, &_start, &_end, &_numa_id);
+
+	   if (p >= _start && p < _end) {
+		   numa_id = _numa_id;
+		   goto out;
+	   }
+   }
+
+out:
+   return numa_id;
+}
+
+int lookup_node(struct process_vm *vm, void *addr)
+{
+	int node, err, reason = PF_POPULATE | PF_USER;
+	pte_t *ptep;
+
+	err = page_fault_process_vm(vm, (void *)addr, reason);
+	if (err) {
+		node = err;
+		goto out;
+	}
+
+	ptep = ihk_mc_pt_lookup_pte(vm->address_space->page_table,
+			(void *)addr, 0, NULL, NULL, NULL);
+	if (!ptep || !pte_is_present(ptep)) {
+		node = -ENOENT;
+		goto out;
+	}
+
+	node = phys_to_nid(pte_get_phys(ptep));
+out:
+	return node;
+}
diff --git a/kernel/syscall.c b/kernel/syscall.c
index 817bfb00..5b708e61 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -10153,6 +10153,20 @@ SYSCALL_DECLARE(get_mempolicy)
 		}
 	}
 
+	/* case of MPOL_F_NODE and MPOL_F_ADDR are specified */
+	if (flags & MPOL_F_NODE && flags & MPOL_F_ADDR) {
+		/* return the node ID which addr is allocated by mode */
+		int nid;
+
+		nid = lookup_node(vm, (void *)addr);
+		error = copy_to_user(mode, &nid, sizeof(int));
+		if (error) {
+			error = -EFAULT;
+			goto out;
+		}
+		goto out;
+	}
+
 	/* Special case of MPOL_F_MEMS_ALLOWED */
 	if (flags == MPOL_F_MEMS_ALLOWED) {
 		if (nodemask) {
diff --git a/lib/include/memory.h b/lib/include/memory.h
index 141111cb..e2b30c7b 100644
--- a/lib/include/memory.h
+++ b/lib/include/memory.h
@@ -20,6 +20,8 @@ struct process_vm;
 
 unsigned long virt_to_phys(void *v);
 void *phys_to_virt(unsigned long p);
+int phys_to_nid(unsigned long p);
+int lookup_node(struct process_vm *vm, void *addr);
 int copy_from_user(void *dst, const void *src, size_t siz);
 int strlen_user(const char *s);
 int strcpy_from_user(char *dst, const char *src);