[PATCH 1/4] kaslr: parse the extended movable_node=nn[KMG]@ss[KMG]

Chao Fan
2017-10-19T10:07:16Z

Extend the movable_node to movable_node=nn[KMG]@ss[KMG].
Since in current code, kaslr may choose the memory region in hot-pluggable
nodes. So we can specific the region in immovable node. And store the
regions in immovable_mem.

Multiple regions can be specified, comma delimited.
Considering the usage of memory, only support for 4 regions.
4 regions contains 2 nodes at least, and is enough for kernel to
extract.

Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
---
arch/x86/boot/compressed/kaslr.c | 63 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 17818ba6906f..3c1f5204693b 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -107,6 +107,12 @@ enum mem_avoid_index {

static struct mem_vector mem_avoid[MEM_AVOID_MAX];

+/* Only supporting at most 4 immovable memory regions with kaslr */
+#define MAX_IMMOVABLE_MEM 4
+
+static struct mem_vector immovable_mem[MAX_IMMOVABLE_MEM];
+static int num_immovable_region;
+
static bool mem_overlaps(struct mem_vector *one, struct mem_vector *two)
{
/* Item one is entirely before item two. */
@@ -167,6 +173,28 @@ parse_memmap(char *p, unsigned long long *start, unsigned long long *size)
return -EINVAL;
}

+static int parse_immovable_mem(char *p,
+ unsigned long long *start,
+ unsigned long long *size)
+{
+ char *oldp;
+
+ if (!p)
+ return -EINVAL;
+
+ oldp = p;
+ *size = memparse(p, &p);
+ if (p == oldp)
+ return -EINVAL;
+
+ if (*p == '@') {
+ *start = memparse(p + 1, &p);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
static void mem_avoid_memmap(char *str)
{
static int i;
@@ -206,6 +234,36 @@ static void mem_avoid_memmap(char *str)
memmap_too_large = true;
}

+#ifdef CONFIG_MEMORY_HOTPLUG
+static void mem_mark_immovable(char *str)
+{
+ int i = 0;
+
+ while (str && (i < MAX_IMMOVABLE_MEM)) {
+ int rc;
+ unsigned long long start, size;
+ char *k = strchr(str, ',');
+
+ if (k)
+ *k++ = 0;
+
+ rc = parse_immovable_mem(str, &start, &size);
+ if (rc < 0)
+ break;
+ str = k;
+
+ immovable_mem[i].start = start;
+ immovable_mem[i].size = size;
+ i++;
+ }
+ num_immovable_region = i;
+}
+#else
+static inline void mem_mark_immovable(char *str)
+{
+}
+#endif
+
static int handle_mem_memmap(void)
{
char *args = (char *)get_cmd_line_ptr();
@@ -214,7 +272,8 @@ static int handle_mem_memmap(void)
char *param, *val;
u64 mem_size;

- if (!strstr(args, "memmap=") && !strstr(args, "mem="))
+ if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
+ !strstr(args, "movable_node="))
return 0;

tmp_cmdline = malloc(len + 1);
@@ -239,6 +298,8 @@ static int handle_mem_memmap(void)

if (!strcmp(param, "memmap")) {
mem_avoid_memmap(val);
+ } else if (!strcmp(param, "movable_node")) {
+ mem_mark_immovable(val);
} else if (!strcmp(param, "mem")) {
char *p = val;

--
2.13.6