kexec: Limit the crash memory ranges according to first kernel's memory limit.

index 4c8c75d..d367643 100644
@@ -132,8 +132,9 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
 				goto err;
 			}
 			n = read_memory_region_limits(fd, &start, &end);
+			/* We are done with fd, close it. */
+			close(fd);
 			if (n != 0) {
-				close(fd);
 				closedir(dmem);
 				closedir(dir);
 				goto err;

@@ -153,8 +154,16 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
 			cstart = crash_base;
 			cend = crash_base + crash_size;
 			/*
-			 * Exclude the region that lies within crashkernel
+			 * Exclude the region that lies within crashkernel.
+			 * If memory limit is set then exclude memory region
+			 * above it.
 			 */
+			if (memory_limit) {
+				if (start >= memory_limit)
+					continue;
+				if (end > memory_limit)
+					end = memory_limit;
+			}
 			if (cstart < end && cend > start) {
 				if (start < cstart && end > cend) {
 					crash_memory_range[memory_ranges].start

@@ -195,7 +204,6 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
 					= RANGE_RAM;
 				memory_ranges++;
 			}
-			close(fd);
 		}
 		closedir(dmem);
 	}

index a377146..84a73aa 100644
@@ -42,5 +42,6 @@ extern unsigned long long crash_base;
 extern unsigned long long crash_size;
 extern unsigned int rtas_base;
 extern unsigned int rtas_size;
+extern uint64_t memory_limit;
 
 #endif /* CRASHDUMP_POWERPC_H */

69 lines not on this page · raw message

index 30ef443..b8a63bd 100644
@@ -84,10 +84,19 @@ static unsigned long long cstart, cend;
 static int memory_ranges;
 
 /*
- * Exclude the region that lies within crashkernel
+ * Exclude the region that lies within crashkernel and above the memory
+ * limit which is reflected by mem= kernel option.
  */
 static void exclude_crash_region(uint64_t start, uint64_t end)
 {
+	/* If memory_limit is set then exclude the memory region above it. */
+	if (memory_limit) {
+		if (start >= memory_limit)
+			return;
+		if (end > memory_limit)
+			end = memory_limit;
+	}
+
 	if (cstart < end && cend > start) {
 		if (start < cstart && end > cend) {
 			crash_memory_range[memory_ranges].start = start;

index be02213..739c61f 100644
@@ -27,6 +27,7 @@ void add_usable_mem_rgns(unsigned long long base, unsigned long long size);
 
 extern uint64_t crash_base;
 extern uint64_t crash_size;
+extern uint64_t memory_limit;
 extern unsigned int rtas_base;
 extern unsigned int rtas_size;
 

index 2f12907..389741a 100644
@@ -39,6 +39,7 @@ static struct memory_range *memory_range = NULL;
 static struct memory_range *base_memory_range = NULL;
 static uint64_t rmo_top;
 uint64_t memory_max = 0;
+uint64_t memory_limit;
 static int nr_memory_ranges, nr_exclude_ranges;
 uint64_t crash_base, crash_size;
 unsigned int rtas_base, rtas_size;

@@ -408,6 +409,32 @@ static int get_devtree_details(unsigned long kexec_flags)
 				add_usable_mem_rgns(0, crash_base + crash_size);
 				reserve(KDUMP_BACKUP_LIMIT, crash_base-KDUMP_BACKUP_LIMIT);
 			}
+			/*
+			 * Read the first kernel's memory limit.
+			 * If the first kernel is booted with mem= option then
+			 * it would export "linux,memory-limit" file
+			 * reflecting value for the same.
+			 */
+			memset(fname, 0, sizeof(fname));
+			strcpy(fname, device_tree);
+			strcat(fname, dentry->d_name);
+			strcat(fname, "/linux,memory-limit");
+			if ((file = fopen(fname, "r")) == NULL) {
+				if (errno != ENOENT) {
+					perror(fname);
+					goto error_opencdir;
+				}
+				errno = 0;
+				/*
+				 * File not present.
+				 * fall through. On older kernel this file
+				 * is not present.
+				 */
+			} else if (fread(&memory_limit, sizeof(uint64_t), 1,
+								file) != 1) {
+				perror(fname);
+				goto error_openfile;
+			}
 
 			memset(fname, 0, sizeof(fname));
 			strcpy(fname, device_tree);