1 files changed, 172 insertions, 24 deletions

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 466569e..3079518 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -113,11 +113,55 @@ int __init early_init_dt_scan_fw_dump(unsigned long node,
 	return 1;
 }
 
+/*
+ * If fadump is registered, check if the memory provided
+ * falls within boot memory area.
+ */
+int is_fadump_boot_memory_area(u64 addr, ulong size)
+{
+	if (!fw_dump.dump_registered)
+		return 0;
+
+	return (addr + size) > RMA_START && addr <= fw_dump.boot_memory_size;
+}
+
 int is_fadump_active(void)
 {
 	return fw_dump.dump_active;
 }
 
+/*
+ * Returns 1, if there are no holes in boot memory area,
+ * 0 otherwise.
+ */
+static int is_boot_memory_area_contiguous(void)
+{
+	struct memblock_region *reg;
+	unsigned long tstart, tend;
+	unsigned long start_pfn = PHYS_PFN(RMA_START);
+	unsigned long end_pfn = PHYS_PFN(RMA_START + fw_dump.boot_memory_size);
+	unsigned int ret = 0;
+
+	for_each_memblock(memory, reg) {
+		tstart = max(start_pfn, memblock_region_memory_base_pfn(reg));
+		tend = min(end_pfn, memblock_region_memory_end_pfn(reg));
+		if (tstart < tend) {
+			/* Memory hole from start_pfn to tstart */
+			if (tstart > start_pfn)
+				break;
+
+			if (tend == end_pfn) {
+				ret = 1;
+				break;
+			}
+
+			start_pfn = tend + 1;
+		}
+	}
+
+	return ret;
+}
+
 /* Print firmware assisted dump configurations for debugging purpose. */
 static void fadump_show_config(void)
 {
@@ -212,20 +256,46 @@ static inline unsigned long fadump_calculate_reserve_size(void)
 	int ret;
 	unsigned long long base, size;
 
+	if (fw_dump.reserve_bootvar)
+		pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n");
+
 	/*
 	 * Check if the size is specified through crashkernel= cmdline
-	 * option. If yes, then use that but ignore base as fadump
-	 * reserves memory at end of RAM.
+	 * option. If yes, then use that but ignore base as fadump reserves
+	 * memory at a predefined offset.
 	 */
 	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 				&size, &base);
 	if (ret == 0 && size > 0) {
+		unsigned long max_size;
+
+		if (fw_dump.reserve_bootvar)
+			pr_info("Using 'crashkernel=' parameter for memory reservation.\n");
+
 		fw_dump.reserve_bootvar = (unsigned long)size;
+
+		/*
+		 * Adjust if the boot memory size specified is above
+		 * the upper limit.
+		 */
+		max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO;
+		if (fw_dump.reserve_bootvar > max_size) {
+			fw_dump.reserve_bootvar = max_size;
+			pr_info("Adjusted boot memory size to %luMB\n",
+				(fw_dump.reserve_bootvar >> 20));
+		}
+
+		return fw_dump.reserve_bootvar;
+	} else if (fw_dump.reserve_bootvar) {
+		/*
+		 * 'fadump_reserve_mem=' is being used to reserve memory
+		 * for firmware-assisted dump.
+		 */
 		return fw_dump.reserve_bootvar;
 	}
 
 	/* divide by 20 to get 5% of value */
-	size = memblock_end_of_DRAM() / 20;
+	size = memblock_phys_mem_size() / 20;
 
 	/* round it down in multiples of 256 */
 	size = size & ~0x0FFFFFFFUL;
@@ -377,9 +447,22 @@ static int __init early_fadump_param(char *p)
 }
 early_param("fadump", early_fadump_param);
 
-static void register_fw_dump(struct fadump_mem_struct *fdm)
+/*
+ * Look for fadump_reserve_mem= cmdline option
+ * TODO: Remove references to 'fadump_reserve_mem=' parameter,
+ *       the sooner 'crashkernel=' parameter is accustomed to.
+ */
+static int __init early_fadump_reserve_mem(char *p)
+{
+	if (p)
+		fw_dump.reserve_bootvar = memparse(p, &p);
+	return 0;
+}
+early_param("fadump_reserve_mem", early_fadump_reserve_mem);
+
+static int register_fw_dump(struct fadump_mem_struct *fdm)
 {
-	int rc;
+	int rc, err;
 	unsigned int wait_time;
 
 	pr_debug("Registering for firmware-assisted kernel dump...\n");
@@ -396,26 +479,38 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
 
 	} while (wait_time);
 
+	err = -EIO;
 	switch (rc) {
+	default:
+		pr_err("Failed to register. Unknown Error(%d).\n", rc);
+		break;
 	case -1:
 		printk(KERN_ERR "Failed to register firmware-assisted kernel"
 			" dump. Hardware Error(%d).\n", rc);
 		break;
 	case -3:
+		if (!is_boot_memory_area_contiguous())
+			pr_err("Can't have holes in boot memory area while "
+			       "registering fadump\n");
+
 		printk(KERN_ERR "Failed to register firmware-assisted kernel"
 			" dump. Parameter Error(%d).\n", rc);
+		err = -EINVAL;
 		break;
 	case -9:
 		printk(KERN_ERR "firmware-assisted kernel dump is already "
 			" registered.");
 		fw_dump.dump_registered = 1;
+		err = -EEXIST;
 		break;
 	case 0:
 		printk(KERN_INFO "firmware-assisted kernel dump registration"
 			" is successful\n");
 		fw_dump.dump_registered = 1;
+		err = 0;
 		break;
 	}
+	return err;
 }
 
 void crash_fadump(struct pt_regs *regs, const char *str)
@@ -831,8 +926,19 @@ static void fadump_setup_crash_memory_ranges(void)
 	for_each_memblock(memory, reg) {
 		start = (unsigned long long)reg->base;
 		end = start + (unsigned long long)reg->size;
-		if (start == RMA_START && end >= fw_dump.boot_memory_size)
-			start = fw_dump.boot_memory_size;
+
+		/*
+		 * skip the first memory chunk that is already added (RMA_START
+		 * through boot_memory_size). This logic needs a relook if and
+		 * when RMA_START changes to a non-zero value.
+		 */
+		BUILD_BUG_ON(RMA_START != 0);
+		if (start < fw_dump.boot_memory_size) {
+			if (end > fw_dump.boot_memory_size)
+				start = fw_dump.boot_memory_size;
+			else
+				continue;
+		}
 
 		/* add this range excluding the reserved dump area. */
 		fadump_exclude_reserved_area(start, end);
@@ -956,7 +1062,7 @@ static unsigned long init_fadump_header(unsigned long addr)
 	return addr;
 }
 
-static void register_fadump(void)
+static int register_fadump(void)
 {
 	unsigned long addr;
 	void *vaddr;
@@ -966,7 +1072,7 @@ static void register_fadump(void)
 	 * assisted dump.
 	 */
 	if (!fw_dump.reserve_dump_area_size)
-		return;
+		return -ENODEV;
 
 	fadump_setup_crash_memory_ranges();
 
@@ -979,7 +1085,7 @@ static void register_fadump(void)
 	fadump_create_elfcore_headers(vaddr);
 
 	/* register the future kernel dump with firmware. */
-	register_fw_dump(&fdm);
+	return register_fw_dump(&fdm);
 }
 
 static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
@@ -1046,28 +1152,71 @@ void fadump_cleanup(void)
 	}
 }
 
+static void fadump_free_reserved_memory(unsigned long start_pfn,
+					unsigned long end_pfn)
+{
+	unsigned long pfn;
+	unsigned long time_limit = jiffies + HZ;
+
+	pr_info("freeing reserved memory (0x%llx - 0x%llx)\n",
+		PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+		free_reserved_page(pfn_to_page(pfn));
+
+		if (time_after(jiffies, time_limit)) {
+			cond_resched();
+			time_limit = jiffies + HZ;
+		}
+	}
+}
+
+/*
+ * Skip memory holes and free memory that was actually reserved.
+ */
+static void fadump_release_reserved_area(unsigned long start, unsigned long end)
+{
+	struct memblock_region *reg;
+	unsigned long tstart, tend;
+	unsigned long start_pfn = PHYS_PFN(start);
+	unsigned long end_pfn = PHYS_PFN(end);
+
+	for_each_memblock(memory, reg) {
+		tstart = max(start_pfn, memblock_region_memory_base_pfn(reg));
+		tend = min(end_pfn, memblock_region_memory_end_pfn(reg));
+		if (tstart < tend) {
+			fadump_free_reserved_memory(tstart, tend);
+
+			if (tend == end_pfn)
+				break;
+
+			start_pfn = tend + 1;
+		}
+	}
+}
+
 /*
  * Release the memory that was reserved in early boot to preserve the memory
  * contents. The released memory will be available for general use.
  */
 static void fadump_release_memory(unsigned long begin, unsigned long end)
 {
-	unsigned long addr;
 	unsigned long ra_start, ra_end;
 
 	ra_start = fw_dump.reserve_dump_area_start;
 	ra_end = ra_start + fw_dump.reserve_dump_area_size;
 
-	for (addr = begin; addr < end; addr += PAGE_SIZE) {
-		/*
-		 * exclude the dump reserve area. Will reuse it for next
-		 * fadump registration.
-		 */
-		if (addr <= ra_end && ((addr + PAGE_SIZE) > ra_start))
-			continue;
-
-		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
-	}
+	/*
+	 * exclude the dump reserve area. Will reuse it for next
+	 * fadump registration.
+	 */
+	if (begin < ra_end && end > ra_start) {
+		if (begin < ra_start)
+			fadump_release_reserved_area(begin, ra_start);
+		if (end > ra_end)
+			fadump_release_reserved_area(ra_end, end);
+	} else
+		fadump_release_reserved_area(begin, end);
 }
 
 static void fadump_invalidate_release_mem(void)
@@ -1161,7 +1310,6 @@ static ssize_t fadump_register_store(struct kobject *kobj,
 	switch (buf[0]) {
 	case '0':
 		if (fw_dump.dump_registered == 0) {
-			ret = -EINVAL;
 			goto unlock_out;
 		}
 		/* Un-register Firmware-assisted dump */
@@ -1169,11 +1317,11 @@ static ssize_t fadump_register_store(struct kobject *kobj,
 		break;
 	case '1':
 		if (fw_dump.dump_registered == 1) {
-			ret = -EINVAL;
+			ret = -EEXIST;
 			goto unlock_out;
 		}
 		/* Register Firmware-assisted dump */
-		register_fadump();
+		ret = register_fadump();
 		break;
 	default:
 		ret = -EINVAL;