1 files changed, 40 insertions, 11 deletions

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 66e70ca47680..d31c3a9290c5 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -69,6 +69,7 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit;
 
 #define CRASH_ADDR_LOW_MAX		arm64_dma_phys_limit
 #define CRASH_ADDR_HIGH_MAX		(PHYS_MASK + 1)
+#define CRASH_HIGH_SEARCH_BASE		SZ_4G
 
 #define DEFAULT_CRASH_KERNEL_LOW_SIZE	(128UL << 20)
 
@@ -101,12 +102,13 @@ static int __init reserve_crashkernel_low(unsigned long long low_size)
  */
 static void __init reserve_crashkernel(void)
 {
-	unsigned long long crash_base, crash_size;
-	unsigned long long crash_low_size = 0;
+	unsigned long long crash_low_size = 0, search_base = 0;
 	unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
+	unsigned long long crash_base, crash_size;
 	char *cmdline = boot_command_line;
-	int ret;
 	bool fixed_base = false;
+	bool high = false;
+	int ret;
 
 	if (!IS_ENABLED(CONFIG_KEXEC_CORE))
 		return;
@@ -129,7 +131,9 @@ static void __init reserve_crashkernel(void)
 		else if (ret)
 			return;
 
+		search_base = CRASH_HIGH_SEARCH_BASE;
 		crash_max = CRASH_ADDR_HIGH_MAX;
+		high = true;
 	} else if (ret || !crash_size) {
 		/* The specified value is invalid */
 		return;
@@ -140,31 +144,51 @@ static void __init reserve_crashkernel(void)
 	/* User specifies base address explicitly. */
 	if (crash_base) {
 		fixed_base = true;
+		search_base = crash_base;
 		crash_max = crash_base + crash_size;
 	}
 
 retry:
 	crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
-					       crash_base, crash_max);
+					       search_base, crash_max);
 	if (!crash_base) {
 		/*
-		 * If the first attempt was for low memory, fall back to
-		 * high memory, the minimum required low memory will be
-		 * reserved later.
+		 * For crashkernel=size[KMG]@offset[KMG], print out failure
+		 * message if can't reserve the specified region.
 		 */
-		if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) {
+		if (fixed_base) {
+			pr_warn("crashkernel reservation failed - memory is in use.\n");
+			return;
+		}
+
+		/*
+		 * For crashkernel=size[KMG], if the first attempt was for
+		 * low memory, fall back to high memory, the minimum required
+		 * low memory will be reserved later.
+		 */
+		if (!high && crash_max == CRASH_ADDR_LOW_MAX) {
 			crash_max = CRASH_ADDR_HIGH_MAX;
+			search_base = CRASH_ADDR_LOW_MAX;
 			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
 			goto retry;
 		}
 
+		/*
+		 * For crashkernel=size[KMG],high, if the first attempt was
+		 * for high memory, fall back to low memory.
+		 */
+		if (high && crash_max == CRASH_ADDR_HIGH_MAX) {
+			crash_max = CRASH_ADDR_LOW_MAX;
+			search_base = 0;
+			goto retry;
+		}
 		pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 			crash_size);
 		return;
 	}
 
-	if ((crash_base > CRASH_ADDR_LOW_MAX - crash_low_size) &&
-	     crash_low_size && reserve_crashkernel_low(crash_low_size)) {
+	if ((crash_base >= CRASH_ADDR_LOW_MAX) && crash_low_size &&
+	     reserve_crashkernel_low(crash_low_size)) {
 		memblock_phys_free(crash_base, crash_size);
 		return;
 	}
@@ -442,7 +466,12 @@ void __init bootmem_init(void)
  */
 void __init mem_init(void)
 {
-	swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE);
+	bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit);
+
+	if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC))
+		swiotlb = true;
+
+	swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
 
 	/* this will put all unused low memory onto the freelists */
 	memblock_free_all();