Merge branch '2021-06-07-arm-cache-cp15-improvements' into next

To quote the series author, Patrick Delaunay:

On STM32MP15x platform we can use OP-TEE, loaded in DDR in a region
protected by a firewall. This region is reserved in the device with
the "no-map" property as defined in the binding file
doc/device-tree-bindings/reserved-memory/reserved-memory.txt.

Sometime the platform boot failed in U-Boot on a Cortex A7 access to
this region (depending of the binary and the issue can change with compiler
version or with code alignment), then the firewall raise an error,
for example:

E/TC:0   tzc_it_handler:19 TZC permission failure
E/TC:0   dump_fail_filter:420 Permission violation on filter 0
E/TC:0   dump_fail_filter:425 Violation @0xde5c6bf0, non-secure privileged read,
         AXI ID 5c0
E/TC:0   Panic

After investigation, the forbidden access is a speculative request performed
by the Cortex A7 because all the DDR is mapped as MEMORY with CACHEABLE
property.

The issue is solved only when the region reserved by OP-TEE is no more
mapped in U-Boot as it is already done in Linux kernel.

Tested on DK2 board with OP-TEE 3.12 / TF-A 2.4:

With hard-coded address for OP-TEE reserved memory,
the error doesn't occur.

 void dram_bank_mmu_setup(int bank)
 {
 ....

    	for (i = start >> MMU_SECTION_SHIFT;
 	     i < (start >> MMU_SECTION_SHIFT) + (size >> MMU_SECTION_SHIFT);
 	     i++) {
 		option = DCACHE_DEFAULT_OPTION;
 		if (i >= 0xde0)
 			option = INVALID_ENTRY;
 		set_section_dcache(i, option);
 	}
 }

Just by modifying the test on 0xde0 to 0xdf0, the OP-TEE memory protected
by firewall is mapped cacheable and the error occurs.

I think that it can be a general issue for ARM architecture: the "no-map" tag
of reserved memory in device should be respected by U-Boot if firewall
is configured before U-Boot execution.

But I don't propose a generic solution in
arm/lib/cache-cp15.c:dram_bank_mmu_setup()
because the device tree parsing done in lmb_init_and_reserve() takes a
long time when it is executed without data cache.

6 files changed, 228 insertions, 39 deletions

diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
index 8115d58b19..592bfd413d 100644
--- a/arch/arm/mach-stm32mp/cpu.c
+++ b/arch/arm/mach-stm32mp/cpu.c
@@ -12,6 +12,7 @@
 #include <env.h>
 #include <init.h>
 #include <log.h>
+#include <lmb.h>
 #include <misc.h>
 #include <net.h>
 #include <asm/io.h>
@@ -90,6 +91,8 @@
  */
 u8 early_tlb[PGTABLE_SIZE] __section(".data") __aligned(0x4000);
 
+struct lmb lmb;
+
 #if !defined(CONFIG_SPL) || defined(CONFIG_SPL_BUILD)
 #ifndef CONFIG_TFABOOT
 static void security_init(void)
@@ -221,6 +224,8 @@ void dram_bank_mmu_setup(int bank)
 	int	i;
 	phys_addr_t start;
 	phys_size_t size;
+	bool use_lmb = false;
+	enum dcache_option option;
 
 	if (IS_ENABLED(CONFIG_SPL_BUILD)) {
 		start = ALIGN_DOWN(STM32_SYSRAM_BASE, MMU_SECTION_SIZE);
@@ -229,6 +234,7 @@ void dram_bank_mmu_setup(int bank)
 		/* bd->bi_dram is available only after relocation */
 		start = bd->bi_dram[bank].start;
 		size =  bd->bi_dram[bank].size;
+		use_lmb = true;
 	} else {
 		/* mark cacheable and executable the beggining of the DDR */
 		start = STM32_DDR_BASE;
@@ -237,8 +243,12 @@ void dram_bank_mmu_setup(int bank)
 
 	for (i = start >> MMU_SECTION_SHIFT;
 	     i < (start >> MMU_SECTION_SHIFT) + (size >> MMU_SECTION_SHIFT);
-	     i++)
-		set_section_dcache(i, DCACHE_DEFAULT_OPTION);
+	     i++) {
+		option = DCACHE_DEFAULT_OPTION;
+		if (use_lmb && lmb_is_reserved_flags(&lmb, i << MMU_SECTION_SHIFT, LMB_NOMAP))
+			option = 0; /* INVALID ENTRY in TLB */
+		set_section_dcache(i, option);
+	}
 }
 /*
  * initialize the MMU and activate cache in SPL or in U-Boot pre-reloc stage
@@ -302,6 +312,9 @@ int arch_cpu_init(void)
 
 void enable_caches(void)
 {
+	/* parse device tree when data cache is still activated */
+	lmb_init_and_reserve(&lmb, gd->bd, (void *)gd->fdt_blob);
+
 	/* I-cache is already enabled in start.S: icache_enable() not needed */
 
 	/* deactivate the data cache, early enabled in arch_cpu_init() */
diff --git a/arch/arm/mach-stm32mp/dram_init.c b/arch/arm/mach-stm32mp/dram_init.c
index 66e81bacca..3c097029bd 100644
--- a/arch/arm/mach-stm32mp/dram_init.c
+++ b/arch/arm/mach-stm32mp/dram_init.c
@@ -50,13 +50,16 @@ ulong board_get_usable_ram_top(ulong total_size)
 	lmb_init(&lmb);
 	lmb_add(&lmb, gd->ram_base, gd->ram_size);
 	boot_fdt_add_mem_rsv_regions(&lmb, (void *)gd->fdt_blob);
-	size = ALIGN(CONFIG_SYS_MALLOC_LEN + total_size, MMU_SECTION_SIZE),
+	/* add 8M for reserved memory for display, fdt, gd,... */
+	size = ALIGN(SZ_8M + CONFIG_SYS_MALLOC_LEN + total_size, MMU_SECTION_SIZE),
 	reg = lmb_alloc(&lmb, size, MMU_SECTION_SIZE);
 
 	if (!reg)
 		reg = gd->ram_top - size;
 
-	mmu_set_region_dcache_behaviour(reg, size, DCACHE_DEFAULT_OPTION);
+	/* before relocation, mark the U-Boot memory as cacheable by default */
+	if (!(gd->flags & GD_FLG_RELOC))
+		mmu_set_region_dcache_behaviour(reg, size, DCACHE_DEFAULT_OPTION);
 
 	return reg + size;
 }
diff --git a/common/image-fdt.c b/common/image-fdt.c
index d50e1ba3fe..06dce92a28 100644
--- a/common/image-fdt.c
+++ b/common/image-fdt.c
@@ -75,18 +75,20 @@ static const image_header_t *image_get_fdt(ulong fdt_addr)
 #endif
 
 static void boot_fdt_reserve_region(struct lmb *lmb, uint64_t addr,
-				    uint64_t size)
+				    uint64_t size, enum lmb_flags flags)
 {
 	long ret;
 
-	ret = lmb_reserve(lmb, addr, size);
+	ret = lmb_reserve_flags(lmb, addr, size, flags);
 	if (ret >= 0) {
-		debug("   reserving fdt memory region: addr=%llx size=%llx\n",
-		      (unsigned long long)addr, (unsigned long long)size);
+		debug("   reserving fdt memory region: addr=%llx size=%llx flags=%x\n",
+		      (unsigned long long)addr,
+		      (unsigned long long)size, flags);
 	} else {
 		puts("ERROR: reserving fdt memory region failed ");
-		printf("(addr=%llx size=%llx)\n",
-		       (unsigned long long)addr, (unsigned long long)size);
+		printf("(addr=%llx size=%llx flags=%x)\n",
+		       (unsigned long long)addr,
+		       (unsigned long long)size, flags);
 	}
 }
 
@@ -106,6 +108,7 @@ void boot_fdt_add_mem_rsv_regions(struct lmb *lmb, void *fdt_blob)
 	int i, total, ret;
 	int nodeoffset, subnode;
 	struct fdt_resource res;
+	enum lmb_flags flags;
 
 	if (fdt_check_header(fdt_blob) != 0)
 		return;
@@ -115,7 +118,7 @@ void boot_fdt_add_mem_rsv_regions(struct lmb *lmb, void *fdt_blob)
 	for (i = 0; i < total; i++) {
 		if (fdt_get_mem_rsv(fdt_blob, i, &addr, &size) != 0)
 			continue;
-		boot_fdt_reserve_region(lmb, addr, size);
+		boot_fdt_reserve_region(lmb, addr, size, LMB_NONE);
 	}
 
 	/* process reserved-memory */
@@ -127,9 +130,13 @@ void boot_fdt_add_mem_rsv_regions(struct lmb *lmb, void *fdt_blob)
 			ret = fdt_get_resource(fdt_blob, subnode, "reg", 0,
 					       &res);
 			if (!ret && fdtdec_get_is_enabled(fdt_blob, subnode)) {
+				flags = LMB_NONE;
+				if (fdtdec_get_bool(fdt_blob, subnode,
+						    "no-map"))
+					flags = LMB_NOMAP;
 				addr = res.start;
 				size = res.end - res.start + 1;
-				boot_fdt_reserve_region(lmb, addr, size);
+				boot_fdt_reserve_region(lmb, addr, size, flags);
 			}
 
 			subnode = fdt_next_subnode(fdt_blob, subnode);
diff --git a/include/lmb.h b/include/lmb.h
index 541e17093c..3c4afdf9f0 100644
--- a/include/lmb.h
+++ b/include/lmb.h
@@ -13,6 +13,16 @@
  */
 
 /**
+ * enum lmb_flags - definition of memory region attributes
+ * @LMB_NONE: no special request
+ * @LMB_NOMAP: don't add to mmu configuration
+ */
+enum lmb_flags {
+	LMB_NONE		= 0x0,
+	LMB_NOMAP		= 0x4,
+};
+
+/**
  * struct lmb_property - Description of one region.
  *
  * @base: Base address of the region.
@@ -21,6 +31,7 @@
 struct lmb_property {
 	phys_addr_t base;
 	phys_size_t size;
+	enum lmb_flags flags;
 };
 
 /**
@@ -69,6 +80,17 @@ extern void lmb_init_and_reserve_range(struct lmb *lmb, phys_addr_t base,
 				       phys_size_t size, void *fdt_blob);
 extern long lmb_add(struct lmb *lmb, phys_addr_t base, phys_size_t size);
 extern long lmb_reserve(struct lmb *lmb, phys_addr_t base, phys_size_t size);
+/**
+ * lmb_reserve_flags - Reserve one region with a specific flags bitfield.
+ *
+ * @lmb		the logical memory block struct
+ * @base	base address of the memory region
+ * @size	size of the memory region
+ * @flags	flags for the memory region
+ * @return 0 if OK, > 0 for coalesced region or a negative error code.
+ */
+long lmb_reserve_flags(struct lmb *lmb, phys_addr_t base,
+		       phys_size_t size, enum lmb_flags flags);
 extern phys_addr_t lmb_alloc(struct lmb *lmb, phys_size_t size, ulong align);
 extern phys_addr_t lmb_alloc_base(struct lmb *lmb, phys_size_t size, ulong align,
 			    phys_addr_t max_addr);
@@ -78,6 +100,15 @@ extern phys_addr_t lmb_alloc_addr(struct lmb *lmb, phys_addr_t base,
 				  phys_size_t size);
 extern phys_size_t lmb_get_free_size(struct lmb *lmb, phys_addr_t addr);
 extern int lmb_is_reserved(struct lmb *lmb, phys_addr_t addr);
+/**
+ * lmb_is_reserved_flags - test if tha address is in reserved region with a bitfield flag
+ *
+ * @lmb		the logical memory block struct
+ * @addr	address to be tested
+ * @flags	flags bitfied to be tested
+ * @return 0 if not reserved or reserved without the requested flag else 1
+ */
+int lmb_is_reserved_flags(struct lmb *lmb, phys_addr_t addr, int flags);
 extern long lmb_free(struct lmb *lmb, phys_addr_t base, phys_size_t size);
 
 extern void lmb_dump_all(struct lmb *lmb);
@@ -92,6 +123,13 @@ lmb_size_bytes(struct lmb_region *type, unsigned long region_nr)
 void board_lmb_reserve(struct lmb *lmb);
 void arch_lmb_reserve(struct lmb *lmb);
 
+/* Low level functions */
+
+static inline bool lmb_is_nomap(struct lmb_property *m)
+{
+	return m->flags & LMB_NOMAP;
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_LMB_H */
diff --git a/lib/lmb.c b/lib/lmb.c
index c08c4d942b..7bd1255f7a 100644
--- a/lib/lmb.c
+++ b/lib/lmb.c
@@ -14,28 +14,32 @@
 
 #define LMB_ALLOC_ANYWHERE	0
 
-void lmb_dump_all_force(struct lmb *lmb)
+static void lmb_dump_region(struct lmb_region *rgn, char *name)
 {
-	unsigned long i;
+	unsigned long long base, size, end;
+	enum lmb_flags flags;
+	int i;
 
-	printf("lmb_dump_all:\n");
-	printf("    memory.cnt		   = 0x%lx\n", lmb->memory.cnt);
-	for (i = 0; i < lmb->memory.cnt; i++) {
-		printf("    memory.reg[0x%lx].base   = 0x%llx\n", i,
-		       (unsigned long long)lmb->memory.region[i].base);
-		printf("		   .size   = 0x%llx\n",
-		       (unsigned long long)lmb->memory.region[i].size);
-	}
+	printf(" %s.cnt  = 0x%lx\n", name, rgn->cnt);
 
-	printf("\n    reserved.cnt	   = 0x%lx\n", lmb->reserved.cnt);
-	for (i = 0; i < lmb->reserved.cnt; i++) {
-		printf("    reserved.reg[0x%lx].base = 0x%llx\n", i,
-		       (unsigned long long)lmb->reserved.region[i].base);
-		printf("		     .size = 0x%llx\n",
-		       (unsigned long long)lmb->reserved.region[i].size);
+	for (i = 0; i < rgn->cnt; i++) {
+		base = rgn->region[i].base;
+		size = rgn->region[i].size;
+		end = base + size - 1;
+		flags = rgn->region[i].flags;
+
+		printf(" %s[%d]\t[0x%llx-0x%llx], 0x%08llx bytes flags: %x\n",
+		       name, i, base, end, size, flags);
 	}
 }
 
+void lmb_dump_all_force(struct lmb *lmb)
+{
+	printf("lmb_dump_all:\n");
+	lmb_dump_region(&lmb->memory, "memory");
+	lmb_dump_region(&lmb->reserved, "reserved");
+}
+
 void lmb_dump_all(struct lmb *lmb)
 {
 #ifdef DEBUG
@@ -81,6 +85,7 @@ static void lmb_remove_region(struct lmb_region *rgn, unsigned long r)
 	for (i = r; i < rgn->cnt - 1; i++) {
 		rgn->region[i].base = rgn->region[i + 1].base;
 		rgn->region[i].size = rgn->region[i + 1].size;
+		rgn->region[i].flags = rgn->region[i + 1].flags;
 	}
 	rgn->cnt--;
 }
@@ -144,7 +149,8 @@ void lmb_init_and_reserve_range(struct lmb *lmb, phys_addr_t base,
 }
 
 /* This routine called with relocation disabled. */
-static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t size)
+static long lmb_add_region_flags(struct lmb_region *rgn, phys_addr_t base,
+				 phys_size_t size, enum lmb_flags flags)
 {
 	unsigned long coalesced = 0;
 	long adjacent, i;
@@ -152,6 +158,7 @@ static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t
 	if (rgn->cnt == 0) {
 		rgn->region[0].base = base;
 		rgn->region[0].size = size;
+		rgn->region[0].flags = flags;
 		rgn->cnt = 1;
 		return 0;
 	}
@@ -160,18 +167,27 @@ static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t
 	for (i = 0; i < rgn->cnt; i++) {
 		phys_addr_t rgnbase = rgn->region[i].base;
 		phys_size_t rgnsize = rgn->region[i].size;
+		phys_size_t rgnflags = rgn->region[i].flags;
 
-		if ((rgnbase == base) && (rgnsize == size))
-			/* Already have this region, so we're done */
-			return 0;
+		if (rgnbase == base && rgnsize == size) {
+			if (flags == rgnflags)
+				/* Already have this region, so we're done */
+				return 0;
+			else
+				return -1; /* regions with new flags */
+		}
 
 		adjacent = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
 		if (adjacent > 0) {
+			if (flags != rgnflags)
+				break;
 			rgn->region[i].base -= size;
 			rgn->region[i].size += size;
 			coalesced++;
 			break;
 		} else if (adjacent < 0) {
+			if (flags != rgnflags)
+				break;
 			rgn->region[i].size += size;
 			coalesced++;
 			break;
@@ -182,8 +198,10 @@ static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t
 	}
 
 	if ((i < rgn->cnt - 1) && lmb_regions_adjacent(rgn, i, i + 1)) {
-		lmb_coalesce_regions(rgn, i, i + 1);
-		coalesced++;
+		if (rgn->region[i].flags == rgn->region[i + 1].flags) {
+			lmb_coalesce_regions(rgn, i, i + 1);
+			coalesced++;
+		}
 	}
 
 	if (coalesced)
@@ -196,9 +214,11 @@ static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t
 		if (base < rgn->region[i].base) {
 			rgn->region[i + 1].base = rgn->region[i].base;
 			rgn->region[i + 1].size = rgn->region[i].size;
+			rgn->region[i + 1].flags = rgn->region[i].flags;
 		} else {
 			rgn->region[i + 1].base = base;
 			rgn->region[i + 1].size = size;
+			rgn->region[i + 1].flags = flags;
 			break;
 		}
 	}
@@ -206,6 +226,7 @@ static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t
 	if (base < rgn->region[0].base) {
 		rgn->region[0].base = base;
 		rgn->region[0].size = size;
+		rgn->region[0].flags = flags;
 	}
 
 	rgn->cnt++;
@@ -213,6 +234,12 @@ static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base, phys_size_t
 	return 0;
 }
 
+static long lmb_add_region(struct lmb_region *rgn, phys_addr_t base,
+			   phys_size_t size)
+{
+	return lmb_add_region_flags(rgn, base, size, LMB_NONE);
+}
+
 /* This routine may be called with relocation disabled. */
 long lmb_add(struct lmb *lmb, phys_addr_t base, phys_size_t size)
 {
@@ -267,14 +294,21 @@ long lmb_free(struct lmb *lmb, phys_addr_t base, phys_size_t size)
 	 * beginging of the hole and add the region after hole.
 	 */
 	rgn->region[i].size = base - rgn->region[i].base;
-	return lmb_add_region(rgn, end + 1, rgnend - end);
+	return lmb_add_region_flags(rgn, end + 1, rgnend - end,
+				    rgn->region[i].flags);
 }
 
-long lmb_reserve(struct lmb *lmb, phys_addr_t base, phys_size_t size)
+long lmb_reserve_flags(struct lmb *lmb, phys_addr_t base, phys_size_t size,
+		       enum lmb_flags flags)
 {
 	struct lmb_region *_rgn = &(lmb->reserved);
 
-	return lmb_add_region(_rgn, base, size);
+	return lmb_add_region_flags(_rgn, base, size, flags);
+}
+
+long lmb_reserve(struct lmb *lmb, phys_addr_t base, phys_size_t size)
+{
+	return lmb_reserve_flags(lmb, base, size, LMB_NONE);
 }
 
 static long lmb_overlaps_region(struct lmb_region *rgn, phys_addr_t base,
@@ -409,7 +443,7 @@ phys_size_t lmb_get_free_size(struct lmb *lmb, phys_addr_t addr)
 	return 0;
 }
 
-int lmb_is_reserved(struct lmb *lmb, phys_addr_t addr)
+int lmb_is_reserved_flags(struct lmb *lmb, phys_addr_t addr, int flags)
 {
 	int i;
 
@@ -417,11 +451,16 @@ int lmb_is_reserved(struct lmb *lmb, phys_addr_t addr)
 		phys_addr_t upper = lmb->reserved.region[i].base +
 			lmb->reserved.region[i].size - 1;
 		if ((addr >= lmb->reserved.region[i].base) && (addr <= upper))
-			return 1;
+			return (lmb->reserved.region[i].flags & flags) == flags;
 	}
 	return 0;
 }
 
+int lmb_is_reserved(struct lmb *lmb, phys_addr_t addr)
+{
+	return lmb_is_reserved_flags(lmb, addr, LMB_NONE);
+}
+
 __weak void board_lmb_reserve(struct lmb *lmb)
 {
 	/* please define platform specific board_lmb_reserve() */
diff --git a/test/lib/lmb.c b/test/lib/lmb.c
index 0d8963fcbf..b2c2b99ef1 100644
--- a/test/lib/lmb.c
+++ b/test/lib/lmb.c
@@ -723,3 +723,92 @@ static int lib_test_lmb_max_regions(struct unit_test_state *uts)
 
 DM_TEST(lib_test_lmb_max_regions,
 	UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
+
+static int lib_test_lmb_flags(struct unit_test_state *uts)
+{
+	const phys_addr_t ram = 0x40000000;
+	const phys_size_t ram_size = 0x20000000;
+	struct lmb lmb;
+	long ret;
+
+	lmb_init(&lmb);
+
+	ret = lmb_add(&lmb, ram, ram_size);
+	ut_asserteq(ret, 0);
+
+	/* reserve, same flag */
+	ret = lmb_reserve_flags(&lmb, 0x40010000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 0);
+	ASSERT_LMB(&lmb, ram, ram_size, 1, 0x40010000, 0x10000,
+		   0, 0, 0, 0);
+
+	/* reserve again, same flag */
+	ret = lmb_reserve_flags(&lmb, 0x40010000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 0);
+	ASSERT_LMB(&lmb, ram, ram_size, 1, 0x40010000, 0x10000,
+		   0, 0, 0, 0);
+
+	/* reserve again, new flag */
+	ret = lmb_reserve_flags(&lmb, 0x40010000, 0x10000, LMB_NONE);
+	ut_asserteq(ret, -1);
+	ASSERT_LMB(&lmb, ram, ram_size, 1, 0x40010000, 0x10000,
+		   0, 0, 0, 0);
+
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[0]), 1);
+
+	/* merge after */
+	ret = lmb_reserve_flags(&lmb, 0x40020000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 1);
+	ASSERT_LMB(&lmb, ram, ram_size, 1, 0x40010000, 0x20000,
+		   0, 0, 0, 0);
+
+	/* merge before */
+	ret = lmb_reserve_flags(&lmb, 0x40000000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 1);
+	ASSERT_LMB(&lmb, ram, ram_size, 1, 0x40000000, 0x30000,
+		   0, 0, 0, 0);
+
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[0]), 1);
+
+	ret = lmb_reserve_flags(&lmb, 0x40030000, 0x10000, LMB_NONE);
+	ut_asserteq(ret, 0);
+	ASSERT_LMB(&lmb, ram, ram_size, 2, 0x40000000, 0x30000,
+		   0x40030000, 0x10000, 0, 0);
+
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[0]), 1);
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[1]), 0);
+
+	/* test that old API use LMB_NONE */
+	ret = lmb_reserve(&lmb, 0x40040000, 0x10000);
+	ut_asserteq(ret, 1);
+	ASSERT_LMB(&lmb, ram, ram_size, 2, 0x40000000, 0x30000,
+		   0x40030000, 0x20000, 0, 0);
+
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[0]), 1);
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[1]), 0);
+
+	ret = lmb_reserve_flags(&lmb, 0x40070000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 0);
+	ASSERT_LMB(&lmb, ram, ram_size, 3, 0x40000000, 0x30000,
+		   0x40030000, 0x20000, 0x40070000, 0x10000);
+
+	ret = lmb_reserve_flags(&lmb, 0x40050000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 0);
+	ASSERT_LMB(&lmb, ram, ram_size, 4, 0x40000000, 0x30000,
+		   0x40030000, 0x20000, 0x40050000, 0x10000);
+
+	/* merge with 2 adjacent regions */
+	ret = lmb_reserve_flags(&lmb, 0x40060000, 0x10000, LMB_NOMAP);
+	ut_asserteq(ret, 2);
+	ASSERT_LMB(&lmb, ram, ram_size, 3, 0x40000000, 0x30000,
+		   0x40030000, 0x20000, 0x40050000, 0x30000);
+
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[0]), 1);
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[1]), 0);
+	ut_asserteq(lmb_is_nomap(&lmb.reserved.region[2]), 1);
+
+	return 0;
+}
+
+DM_TEST(lib_test_lmb_flags,
+	UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);