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.

1 files changed, 15 insertions, 8 deletions

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);