[PATCH] arm64:kexec: Memstart should not be before the kernel start address

[Sameer Goel]

Starting 4.6-rc4 the kernel memblock start is rounded down to a desirable
alignment. So, the kernel can see reserved memory regions before the kernel
start address in the iomem query.
Need to make sure that the right kernel start address is picked from the iomem
query.
---
 kexec/arch/arm64/kexec-arm64.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 776596a..5e39f4f 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -30,6 +30,12 @@
 #include "kexec-syscall.h"
 #include "arch/options.h"
 
+#define SZ_2M 0x200000
+
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+#define round_down(x, y) ((x) & ~__round_mask(x, y))
+
 /* Global varables the core kexec routines expect. */
 
 unsigned char reuse_initrd;
@@ -944,6 +950,10 @@ static int get_memory_ranges_iomem(struct memory_range *array,
 		str = line + consumed;
 		r.end++;
 
+		if (memcmp(str, "Kernel code\n", 12)==0) {
+			set_memstart(round_down(r.start,SZ_2M));
+		}
+
 		if (memcmp(str, "System RAM\n", 11)) {
 			dbgprintf("%s:%d: SKIP: %016Lx - %016Lx : %s", __func__,
 				__LINE__, r.start, r.end, str);
@@ -956,8 +966,6 @@ static int get_memory_ranges_iomem(struct memory_range *array,
 			__LINE__, r.start, r.end, str);
 
 		array[(*count)++] = r;
-
-		set_memstart(r.start);
 	}
 
 	fclose(fp);
-- 
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