[Crash-utility] [PATCH 2/3] arm64: read pagesize

[Andrew Jones]

Thanks to kernel commit 9d372c9fab34 "arm64: Add page size to the
kernel image header", we don't need a heuristic to determine the
pagesize on arm64. Keep the heuristic for older kernels, but try
reading the header first.
---
 arm64.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arm64.c b/arm64.c
index 8cfb863d1bfe2..6187b96d25a4d 100644
--- a/arm64.c
+++ b/arm64.c
@@ -19,6 +19,7 @@
 
 #include "defs.h"
 #include <elf.h>
+#include <endian.h>
 
 #define NOT_IMPLEMENTED(X) error((X), "%s: function not implemented\n", __func__)
 
@@ -98,6 +99,35 @@ arm64_init(int when)
 
 	case PRE_GDB:
 		if (!machdep->pagesize &&
+		    kernel_symbol_exists("_kernel_flags_le")) {
+
+			/*
+			 * Kerneldoc Documentation/arm64/booting.txt describes
+			 * the kernel image header flags field.
+			 */
+
+			value = le64toh(symbol_value("_kernel_flags_le"));
+			value = (value >> 1) & 3;
+
+			switch(value)
+			{
+			case 0:
+				break;
+			case 1:
+				machdep->pagesize = 4096;
+				break;
+			case 2:
+				/* TODO: machdep->pagesize = 16384; */
+				error(FATAL, "16K pages not supported.");
+				break;
+			case 3:
+				machdep->pagesize = 65536;
+				break;
+			}
+
+		}
+
+		if (!machdep->pagesize &&
 		    kernel_symbol_exists("swapper_pg_dir") &&
 		    kernel_symbol_exists("idmap_pg_dir")) {
 			value = symbol_value("swapper_pg_dir") -
-- 
2.4.3