[Crash-utility] [PATCH] Fix pvops Xen detection for arm machine

[Qi Zheng]

Since the xen_start_info on the arm/arm64 platform is static defined:

./arm/xen/enlighten.c:40:static struct start_info _xen_start_info;
./arm/xen/enlighten.c:41:struct start_info *xen_start_info = &_xen_start_info;
./arm/xen/enlighten.c:42:EXPORT_SYMBOL(xen_start_info);

The is_pvops_xen() in commit 4badc6229c69f5cd9da7eb7bdf400a53ec6db01a
("Fix pvops Xen detection for kernels >= v4.20") always return TRUE.
Then the following error will be reported because p2m_mid_missing
and xen_p2m_addr are not defined:

	crash: cannot resolve "p2m_top"

For the arm/arm64 platform, fix it by using xen_vcpu_info instead of
xen_start_info to detect Xen dumps.

Signed-off-by: Qi Zheng <zhengqi.arch at bytedance.com>
---
 kernel.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/kernel.c b/kernel.c
index f4598ea..4b4d789 100644
--- a/kernel.c
+++ b/kernel.c
@@ -10757,11 +10757,18 @@ is_pvops_xen(void)
 	     STREQ(sym, "paravirt_patch_default")))
 		return TRUE;
 
-	if (symbol_exists("xen_start_info") &&
-	    readmem(symbol_value("xen_start_info"), KVADDR, &addr,
-	    sizeof(void *), "xen_start_info", RETURN_ON_ERROR) &&
-	    addr != 0)
+	if (machine_type("ARM") || machine_type("ARM64")) {
+		if (symbol_exists("xen_vcpu_info") &&
+		    readmem(symbol_value("xen_vcpu_info"), KVADDR, &addr,
+		    sizeof(void *), "xen_vcpu_info", RETURN_ON_ERROR) &&
+		    addr != 0)
+			return TRUE;
+	} else if (symbol_exists("xen_start_info") &&
+		   readmem(symbol_value("xen_start_info"), KVADDR, &addr,
+		   sizeof(void *), "xen_start_info", RETURN_ON_ERROR) &&
+		   addr != 0) {
 		return TRUE;
+	}
 
 	return FALSE;
 }
-- 
2.11.0