[PATCH 3/5] x86/xen: Read variables from dynamically allocated per_cpu data

[Daniel Kiper]

per_cpu data is dynamically allocated since 21416 changeset (x86: Dynamically
allocate percpu data area when a CPU comes online). Take into account that
and read variables from correct address.

Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>

diff -Npru crash-6.0.8.orig/xen_hyper.c crash-6.0.8/xen_hyper.c
--- crash-6.0.8.orig/xen_hyper.c	2012-07-05 15:47:09.000000000 +0200
+++ crash-6.0.8/xen_hyper.c	2012-07-05 15:50:19.000000000 +0200
@@ -64,7 +64,6 @@ xen_hyper_init(void)
 	machdep->get_smp_cpus();
 	machdep->memory_size();
 
-#ifdef IA64
 	if (symbol_exists("__per_cpu_offset")) {
 		xht->flags |= XEN_HYPER_SMP;
 		if((xht->__per_cpu_offset = malloc(sizeof(ulong) * XEN_HYPER_MAX_CPUS())) == NULL) {
@@ -76,7 +75,6 @@ xen_hyper_init(void)
 			error(FATAL, "cannot read __per_cpu_offset.\n");
 		}
 	}
-#endif
 
 #if defined(X86) || defined(X86_64)
 	if (symbol_exists("__per_cpu_shift")) {
diff -Npru crash-6.0.8.orig/xen_hyper_defs.h crash-6.0.8/xen_hyper_defs.h
--- crash-6.0.8.orig/xen_hyper_defs.h	2012-06-29 16:59:18.000000000 +0200
+++ crash-6.0.8/xen_hyper_defs.h	2012-07-05 15:50:19.000000000 +0200
@@ -136,7 +136,13 @@ typedef uint32_t	Elf_Word;
 
 #if defined(X86) || defined(X86_64)
 #define xen_hyper_per_cpu(var, cpu)  \
-	((ulong)(var) + (((ulong)(cpu))<<xht->percpu_shift))
+	({ ulong __var_addr; \
+	   if (xht->__per_cpu_offset) \
+		__var_addr = (xht->flags & XEN_HYPER_SMP) ? \
+			((ulong)(var) + xht->__per_cpu_offset[cpu]) : (ulong)(var); \
+	   else \
+		__var_addr = (ulong)(var) + ((ulong)(cpu) << xht->percpu_shift); \
+	   __var_addr; })
 #elif defined(IA64)
 #define xen_hyper_per_cpu(var, cpu)  \
 	((xht->flags & XEN_HYPER_SMP) ? \