zdump: Use os_info data to convert dump vaddr to paddr

For vr-kernel dumps use the offsets stored in os_info entries for
virt to phys address conversion when dump virtual address is to be
read, (e.g. vmcoreinfo symbols) using similar method as implemented
in crash-utility.
It is mainly required for reading "init_uts_ns" symbol and, in case
of crashed kdump, "lowcore_ptr" symbol along with a pointers to the
lowcore of every CPU.

Acked-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>

zdump/dfi.c

@@ -695,6 +695,8 @@ static void kdump_select_prod_init(void)
 	unsigned long prefix, ptr, count, tv_sec, i;
 	struct timeval timeval;
 
+	util_log_print(UTIL_LOG_TRACE, "DFI kdump production system dump initialization\n");
+
 	if (g.opts.select_specified && !l.kdump_base)
 		ERR_EXIT("The \"--select\" option is not possible with this "
 			 "dump");
@@ -712,9 +714,10 @@ static void kdump_select_prod_init(void)
 	}
 	dfi_cpu_info_init(DFI_CPU_CONTENT_ALL);
 	for (i = 0; i < count; i++) {
-		if (dfi_mem_virt_read(ptr + i * sizeof(long), &prefix,
+		if (dfi_mem_virt_read(dfi_vm_vtop(ptr) + i * sizeof(long), &prefix,
 				      sizeof(prefix)))
 			continue;
+		prefix = dfi_vm_vtop(prefix);
 		if (prefix == 0)
 			continue;
 		if (prefix % 0x1000)
@@ -736,7 +739,7 @@ static void utsname_init(void)
 
 	if (dfi_vmcoreinfo_symbol(&ptr, "init_uts_ns"))
 		return;
-	if (dfi_mem_virt_read(ptr, buf, sizeof(buf)))
+	if (dfi_mem_virt_read(dfi_vm_vtop(ptr), buf, sizeof(buf)))
 		return;
 	utsname = memchr(buf, 'L', sizeof(buf) - sizeof(*utsname));
 	if (!utsname)

zdump/dfi_mem_chunk.c

@@ -439,6 +439,10 @@ void dfi_mem_unmap(u64 start, u64 size)
 	struct dfi_mem_chunk *mem_chunk, *tmp;
 	u64 end = start + size - 1;
 
+	util_log_print(UTIL_LOG_TRACE,
+		       "DFI mem unmap  start 0x%016lx, size 0x%016lx\n",
+		       start, size);
+
 	util_list_iterate_safe(&l.mem_virt.chunk_list, mem_chunk, tmp) {
 		/*
 		 * Chunk not hit?
@@ -504,6 +508,10 @@ void dfi_mem_unmap(u64 start, u64 size)
  */
 void dfi_mem_map(u64 start, u64 size, u64 start_phys)
 {
+	util_log_print(UTIL_LOG_TRACE,
+		       "DFI mem map  start 0x%016lx, size 0x%016lx, base 0x%016lx\n",
+		       start, size, start_phys);
+
 	if (mem_range_mapped(start, size)) {
 		dfi_mem_map_print(false);
 		ABORT("Map request for already mapped region (%llx/%llx/%llx)",

zdump/dfi_vmcoreinfo.c

@@ -30,12 +30,21 @@
 
 #define LC_OS_INFO		0xe18
 
+struct vm_info {
+	u64	identity_base;
+	u64	kaslr_offset;
+	u64	kaslr_offset_phys;
+	u64	amode31_start;
+	u64	amode31_end;
+};
+
 /*
  * File local static data
  */
 static struct {
 	char		*vmcoreinfo;
 	struct os_info	*os_info;
+	struct vm_info  *vm_info;
 } l;
 
 static u32 os_info_csum(struct os_info *os_info)
@@ -53,6 +62,7 @@ static struct os_info *os_info_get(void)
 
 	if (dfi_mem_virt_read(LC_OS_INFO, &addr, sizeof(addr)))
 		return NULL;
+	util_log_print(UTIL_LOG_DEBUG, "DFI osinfo addr: 0x%016lx\n", addr);
 	if (addr % 0x1000)
 		return NULL;
 	if (dfi_mem_virt_read(addr, &os_info, sizeof(os_info)))
@@ -61,9 +71,46 @@ static struct os_info *os_info_get(void)
 		return NULL;
 	if (os_info.csum != os_info_csum(&os_info))
 		return NULL;
+
+	util_log_print(UTIL_LOG_DEBUG, "DFI found valid osinfo!\n");
 	return &os_info;
 }
 
+static struct vm_info *vm_info_get(void)
+{
+	static struct vm_info vm_info = { 0 };
+
+	util_log_print(UTIL_LOG_TRACE, "DFI read vm_info\n");
+
+	vm_info.identity_base = l.os_info->entry[OS_INFO_IDENTITY_BASE].val;
+	if (vm_info.identity_base == 0)
+		return NULL;
+	vm_info.kaslr_offset = l.os_info->entry[OS_INFO_KASLR_OFFSET].val;
+	vm_info.kaslr_offset_phys = l.os_info->entry[OS_INFO_KASLR_OFF_PHYS].val;
+	vm_info.amode31_start = l.os_info->entry[OS_INFO_AMODE31_START].val;
+	vm_info.amode31_end = l.os_info->entry[OS_INFO_AMODE31_END].val;
+
+	return &vm_info;
+}
+
+/*
+ * Convert virual address in the dump to the physical address using
+ * vm_info data derived from os_info
+ */
+u64 dfi_vm_vtop(u64 vaddr)
+{
+	if (!l.vm_info)
+		return vaddr;
+	if (vaddr < LOWCORE_SIZE)
+		return vaddr;
+	if ((vaddr < l.vm_info->amode31_end) &&
+	    (vaddr >= l.vm_info->amode31_start))
+		return vaddr;
+	if (vaddr < l.vm_info->kaslr_offset)
+		return vaddr - l.vm_info->identity_base;
+	return vaddr - l.vm_info->kaslr_offset + l.vm_info->kaslr_offset_phys;
+}
+
 /*
  * Initialize vmcoreinfo
  */
@@ -76,6 +123,8 @@ void dfi_vmcoreinfo_init(void)
 	util_log_print(UTIL_LOG_TRACE, "DFI vmcoreinfo initialization\n");
 
 	l.os_info = os_info_get();
+	if (l.os_info)
+		l.vm_info = vm_info_get();
 
 	if (l.os_info && l.os_info->entry[OS_INFO_VMCOREINFO].size) {
 		util_log_print(UTIL_LOG_DEBUG, "DFI found valid osinfo\n");
@@ -157,6 +206,7 @@ static int vmcoreinfo_item_ulong(unsigned long *val, const char *fmt,
 	int rc;
 
 	rc = vmcoreinfo_item(str, sizeof(str), fmt, sym);
+	util_log_print(UTIL_LOG_DEBUG, "DFI vmcoreinfo symbol %s : %s\n", sym, str);
 	if (rc)
 		return rc;
 	*val = strtoul(str, NULL, base);

zdump/dfi_vmcoreinfo.h

@@ -16,5 +16,6 @@ int dfi_vmcoreinfo_offset(unsigned long *offs, const char *sym);
 int dfi_vmcoreinfo_size(unsigned long *size, const char *sym);
 int dfi_vmcoreinfo_length(unsigned long *len, const char *sym);
 int dfi_vmcoreinfo_val(unsigned long *val, const char *sym);
+u64 dfi_vm_vtop(u64 vaddr);
 
 #endif /* DFI_VMCOREINFO_H */