diff --git a/include/asm-ia64/pal.h b/include/asm-ia64/pal.h
index 5dd477f..2303a10 100644
--- a/include/asm-ia64/pal.h
+++ b/include/asm-ia64/pal.h
@@ -67,6 +67,7 @@
 #define PAL_REGISTER_INFO	39	/* return AR and CR register information*/
 #define PAL_SHUTDOWN		40	/* enter processor shutdown state */
 #define PAL_PREFETCH_VISIBILITY	41	/* Make Processor Prefetches Visible */
+#define PAL_LOGICAL_TO_PHYSICAL 42	/* returns information on logical to physical processor mapping */
 
 #define PAL_COPY_PAL		256	/* relocate PAL procedures and PAL PMI */
 #define PAL_HALT_INFO		257	/* return the low power capabilities of processor */
@@ -1559,6 +1560,73 @@
 	return iprv.status;
 }
 
+/* data structure for getting information on logical to physical mappings */
+typedef union pal_log_overview_u {
+	struct {
+		u64	num_log		:16,	/* Total number of logical
+						 * processors on this die
+						 */
+			tpc		:8,	/* Threads per core */
+			reserved3	:8,	/* Reserved */
+			cpp		:8,	/* Cores per processor */
+			reserved2	:8,	/* Reserved */
+			ppid		:8,	/* Physical processor ID */
+			reserved1	:8;	/* Reserved */
+	} overview_bits;
+	u64 overview_data;
+} pal_log_overview_t;
+
+typedef union pal_proc_n_log_info1_u{
+	struct {
+		u64	tid		:16,	/* Thread id */
+			reserved2	:16,	/* Reserved */
+			cid		:16,	/* Core id */
+			reserved1	:16;	/* Reserved */
+	} ppli1_bits;
+	u64	ppli1_data;
+} pal_proc_n_log_info1_t;
+
+typedef union pal_proc_n_log_info2_u {
+	struct {
+		u64	la		:16,	/* Logical address */
+			reserved	:48;	/* Reserved */
+	} ppli2_bits;
+	u64	ppli2_data;
+} pal_proc_n_log_info2_t;
+
+typedef struct pal_logical_to_physical_s
+{
+	pal_log_overview_t overview;
+	pal_proc_n_log_info1_t ppli1;
+	pal_proc_n_log_info2_t ppli2;
+} pal_logical_to_physical_t;
+
+#define overview_num_log	overview.overview_bits.num_log
+#define overview_tpc		overview.overview_bits.tpc
+#define overview_cpp		overview.overview_bits.cpp
+#define overview_ppid		overview.overview_bits.ppid
+#define log1_tid		ppli1.ppli1_bits.tid
+#define log1_cid		ppli1.ppli1_bits.cid
+#define log2_la			ppli2.ppli2_bits.la
+
+/* Get information on logical to physical processor mappings. */
+static inline s64
+ia64_pal_logical_to_phys(u64 proc_number, pal_logical_to_physical_t *mapping)
+{
+	struct ia64_pal_retval iprv;
+
+	PAL_CALL(iprv, PAL_LOGICAL_TO_PHYSICAL, proc_number, 0, 0);
+
+	if (iprv.status == PAL_STATUS_SUCCESS)
+	{
+		if (proc_number == 0)
+			mapping->overview.overview_data = iprv.v0;
+		mapping->ppli1.ppli1_data = iprv.v1;
+		mapping->ppli2.ppli2_data = iprv.v2;
+	}
+
+	return iprv.status;
+}
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_IA64_PAL_H */