According to the "Intel 64 and IA-32 Architectures Software Developer's Manual", CPUID.80000001H:EDX.Page1GB [bit 26] indicates whether 1-GByte pages are supported with IA-32e paging.
I think the diff below adds support for identifying this feature in dmesg, but my X201s is seemingly to old to support it. ok? Index: amd64/include/specialreg.h =================================================================== RCS file: /home/matthew/anoncvs/cvs/src/sys/arch/amd64/include/specialreg.h,v retrieving revision 1.27 diff -w -u -p -r1.27 specialreg.h --- amd64/include/specialreg.h 24 Aug 2013 04:26:16 -0000 1.27 +++ amd64/include/specialreg.h 3 Jul 2014 05:17:18 -0000 @@ -207,6 +207,7 @@ #define CPUID_NXE 0x00100000 /* No-Execute Extension */ #define CPUID_MMXX 0x00400000 /* AMD MMX Extensions */ #define CPUID_FFXSR 0x02000000 /* fast FP/MMX save/restore */ +#define CPUID_PAGE1GB 0x04000000 /* 1-GByte pages */ #define CPUID_LONG 0x20000000 /* long mode */ #define CPUID_3DNOW2 0x40000000 /* 3DNow! Instruction Extension */ #define CPUID_3DNOW 0x80000000 /* 3DNow! Instructions */ Index: amd64/amd64/identcpu.c =================================================================== RCS file: /home/matthew/anoncvs/cvs/src/sys/arch/amd64/amd64/identcpu.c,v retrieving revision 1.52 diff -w -u -p -r1.52 identcpu.c --- amd64/amd64/identcpu.c 19 Nov 2013 04:12:17 -0000 1.52 +++ amd64/amd64/identcpu.c 3 Jul 2014 05:19:54 -0000 @@ -96,6 +96,7 @@ const struct { { CPUID_NXE, "NXE" }, { CPUID_MMXX, "MMXX" }, { CPUID_FFXSR, "FFXSR" }, + { CPUID_PAGE1GB, "PAGE1GB" }, { CPUID_LONG, "LONG" }, { CPUID_3DNOW2, "3DNOW2" }, { CPUID_3DNOW, "3DNOW" } Index: i386/include/specialreg.h =================================================================== RCS file: /home/matthew/anoncvs/cvs/src/sys/arch/i386/include/specialreg.h,v retrieving revision 1.46 diff -w -u -p -r1.46 specialreg.h --- i386/include/specialreg.h 24 Aug 2013 04:26:16 -0000 1.46 +++ i386/include/specialreg.h 3 Jul 2014 05:20:23 -0000 @@ -206,6 +206,7 @@ #define CPUID_NXE 0x00100000 /* No-Execute Extension */ #define CPUID_MMXX 0x00400000 /* AMD MMX Extensions */ #define CPUID_FFXSR 0x02000000 /* fast FP/MMX save/restore */ +#define CPUID_PAGE1GB 0x04000000 /* 1-GByte pages */ #define CPUID_LONG 0x20000000 /* long mode */ #define CPUID_3DNOW2 0x40000000 /* 3DNow! Instruction Extension */ #define CPUID_3DNOW 0x80000000 /* 3DNow! Instructions */ Index: i386/i386/machdep.c =================================================================== RCS file: /home/matthew/anoncvs/cvs/src/sys/arch/i386/i386/machdep.c,v retrieving revision 1.539 diff -w -u -p -r1.539 machdep.c --- i386/i386/machdep.c 15 Jun 2014 11:43:24 -0000 1.539 +++ i386/i386/machdep.c 3 Jul 2014 05:20:56 -0000 @@ -1001,6 +1001,7 @@ const struct cpu_cpuid_feature i386_ecpu { CPUID_NXE, "NXE" }, { CPUID_MMXX, "MMXX" }, { CPUID_FFXSR, "FFXSR" }, + { CPUID_PAGE1GB, "PAGE1GB" }, { CPUID_LONG, "LONG" }, { CPUID_3DNOW2, "3DNOW2" }, { CPUID_3DNOW, "3DNOW" }