s390: add zEC12 code generation support

Allow to generate code that only runs on zEC12 machines.

Also add a check which prevents the kernel to run on machines which
do not have any of the following new facilities installed:

- (48) decimal-floating-point zoned-conversion
- (49) execution-hint
- (49) load-and-trap
- (49) miscellaneous-instruction-extensions
- (49) processor-assist
- (50) constrained transactional-execution
- (73) transactional-execution

48, 49, 50 and 73 are the bit numbers of the facility indications for
each of the required facilities.

Note that we assume that user-space gets compiled with the same
compiler options, therefore we also test for a dfp facility even
if the kernel doesn't make use of it.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

arch/s390/Kconfig

@@ -169,6 +169,10 @@ config HAVE_MARCH_Z196_FEATURES
 	def_bool n
 	select HAVE_MARCH_Z10_FEATURES
 
+config HAVE_MARCH_ZEC12_FEATURES
+	def_bool n
+	select HAVE_MARCH_Z196_FEATURES
+
 choice
 	prompt "Processor type"
 	default MARCH_G5
@@ -220,6 +224,13 @@ config MARCH_Z196
 	  (2818 and 2817 series). The kernel will be slightly faster but will
 	  not work on older machines.
 
+config MARCH_ZEC12
+	bool "IBM zEC12"
+	select HAVE_MARCH_ZEC12_FEATURES if 64BIT
+	help
+	  Select this to enable optimizations for IBM zEC12 (2827 series). The
+	  kernel will be slightly faster but will not work on older machines.
+
 endchoice
 
 config 64BIT

arch/s390/Makefile

@@ -41,6 +41,7 @@ cflags-$(CONFIG_MARCH_Z990) += $(call cc-option,-march=z990)
 cflags-$(CONFIG_MARCH_Z9_109) += $(call cc-option,-march=z9-109)
 cflags-$(CONFIG_MARCH_Z10) += $(call cc-option,-march=z10)
 cflags-$(CONFIG_MARCH_Z196) += $(call cc-option,-march=z196)
+cflags-$(CONFIG_MARCH_ZEC12) += $(call cc-option,-march=zEC12)
 
 #KBUILD_IMAGE is necessary for make rpm
 KBUILD_IMAGE	:=arch/s390/boot/image

arch/s390/kernel/head.S

@@ -393,64 +393,78 @@ ENTRY(startup_kdump)
 	xc	0x300(256),0x300
 	xc	0xe00(256),0xe00
 	stck	__LC_LAST_UPDATE_CLOCK
-	spt	5f-.LPG0(%r13)
-	mvc	__LC_LAST_UPDATE_TIMER(8),5f-.LPG0(%r13)
+	spt	6f-.LPG0(%r13)
+	mvc	__LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)
 	xc	__LC_STFL_FAC_LIST(8),__LC_STFL_FAC_LIST
 #ifndef CONFIG_MARCH_G5
 	# check capabilities against MARCH_{G5,Z900,Z990,Z9_109,Z10}
 	.insn	s,0xb2b10000,__LC_STFL_FAC_LIST	# store facility list
 	tm	__LC_STFL_FAC_LIST,0x01	# stfle available ?
 	jz	0f
-	la	%r0,0
+	la	%r0,1
 	.insn	s,0xb2b00000,__LC_STFL_FAC_LIST	# store facility list extended
-0:	l	%r0,__LC_STFL_FAC_LIST
-	n	%r0,2f+8-.LPG0(%r13)
-	cl	%r0,2f+8-.LPG0(%r13)
-	jne	1f
-	l	%r0,__LC_STFL_FAC_LIST+4
-	n	%r0,2f+12-.LPG0(%r13)
-	cl	%r0,2f+12-.LPG0(%r13)
-	je	3f
-1:	l	%r15,.Lstack-.LPG0(%r13)
+	# verify if all required facilities are supported by the machine
+0:	la	%r1,__LC_STFL_FAC_LIST
+	la	%r2,3f+8-.LPG0(%r13)
+	l	%r3,0(%r2)
+1:	l	%r0,0(%r1)
+	n	%r0,4(%r2)
+	cl	%r0,4(%r2)
+	jne	2f
+	la	%r1,4(%r1)
+	la	%r2,4(%r2)
+	ahi	%r3,-1
+	jnz	1b
+	j	4f
+2:	l	%r15,.Lstack-.LPG0(%r13)
 	ahi	%r15,-96
 	la	%r2,.Lals_string-.LPG0(%r13)
 	l	%r3,.Lsclp_print-.LPG0(%r13)
 	basr	%r14,%r3
-	lpsw	2f-.LPG0(%r13)		# machine type not good enough, crash
+	lpsw	3f-.LPG0(%r13)		# machine type not good enough, crash
 .Lals_string:
 	.asciz	"The Linux kernel requires more recent processor hardware"
 .Lsclp_print:
 	.long	_sclp_print_early
 .Lstack:
 	.long	0x8000 + (1<<(PAGE_SHIFT+THREAD_ORDER))
 	.align 16
-2:	.long	0x000a0000,0x8badcccc
+3:	.long	0x000a0000,0x8badcccc
+
+# List of facilities that are required. If not all facilities are present
+# the kernel will crash. Format is number of facility words with bits set,
+# followed by the facility words.
+
 #if defined(CONFIG_64BIT)
-#if defined(CONFIG_MARCH_Z196)
-	.long 0xc100efe3, 0xf46c0000
+#if defined(CONFIG_MARCH_ZEC12)
+	.long 3, 0xc100efe3, 0xf46ce000, 0x00400000
+#elif defined(CONFIG_MARCH_Z196)
+	.long 2, 0xc100efe3, 0xf46c0000
 #elif defined(CONFIG_MARCH_Z10)
-	.long 0xc100efe3, 0xf0680000
+	.long 2, 0xc100efe3, 0xf0680000
 #elif defined(CONFIG_MARCH_Z9_109)
-	.long 0xc100efc3, 0x00000000
+	.long 1, 0xc100efc3
 #elif defined(CONFIG_MARCH_Z990)
-	.long 0xc0002000, 0x00000000
+	.long 1, 0xc0002000
 #elif defined(CONFIG_MARCH_Z900)
-	.long 0xc0000000, 0x00000000
+	.long 1, 0xc0000000
 #endif
 #else
-#if defined(CONFIG_MARCH_Z196)
-	.long 0x8100c880, 0x00000000
+#if defined(CONFIG_MARCH_ZEC12)
+	.long 1, 0x8100c880
+#elif defined(CONFIG_MARCH_Z196)
+	.long 1, 0x8100c880
 #elif defined(CONFIG_MARCH_Z10)
-	.long 0x8100c880, 0x00000000
+	.long 1, 0x8100c880
 #elif defined(CONFIG_MARCH_Z9_109)
-	.long 0x8100c880, 0x00000000
+	.long 1, 0x8100c880
 #elif defined(CONFIG_MARCH_Z990)
-	.long 0x80002000, 0x00000000
+	.long 1, 0x80002000
 #elif defined(CONFIG_MARCH_Z900)
-	.long 0x80000000, 0x00000000
+	.long 1, 0x80000000
 #endif
 #endif
-3:
+4:
 #endif
 
 #ifdef CONFIG_64BIT
@@ -459,14 +473,14 @@ ENTRY(startup_kdump)
 	jg	startup_continue
 #else
 	/* Continue with 31bit startup code in head31.S */
-	l	%r13,4f-.LPG0(%r13)
+	l	%r13,5f-.LPG0(%r13)
 	b	0(%r13)
 	.align	8
-4:	.long	startup_continue
+5:	.long	startup_continue
 #endif
 
 	.align	8
-5:	.long	0x7fffffff,0xffffffff
+6:	.long	0x7fffffff,0xffffffff
 
 #include "head_kdump.S"
 

arch/s390/kernel/setup.c

@@ -1006,6 +1006,9 @@ static void __init setup_hwcaps(void)
 	case 0x2818:
 		strcpy(elf_platform, "z196");
 		break;
+	case 0x2827:
+		strcpy(elf_platform, "zEC12");
+		break;
 	}
 }