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>

4 files changed, 59 insertions, 30 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d385f396dfee..1bf4b294c6e9 100644
--- a/arch/s390/Kconfig
+++ b/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
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 49e76e8b477d..4b8e08b56f49 100644
--- a/arch/s390/Makefile
+++ b/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
diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index 984726cbce16..fd8db63dfc94 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -393,30 +393,35 @@ 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:
@@ -424,33 +429,42 @@ ENTRY(startup_kdump)
 .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"
 
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index cfdad57957fe..2568590973ad 100644
--- a/arch/s390/kernel/setup.c
+++ b/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;
         }
 }