[S390] add hardware capability support (ELF_HWCAP).

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 120 insertions, 6 deletions

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 82b7fe32d86c..6bfb0889eb10 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -74,6 +74,8 @@ unsigned int console_mode = 0;
 unsigned int console_devno = -1;
 unsigned int console_irq = -1;
 unsigned long machine_flags = 0;
+unsigned long elf_hwcap = 0;
+char elf_platform[ELF_PLATFORM_SIZE];
 
 struct mem_chunk __initdata memory_chunk[MEMORY_CHUNKS];
 volatile int __cpu_logical_map[NR_CPUS]; /* logical cpu to cpu address */
@@ -749,6 +751,98 @@ setup_memory(void)
 #endif
 }
 
+static __init unsigned int stfl(void)
+{
+        asm volatile(
+                "       .insn   s,0xb2b10000,0(0)\n" /* stfl */
+                "0:\n"
+                EX_TABLE(0b,0b));
+        return S390_lowcore.stfl_fac_list;
+}
+
+static __init int stfle(unsigned long long *list, int doublewords)
+{
+        typedef struct { unsigned long long _[doublewords]; } addrtype;
+        register unsigned long __nr asm("0") = doublewords - 1;
+
+        asm volatile(".insn s,0xb2b00000,%0" /* stfle */
+                     : "=m" (*(addrtype *) list), "+d" (__nr) : : "cc");
+        return __nr + 1;
+}
+
+/*
+ * Setup hardware capabilities.
+ */
+static void __init setup_hwcaps(void)
+{
+        static const int stfl_bits[6] = { 0, 2, 7, 17, 19, 21 };
+        struct cpuinfo_S390 *cpuinfo = &S390_lowcore.cpu_data;
+        unsigned long long facility_list_extended;
+        unsigned int facility_list;
+        int i;
+
+        facility_list = stfl();
+        /*
+         * The store facility list bits numbers as found in the principles
+         * of operation are numbered with bit 1UL<<31 as number 0 to
+         * bit 1UL<<0 as number 31.
+         *   Bit 0: instructions named N3, "backported" to esa-mode
+         *   Bit 2: z/Architecture mode is active
+         *   Bit 7: the store-facility-list-extended facility is installed
+         *   Bit 17: the message-security assist is installed
+         *   Bit 19: the long-displacement facility is installed
+         *   Bit 21: the extended-immediate facility is installed
+         * These get translated to:
+         *   HWCAP_S390_ESAN3 bit 0, HWCAP_S390_ZARCH bit 1,
+         *   HWCAP_S390_STFLE bit 2, HWCAP_S390_MSA bit 3,
+         *   HWCAP_S390_LDISP bit 4, and HWCAP_S390_EIMM bit 5.
+         */
+        for (i = 0; i < 6; i++)
+                if (facility_list & (1UL << (31 - stfl_bits[i])))
+                        elf_hwcap |= 1UL << i;
+
+        /*
+         * Check for additional facilities with store-facility-list-extended.
+         * stfle stores doublewords (8 byte) with bit 1ULL<<63 as bit 0
+         * and 1ULL<<0 as bit 63. Bits 0-31 contain the same information
+         * as stored by stfl, bits 32-xxx contain additional facilities.
+         * How many facility words are stored depends on the number of
+         * doublewords passed to the instruction. The additional facilites
+         * are:
+         *   Bit 43: decimal floating point facility is installed
+         * translated to:
+         *   HWCAP_S390_DFP bit 6.
+         */
+        if ((elf_hwcap & (1UL << 2)) &&
+            stfle(&facility_list_extended, 1) > 0) {
+                if (facility_list_extended & (1ULL << (64 - 43)))
+                        elf_hwcap |= 1UL << 6;
+        }
+
+        switch (cpuinfo->cpu_id.machine) {
+        case 0x9672:
+#if !defined(CONFIG_64BIT)
+        default:        /* Use "g5" as default for 31 bit kernels. */
+#endif
+                strcpy(elf_platform, "g5");
+                break;
+        case 0x2064:
+        case 0x2066:
+#if defined(CONFIG_64BIT)
+        default:        /* Use "z900" as default for 64 bit kernels. */
+#endif
+                strcpy(elf_platform, "z900");
+                break;
+        case 0x2084:
+        case 0x2086:
+                strcpy(elf_platform, "z990");
+                break;
+        case 0x2094:
+                strcpy(elf_platform, "z9-109");
+                break;
+        }
+}
+
 /*
  * Setup function called from init/main.c just after the banner
  * was printed.
@@ -805,6 +899,11 @@ setup_arch(char **cmdline_p)
         smp_setup_cpu_possible_map();
 
         /*
+         * Setup capabilities (ELF_HWCAP & ELF_PLATFORM).
+         */
+        setup_hwcaps();
+
+        /*
          * Create kernel page tables and switch to virtual addressing.
          */
         paging_init();
@@ -839,8 +938,12 @@ void print_cpu_info(struct cpuinfo_S390 *cpuinfo)
 
 static int show_cpuinfo(struct seq_file *m, void *v)
 {
+        static const char *hwcap_str[7] = {
+                "esan3", "zarch", "stfle", "msa", "ldisp", "eimm", "dfp"
+        };
         struct cpuinfo_S390 *cpuinfo;
         unsigned long n = (unsigned long) v - 1;
+        int i;
 
         s390_adjust_jiffies();
         preempt_disable();
@@ -850,7 +953,13 @@ static int show_cpuinfo(struct seq_file *m, void *v)
                                "bogomips per cpu: %lu.%02lu\n",
                                num_online_cpus(), loops_per_jiffy/(500000/HZ),
                                (loops_per_jiffy/(5000/HZ))%100);
+                seq_puts(m, "features\t: ");
+                for (i = 0; i < 7; i++)
+                        if (hwcap_str[i] && (elf_hwcap & (1UL << i)))
+                                seq_printf(m, "%s ", hwcap_str[i]);
+                seq_puts(m, "\n");
         }
+
         if (cpu_online(n)) {
 #ifdef CONFIG_SMP
                 if (smp_processor_id() == n)
diff --git a/include/asm-s390/elf.h b/include/asm-s390/elf.h
index c0d629d61d3e..91d06325cc79 100644
--- a/include/asm-s390/elf.h
+++ b/include/asm-s390/elf.h
@@ -188,7 +188,8 @@ static inline int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 /* This yields a mask that user programs can use to figure out what
    instruction set this CPU supports. */
 
-#define ELF_HWCAP (0)
+extern unsigned long elf_hwcap;
+#define ELF_HWCAP (elf_hwcap)
 
 /* This yields a string that ld.so will use to load implementation
    specific libraries for optimization.  This is more specific in
@@ -197,7 +198,9 @@ static inline int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
    For the moment, we have only optimizations for the Intel generations,
    but that could change... */
 
-#define ELF_PLATFORM (NULL)
+#define ELF_PLATFORM_SIZE 8
+extern char elf_platform[];
+#define ELF_PLATFORM (elf_platform)
 
 #ifndef __s390x__
 #define SET_PERSONALITY(ex, ibcs2) set_personality((ibcs2)?PER_SVR4:PER_LINUX)
diff --git a/include/asm-s390/lowcore.h b/include/asm-s390/lowcore.h
index ffc9788a21a7..801a6fd35b5b 100644
--- a/include/asm-s390/lowcore.h
+++ b/include/asm-s390/lowcore.h
@@ -229,17 +229,19 @@ struct _lowcore
         __u16        subchannel_nr;            /* 0x0ba */
         __u32        io_int_parm;              /* 0x0bc */
         __u32        io_int_word;              /* 0x0c0 */
-        __u8         pad3[0xD4-0xC4];          /* 0x0c4 */
+        __u8         pad3[0xc8-0xc4];          /* 0x0c4 */
+        __u32        stfl_fac_list;            /* 0x0c8 */
+        __u8         pad4[0xd4-0xcc];          /* 0x0cc */
         __u32        extended_save_area_addr;  /* 0x0d4 */
         __u32        cpu_timer_save_area[2];   /* 0x0d8 */
         __u32        clock_comp_save_area[2];  /* 0x0e0 */
         __u32        mcck_interruption_code[2]; /* 0x0e8 */
-        __u8         pad4[0xf4-0xf0];          /* 0x0f0 */
+        __u8         pad5[0xf4-0xf0];          /* 0x0f0 */
         __u32        external_damage_code;     /* 0x0f4 */
         __u32        failing_storage_address;  /* 0x0f8 */
-        __u8         pad5[0x100-0xfc];         /* 0x0fc */
+        __u8         pad6[0x100-0xfc];         /* 0x0fc */
         __u32        st_status_fixed_logout[4];/* 0x100 */
-        __u8         pad6[0x120-0x110];        /* 0x110 */
+        __u8         pad7[0x120-0x110];        /* 0x110 */
         __u32        access_regs_save_area[16];/* 0x120 */
         __u32        floating_pt_save_area[8]; /* 0x160 */
         __u32        gpregs_save_area[16];     /* 0x180 */