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sparc: Sanitize cpu feature detection and reporting.
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Instead of evaluating the cpu features for ELF_HWCAP every exec,
calculate it once at boot time.

Add AV_SPARC_* capability flag bits, compatible with what Solaris
reports to applications.

Report these capabilities once in the kernel log, and also via
/proc/cpuinfo in a new "cpucaps" entry.

If available, fetch the cpu features from the machine description
'hwcap-list' property of the 'cpu' node.

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Jul 29, 2011
1 parent 55f9c40 commit ac85fe8
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Showing 4 changed files with 185 additions and 36 deletions.
65 changes: 29 additions & 36 deletions arch/sparc/include/asm/elf_64.h
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Original file line number Diff line number Diff line change
Expand Up @@ -59,15 +59,33 @@
#define R_SPARC_6 45

/* Bits present in AT_HWCAP, primarily for Sparc32. */

#define HWCAP_SPARC_FLUSH 1 /* CPU supports flush instruction. */
#define HWCAP_SPARC_STBAR 2
#define HWCAP_SPARC_SWAP 4
#define HWCAP_SPARC_MULDIV 8
#define HWCAP_SPARC_V9 16
#define HWCAP_SPARC_ULTRA3 32
#define HWCAP_SPARC_BLKINIT 64
#define HWCAP_SPARC_N2 128
#define HWCAP_SPARC_FLUSH 0x00000001
#define HWCAP_SPARC_STBAR 0x00000002
#define HWCAP_SPARC_SWAP 0x00000004
#define HWCAP_SPARC_MULDIV 0x00000008
#define HWCAP_SPARC_V9 0x00000010
#define HWCAP_SPARC_ULTRA3 0x00000020
#define HWCAP_SPARC_BLKINIT 0x00000040
#define HWCAP_SPARC_N2 0x00000080

/* Solaris compatible AT_HWCAP bits. */
#define AV_SPARC_MUL32 0x00000100 /* 32x32 multiply is efficient */
#define AV_SPARC_DIV32 0x00000200 /* 32x32 divide is efficient */
#define AV_SPARC_FSMULD 0x00000400 /* 'fsmuld' is efficient */
#define AV_SPARC_V8PLUS 0x00000800 /* v9 insn available to 32bit */
#define AV_SPARC_POPC 0x00001000 /* 'popc' is efficient */
#define AV_SPARC_VIS 0x00002000 /* VIS insns available */
#define AV_SPARC_VIS2 0x00004000 /* VIS2 insns available */
#define AV_SPARC_ASI_BLK_INIT 0x00008000 /* block init ASIs available */
#define AV_SPARC_FMAF 0x00010000 /* fused multiply-add */
#define AV_SPARC_VIS3 0x00020000 /* VIS3 insns available */
#define AV_SPARC_HPC 0x00040000 /* HPC insns available */
#define AV_SPARC_RANDOM 0x00080000 /* 'random' insn available */
#define AV_SPARC_TRANS 0x00100000 /* transaction insns available */
#define AV_SPARC_FJFMAU 0x00200000 /* unfused multiply-add */
#define AV_SPARC_IMA 0x00400000 /* integer multiply-add */
#define AV_SPARC_ASI_CACHE_SPARING \
0x00800000 /* cache sparing ASIs available */

#define CORE_DUMP_USE_REGSET

Expand Down Expand Up @@ -162,33 +180,8 @@ typedef struct {
#define ELF_ET_DYN_BASE 0x0000010000000000UL
#define COMPAT_ELF_ET_DYN_BASE 0x0000000070000000UL


/* This yields a mask that user programs can use to figure out what
instruction set this cpu supports. */

/* On Ultra, we support all of the v8 capabilities. */
static inline unsigned int sparc64_elf_hwcap(void)
{
unsigned int cap = (HWCAP_SPARC_FLUSH | HWCAP_SPARC_STBAR |
HWCAP_SPARC_SWAP | HWCAP_SPARC_MULDIV |
HWCAP_SPARC_V9);

if (tlb_type == cheetah || tlb_type == cheetah_plus)
cap |= HWCAP_SPARC_ULTRA3;
else if (tlb_type == hypervisor) {
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA1 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA3)
cap |= HWCAP_SPARC_BLKINIT;
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA3)
cap |= HWCAP_SPARC_N2;
}

return cap;
}

#define ELF_HWCAP sparc64_elf_hwcap()
extern unsigned long sparc64_elf_hwcap;
#define ELF_HWCAP sparc64_elf_hwcap

/* This yields a string that ld.so will use to load implementation
specific libraries for optimization. This is more specific in
Expand Down
1 change: 1 addition & 0 deletions arch/sparc/kernel/cpu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -396,6 +396,7 @@ static int show_cpuinfo(struct seq_file *m, void *__unused)
, cpu_data(0).clock_tick
#endif
);
cpucap_info(m);
#ifdef CONFIG_SMP
smp_bogo(m);
#endif
Expand Down
6 changes: 6 additions & 0 deletions arch/sparc/kernel/kernel.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,12 @@ extern const char *sparc_pmu_type;
extern unsigned int fsr_storage;
extern int ncpus_probed;

#ifdef CONFIG_SPARC64
/* setup_64.c */
struct seq_file;
extern void cpucap_info(struct seq_file *);
#endif

#ifdef CONFIG_SPARC32
/* cpu.c */
extern void cpu_probe(void);
Expand Down
149 changes: 149 additions & 0 deletions arch/sparc/kernel/setup_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/initrd.h>
#include <linux/module.h>

#include <asm/system.h>
#include <asm/io.h>
Expand All @@ -46,6 +47,8 @@
#include <asm/mmu.h>
#include <asm/ns87303.h>
#include <asm/btext.h>
#include <asm/elf.h>
#include <asm/mdesc.h>

#ifdef CONFIG_IP_PNP
#include <net/ipconfig.h>
Expand Down Expand Up @@ -278,6 +281,151 @@ void __init boot_cpu_id_too_large(int cpu)
}
#endif

/* On Ultra, we support all of the v8 capabilities. */
unsigned long sparc64_elf_hwcap = (HWCAP_SPARC_FLUSH | HWCAP_SPARC_STBAR |
HWCAP_SPARC_SWAP | HWCAP_SPARC_MULDIV |
HWCAP_SPARC_V9);
EXPORT_SYMBOL(sparc64_elf_hwcap);

static const char *hwcaps[] = {
"flush", "stbar", "swap", "muldiv", "v9",
"ultra3", "blkinit", "n2",

/* These strings are as they appear in the machine description
* 'hwcap-list' property for cpu nodes.
*/
"mul32", "div32", "fsmuld", "v8plus", "popc", "vis", "vis2",
"ASIBlkInit", "fmaf", "vis3", "hpc", "random", "trans", "fjfmau",
"ima", "cspare",
};

void cpucap_info(struct seq_file *m)
{
unsigned long caps = sparc64_elf_hwcap;
int i, printed = 0;

seq_puts(m, "cpucaps\t\t: ");
for (i = 0; i < ARRAY_SIZE(hwcaps); i++) {
unsigned long bit = 1UL << i;
if (caps & bit) {
seq_printf(m, "%s%s",
printed ? "," : "", hwcaps[i]);
printed++;
}
}
seq_putc(m, '\n');
}

static void __init report_hwcaps(unsigned long caps)
{
int i, printed = 0;

printk(KERN_INFO "CPU CAPS: [");
for (i = 0; i < ARRAY_SIZE(hwcaps); i++) {
unsigned long bit = 1UL << i;
if (caps & bit) {
printk(KERN_CONT "%s%s",
printed ? "," : "", hwcaps[i]);
if (++printed == 8) {
printk(KERN_CONT "]\n");
printk(KERN_INFO "CPU CAPS: [");
printed = 0;
}
}
}
printk(KERN_CONT "]\n");
}

static unsigned long __init mdesc_cpu_hwcap_list(void)
{
struct mdesc_handle *hp;
unsigned long caps = 0;
const char *prop;
int len;
u64 pn;

hp = mdesc_grab();
if (!hp)
return 0;

pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "cpu");
if (pn == MDESC_NODE_NULL)
goto out;

prop = mdesc_get_property(hp, pn, "hwcap-list", &len);
if (!prop)
goto out;

while (len) {
int i, plen;

for (i = 0; i < ARRAY_SIZE(hwcaps); i++) {
unsigned long bit = 1UL << i;

if (!strcmp(prop, hwcaps[i])) {
caps |= bit;
break;
}
}

plen = strlen(prop) + 1;
prop += plen;
len -= plen;
}

out:
mdesc_release(hp);
return caps;
}

/* This yields a mask that user programs can use to figure out what
* instruction set this cpu supports.
*/
static void __init init_sparc64_elf_hwcap(void)
{
unsigned long cap = sparc64_elf_hwcap;
unsigned long mdesc_caps;

if (tlb_type == cheetah || tlb_type == cheetah_plus)
cap |= HWCAP_SPARC_ULTRA3;
else if (tlb_type == hypervisor) {
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA1 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA3)
cap |= HWCAP_SPARC_BLKINIT;
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA3)
cap |= HWCAP_SPARC_N2;
}

cap |= (AV_SPARC_MUL32 | AV_SPARC_DIV32 | AV_SPARC_V8PLUS);

mdesc_caps = mdesc_cpu_hwcap_list();
if (!mdesc_caps) {
if (tlb_type == spitfire)
cap |= AV_SPARC_VIS;
if (tlb_type == cheetah || tlb_type == cheetah_plus)
cap |= AV_SPARC_VIS | AV_SPARC_VIS2;
if (tlb_type == cheetah_plus)
cap |= AV_SPARC_POPC;
if (tlb_type == hypervisor) {
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA1)
cap |= AV_SPARC_ASI_BLK_INIT;
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
sun4v_chip_type == SUN4V_CHIP_NIAGARA3)
cap |= (AV_SPARC_VIS | AV_SPARC_VIS2 |
AV_SPARC_ASI_BLK_INIT |
AV_SPARC_POPC);
if (sun4v_chip_type == SUN4V_CHIP_NIAGARA3)
cap |= (AV_SPARC_VIS3 | AV_SPARC_HPC |
AV_SPARC_FMAF);
}
}
sparc64_elf_hwcap = cap | mdesc_caps;

report_hwcaps(sparc64_elf_hwcap);
}

void __init setup_arch(char **cmdline_p)
{
/* Initialize PROM console and command line. */
Expand Down Expand Up @@ -337,6 +485,7 @@ void __init setup_arch(char **cmdline_p)
init_cur_cpu_trap(current_thread_info());

paging_init();
init_sparc64_elf_hwcap();
}

extern int stop_a_enabled;
Expand Down

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