diff options
Diffstat (limited to 'arch/arm/kernel/setup.c')
| -rw-r--r-- | arch/arm/kernel/setup.c | 82 |
1 files changed, 81 insertions, 1 deletions
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 1c8278de6c46..9b653278c9e8 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -367,7 +367,7 @@ void __init early_print(const char *str, ...) static void __init cpuid_init_hwcaps(void) { - unsigned int divide_instrs; + unsigned int divide_instrs, vmsa; if (cpu_architecture() < CPU_ARCH_ARMv7) return; @@ -380,6 +380,11 @@ static void __init cpuid_init_hwcaps(void) case 1: elf_hwcap |= HWCAP_IDIVT; } + + /* LPAE implies atomic ldrd/strd instructions */ + vmsa = (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xf) >> 0; + if (vmsa >= 5) + elf_hwcap |= HWCAP_LPAE; } static void __init feat_v6_fixup(void) @@ -470,9 +475,82 @@ void __init smp_setup_processor_id(void) for (i = 1; i < nr_cpu_ids; ++i) cpu_logical_map(i) = i == cpu ? 0 : i; + /* + * clear __my_cpu_offset on boot CPU to avoid hang caused by + * using percpu variable early, for example, lockdep will + * access percpu variable inside lock_release + */ + set_my_cpu_offset(0); + printk(KERN_INFO "Booting Linux on physical CPU 0x%x\n", mpidr); } +struct mpidr_hash mpidr_hash; +#ifdef CONFIG_SMP +/** + * smp_build_mpidr_hash - Pre-compute shifts required at each affinity + * level in order to build a linear index from an + * MPIDR value. Resulting algorithm is a collision + * free hash carried out through shifting and ORing + */ +static void __init smp_build_mpidr_hash(void) +{ + u32 i, affinity; + u32 fs[3], bits[3], ls, mask = 0; + /* + * Pre-scan the list of MPIDRS and filter out bits that do + * not contribute to affinity levels, ie they never toggle. + */ + for_each_possible_cpu(i) + mask |= (cpu_logical_map(i) ^ cpu_logical_map(0)); + pr_debug("mask of set bits 0x%x\n", mask); + /* + * Find and stash the last and first bit set at all affinity levels to + * check how many bits are required to represent them. + */ + for (i = 0; i < 3; i++) { + affinity = MPIDR_AFFINITY_LEVEL(mask, i); + /* + * Find the MSB bit and LSB bits position + * to determine how many bits are required + * to express the affinity level. + */ + ls = fls(affinity); + fs[i] = affinity ? ffs(affinity) - 1 : 0; + bits[i] = ls - fs[i]; + } + /* + * An index can be created from the MPIDR by isolating the + * significant bits at each affinity level and by shifting + * them in order to compress the 24 bits values space to a + * compressed set of values. This is equivalent to hashing + * the MPIDR through shifting and ORing. It is a collision free + * hash though not minimal since some levels might contain a number + * of CPUs that is not an exact power of 2 and their bit + * representation might contain holes, eg MPIDR[7:0] = {0x2, 0x80}. + */ + mpidr_hash.shift_aff[0] = fs[0]; + mpidr_hash.shift_aff[1] = MPIDR_LEVEL_BITS + fs[1] - bits[0]; + mpidr_hash.shift_aff[2] = 2*MPIDR_LEVEL_BITS + fs[2] - + (bits[1] + bits[0]); + mpidr_hash.mask = mask; + mpidr_hash.bits = bits[2] + bits[1] + bits[0]; + pr_debug("MPIDR hash: aff0[%u] aff1[%u] aff2[%u] mask[0x%x] bits[%u]\n", + mpidr_hash.shift_aff[0], + mpidr_hash.shift_aff[1], + mpidr_hash.shift_aff[2], + mpidr_hash.mask, + mpidr_hash.bits); + /* + * 4x is an arbitrary value used to warn on a hash table much bigger + * than expected on most systems. + */ + if (mpidr_hash_size() > 4 * num_possible_cpus()) + pr_warn("Large number of MPIDR hash buckets detected\n"); + sync_cache_w(&mpidr_hash); +} +#endif + static void __init setup_processor(void) { struct proc_info_list *list; @@ -820,6 +898,7 @@ void __init setup_arch(char **cmdline_p) smp_set_ops(mdesc->smp); } smp_init_cpus(); + smp_build_mpidr_hash(); } #endif @@ -892,6 +971,7 @@ static const char *hwcap_str[] = { "vfpv4", "idiva", "idivt", + "lpae", NULL }; |