diff options
Diffstat (limited to 'arch/riscv/kernel/cpufeature.c')
| -rw-r--r-- | arch/riscv/kernel/cpufeature.c | 115 |
1 files changed, 93 insertions, 22 deletions
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index e12cd22755..b3785ffc15 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -8,6 +8,7 @@ #include <linux/acpi.h> #include <linux/bitmap.h> +#include <linux/cpuhotplug.h> #include <linux/ctype.h> #include <linux/log2.h> #include <linux/memory.h> @@ -29,6 +30,7 @@ #define MISALIGNED_ACCESS_JIFFIES_LG2 1 #define MISALIGNED_BUFFER_SIZE 0x4000 +#define MISALIGNED_BUFFER_ORDER get_order(MISALIGNED_BUFFER_SIZE) #define MISALIGNED_COPY_SIZE ((MISALIGNED_BUFFER_SIZE / 2) - 0x80) unsigned long elf_hwcap __read_mostly; @@ -93,10 +95,10 @@ static bool riscv_isa_extension_check(int id) return true; case RISCV_ISA_EXT_ZICBOZ: if (!riscv_cboz_block_size) { - pr_err("Zicboz detected in ISA string, but no cboz-block-size found\n"); + pr_err("Zicboz detected in ISA string, disabling as no cboz-block-size found\n"); return false; } else if (!is_power_of_2(riscv_cboz_block_size)) { - pr_err("cboz-block-size present, but is not a power-of-2\n"); + pr_err("Zicboz disabled as cboz-block-size present, but is not a power-of-2\n"); return false; } return true; @@ -167,6 +169,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = { __RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM), __RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ), __RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR), + __RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND), __RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR), __RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI), __RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE), @@ -175,6 +178,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = { __RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB), __RISCV_ISA_EXT_DATA(zbs, RISCV_ISA_EXT_ZBS), __RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA), + __RISCV_ISA_EXT_DATA(smstateen, RISCV_ISA_EXT_SMSTATEEN), __RISCV_ISA_EXT_DATA(ssaia, RISCV_ISA_EXT_SSAIA), __RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF), __RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC), @@ -204,10 +208,11 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc switch (*ext) { case 's': /* - * Workaround for invalid single-letter 's' & 'u'(QEMU). + * Workaround for invalid single-letter 's' & 'u' (QEMU). * No need to set the bit in riscv_isa as 's' & 'u' are - * not valid ISA extensions. It works until multi-letter - * extension starting with "Su" appears. + * not valid ISA extensions. It works unless the first + * multi-letter extension in the ISA string begins with + * "Su" and is not prefixed with an underscore. */ if (ext[-1] != '_' && ext[1] == 'u') { ++isa; @@ -556,27 +561,21 @@ unsigned long riscv_get_elf_hwcap(void) return hwcap; } -void check_unaligned_access(int cpu) +static int check_unaligned_access(void *param) { + int cpu = smp_processor_id(); u64 start_cycles, end_cycles; u64 word_cycles; u64 byte_cycles; int ratio; unsigned long start_jiffies, now; - struct page *page; + struct page *page = param; void *dst; void *src; long speed = RISCV_HWPROBE_MISALIGNED_SLOW; - /* We are already set since the last check */ - if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN) - return; - - page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE)); - if (!page) { - pr_warn("Can't alloc pages to measure memcpy performance"); - return; - } + if (check_unaligned_access_emulated(cpu)) + return 0; /* Make an unaligned destination buffer. */ dst = (void *)((unsigned long)page_address(page) | 0x1); @@ -630,7 +629,7 @@ void check_unaligned_access(int cpu) pr_warn("cpu%d: rdtime lacks granularity needed to measure unaligned access speed\n", cpu); - goto out; + return 0; } if (word_cycles < byte_cycles) @@ -644,18 +643,90 @@ void check_unaligned_access(int cpu) (speed == RISCV_HWPROBE_MISALIGNED_FAST) ? "fast" : "slow"); per_cpu(misaligned_access_speed, cpu) = speed; + return 0; +} -out: - __free_pages(page, get_order(MISALIGNED_BUFFER_SIZE)); +static void check_unaligned_access_nonboot_cpu(void *param) +{ + unsigned int cpu = smp_processor_id(); + struct page **pages = param; + + if (smp_processor_id() != 0) + check_unaligned_access(pages[cpu]); } -static int check_unaligned_access_boot_cpu(void) +static int riscv_online_cpu(unsigned int cpu) { - check_unaligned_access(0); + static struct page *buf; + + /* We are already set since the last check */ + if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN) + return 0; + + buf = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER); + if (!buf) { + pr_warn("Allocation failure, not measuring misaligned performance\n"); + return -ENOMEM; + } + + check_unaligned_access(buf); + __free_pages(buf, MISALIGNED_BUFFER_ORDER); return 0; } -arch_initcall(check_unaligned_access_boot_cpu); +/* Measure unaligned access on all CPUs present at boot in parallel. */ +static int check_unaligned_access_all_cpus(void) +{ + unsigned int cpu; + unsigned int cpu_count = num_possible_cpus(); + struct page **bufs = kzalloc(cpu_count * sizeof(struct page *), + GFP_KERNEL); + + if (!bufs) { + pr_warn("Allocation failure, not measuring misaligned performance\n"); + return 0; + } + + /* + * Allocate separate buffers for each CPU so there's no fighting over + * cache lines. + */ + for_each_cpu(cpu, cpu_online_mask) { + bufs[cpu] = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER); + if (!bufs[cpu]) { + pr_warn("Allocation failure, not measuring misaligned performance\n"); + goto out; + } + } + + /* Check everybody except 0, who stays behind to tend jiffies. */ + on_each_cpu(check_unaligned_access_nonboot_cpu, bufs, 1); + + /* Check core 0. */ + smp_call_on_cpu(0, check_unaligned_access, bufs[0], true); + + /* Setup hotplug callback for any new CPUs that come online. */ + cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online", + riscv_online_cpu, NULL); + +out: + unaligned_emulation_finish(); + for_each_cpu(cpu, cpu_online_mask) { + if (bufs[cpu]) + __free_pages(bufs[cpu], MISALIGNED_BUFFER_ORDER); + } + + kfree(bufs); + return 0; +} + +arch_initcall(check_unaligned_access_all_cpus); + +void riscv_user_isa_enable(void) +{ + if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICBOZ)) + csr_set(CSR_SENVCFG, ENVCFG_CBZE); +} #ifdef CONFIG_RISCV_ALTERNATIVE /* |