diff options
Diffstat (limited to 'arch/riscv/kernel/traps_misaligned.c')
| -rw-r--r-- | arch/riscv/kernel/traps_misaligned.c | 116 |
1 files changed, 102 insertions, 14 deletions
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index 77c788660223..dd8e4af6583f 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -16,6 +16,7 @@ #include <asm/entry-common.h> #include <asm/hwprobe.h> #include <asm/cpufeature.h> +#include <asm/sbi.h> #include <asm/vector.h> #define INSN_MATCH_LB 0x3 @@ -368,9 +369,7 @@ static int handle_scalar_misaligned_load(struct pt_regs *regs) perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); -#ifdef CONFIG_RISCV_PROBE_UNALIGNED_ACCESS *this_cpu_ptr(&misaligned_access_speed) = RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED; -#endif if (!unaligned_enabled) return -1; @@ -455,7 +454,7 @@ static int handle_scalar_misaligned_load(struct pt_regs *regs) val.data_u64 = 0; if (user_mode(regs)) { - if (copy_from_user(&val, (u8 __user *)addr, len)) + if (copy_from_user_nofault(&val, (u8 __user *)addr, len)) return -1; } else { memcpy(&val, (u8 *)addr, len); @@ -556,7 +555,7 @@ static int handle_scalar_misaligned_store(struct pt_regs *regs) return -EOPNOTSUPP; if (user_mode(regs)) { - if (copy_to_user((u8 __user *)addr, &val, len)) + if (copy_to_user_nofault((u8 __user *)addr, &val, len)) return -1; } else { memcpy((u8 *)addr, &val, len); @@ -626,6 +625,10 @@ bool __init check_vector_unaligned_access_emulated_all_cpus(void) { int cpu; + /* + * While being documented as very slow, schedule_on_each_cpu() is used since + * kernel_vector_begin() expects irqs to be enabled or it will panic() + */ schedule_on_each_cpu(check_vector_unaligned_access_emulated); for_each_online_cpu(cpu) @@ -642,11 +645,23 @@ bool __init check_vector_unaligned_access_emulated_all_cpus(void) } #endif +static bool all_cpus_unaligned_scalar_access_emulated(void) +{ + int cpu; + + for_each_online_cpu(cpu) + if (per_cpu(misaligned_access_speed, cpu) != + RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED) + return false; + + return true; +} + #ifdef CONFIG_RISCV_SCALAR_MISALIGNED static bool unaligned_ctl __read_mostly; -void check_unaligned_access_emulated(struct work_struct *work __always_unused) +static void check_unaligned_access_emulated(void *arg __always_unused) { int cpu = smp_processor_id(); long *mas_ptr = per_cpu_ptr(&misaligned_access_speed, cpu); @@ -657,6 +672,13 @@ void check_unaligned_access_emulated(struct work_struct *work __always_unused) __asm__ __volatile__ ( " "REG_L" %[tmp], 1(%[ptr])\n" : [tmp] "=r" (tmp_val) : [ptr] "r" (&tmp_var) : "memory"); +} + +static int cpu_online_check_unaligned_access_emulated(unsigned int cpu) +{ + long *mas_ptr = per_cpu_ptr(&misaligned_access_speed, cpu); + + check_unaligned_access_emulated(NULL); /* * If unaligned_ctl is already set, this means that we detected that all @@ -665,26 +687,23 @@ void check_unaligned_access_emulated(struct work_struct *work __always_unused) */ if (unlikely(unaligned_ctl && (*mas_ptr != RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED))) { pr_crit("CPU misaligned accesses non homogeneous (expected all emulated)\n"); - while (true) - cpu_relax(); + return -EINVAL; } + + return 0; } bool __init check_unaligned_access_emulated_all_cpus(void) { - int cpu; - /* * We can only support PR_UNALIGN controls if all CPUs have misaligned * accesses emulated since tasks requesting such control can run on any * CPU. */ - schedule_on_each_cpu(check_unaligned_access_emulated); + on_each_cpu(check_unaligned_access_emulated, NULL, 1); - for_each_online_cpu(cpu) - if (per_cpu(misaligned_access_speed, cpu) - != RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED) - return false; + if (!all_cpus_unaligned_scalar_access_emulated()) + return false; unaligned_ctl = true; return true; @@ -699,4 +718,73 @@ bool __init check_unaligned_access_emulated_all_cpus(void) { return false; } +static int cpu_online_check_unaligned_access_emulated(unsigned int cpu) +{ + return 0; +} +#endif + +static bool misaligned_traps_delegated; + +#ifdef CONFIG_RISCV_SBI + +static int cpu_online_sbi_unaligned_setup(unsigned int cpu) +{ + if (sbi_fwft_set(SBI_FWFT_MISALIGNED_EXC_DELEG, 1, 0) && + misaligned_traps_delegated) { + pr_crit("Misaligned trap delegation non homogeneous (expected delegated)"); + return -EINVAL; + } + + return 0; +} + +void __init unaligned_access_init(void) +{ + int ret; + + ret = sbi_fwft_set_online_cpus(SBI_FWFT_MISALIGNED_EXC_DELEG, 1, 0); + if (ret) + return; + + misaligned_traps_delegated = true; + pr_info("SBI misaligned access exception delegation ok\n"); + /* + * Note that we don't have to take any specific action here, if + * the delegation is successful, then + * check_unaligned_access_emulated() will verify that indeed the + * platform traps on misaligned accesses. + */ +} +#else +void __init unaligned_access_init(void) {} + +static int cpu_online_sbi_unaligned_setup(unsigned int cpu __always_unused) +{ + return 0; +} + #endif + +int cpu_online_unaligned_access_init(unsigned int cpu) +{ + int ret; + + ret = cpu_online_sbi_unaligned_setup(cpu); + if (ret) + return ret; + + return cpu_online_check_unaligned_access_emulated(cpu); +} + +bool misaligned_traps_can_delegate(void) +{ + /* + * Either we successfully requested misaligned traps delegation for all + * CPUs, or the SBI does not implement the FWFT extension but delegated + * the exception by default. + */ + return misaligned_traps_delegated || + all_cpus_unaligned_scalar_access_emulated(); +} +EXPORT_SYMBOL_GPL(misaligned_traps_can_delegate); 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