1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2017 SiFive 4 */ 5 6 #include <asm/pgtable.h> 7 #include <asm/cacheflush.h> 8 9 #ifdef CONFIG_SMP 10 11 #include <asm/sbi.h> 12 13 void flush_icache_all(void) 14 { 15 sbi_remote_fence_i(NULL); 16 } 17 18 /* 19 * Performs an icache flush for the given MM context. RISC-V has no direct 20 * mechanism for instruction cache shoot downs, so instead we send an IPI that 21 * informs the remote harts they need to flush their local instruction caches. 22 * To avoid pathologically slow behavior in a common case (a bunch of 23 * single-hart processes on a many-hart machine, ie 'make -j') we avoid the 24 * IPIs for harts that are not currently executing a MM context and instead 25 * schedule a deferred local instruction cache flush to be performed before 26 * execution resumes on each hart. 27 */ 28 void flush_icache_mm(struct mm_struct *mm, bool local) 29 { 30 unsigned int cpu; 31 cpumask_t others, hmask, *mask; 32 33 preempt_disable(); 34 35 /* Mark every hart's icache as needing a flush for this MM. */ 36 mask = &mm->context.icache_stale_mask; 37 cpumask_setall(mask); 38 /* Flush this hart's I$ now, and mark it as flushed. */ 39 cpu = smp_processor_id(); 40 cpumask_clear_cpu(cpu, mask); 41 local_flush_icache_all(); 42 43 /* 44 * Flush the I$ of other harts concurrently executing, and mark them as 45 * flushed. 46 */ 47 cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu)); 48 local |= cpumask_empty(&others); 49 if (mm != current->active_mm || !local) { 50 riscv_cpuid_to_hartid_mask(&others, &hmask); 51 sbi_remote_fence_i(hmask.bits); 52 } else { 53 /* 54 * It's assumed that at least one strongly ordered operation is 55 * performed on this hart between setting a hart's cpumask bit 56 * and scheduling this MM context on that hart. Sending an SBI 57 * remote message will do this, but in the case where no 58 * messages are sent we still need to order this hart's writes 59 * with flush_icache_deferred(). 60 */ 61 smp_mb(); 62 } 63 64 preempt_enable(); 65 } 66 67 #endif /* CONFIG_SMP */ 68 69 void flush_icache_pte(pte_t pte) 70 { 71 struct page *page = pte_page(pte); 72 73 if (!test_and_set_bit(PG_dcache_clean, &page->flags)) 74 flush_icache_all(); 75 } 76