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From: Christoph Hellwig <hch@lst.de>
To: Palmer Dabbelt <palmer@sifive.com>
Cc: linux-mm@kvack.org, Damien Le Moal <damien.lemoal@wdc.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	uclinux-dev@uclinux.org
Subject: [PATCH 13/17] riscv: implement remote sfence.i natively for M-mode
Date: Tue, 11 Jun 2019 00:16:17 +0200
Message-ID: <20190610221621.10938-14-hch@lst.de> (raw)
In-Reply-To: <20190610221621.10938-1-hch@lst.de>

The RISC-V ISA only supports flushing the instruction cache for the local
CPU core.  For normal S-mode Linux remote flushing is offloaded to
machine mode using ecalls, but for M-mode Linux we'll have to do it
ourselves.  Use the same implementation as all the existing open source
SBI implementations by just doing an IPI to all remote cores to execute
th sfence.i instruction on every live core.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/riscv/mm/cacheflush.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 9ebcff8ba263..10875ea1065e 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -10,10 +10,35 @@
 
 #include <asm/sbi.h>
 
+#ifdef CONFIG_M_MODE
+static void ipi_remote_fence_i(void *info)
+{
+	return local_flush_icache_all();
+}
+
+void flush_icache_all(void)
+{
+	on_each_cpu(ipi_remote_fence_i, NULL, 1);
+}
+
+static void flush_icache_cpumask(const cpumask_t *mask)
+{
+	on_each_cpu_mask(mask, ipi_remote_fence_i, NULL, 1);
+}
+#else /* CONFIG_M_MODE */
 void flush_icache_all(void)
 {
 	sbi_remote_fence_i(NULL);
 }
+static void flush_icache_cpumask(const cpumask_t *mask)
+{
+	cpumask_t hmask;
+
+	cpumask_clear(&hmask);
+	riscv_cpuid_to_hartid_mask(mask, &hmask);
+	sbi_remote_fence_i(hmask.bits);
+}
+#endif /* CONFIG_M_MODE */
 
 /*
  * Performs an icache flush for the given MM context.  RISC-V has no direct
@@ -28,7 +53,7 @@ void flush_icache_all(void)
 void flush_icache_mm(struct mm_struct *mm, bool local)
 {
 	unsigned int cpu;
-	cpumask_t others, hmask, *mask;
+	cpumask_t others, *mask;
 
 	preempt_disable();
 
@@ -47,9 +72,7 @@ void flush_icache_mm(struct mm_struct *mm, bool local)
 	cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
 	local |= cpumask_empty(&others);
 	if (mm != current->active_mm || !local) {
-		cpumask_clear(&hmask);
-		riscv_cpuid_to_hartid_mask(&others, &hmask);
-		sbi_remote_fence_i(hmask.bits);
+		flush_icache_cpumask(&others);
 	} else {
 		/*
 		 * It's assumed that at least one strongly ordered operation is
-- 
2.20.1


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  parent reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-10 22:16 RISC-V nommu support Christoph Hellwig
2019-06-10 22:16 ` [PATCH 01/17] mm: provide a print_vma_addr stub for !CONFIG_MMU Christoph Hellwig
2019-06-11 10:11   ` Vladimir Murzin
2019-06-10 22:16 ` [PATCH 02/17] mm: stub out all of swapops.h " Christoph Hellwig
2019-06-11 10:15   ` Vladimir Murzin
2019-06-11 14:18     ` Christoph Hellwig
2019-06-11 14:36       ` Vladimir Murzin
2019-06-14  9:48         ` Christoph Hellwig
2019-06-10 22:16 ` [PATCH 03/17] mm/nommu: fix the MAP_UNINITIALIZED flag Christoph Hellwig
2019-06-11 10:19   ` Vladimir Murzin
2019-06-10 22:16 ` [PATCH 04/17] irqchip/sifive-plic: set max threshold for ignored handlers Christoph Hellwig
2019-06-10 22:16 ` [PATCH 05/17] riscv: use CSR_SATP instead of the legacy sptbr name in switch_mm Christoph Hellwig
2019-06-10 22:16 ` [PATCH 06/17] riscv: clear the instruction cache and all registers when booting Christoph Hellwig
2019-06-10 22:16 ` [PATCH 07/17] riscv: refactor the IPI code Christoph Hellwig
2019-06-10 22:16 ` [PATCH 08/17] riscv: abstract out CSR names for supervisor vs machine mode Christoph Hellwig
2019-06-10 22:16 ` [PATCH 09/17] riscv: improve the default power off implementation Christoph Hellwig
2019-06-10 22:16 ` [PATCH 10/17] riscv: provide a flat entry loader Christoph Hellwig
2019-06-10 22:16 ` [PATCH 11/17] riscv: read hart ID from mhartid on boot Christoph Hellwig
2019-06-10 22:16 ` [PATCH 12/17] riscv: provide native clint access for M-mode Christoph Hellwig
2019-06-10 22:16 ` Christoph Hellwig [this message]
2019-06-10 22:16 ` [PATCH 14/17] riscv: poison SBI calls " Christoph Hellwig
2019-06-10 22:16 ` [PATCH 15/17] riscv: don't allow selecting SBI-based drivers " Christoph Hellwig
2019-06-10 22:16 ` [PATCH 16/17] riscv: use the correct interrupt levels " Christoph Hellwig
2019-06-10 22:16 ` [PATCH 17/17] riscv: add nommu support Christoph Hellwig
2019-06-11 10:32   ` Vladimir Murzin
2019-06-11 12:44   ` David Hildenbrand

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