linux-kernel - [PATCH] riscv: Invalid instruction cache after copy the xol area

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Date:   Wed, 18 May 2022 16:17:53 +0800
From:   Po-Kai Chi <po-kai.chi@...ive.com>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Po-Kai Chi <po-kai.chi@...ive.com>
Subject: [PATCH] riscv: Invalid instruction cache after copy the xol area

We need to invalid the relevant instruction cache after
copying the xol area, to ensure the changes takes effect.

Signed-off-by: Po-Kai Chi <po-kai.chi@...ive.com>
---
 arch/riscv/kernel/probes/uprobes.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kernel/probes/uprobes.c b/arch/riscv/kernel/probes/uprobes.c
index 7a057b5f0adc..9d52beeac73c 100644
--- a/arch/riscv/kernel/probes/uprobes.c
+++ b/arch/riscv/kernel/probes/uprobes.c
@@ -165,6 +165,7 @@ void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
 	/* Initialize the slot */
 	void *kaddr = kmap_atomic(page);
 	void *dst = kaddr + (vaddr & ~PAGE_MASK);
+	unsigned long addr = (unsigned long)dst;
 
 	memcpy(dst, src, len);
 
@@ -177,10 +178,9 @@ void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
 	kunmap_atomic(kaddr);
 
 	/*
-	 * We probably need flush_icache_user_page() but it needs vma.
-	 * This should work on most of architectures by default. If
-	 * architecture needs to do something different it can define
-	 * its own version of the function.
+	 * Flush both I/D cache to ensure instruction modification
+	 * takes effect.
 	 */
 	flush_dcache_page(page);
+	flush_icache_range(addr, addr + len);
 }
-- 
2.36.1