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From:   Alexandre Ghiti <alex@ghiti.fr>
To:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Jisheng Zhang <jszhang@kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        Zong Li <zong.li@sifive.com>, Anup Patel <anup@brainfault.org>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Alexandre Ghiti <alex@ghiti.fr>
Subject: [PATCH v4 3/4] riscv: Introduce set_kernel_memory helper
Date:   Fri,  4 Jun 2021 13:49:49 +0200
Message-Id: <20210604114950.1446390-4-alex@ghiti.fr>
In-Reply-To: <20210604114950.1446390-1-alex@ghiti.fr>
References: <20210604114950.1446390-1-alex@ghiti.fr>
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This helper should be used for setting permissions to the kernel
mapping as it takes pointers as arguments and then avoids explicit cast
to unsigned long needed for the set_memory_* API.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/include/asm/set_memory.h |  5 +++++
 arch/riscv/mm/pageattr.c            | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
index 086f757e8ba3..7a411fed9e0e 100644
--- a/arch/riscv/include/asm/set_memory.h
+++ b/arch/riscv/include/asm/set_memory.h
@@ -16,6 +16,7 @@ int set_memory_rw(unsigned long addr, int numpages);
 int set_memory_x(unsigned long addr, int numpages);
 int set_memory_nx(unsigned long addr, int numpages);
 int set_memory_rw_nx(unsigned long addr, int numpages);
+int set_kernel_memory(char *start, char *end, int (*set_memory)(unsigned long, int));
 void protect_kernel_text_data(void);
 #else
 static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; }
@@ -24,6 +25,10 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
 static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
 static inline void protect_kernel_text_data(void) {}
 static inline int set_memory_rw_nx(unsigned long addr, int numpages) { return 0; }
+static inline int set_kernel_memory(char *start, char *end, int (*set_memory)(unsigned long, int))
+{
+	return 0;
+}
 #endif
 
 #if defined(CONFIG_64BIT) && defined(CONFIG_STRICT_KERNEL_RWX)
diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index 5e49e4b4a4cc..c47ac6a432ac 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -156,6 +156,16 @@ int set_memory_nx(unsigned long addr, int numpages)
 	return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
 }
 
+int set_kernel_memory(char *startp, char *endp,
+		      int (*set_memory)(unsigned long start, int num_pages))
+{
+	unsigned long start = (unsigned long)startp;
+	unsigned long end = (unsigned long)endp;
+	int num_pages = PAGE_ALIGN(end - start) >> PAGE_SHIFT;
+
+	return set_memory(start, num_pages);
+}
+
 int set_direct_map_invalid_noflush(struct page *page)
 {
 	int ret;
-- 
2.30.2