linux-kernel - [PATCH v7 1/2] riscv: Introduce set_kernel

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Message-Id: <20210622082134.2404162-2-alex@ghiti.fr>
Date:   Tue, 22 Jun 2021 10:21:33 +0200
From:   Alexandre Ghiti <alex@...ti.fr>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Jisheng Zhang <jszhang@...nel.org>,
        Christoph Hellwig <hch@...radead.org>,
        Zong Li <zong.li@...ive.com>, Anup Patel <anup@...infault.org>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Alexandre Ghiti <alex@...ti.fr>
Subject: [PATCH v7 1/2] riscv: Introduce set_kernel_memory helper

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@...radead.org>
Signed-off-by: Alexandre Ghiti <alex@...ti.fr>
Reviewed-by: Anup Patel <anup@...infault.org>
---
 arch/riscv/include/asm/set_memory.h |  8 ++++++++
 arch/riscv/mm/pageattr.c            | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
index 9d4d455726d4..4f9fc54d1806 100644
--- a/arch/riscv/include/asm/set_memory.h
+++ b/arch/riscv/include/asm/set_memory.h
@@ -16,6 +16,8 @@ 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 start, int num_pages));
 void protect_kernel_text_data(void);
 #else
 static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; }
@@ -24,6 +26,12 @@ 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 start,
+						      int num_pages))
+{
+	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..11d0b0f4c65d 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -156,6 +156,17 @@ int set_memory_nx(unsigned long addr, int numpages)
 	return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
 }
 
+__always_inline 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