[PATCH v2] riscv: mm: implement pgprot_nx

[Jisheng Zhang]

commit cca98e9f8b5e ("mm: enforce that vmap can't map pages
executable") enforces the W^X protection by not allowing remapping
existing pages as executable. Add riscv bits so that riscv can benefit
the same protection.

Signed-off-by: Jisheng Zhang <jszhang at kernel.org>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Reviewed-by: Samuel Holland <samuel.holland at sifive.com>
Tested-by: Samuel Holland <samuel.holland at sifive.com>
Reviewed-by: Alexandre Ghiti <alexghiti at rivosinc.com>
---
since v1:
 - rebase on v6.8-rc1
 - collect Reviewed-by and Tested-by tag

 arch/riscv/include/asm/pgtable.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 0c94260b5d0c..c931863bbd1a 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -591,6 +591,12 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
 	return ptep_test_and_clear_young(vma, address, ptep);
 }
 
+#define pgprot_nx pgprot_nx
+static inline pgprot_t pgprot_nx(pgprot_t _prot)
+{
+	return __pgprot(pgprot_val(_prot) & ~_PAGE_EXEC);
+}
+
 #define pgprot_noncached pgprot_noncached
 static inline pgprot_t pgprot_noncached(pgprot_t _prot)
 {
-- 
2.43.0