[PATCH] riscv: Add HAVE_IOREMAP_PROT support

[guoren]

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

Add pte_pgprot macro, then riscv could have HAVE_IOREMAP_PROT,
which will enable generic_access_phys() code, it is useful for
debug, eg, gdb.

Because generic_access_phys() would call ioremap_prot()->
pgprot_nx() to disable excutable attribute, add definition
of pgprot_nx() for riscv.

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
---
 .../features/vm/ioremap_prot/arch-support.txt     |  2 +-
 arch/riscv/Kconfig                                |  1 +
 arch/riscv/include/asm/pgtable.h                  | 15 +++++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/features/vm/ioremap_prot/arch-support.txt b/Documentation/features/vm/ioremap_prot/arch-support.txt
index a24149e59d73..ea8c8a361455 100644
--- a/Documentation/features/vm/ioremap_prot/arch-support.txt
+++ b/Documentation/features/vm/ioremap_prot/arch-support.txt
@@ -21,7 +21,7 @@
     |    openrisc: | TODO |
     |      parisc: | TODO |
     |     powerpc: |  ok  |
-    |       riscv: | TODO |
+    |       riscv: |  ok  |
     |        s390: |  ok  |
     |          sh: |  ok  |
     |       sparc: | TODO |
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4c07b9189c86..15900fa20797 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -117,6 +117,7 @@ config RISCV
 	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_GCC_PLUGINS
 	select HAVE_GENERIC_VDSO if MMU && 64BIT
+	select HAVE_IOREMAP_PROT
 	select HAVE_IRQ_TIME_ACCOUNTING
 	select HAVE_KPROBES if !XIP_KERNEL
 	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 75970ee2bda2..c9552a161f90 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -415,6 +415,11 @@ static inline pte_t pte_mkhuge(pte_t pte)
 	return pte;
 }
 
+static inline pgprot_t pte_pgprot(pte_t pte)
+{
+	return __pgprot(pte_val(pte) & ~_PAGE_PFN_MASK);
+}
+
 #ifdef CONFIG_NUMA_BALANCING
 /*
  * See the comment in include/asm-generic/pgtable.h
@@ -573,6 +578,16 @@ 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)
+{
+	unsigned long prot = pgprot_val(_prot);
+
+	prot &= ~_PAGE_EXEC;
+
+	return __pgprot(prot);
+}
+
 #define pgprot_noncached pgprot_noncached
 static inline pgprot_t pgprot_noncached(pgprot_t _prot)
 {
-- 
2.36.1