[PATCH v2 2/9] riscv: add ARCH_HAS_SET_DIRECT_MAP support

Zong Li
2020-03-09T08:22:47Z

Add set_direct_map_*() functions for setting the direct map alias for
the page to its default permissions and to an invalid state that cannot
be cached in a TLB. (See d253ca0c ("x86/mm/cpa: Add set_direct_map_*()
functions")) Add a similar implementation for RISC-V.

Signed-off-by: Zong Li <zong.li@sifive.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/set_memory.h | 3 +++
arch/riscv/mm/pageattr.c | 24 ++++++++++++++++++++++++
3 files changed, 28 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 76ed36543b3a..07bf1a7c0dd2 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -60,6 +60,7 @@ config RISCV
select HAVE_EBPF_JIT if 64BIT
select EDAC_SUPPORT
select ARCH_HAS_GIGANTIC_PAGE
+ select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_SET_MEMORY
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select SPARSEMEM_STATIC if 32BIT
diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
index 936f08063566..a9783a878dca 100644
--- a/arch/riscv/include/asm/set_memory.h
+++ b/arch/riscv/include/asm/set_memory.h
@@ -14,4 +14,7 @@ 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_direct_map_invalid_noflush(struct page *page);
+int set_direct_map_default_noflush(struct page *page);
+
#endif /* _ASM_RISCV_SET_MEMORY_H */
diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index fcd59ef2835b..7be6cd67e2ef 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -148,3 +148,27 @@ int set_memory_nx(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
}
+
+int set_direct_map_invalid_noflush(struct page *page)
+{
+ unsigned long start = (unsigned long)page_address(page);
+ unsigned long end = start + PAGE_SIZE;
+ struct pageattr_masks masks = {
+ .set_mask = __pgprot(0),
+ .clear_mask = __pgprot(_PAGE_PRESENT)
+ };
+
+ return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+ unsigned long start = (unsigned long)page_address(page);
+ unsigned long end = start + PAGE_SIZE;
+ struct pageattr_masks masks = {
+ .set_mask = PAGE_KERNEL,
+ .clear_mask = __pgprot(0)
+ };
+
+ return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
+}
--
2.25.1