Re: [PATCH] RISC-V: fix virtual address overlapped in FIXADDR_START and VMEMMAP_START

Paul Walmsley
2019-10-16T15:24:12Z

On Wed, 16 Oct 2019, greentime.hu@sifive.com wrote:

> From: Greentime Hu <greentime.hu@sifive.com>
>
> This patch fixes the virtual address layout in pgtable.h.
> The virtual address of FIXADDR_START and VMEMMAP_START should not be overlapped.
> These addresses will be existed at the same time in Linux kernel that they can't
> be overlapped.
>
> Fixes: d95f1a542c3d ("RISC-V: Implement sparsemem")
> Signed-off-by: Greentime Hu <greentime.hu@sifive.com>

Thanks, here's what's been queued for v5.4-rc.

- Paul

From: Greentime Hu <greentime.hu@sifive.com>
Date: Tue, 8 Oct 2019 14:45:24 +0800
Subject: [PATCH] RISC-V: fix virtual address overlapped in FIXADDR_START and
VMEMMAP_START

This patch fixes the virtual address layout in pgtable.h. The virtual
address of FIXADDR_START and VMEMMAP_START should not be overlapped.

Fixes: d95f1a542c3d ("RISC-V: Implement sparsemem")
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: fixed patch description]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
---
arch/riscv/include/asm/pgtable.h | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 7255f2d8395b..42292d99cc74 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -87,14 +87,6 @@ extern pgd_t swapper_pg_dir[];
#define VMALLOC_END (PAGE_OFFSET - 1)
#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)

-#define FIXADDR_TOP VMALLOC_START
-#ifdef CONFIG_64BIT
-#define FIXADDR_SIZE PMD_SIZE
-#else
-#define FIXADDR_SIZE PGDIR_SIZE
-#endif
-#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
-
/*
* Roughly size the vmemmap space to be large enough to fit enough
* struct pages to map half the virtual address space. Then
@@ -108,6 +100,14 @@ extern pgd_t swapper_pg_dir[];

#define vmemmap ((struct page *)VMEMMAP_START)

+#define FIXADDR_TOP (VMEMMAP_START)
+#ifdef CONFIG_64BIT
+#define FIXADDR_SIZE PMD_SIZE
+#else
+#define FIXADDR_SIZE PGDIR_SIZE
+#endif
+#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+
/*
* ZERO_PAGE is a global shared page that is always zero,
* used for zero-mapped memory areas, etc.
--
2.23.0