[PATCH v3 2/4] RISC-V: Fix ioremap_cache() and ioremap_wc() for systems with Svpbmt

Anup Patel
2022-10-19T12:38:20Z

Currently, all flavors of ioremap_xyz() function maps to the generic
ioremap() which means any ioremap_xyz() call will always map the
target memory as IO using _PAGE_IOREMAP page attributes. This breaks
ioremap_cache() and ioremap_wc() on systems with Svpbmt because memory
remapped using ioremap_cache() and ioremap_wc() will use _PAGE_IOREMAP
page attributes.

To address above (just like other architectures), we implement RISC-V
specific ioremap_cache() and ioremap_wc() which maps memory using page
attributes as defined by the Svpbmt specification.

Fixes: ff689fd21cb1 ("riscv: add RISC-V Svpbmt extension support")
Co-developed-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/include/asm/io.h | 10 ++++++++++
arch/riscv/include/asm/pgtable.h | 2 ++
2 files changed, 12 insertions(+)

diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index 92080a227937..92a31e543388 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -133,6 +133,16 @@ __io_writes_outs(outs, u64, q, __io_pbr(), __io_paw())
#define outsq(addr, buffer, count) __outsq(PCI_IOBASE + (addr), buffer, count)
#endif

+#ifdef CONFIG_MMU
+#define ioremap_wc(addr, size) \
+ ioremap_prot((addr), (size), _PAGE_IOREMAP_WC)
+#endif
+
#include <asm-generic/io.h>

+#ifdef CONFIG_MMU
+#define ioremap_cache(addr, size) \
+ ioremap_prot((addr), (size), _PAGE_KERNEL)
+#endif
+
#endif /* _ASM_RISCV_IO_H */
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 7ec936910a96..346b7c1a3eeb 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -182,6 +182,8 @@ extern struct pt_alloc_ops pt_ops __initdata;
#define PAGE_TABLE __pgprot(_PAGE_TABLE)

#define _PAGE_IOREMAP ((_PAGE_KERNEL & ~_PAGE_MTMASK) | _PAGE_IO)
+#define _PAGE_IOREMAP_WC ((_PAGE_KERNEL & ~_PAGE_MTMASK) | \
+ _PAGE_NOCACHE)
#define PAGE_KERNEL_IO __pgprot(_PAGE_IOREMAP)

extern pgd_t swapper_pg_dir[];
--
2.34.1