When SVPBMT is enabled, __acpi_map_table() will directly access the
data in DDR through the IO attribute, rather than through hardware
cache consistency, resulting in incorrect data in the obtained ACPI
table.

The log: ACPI: [ACPI:0x18] Invalid zero length.

We do not assume whether the bootloader flushes or not. We should
access in a cacheable way instead of maintaining cache consistency
by software.

Fixes: 3b426d4b5b14 ("RISC-V: ACPI : Fix for usage of pointers in different address space")
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 arch/riscv/kernel/acpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/acpi.c b/arch/riscv/kernel/acpi.c
index 6e0d333f57e5..2fd29695a788 100644
--- a/arch/riscv/kernel/acpi.c
+++ b/arch/riscv/kernel/acpi.c
@@ -210,7 +210,7 @@ void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
 	if (!size)
 		return NULL;
 
-	return early_ioremap(phys, size);
+	return early_memremap(phys, size);
 }
 
 void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
@@ -218,7 +218,7 @@ void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
 	if (!map || !size)
 		return;
 
-	early_iounmap(map, size);
+	early_memunmap(map, size);
 }
 
 void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)
-- 
2.39.2

On Mon, Oct 14, 2024 at 09:01:41PM +0800, Yunhui Cui wrote:
> When SVPBMT is enabled, __acpi_map_table() will directly access the
> data in DDR through the IO attribute, rather than through hardware
> cache consistency, resulting in incorrect data in the obtained ACPI
> table.
> 
> The log: ACPI: [ACPI:0x18] Invalid zero length.
> 
> We do not assume whether the bootloader flushes or not. We should
> access in a cacheable way instead of maintaining cache consistency
> by software.
> 
> Fixes: 3b426d4b5b14 ("RISC-V: ACPI : Fix for usage of pointers in different address space")
> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>  arch/riscv/kernel/acpi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/kernel/acpi.c b/arch/riscv/kernel/acpi.c
> index 6e0d333f57e5..2fd29695a788 100644
> --- a/arch/riscv/kernel/acpi.c
> +++ b/arch/riscv/kernel/acpi.c
> @@ -210,7 +210,7 @@ void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
>  	if (!size)
>  		return NULL;
>  
> -	return early_ioremap(phys, size);
> +	return early_memremap(phys, size);
>  }
>  
>  void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
> @@ -218,7 +218,7 @@ void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
>  	if (!map || !size)
>  		return;
>  
> -	early_iounmap(map, size);
> +	early_memunmap(map, size);
>  }
>  
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>

Thanks,
Sunil