[PATCH] LoongArch: Use correct API to map cmdline in relocate_kernel()

[PATCH] LoongArch: Use correct API to map cmdline in relocate_kernel()

[Huacai Chen]

fw_arg1 is in memory space rather than I/O space, so we should use
early_memremap_ro() instead of early_ioremap() to map the cmdline.
Moreover, we should unmap it after using.

Suggested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 arch/loongarch/kernel/relocate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c
index 1acfa704c8d0..0eddd4a66b87 100644
--- a/arch/loongarch/kernel/relocate.c
+++ b/arch/loongarch/kernel/relocate.c
@@ -13,6 +13,7 @@
 #include <asm/bootinfo.h>
 #include <asm/early_ioremap.h>
 #include <asm/inst.h>
+#include <asm/io.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 
@@ -170,7 +171,7 @@ unsigned long __init relocate_kernel(void)
 	unsigned long kernel_length;
 	unsigned long random_offset = 0;
 	void *location_new = _text; /* Default to original kernel start */
-	char *cmdline = early_ioremap(fw_arg1, COMMAND_LINE_SIZE); /* Boot command line is passed in fw_arg1 */
+	char *cmdline = early_memremap_ro(fw_arg1, COMMAND_LINE_SIZE); /* Boot command line is passed in fw_arg1 */
 
 	strscpy(boot_command_line, cmdline, COMMAND_LINE_SIZE);
 
@@ -182,6 +183,7 @@ unsigned long __init relocate_kernel(void)
 		random_offset = (unsigned long)location_new - (unsigned long)(_text);
 #endif
 	reloc_offset = (unsigned long)_text - VMLINUX_LOAD_ADDRESS;
+	early_memunmap(cmdline, COMMAND_LINE_SIZE);
 
 	if (random_offset) {
 		kernel_length = (long)(_end) - (long)(_text);
-- 
2.43.0

Re: [PATCH] LoongArch: Use correct API to map cmdline in relocate_kernel()

[Jiaxun Yang]

在2024年7月2日七月 下午11:14，Huacai Chen写道：
> fw_arg1 is in memory space rather than I/O space, so we should use
> early_memremap_ro() instead of early_ioremap() to map the cmdline.
> Moreover, we should unmap it after using.
>
> Suggested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

Thanks for correcting that.

> ---
>  arch/loongarch/kernel/relocate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c
> index 1acfa704c8d0..0eddd4a66b87 100644
> --- a/arch/loongarch/kernel/relocate.c
> +++ b/arch/loongarch/kernel/relocate.c
> @@ -13,6 +13,7 @@
>  #include <asm/bootinfo.h>
>  #include <asm/early_ioremap.h>
>  #include <asm/inst.h>
> +#include <asm/io.h>
>  #include <asm/sections.h>
>  #include <asm/setup.h>
> 
> @@ -170,7 +171,7 @@ unsigned long __init relocate_kernel(void)
>  	unsigned long kernel_length;
>  	unsigned long random_offset = 0;
>  	void *location_new = _text; /* Default to original kernel start */
> -	char *cmdline = early_ioremap(fw_arg1, COMMAND_LINE_SIZE); /* Boot 
> command line is passed in fw_arg1 */
> +	char *cmdline = early_memremap_ro(fw_arg1, COMMAND_LINE_SIZE); /* 
> Boot command line is passed in fw_arg1 */
> 
>  	strscpy(boot_command_line, cmdline, COMMAND_LINE_SIZE);
> 
> @@ -182,6 +183,7 @@ unsigned long __init relocate_kernel(void)
>  		random_offset = (unsigned long)location_new - (unsigned long)(_text);
>  #endif
>  	reloc_offset = (unsigned long)_text - VMLINUX_LOAD_ADDRESS;
> +	early_memunmap(cmdline, COMMAND_LINE_SIZE);
> 
>  	if (random_offset) {
>  		kernel_length = (long)(_end) - (long)(_text);
> -- 
> 2.43.0

-- 
- Jiaxun