diff mbox series

[v7,3/4] arm64: Make use of memblock_isolate_memory for the linear mapping

Message ID 20230310094539.764357-4-alexghiti@rivosinc.com (mailing list archive)
State New, archived
Headers show
Series riscv: Use PUD/P4D/PGD pages for the linear mapping | expand

Commit Message

Alexandre Ghiti March 10, 2023, 9:45 a.m. UTC
In order to isolate the kernel text mapping, we used some sort of hack
to isolate the kernel text range which consisted in marking this region
as not mappable with memblock_mark_nomap. Simply use the newly introduced
memblock_isolate_memory function which does exactly the same but does not
uselessly mark the region as not mappable.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/arm64/mm/mmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Andrew Jones March 13, 2023, 9:43 a.m. UTC | #1
On Fri, Mar 10, 2023 at 10:45:38AM +0100, Alexandre Ghiti wrote:
> In order to isolate the kernel text mapping, we used some sort of hack
> to isolate the kernel text range which consisted in marking this region
> as not mappable with memblock_mark_nomap. Simply use the newly introduced
> memblock_isolate_memory function which does exactly the same but does not
> uselessly mark the region as not mappable.
> 
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
>  arch/arm64/mm/mmu.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 6f9d8898a025..408dc852805c 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -552,7 +552,7 @@ static void __init map_mem(pgd_t *pgdp)
>  	 * So temporarily mark them as NOMAP to skip mappings in
>  	 * the following for-loop
>  	 */

The comment above doesn't apply anymore.

> -	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
> +	memblock_isolate_memory(kernel_start, kernel_end - kernel_start);
>  
>  #ifdef CONFIG_KEXEC_CORE
>  	if (crash_mem_map) {
> @@ -568,6 +568,7 @@ static void __init map_mem(pgd_t *pgdp)
>  	for_each_mem_range(i, &start, &end) {
>  		if (start >= end)
>  			break;
> +

Mark nomap is also used for the crash kernel. Does the new API not work
for it?

Thanks,
drew

>  		/*
>  		 * The linear map must allow allocation tags reading/writing
>  		 * if MTE is present. Otherwise, it has the same attributes as
> @@ -589,7 +590,6 @@ static void __init map_mem(pgd_t *pgdp)
>  	 */
>  	__map_memblock(pgdp, kernel_start, kernel_end,
>  		       PAGE_KERNEL, NO_CONT_MAPPINGS);
> -	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
>  
>  	/*
>  	 * Use page-level mappings here so that we can shrink the region
> -- 
> 2.37.2
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Alexandre Ghiti March 13, 2023, 10:01 a.m. UTC | #2
Hi Andrew,

On 3/13/23 10:43, Andrew Jones wrote:
> On Fri, Mar 10, 2023 at 10:45:38AM +0100, Alexandre Ghiti wrote:
>> In order to isolate the kernel text mapping, we used some sort of hack
>> to isolate the kernel text range which consisted in marking this region
>> as not mappable with memblock_mark_nomap. Simply use the newly introduced
>> memblock_isolate_memory function which does exactly the same but does not
>> uselessly mark the region as not mappable.
>>
>> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> ---
>>   arch/arm64/mm/mmu.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
>> index 6f9d8898a025..408dc852805c 100644
>> --- a/arch/arm64/mm/mmu.c
>> +++ b/arch/arm64/mm/mmu.c
>> @@ -552,7 +552,7 @@ static void __init map_mem(pgd_t *pgdp)
>>   	 * So temporarily mark them as NOMAP to skip mappings in
>>   	 * the following for-loop
>>   	 */
> The comment above doesn't apply anymore.


Yep, noticed this one after sending, thanks anyway!


>
>> -	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
>> +	memblock_isolate_memory(kernel_start, kernel_end - kernel_start);
>>   
>>   #ifdef CONFIG_KEXEC_CORE
>>   	if (crash_mem_map) {
>> @@ -568,6 +568,7 @@ static void __init map_mem(pgd_t *pgdp)
>>   	for_each_mem_range(i, &start, &end) {
>>   		if (start >= end)
>>   			break;
>> +
> Mark nomap is also used for the crash kernel. Does the new API not work
> for it?


Seems you're right, I missed it.

Thanks,

Alex


>
> Thanks,
> drew
>
>>   		/*
>>   		 * The linear map must allow allocation tags reading/writing
>>   		 * if MTE is present. Otherwise, it has the same attributes as
>> @@ -589,7 +590,6 @@ static void __init map_mem(pgd_t *pgdp)
>>   	 */
>>   	__map_memblock(pgdp, kernel_start, kernel_end,
>>   		       PAGE_KERNEL, NO_CONT_MAPPINGS);
>> -	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
>>   
>>   	/*
>>   	 * Use page-level mappings here so that we can shrink the region
>> -- 
>> 2.37.2
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
diff mbox series

Patch

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6f9d8898a025..408dc852805c 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -552,7 +552,7 @@  static void __init map_mem(pgd_t *pgdp)
 	 * So temporarily mark them as NOMAP to skip mappings in
 	 * the following for-loop
 	 */
-	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
+	memblock_isolate_memory(kernel_start, kernel_end - kernel_start);
 
 #ifdef CONFIG_KEXEC_CORE
 	if (crash_mem_map) {
@@ -568,6 +568,7 @@  static void __init map_mem(pgd_t *pgdp)
 	for_each_mem_range(i, &start, &end) {
 		if (start >= end)
 			break;
+
 		/*
 		 * The linear map must allow allocation tags reading/writing
 		 * if MTE is present. Otherwise, it has the same attributes as
@@ -589,7 +590,6 @@  static void __init map_mem(pgd_t *pgdp)
 	 */
 	__map_memblock(pgdp, kernel_start, kernel_end,
 		       PAGE_KERNEL, NO_CONT_MAPPINGS);
-	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
 
 	/*
 	 * Use page-level mappings here so that we can shrink the region