diff mbox series

[07/46] Loongarch: reserved_mem: Implement the new processing order for reserved memory

Message ID 20240126235425.12233-8-quic_obabatun@quicinc.com
State New
Headers show
Series Dynamic allocation of reserved_mem array. | expand

Commit Message

Oreoluwa Babatunde Jan. 26, 2024, 11:53 p.m. UTC
Call early_fdt_scan_reserved_mem() in place of
early_init_fdt_scan_reserved_mem() to carry out the first stage of the
reserved memory processing only.

The early_fdt_scan_reserved_mem() function is used to scan through the
DT and mark all the reserved memory regions as reserved or nomap as
needed, as well as allocate the memory required by the
dynamically-placed
reserved memory regions.

The second stage of the reserved memory processing is done by
fdt_init_reserved_mem(). This function is used to store the information
of the statically-placed reserved memory nodes in the reserved_mem
array as well as call the region specific initialization function on all
the stored reserved memory regions.

The call to fdt_init_reserved_mem() is placed right after
early_fdt_scan_reserved_mem() since memblock allocated memory should
already be writable at this point.

Signed-off-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com>
---
 arch/loongarch/kernel/setup.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Rob Herring (Arm) Jan. 31, 2024, 3:27 p.m. UTC | #1
On Fri, Jan 26, 2024 at 03:53:46PM -0800, Oreoluwa Babatunde wrote:
> Call early_fdt_scan_reserved_mem() in place of
> early_init_fdt_scan_reserved_mem() to carry out the first stage of the
> reserved memory processing only.
> 
> The early_fdt_scan_reserved_mem() function is used to scan through the
> DT and mark all the reserved memory regions as reserved or nomap as
> needed, as well as allocate the memory required by the
> dynamically-placed
> reserved memory regions.
> 
> The second stage of the reserved memory processing is done by
> fdt_init_reserved_mem(). This function is used to store the information
> of the statically-placed reserved memory nodes in the reserved_mem
> array as well as call the region specific initialization function on all
> the stored reserved memory regions.
> 
> The call to fdt_init_reserved_mem() is placed right after
> early_fdt_scan_reserved_mem() since memblock allocated memory should
> already be writable at this point.
> 
> Signed-off-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com>
> ---
>  arch/loongarch/kernel/setup.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
> index edf2bba80130..72b164d3ace0 100644
> --- a/arch/loongarch/kernel/setup.c
> +++ b/arch/loongarch/kernel/setup.c
> @@ -30,6 +30,7 @@
>  #include <linux/dma-map-ops.h>
>  #include <linux/libfdt.h>
>  #include <linux/of_fdt.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/of_address.h>
>  #include <linux/suspend.h>
>  #include <linux/swiotlb.h>
> @@ -390,8 +391,9 @@ static void __init arch_mem_init(char **cmdline_p)
>  
>  	check_kernel_sections_mem();
>  
> -	early_init_fdt_scan_reserved_mem();
> +	early_fdt_scan_reserved_mem();

Looking at the loongarch code, there's an existing problem with the 
order of init. This is done after unflattening and copying the DT. That 
means the kernel could freely allocate memory for the DT in a reserved 
region.

Rob
diff mbox series

Patch

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index edf2bba80130..72b164d3ace0 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -30,6 +30,7 @@ 
 #include <linux/dma-map-ops.h>
 #include <linux/libfdt.h>
 #include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/of_address.h>
 #include <linux/suspend.h>
 #include <linux/swiotlb.h>
@@ -390,8 +391,9 @@  static void __init arch_mem_init(char **cmdline_p)
 
 	check_kernel_sections_mem();
 
-	early_init_fdt_scan_reserved_mem();
+	early_fdt_scan_reserved_mem();
 
+	fdt_init_reserved_mem();
 	/*
 	 * In order to reduce the possibility of kernel panic when failed to
 	 * get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate