The unflatten_device_tree() function contains a call to
memblock_alloc(). This is a problem because this allocation is done
before any of the reserved memory is set aside in paging_init().
This means that there is a possibility for memblock to allocate from
any of the memory regions that are supposed to be set aside as reserved.

Hence, move the call to paging_init() to be earlier in the init
sequence so that the reserved memory regions are set aside before any
allocations are done using memblock.

Signed-off-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com>
---
 arch/sh/kernel/setup.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index d3175f0..ea40798 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c
@@ -322,6 +322,8 @@ void __init setup_arch(char **cmdline_p)
 	/* Let earlyprintk output early console messages */
 	sh_early_platform_driver_probe("earlyprintk", 1, 1);
 
+	paging_init();
+
 #ifdef CONFIG_OF_EARLY_FLATTREE
 #ifdef CONFIG_USE_BUILTIN_DTB
 	unflatten_and_copy_device_tree();
@@ -330,8 +332,6 @@ void __init setup_arch(char **cmdline_p)
 #endif
 #endif
 
-	paging_init();
-
 	/* Perform the machine specific initialisation */
 	if (likely(sh_mv.mv_setup))
 		sh_mv.mv_setup(cmdline_p);
--

On Fri, Feb 9, 2024 at 5:29 PM Oreoluwa Babatunde
<quic_obabatun@quicinc.com> wrote:
>
> The unflatten_device_tree() function contains a call to
> memblock_alloc(). This is a problem because this allocation is done
> before any of the reserved memory is set aside in paging_init().
> This means that there is a possibility for memblock to allocate from
> any of the memory regions that are supposed to be set aside as reserved.
>
> Hence, move the call to paging_init() to be earlier in the init
> sequence so that the reserved memory regions are set aside before any
> allocations are done using memblock.
>
> Signed-off-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com>
> ---
>  arch/sh/kernel/setup.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Rob Herring <robh@kernel.org>