On 10/19/2023 12:46 PM, Rob Herring wrote: > On Thu, Oct 19, 2023 at 1:49 PM Oreoluwa Babatunde > <quic_obabatun@xxxxxxxxxxx> wrote: >> The dynamic allocation of the reserved_mem array needs to be done after >> paging_init() is called because memory allocated using memblock_alloc() >> is not writeable before that. >> >> Nodes that already have their starting address specified in the DT >> (i.e. nodes that are defined using the "reg" property) can wait until >> after paging_init() to be stored in the array. >> But nodes that are dynamically placed need to be reserved and saved in >> the array before paging_init() so that page table entries are not >> created for these regions. >> >> Hence, change the code to: >> 1. Before paging_init(), allocate and store information for the >> dynamically placed reserved memory regions. >> 2. After paging_init(), store the rest of the reserved memory regions >> which are defined with the "reg" property. >> >> Signed-off-by: Oreoluwa Babatunde <quic_obabatun@xxxxxxxxxxx> >> --- >> arch/arm64/kernel/setup.c | 4 +++ >> drivers/of/fdt.c | 56 ++++++++++++++++++++++++++------- >> drivers/of/of_private.h | 1 - >> drivers/of/of_reserved_mem.c | 54 ++++++++++++++----------------- >> include/linux/of_fdt.h | 1 + >> include/linux/of_reserved_mem.h | 9 ++++++ >> 6 files changed, 83 insertions(+), 42 deletions(-) >> >> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c >> index 417a8a86b2db..6002d3ad0b19 100644 >> --- a/arch/arm64/kernel/setup.c >> +++ b/arch/arm64/kernel/setup.c >> @@ -27,6 +27,8 @@ >> #include <linux/proc_fs.h> >> #include <linux/memblock.h> >> #include <linux/of_fdt.h> >> +#include <linux/of_reserved_mem.h> >> + >> #include <linux/efi.h> >> #include <linux/psci.h> >> #include <linux/sched/task.h> >> @@ -346,6 +348,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p) >> >> paging_init(); >> >> + fdt_init_reserved_mem(); >> + > You removed this call from the common code and add it to arm64 arch > code, doesn't that break every other arch? Yes, the same changes will be needed for every other arch. I was hoping to get some feedback on the RFC before implementing this on other archs which is why the change is currently only in arm64. > The very next thing done here is unflattening the DT. So another call > from the arch code to the DT code isn't needed either. Yes, I see that unflatten_device_tree() is being called right after here. Just to clarify, are you suggesting to move fdt_init_reserved_mem() into the unflatten_device_tree() call? Thanks, Oreoluwa
