On Thu, Oct 3, 2024 at 4:38 AM Usama Arif <usamaarif642@xxxxxxxxx> wrote:
>
> __pa() is only intended to be used for linear map addresses and using
> it for initial_boot_params which is in fixmap for arm64 will give an
> incorrect value. Hence stash the physical address when it is known at
> boot time and use it at kexec time instead of converting the virtual
> address using __pa().
>
> Reported-by: Breno Leitao <leitao@xxxxxxxxxx>
> Suggested-by: Mark Rutland <mark.rutland@xxxxxxx>
> Signed-off-by: Usama Arif <usamaarif642@xxxxxxxxx>
> Fixes: ac10be5cdbfa ("arm64: Use common of_kexec_alloc_and_setup_fdt()")
> ---
> arch/arm64/kernel/setup.c | 8 ++++++++
> drivers/of/fdt.c | 6 ++++++
> drivers/of/kexec.c | 8 ++++++--
> include/linux/of_fdt.h | 2 ++
> 4 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index b22d28ec8028..a4d96f5e2e05 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -194,6 +194,14 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
> /* Early fixups are done, map the FDT as read-only now */
> fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
>
> + /*
> + * Save dt_phys address so that it can be used later for kexec. This
> + * is done as __pa() is only intended to be used for linear map addresses
> + * and using it for initial_boot_params which is in fixmap will give an
> + * incorrect value.
> + */
> + set_initial_boot_params_pa(dt_phys);
> +
> name = of_flat_dt_get_machine_name();
> if (!name)
> return;
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 4d528c10df3a..9e312b7c246e 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -457,6 +457,7 @@ int __initdata dt_root_addr_cells;
> int __initdata dt_root_size_cells;
>
> void *initial_boot_params __ro_after_init;
> +phys_addr_t initial_boot_params_pa __ro_after_init;
>
> #ifdef CONFIG_OF_EARLY_FLATTREE
>
> @@ -1185,6 +1186,11 @@ bool __init early_init_dt_scan(void *params)
> return true;
> }
>
> +void __init set_initial_boot_params_pa(phys_addr_t params)
> +{
> + initial_boot_params_pa = params;
> +}
> +
> static void *__init copy_device_tree(void *fdt)
> {
> int size;
> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
> index 9ccde2fd77cb..ca9f27b27f71 100644
> --- a/drivers/of/kexec.c
> +++ b/drivers/of/kexec.c
> @@ -300,8 +300,12 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
> goto out;
> }
>
> - /* Remove memory reservation for the current device tree. */
> - ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
> + /* Remove memory reservation for the current device tree.
> + * For arm64, initial_boot_params is a fixmap address, hence __pa(),
> + * can't be used to get the physical address.
> + */
> + ret = fdt_find_and_del_mem_rsv(fdt, IS_ENABLED(CONFIG_ARM64) ?
> + initial_boot_params_pa : __pa(initial_boot_params),
> fdt_totalsize(initial_boot_params));
Not sure about the correctness of the patch (not a kexec expert) but
no need to do all of this inside a function parameter. Just create a
variable and use it here.
-Saravana
> if (ret == -EINVAL) {
> pr_err("Error removing memory reservation.\n");
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index d69ad5bb1eb1..dbd99bf21ac8 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -31,6 +31,7 @@ extern void *of_fdt_unflatten_tree(const unsigned long *blob,
> extern int __initdata dt_root_addr_cells;
> extern int __initdata dt_root_size_cells;
> extern void *initial_boot_params;
> +extern phys_addr_t initial_boot_params_pa;
>
> extern char __dtb_start[];
> extern char __dtb_end[];
> @@ -73,6 +74,7 @@ extern int early_init_dt_scan_root(void);
> extern bool early_init_dt_scan(void *params);
> extern bool early_init_dt_verify(void *params);
> extern void early_init_dt_scan_nodes(void);
> +extern void set_initial_boot_params_pa(phys_addr_t params);
>
> extern const char *of_flat_dt_get_machine_name(void);
> extern const void *of_flat_dt_match_machine(const void *default_match,
> --
> 2.43.5
>
