On Wed, Jan 17, 2024 at 02:46:55PM +0000, Alexander Graf wrote: > We now have all bits in place to support KHO kexecs. This patch adds > awareness of KHO in the kexec file as well as boot path for arm64 and > adds the respective kconfig option to the architecture so that it can > use KHO successfully. > > Signed-off-by: Alexander Graf <graf@xxxxxxxxxx> > > --- > > v1 -> v2: > > - test bot warning fix > - Change kconfig option to ARCH_SUPPORTS_KEXEC_KHO > - s/kho_reserve_mem/kho_reserve_previous_mem/g > - s/kho_reserve/kho_reserve_scratch/g > - Remove / reduce ifdefs for kho fdt code > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/kernel/setup.c | 2 ++ > arch/arm64/mm/init.c | 8 ++++++ > drivers/of/fdt.c | 39 ++++++++++++++++++++++++++++ > drivers/of/kexec.c | 54 +++++++++++++++++++++++++++++++++++++++ > 5 files changed, 106 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 8f6cf1221b6a..44d8923d9db4 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1496,6 +1496,9 @@ config ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG > config ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG > def_bool y > > +config ARCH_SUPPORTS_KEXEC_KHO > + def_bool y > + > config ARCH_SUPPORTS_CRASH_DUMP > def_bool y > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index 417a8a86b2db..9aa05b84d202 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -346,6 +346,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p) > > paging_init(); > > + kho_reserve_previous_mem(); > + > acpi_table_upgrade(); > > /* Parse the ACPI tables for possible boot-time configuration */ > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 74c1db8ce271..1a8fc91509af 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -358,6 +358,8 @@ void __init bootmem_init(void) > */ > arch_reserve_crashkernel(); > > + kho_reserve_scratch(); > + > memblock_dump_all(); > } > > @@ -386,6 +388,12 @@ void __init mem_init(void) > /* this will put all unused low memory onto the freelists */ > memblock_free_all(); > > + /* > + * Now that all KHO pages are marked as reserved, let's flip them back > + * to normal pages with accurate refcount. > + */ > + kho_populate_refcount(); > + > /* > * Check boundaries twice: Some fundamental inconsistencies can be > * detected at build time already. > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index bf502ba8da95..f9b9a36fb722 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -1006,6 +1006,42 @@ void __init early_init_dt_check_for_usable_mem_range(void) > memblock_add(rgn[i].base, rgn[i].size); > } > > +/** > + * early_init_dt_check_kho - Decode info required for kexec handover from DT > + */ > +static void __init early_init_dt_check_kho(void) > +{ > + unsigned long node = chosen_node_offset; > + u64 kho_start, scratch_start, scratch_size, mem_start, mem_size; > + const __be32 *p; > + int l; > + > + if (!IS_ENABLED(CONFIG_KEXEC_KHO) || (long)node < 0) > + return; > + > + p = of_get_flat_dt_prop(node, "linux,kho-dt", &l); These need to be documented. chosen node schema lives in dtschema. > + if (l != (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32)) > + return; I would just make all these fixed 64-bit values rather than based on address and size cells. That's what we've done on more recent chosen properties describing regions. Rob