[PATCH v4 01/30] kho: allow to drive kho from within kernel
From: Pasha Tatashin <pasha.tatashin@soleen.com>
Date: 2025-09-29 01:03:33
Also in:
linux-doc, linux-fsdevel, linux-mm, lkml
Subsystem:
kexec, kexec handover (kho), the rest · Maintainers:
Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
Allow to do finalize and abort from kernel modules, so LUO could drive the KHO sequence via its own state machine. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> --- include/linux/kexec_handover.h | 15 +++++++++ kernel/kexec_handover.c | 56 ++++++++++++++++++++++++++++++++-- 2 files changed, 69 insertions(+), 2 deletions(-)
diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h
index 25042c1d8d54..04d0108db98e 100644
--- a/include/linux/kexec_handover.h
+++ b/include/linux/kexec_handover.h@@ -67,6 +67,10 @@ void kho_memory_init(void); void kho_populate(phys_addr_t fdt_phys, u64 fdt_len, phys_addr_t scratch_phys, u64 scratch_len); + +int kho_finalize(void); +int kho_abort(void); + #else static inline bool kho_is_enabled(void) {
@@ -139,6 +143,17 @@ static inline void kho_populate(phys_addr_t fdt_phys, u64 fdt_len, phys_addr_t scratch_phys, u64 scratch_len) { } + +static inline int kho_finalize(void) +{ + return -EOPNOTSUPP; +} + +static inline int kho_abort(void) +{ + return -EOPNOTSUPP; +} + #endif /* CONFIG_KEXEC_HANDOVER */ #endif /* LINUX_KEXEC_HANDOVER_H */
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index 76f0940fb485..0ba5a2dbae28 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c@@ -1067,7 +1067,7 @@ static int kho_out_update_debugfs_fdt(void) return err; } -static int kho_abort(void) +static int __kho_abort(void) { int err; unsigned long order;
@@ -1100,7 +1100,33 @@ static int kho_abort(void) return err; } -static int kho_finalize(void) +int kho_abort(void) +{ + int ret = 0; + + if (!kho_enable) + return -EOPNOTSUPP; + + mutex_lock(&kho_out.lock); + + if (!kho_out.finalized) { + ret = -ENOENT; + goto unlock; + } + + ret = __kho_abort(); + if (ret) + goto unlock; + + kho_out.finalized = false; + ret = kho_out_update_debugfs_fdt(); + +unlock: + mutex_unlock(&kho_out.lock); + return ret; +} + +static int __kho_finalize(void) { int err = 0; u64 *preserved_mem_map;
@@ -1149,6 +1175,32 @@ static int kho_finalize(void) return err; } +int kho_finalize(void) +{ + int ret = 0; + + if (!kho_enable) + return -EOPNOTSUPP; + + mutex_lock(&kho_out.lock); + + if (kho_out.finalized) { + ret = -EEXIST; + goto unlock; + } + + ret = __kho_finalize(); + if (ret) + goto unlock; + + kho_out.finalized = true; + ret = kho_out_update_debugfs_fdt(); + +unlock: + mutex_unlock(&kho_out.lock); + return ret; +} + static int kho_out_finalize_get(void *data, u64 *val) { mutex_lock(&kho_out.lock);
--
2.51.0.536.g15c5d4f767-goog