Entirely remove the LUO FDT wrapper since the FDT only carries the compatible string and the pointer to the centralized struct luo_ser. Instead, register the struct luo_ser via the KHO raw subtree API, placing the compatibility string inside the structure itself.
Signed-off-by: Pasha Tatashin <[email protected]> --- include/linux/kho/abi/luo.h | 57 +++++++++--------------- kernel/liveupdate/luo_core.c | 85 +++++++++++------------------------- 2 files changed, 46 insertions(+), 96 deletions(-) diff --git a/include/linux/kho/abi/luo.h b/include/linux/kho/abi/luo.h index 1b2f865a771a..9a4fe491812b 100644 --- a/include/linux/kho/abi/luo.h +++ b/include/linux/kho/abi/luo.h @@ -10,11 +10,11 @@ * * Live Update Orchestrator uses the stable Application Binary Interface * defined below to pass state from a pre-update kernel to a post-update - * kernel. The ABI is built upon the Kexec HandOver framework and uses a - * Flattened Device Tree to describe the preserved data. + * kernel. The ABI is built upon the Kexec HandOver framework and registers + * the central `struct luo_ser` via the KHO raw subtree API. * - * This interface is a contract. Any modification to the FDT structure, node - * properties, compatible strings, or the layout of the `__packed` serialization + * This interface is a contract. Any modification to the structure fields, + * compatible strings, or the layout of the `__packed` serialization * structures defined here constitutes a breaking change. Such changes require * incrementing the version number in the relevant `_COMPATIBLE` string to * prevent a new kernel from misinterpreting data from an old kernel. @@ -23,31 +23,15 @@ * however, backward/forward compatibility is only guaranteed for kernels * supporting the same ABI version. * - * FDT Structure Overview: + * KHO Structure Overview: * The entire LUO state is encapsulated within a single KHO entry named "LUO". - * This entry contains an FDT with the following layout: - * - * .. code-block:: none - * - * / { - * compatible = "luo-v2"; - * luo-abi-header = <phys_addr_of_luo_ser>; - * }; - * - * Main LUO Node (/): - * - * - compatible: "luo-v2" - * Identifies the overall LUO ABI version. - * - luo-abi-header: u64 - * The physical address of `struct luo_ser`. + * This entry contains the `struct luo_ser` structure. * * Serialization Structures: - * The FDT properties point to memory regions containing arrays of simple, - * `__packed` structures. These structures contain the actual preserved state. - * * - struct luo_ser: * The central ABI structure that contains the overall state of the LUO. - * It includes the liveupdate-number and pointers to sessions and FLBs. + * It includes the compatibility string, the liveupdate-number, and pointers + * to sessions and FLBs. * * - struct luo_session_header_ser: * Header for the session array. Contains the total page count of the @@ -78,26 +62,27 @@ #ifndef _LINUX_KHO_ABI_LUO_H #define _LINUX_KHO_ABI_LUO_H +#include <linux/align.h> #include <uapi/linux/liveupdate.h> /* - * The LUO FDT hooks all LUO state for sessions, fds, etc. + * The LUO state is registered under this KHO entry name. */ -#define LUO_FDT_SIZE PAGE_SIZE -#define LUO_FDT_KHO_ENTRY_NAME "LUO" -#define LUO_FDT_COMPATIBLE "luo-v2" -#define LUO_FDT_ABI_HEADER "luo-abi-header" +#define LUO_KHO_ENTRY_NAME "LUO" +#define LUO_ABI_COMPATIBLE "luo-v3" +#define LUO_ABI_COMPAT_LEN ALIGN(sizeof(LUO_ABI_COMPATIBLE), 8) /** * struct luo_ser - Centralized LUO ABI header. + * @compatible: Compatibility string identifying the LUO ABI version. * @liveupdate_num: A counter tracking the number of successful live updates. * @sessions_pa: Physical address of the first session block header. * @flbs_pa: Physical address of the FLB header. * - * This structure is the root of all preserved LUO state. It is pointed to by - * the "luo-abi-header" property in the LUO FDT. + * This structure is the root of all preserved LUO state. */ struct luo_ser { + char compatible[LUO_ABI_COMPAT_LEN]; u64 liveupdate_num; u64 sessions_pa; u64 flbs_pa; @@ -111,7 +96,7 @@ struct luo_ser { * @data: Private data * @token: User provided token for this file * - * If this structure is modified, LUO_SESSION_COMPATIBLE must be updated. + * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated. */ struct luo_file_ser { char compatible[LIVEUPDATE_HNDL_COMPAT_LENGTH]; @@ -142,7 +127,7 @@ struct luo_file_set_ser { * physical memory preserved across the kexec. It provides the necessary * metadata to interpret the array of session entries that follow. * - * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated. + * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated. */ struct luo_session_header_ser { u64 count; @@ -159,7 +144,7 @@ struct luo_session_header_ser { * session) is created and passed to the new kernel, allowing it to reconstruct * the session context. * - * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated. + * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated. */ struct luo_session_ser { char name[LIVEUPDATE_SESSION_NAME_LENGTH]; @@ -180,7 +165,7 @@ struct luo_session_ser { * This structure is located at the physical address specified by the * flbs_pa in luo_ser. * - * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated. + * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated. */ struct luo_flb_header_ser { u64 pgcnt; @@ -202,7 +187,7 @@ struct luo_flb_header_ser { * passed to the new kernel. Each entry allows the LUO core to restore one * global, shared object. * - * If this structure is modified, `LUO_FDT_COMPATIBLE` must be updated. + * If this structure is modified, `LUO_ABI_COMPATIBLE` must be updated. */ struct luo_flb_ser { char name[LIVEUPDATE_FLB_COMPAT_LENGTH]; diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c index c1c290aefc76..5e12c8f8669b 100644 --- a/kernel/liveupdate/luo_core.c +++ b/kernel/liveupdate/luo_core.c @@ -50,7 +50,6 @@ #include <linux/kexec_handover.h> #include <linux/kho/abi/luo.h> #include <linux/kobject.h> -#include <linux/libfdt.h> #include <linux/liveupdate.h> #include <linux/miscdevice.h> #include <linux/mm.h> @@ -63,8 +62,7 @@ static struct { bool enabled; - void *fdt_out; - void *fdt_in; + struct luo_ser *luo_ser_out; u64 liveupdate_num; } luo_global; @@ -81,11 +79,10 @@ early_param("liveupdate", early_liveupdate_param); static int __init luo_early_startup(void) { + phys_addr_t luo_ser_phys; struct luo_ser *luo_ser; - int err, header_size; - phys_addr_t fdt_phys; - const void *ptr; - u64 luo_ser_pa; + size_t len; + int err; if (!kho_is_enabled()) { if (liveupdate_enabled()) @@ -94,40 +91,29 @@ static int __init luo_early_startup(void) return 0; } - /* Retrieve LUO subtree, and verify its format. */ - err = kho_retrieve_subtree(LUO_FDT_KHO_ENTRY_NAME, &fdt_phys, NULL); + /* Retrieve LUO state from KHO. */ + err = kho_retrieve_subtree(LUO_KHO_ENTRY_NAME, &luo_ser_phys, &len); if (err) { if (err != -ENOENT) { - pr_err("failed to retrieve FDT '%s' from KHO: %pe\n", - LUO_FDT_KHO_ENTRY_NAME, ERR_PTR(err)); + pr_err("failed to retrieve LUO state '%s' from KHO: %pe\n", + LUO_KHO_ENTRY_NAME, ERR_PTR(err)); return err; } return 0; } - luo_global.fdt_in = phys_to_virt(fdt_phys); - err = fdt_node_check_compatible(luo_global.fdt_in, 0, - LUO_FDT_COMPATIBLE); - if (err) { - pr_err("FDT '%s' is incompatible with '%s' [%d]\n", - LUO_FDT_KHO_ENTRY_NAME, LUO_FDT_COMPATIBLE, err); - + if (len < sizeof(*luo_ser)) { + pr_err("LUO state is too small (%zu < %zu)\n", len, sizeof(*luo_ser)); return -EINVAL; } - header_size = 0; - ptr = fdt_getprop(luo_global.fdt_in, 0, LUO_FDT_ABI_HEADER, &header_size); - if (!ptr || header_size != sizeof(u64)) { - pr_err("Unable to get ABI header '%s' [%d]\n", - LUO_FDT_ABI_HEADER, header_size); - + luo_ser = phys_to_virt(luo_ser_phys); + if (strncmp(luo_ser->compatible, LUO_ABI_COMPATIBLE, LUO_ABI_COMPAT_LEN)) { + pr_err("LUO state is incompatible with '%s'\n", LUO_ABI_COMPATIBLE); return -EINVAL; } - luo_ser_pa = get_unaligned((u64 *)ptr); - luo_ser = phys_to_virt(luo_ser_pa); - luo_global.liveupdate_num = luo_ser->liveupdate_num; pr_info("Retrieved live update data, liveupdate number: %lld\n", luo_global.liveupdate_num); @@ -156,37 +142,20 @@ static int __init liveupdate_early_init(void) } early_initcall(liveupdate_early_init); -/* Called during boot to create outgoing LUO fdt tree */ -static int __init luo_fdt_setup(void) +/* Called during boot to create outgoing LUO state */ +static int __init luo_state_setup(void) { struct luo_ser *luo_ser; - u64 luo_ser_pa; - void *fdt_out; int err; - fdt_out = kho_alloc_preserve(LUO_FDT_SIZE); - if (IS_ERR(fdt_out)) { - pr_err("failed to allocate/preserve FDT memory\n"); - return PTR_ERR(fdt_out); - } - luo_ser = kho_alloc_preserve(sizeof(*luo_ser)); if (IS_ERR(luo_ser)) { - err = PTR_ERR(luo_ser); - goto exit_free_fdt; + pr_err("failed to allocate/preserve LUO state memory\n"); + return PTR_ERR(luo_ser); } - luo_ser_pa = virt_to_phys(luo_ser); - - err = fdt_create(fdt_out, LUO_FDT_SIZE); - err |= fdt_finish_reservemap(fdt_out); - err |= fdt_begin_node(fdt_out, ""); - err |= fdt_property_string(fdt_out, "compatible", LUO_FDT_COMPATIBLE); - err |= fdt_property(fdt_out, LUO_FDT_ABI_HEADER, &luo_ser_pa, - sizeof(luo_ser_pa)); - err |= fdt_end_node(fdt_out); - err |= fdt_finish(fdt_out); - if (err) - goto exit_free_luo_ser; + + strscpy(luo_ser->compatible, LUO_ABI_COMPATIBLE, sizeof(luo_ser->compatible)); + luo_ser->liveupdate_num = luo_global.liveupdate_num + 1; err = luo_session_setup_outgoing(&luo_ser->sessions_pa); if (err) @@ -196,21 +165,17 @@ static int __init luo_fdt_setup(void) if (err) goto exit_free_luo_ser; - luo_ser->liveupdate_num = luo_global.liveupdate_num + 1; - - err = kho_add_subtree(LUO_FDT_KHO_ENTRY_NAME, fdt_out, - fdt_totalsize(fdt_out)); + err = kho_add_subtree(LUO_KHO_ENTRY_NAME, luo_ser, sizeof(*luo_ser)); if (err) goto exit_free_luo_ser; - luo_global.fdt_out = fdt_out; + + luo_global.luo_ser_out = luo_ser; return 0; exit_free_luo_ser: kho_unpreserve_free(luo_ser); -exit_free_fdt: - kho_unpreserve_free(fdt_out); - pr_err("failed to prepare LUO FDT: %d\n", err); + pr_err("failed to prepare LUO state: %d\n", err); return err; } @@ -226,7 +191,7 @@ static int __init luo_late_startup(void) if (!liveupdate_enabled()) return 0; - err = luo_fdt_setup(); + err = luo_state_setup(); if (err) luo_global.enabled = false; -- 2.53.0
