From aa5c99f331a118dd8f5dc839b423806fab0fe942 Mon Sep 17 00:00:00 2001 From: Pawel Wieczorkiewicz Date: Wed, 21 Aug 2019 08:20:45 +0000 Subject: [PATCH] create-diff-object: Add new entries to special sections array Handle .livepatch.hooks* and .altinstr_replacement sections as the special sections with assigned group_size resolution function. By default each .livepatch.hooks* sections' entry is 8 bytes long (a pointer). The .altinstr_replacement section has undefined group_size. Allow to specify different .livepatch.hooks* section entry size using shell environment variable HOOK_STRUCT_SIZE. Add an explicit check to kpatch_regenerate_special_section() skipping regeneration of special sections, whose group_size is 0. Signed-off-by: Pawel Wieczorkiewicz Reviewed-by: Andra-Irina Paraschiv Reviewed-by: Bjoern Doebel Reviewed-by: Norbert Manthey Reviewed-by: Ross Lagerwall Signed-off-by: Ross Lagerwall --- create-diff-object.c | 42 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 39 insertions(+), 3 deletions(-) diff --git a/create-diff-object.c b/create-diff-object.c index c6183c3..0d231d5 100644 --- a/create-diff-object.c +++ b/create-diff-object.c @@ -995,6 +995,24 @@ static int altinstructions_group_size(struct kpatch_elf *kelf, int offset) return size; } +static int livepatch_hooks_group_size(struct kpatch_elf *kelf, int offset) +{ + static int size = 0; + char *str; + if (!size) { + str = getenv("HOOK_STRUCT_SIZE"); + size = str ? atoi(str) : 8; + } + + log_debug("livepatch_hooks_size=%d\n", size); + return size; +} + +static int undefined_group_size(struct kpatch_elf *kelf, int offset) +{ + return 0; +} + /* * The rela groups in the .fixup section vary in size. The beginning of each * .fixup rela group is referenced by the .ex_table section. To find the size @@ -1072,6 +1090,18 @@ static struct special_section special_sections[] = { .name = ".altinstructions", .group_size = altinstructions_group_size, }, + { + .name = ".altinstr_replacement", + .group_size = undefined_group_size, + }, + { + .name = ".livepatch.hooks.load", + .group_size = livepatch_hooks_group_size, + }, + { + .name = ".livepatch.hooks.unload", + .group_size = livepatch_hooks_group_size, + }, {}, }; @@ -1142,6 +1172,15 @@ static void kpatch_regenerate_special_section(struct kpatch_elf *kelf, LIST_HEAD(newrelas); + src_offset = 0; + dest_offset = 0; + group_size = special->group_size(kelf, src_offset); + if (group_size == 0) { + log_normal("Skipping regeneration of a special section: %s\n", + special->name); + return; + } + src = sec->base->data->d_buf; /* alloc buffer for new base section */ dest = malloc(sec->base->sh.sh_size); @@ -1156,9 +1195,6 @@ static void kpatch_regenerate_special_section(struct kpatch_elf *kelf, } } - group_size = 0; - src_offset = 0; - dest_offset = 0; for ( ; src_offset < sec->base->sh.sh_size; src_offset += group_size) { group_size = special->group_size(kelf, src_offset); -- 2.39.5