On 8/8/19 1:35 PM, Pawel Wieczorkiewicz wrote:
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. Signed-off-by: Pawel Wieczorkiewicz <wipa...@amazon.de> Reviewed-by: Andra-Irina Paraschiv <andra...@amazon.com> Reviewed-by: Bjoern Doebel <doe...@amazon.de> Reviewed-by: Norbert Manthey <nmant...@amazon.de> --- v2: * Applied suggestions from Ross and neccessary changes enforced by previous patch of the series: - fixed indentation - used log_debug() instead of printf() - added aux. function undefined_group_size() returning 0 for a undefined group_size - added .altinstr_replacement to the special_sections array and fixed its group_size to undefined (0). --- create-diff-object.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/create-diff-object.c b/create-diff-object.c index c6183c3..8365af0 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, + }, {}, };
Unless I'm misunderstanding something, I can't see how kpatch_regenerate_special_section would work with .altinstr_replacement having a group size of 0. It looks to me like the for loop in that function would become an infinite loop (due to incrementing by group_size) and should_keep_rela_group would always return false.
Regards, -- Ross Lagerwall _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
