From 56067812d5b0e737ac2063e94a50f76b810d6ca3 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 3 Feb 2017 09:54:05 +0000 Subject: kbuild: modversions: add infrastructure for emitting relative CRCs This add the kbuild infrastructure that will allow architectures to emit vmlinux symbol CRCs as 32-bit offsets to another location in the kernel where the actual value is stored. This works around problems with CRCs being mistaken for relocatable symbols on kernels that self relocate at runtime (i.e., powerpc with CONFIG_RELOCATABLE=y) For the kbuild side of things, this comes down to the following: - introducing a Kconfig symbol MODULE_REL_CRCS - adding a -R switch to genksyms to instruct it to emit the CRC symbols as references into the .rodata section - making modpost distinguish such references from absolute CRC symbols by the section index (SHN_ABS) - making kallsyms disregard non-absolute symbols with a __crc_ prefix Signed-off-by: Ard Biesheuvel Signed-off-by: Linus Torvalds --- scripts/kallsyms.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'scripts/kallsyms.c') diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 299b92ca1ae0..5d554419170b 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -219,6 +219,10 @@ static int symbol_valid(struct sym_entry *s) "_SDA2_BASE_", /* ppc */ NULL }; + static char *special_prefixes[] = { + "__crc_", /* modversions */ + NULL }; + static char *special_suffixes[] = { "_veneer", /* arm */ "_from_arm", /* arm */ @@ -259,6 +263,14 @@ static int symbol_valid(struct sym_entry *s) if (strcmp(sym_name, special_symbols[i]) == 0) return 0; + for (i = 0; special_prefixes[i]; i++) { + int l = strlen(special_prefixes[i]); + + if (l <= strlen(sym_name) && + strncmp(sym_name, special_prefixes[i], l) == 0) + return 0; + } + for (i = 0; special_suffixes[i]; i++) { int l = strlen(sym_name) - strlen(special_suffixes[i]); -- cgit v1.2.3-59-g8ed1b