From 1102f9f85bf66b1a7bd6a40afb40efbbe05dfc05 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 23 Mar 2024 20:45:11 +0900 Subject: modpost: do not make find_tosym() return NULL As mentioned in commit 397586506c3d ("modpost: Add '.ltext' and '.ltext.*' to TEXT_SECTIONS"), modpost can result in a segmentation fault due to a NULL pointer dereference in default_mismatch_handler(). find_tosym() can return the original symbol pointer instead of NULL if a better one is not found. This fixes the reported segmentation fault. Fixes: a23e7584ecf3 ("modpost: unify 'sym' and 'to' in default_mismatch_handler()") Reported-by: Nathan Chancellor Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 6b37039c9e92..2f5b91da5afa 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1007,6 +1007,8 @@ static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) { + Elf_Sym *new_sym; + /* If the supplied symbol has a valid name, return it */ if (is_valid_name(elf, sym)) return sym; @@ -1015,8 +1017,9 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) * Strive to find a better symbol name, but the resulting name may not * match the symbol referenced in the original code. */ - return symsearch_find_nearest(elf, addr, get_secindex(elf, sym), - true, 20); + new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym), + true, 20); + return new_sym ? new_sym : sym; } static bool is_executable_section(struct elf_info *elf, unsigned int secndx) -- cgit From ba05b39d54eef78043b5c8ee90545cb06a98ae6f Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 17 Jan 2024 11:50:49 +0100 Subject: s390/expoline: Make modules use kernel expolines Currently, kernel modules contain their own set of expoline thunks. In the case of EXPOLINE_EXTERN, this involves postlinking of precompiled expoline.o. expoline.o is also necessary for out-of-source tree module builds. Now that the kernel modules area is less than 4 GB away from kernel expoline thunks, make modules use kernel expolines. Also make EXPOLINE_EXTERN the default if the compiler supports it. This simplifies build and aligns with the approach adopted by other architectures. Signed-off-by: Vasily Gorbik Signed-off-by: Alexander Gordeev --- arch/s390/Kconfig | 2 +- arch/s390/Makefile | 6 ------ arch/s390/include/asm/asm-prototypes.h | 1 + arch/s390/include/asm/nospec-branch.h | 20 ++++++++++++++++++++ arch/s390/include/asm/nospec-insn.h | 13 +++++++------ arch/s390/lib/Makefile | 2 +- arch/s390/lib/expoline.S | 12 ++++++++++++ arch/s390/lib/expoline/Makefile | 3 --- arch/s390/lib/expoline/expoline.S | 12 ------------ scripts/mod/modpost.c | 5 ----- 10 files changed, 42 insertions(+), 34 deletions(-) create mode 100644 arch/s390/lib/expoline.S delete mode 100644 arch/s390/lib/expoline/Makefile delete mode 100644 arch/s390/lib/expoline/expoline.S (limited to 'scripts/mod/modpost.c') diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index df6b371ed214..a077ded1b9e6 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -555,7 +555,7 @@ config EXPOLINE If unsure, say N. config EXPOLINE_EXTERN - def_bool n + def_bool y if EXPOLINE depends on EXPOLINE depends on CC_IS_GCC && GCC_VERSION >= 110200 depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC)) diff --git a/arch/s390/Makefile b/arch/s390/Makefile index 2dbb2d2f22f9..64821f54f1e0 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -88,7 +88,6 @@ endif ifdef CONFIG_EXPOLINE ifdef CONFIG_EXPOLINE_EXTERN - KBUILD_LDFLAGS_MODULE += arch/s390/lib/expoline/expoline.o CC_FLAGS_EXPOLINE := -mindirect-branch=thunk-extern CC_FLAGS_EXPOLINE += -mfunction-return=thunk-extern else @@ -167,11 +166,6 @@ vdso_prepare: prepare0 vdso-install-y += arch/s390/kernel/vdso64/vdso64.so.dbg vdso-install-$(CONFIG_COMPAT) += arch/s390/kernel/vdso32/vdso32.so.dbg -ifdef CONFIG_EXPOLINE_EXTERN -modules_prepare: expoline_prepare -expoline_prepare: scripts - $(Q)$(MAKE) $(build)=arch/s390/lib/expoline arch/s390/lib/expoline/expoline.o -endif endif # Don't use tabs in echo arguments diff --git a/arch/s390/include/asm/asm-prototypes.h b/arch/s390/include/asm/asm-prototypes.h index 56096ae26f29..f662eb4b9246 100644 --- a/arch/s390/include/asm/asm-prototypes.h +++ b/arch/s390/include/asm/asm-prototypes.h @@ -4,6 +4,7 @@ #include #include #include +#include #include __int128_t __ashlti3(__int128_t a, int b); diff --git a/arch/s390/include/asm/nospec-branch.h b/arch/s390/include/asm/nospec-branch.h index 82725cf783c7..b9c1f3cae842 100644 --- a/arch/s390/include/asm/nospec-branch.h +++ b/arch/s390/include/asm/nospec-branch.h @@ -17,6 +17,26 @@ static inline bool nospec_uses_trampoline(void) return __is_defined(CC_USING_EXPOLINE) && !nospec_disable; } +#ifdef CONFIG_EXPOLINE_EXTERN + +void __s390_indirect_jump_r1(void); +void __s390_indirect_jump_r2(void); +void __s390_indirect_jump_r3(void); +void __s390_indirect_jump_r4(void); +void __s390_indirect_jump_r5(void); +void __s390_indirect_jump_r6(void); +void __s390_indirect_jump_r7(void); +void __s390_indirect_jump_r8(void); +void __s390_indirect_jump_r9(void); +void __s390_indirect_jump_r10(void); +void __s390_indirect_jump_r11(void); +void __s390_indirect_jump_r12(void); +void __s390_indirect_jump_r13(void); +void __s390_indirect_jump_r14(void); +void __s390_indirect_jump_r15(void); + +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_S390_EXPOLINE_H */ diff --git a/arch/s390/include/asm/nospec-insn.h b/arch/s390/include/asm/nospec-insn.h index 7a946c42ad13..cb15dd25bf21 100644 --- a/arch/s390/include/asm/nospec-insn.h +++ b/arch/s390/include/asm/nospec-insn.h @@ -16,24 +16,25 @@ */ .macro __THUNK_PROLOG_NAME name #ifdef CONFIG_EXPOLINE_EXTERN - .pushsection .text,"ax",@progbits - __ALIGN + SYM_CODE_START(\name) #else .pushsection .text.\name,"axG",@progbits,\name,comdat -#endif .globl \name .hidden \name .type \name,@function \name: CFI_STARTPROC +#endif .endm .macro __THUNK_EPILOG_NAME name - CFI_ENDPROC #ifdef CONFIG_EXPOLINE_EXTERN - .size \name, .-\name -#endif + SYM_CODE_END(\name) + EXPORT_SYMBOL(\name) +#else + CFI_ENDPROC .popsection +#endif .endm .macro __THUNK_PROLOG_BR r1 diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile index 90eac15ea62a..f43f897d3fc0 100644 --- a/arch/s390/lib/Makefile +++ b/arch/s390/lib/Makefile @@ -23,4 +23,4 @@ obj-$(CONFIG_S390_MODULES_SANITY_TEST_HELPERS) += test_modules_helpers.o lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o -obj-$(CONFIG_EXPOLINE_EXTERN) += expoline/ +obj-$(CONFIG_EXPOLINE_EXTERN) += expoline.o diff --git a/arch/s390/lib/expoline.S b/arch/s390/lib/expoline.S new file mode 100644 index 000000000000..92ed8409a7a4 --- /dev/null +++ b/arch/s390/lib/expoline.S @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include + +.macro GEN_ALL_BR_THUNK_EXTERN + .irp r1,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 + GEN_BR_THUNK_EXTERN %r\r1 + .endr +.endm + +GEN_ALL_BR_THUNK_EXTERN diff --git a/arch/s390/lib/expoline/Makefile b/arch/s390/lib/expoline/Makefile deleted file mode 100644 index 854631d9cb03..000000000000 --- a/arch/s390/lib/expoline/Makefile +++ /dev/null @@ -1,3 +0,0 @@ -# SPDX-License-Identifier: GPL-2.0 - -obj-y += expoline.o diff --git a/arch/s390/lib/expoline/expoline.S b/arch/s390/lib/expoline/expoline.S deleted file mode 100644 index 92ed8409a7a4..000000000000 --- a/arch/s390/lib/expoline/expoline.S +++ /dev/null @@ -1,12 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ - -#include -#include - -.macro GEN_ALL_BR_THUNK_EXTERN - .irp r1,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 - GEN_BR_THUNK_EXTERN %r\r1 - .endr -.endm - -GEN_ALL_BR_THUNK_EXTERN diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2f5b91da5afa..937294ff164f 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -601,11 +601,6 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname) strstarts(symname, "_savevr_") || strcmp(symname, ".TOC.") == 0) return 1; - - if (info->hdr->e_machine == EM_S390) - /* Expoline thunks are linked on all kernel modules during final link of .ko */ - if (strstarts(symname, "__s390_indirect_jump_r")) - return 1; /* Do not ignore this symbol */ return 0; } -- cgit