From a257cacc38718c83cee003487e03197f237f5c3f Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 15 Feb 2022 13:41:02 +0100 Subject: asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of 'dereference_function_descriptor' macro to know whether an arch has function descriptors. To limit churn in one of the following patches, use an #ifdef/#else construct with empty first part instead of an #ifndef in asm-generic/sections.h On powerpc, make sure the config option matches the ABI used by the compiler with a BUILD_BUG_ON() and add missing _CALL_ELF=2 when calling 'sparse' so that sparse sees the same piece of code as GCC. And include a helper to check whether an arch has function descriptors or not : have_function_descriptors() Signed-off-by: Christophe Leroy Reviewed-by: Kees Cook Reviewed-by: Nicholas Piggin Acked-by: Helge Deller Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/4a0f11fb0ea74a3197bc44dd7ba25e53a24fd03d.1644928018.git.christophe.leroy@csgroup.eu --- include/asm-generic/sections.h | 8 +++++++- include/linux/kallsyms.h | 2 +- 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 690f741764e1..3ef83e1aebee 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -59,11 +59,17 @@ extern char __noinstr_text_start[], __noinstr_text_end[]; extern __visible const void __nosave_begin, __nosave_end; /* Function descriptor handling (if any). Override in asm/sections.h */ -#ifndef dereference_function_descriptor +#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS +#else #define dereference_function_descriptor(p) ((void *)(p)) #define dereference_kernel_function_descriptor(p) ((void *)(p)) #endif +static inline bool have_function_descriptors(void) +{ + return IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS); +} + /** * memory_contains - checks if an object is contained within a memory region * @begin: virtual address of the beginning of the memory region diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 4176c7eca7b5..ce1bd2fbf23e 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -48,7 +48,7 @@ static inline int is_ksym_addr(unsigned long addr) static inline void *dereference_symbol_descriptor(void *ptr) { -#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR +#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS struct module *mod; ptr = dereference_kernel_function_descriptor(ptr); -- cgit v1.2.3