From abc7da58c4b388ab9f6a756c0f297c29d3af665f Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Wed, 23 Mar 2022 16:06:11 -0700 Subject: init.h: improve __setup and early_param documentation Igor noted in [1] that there are quite a few __setup() handling functions that return incorrect values. Doing this can be harmless, but it can also cause strings to be added to init's argument or environment list, polluting them. Since __setup() handling and return values are not documented, first add documentation for that. Also add more documentation for early_param() handling and return values. For __setup() functions, returning 0 (not handled) has questionable value if it is just a malformed option value, as in rodata=junk since returning 0 would just cause "rodata=junk" to be added to init's environment unnecessarily: Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux splash=native rodata=junk Also, there are no recommendations on whether to print a warning when an unknown parameter value is seen. I am not addressing that here. [1] lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Link: https://lkml.kernel.org/r/20220221050852.1147-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Reported-by: Igor Zhbanov Cc: Ingo Molnar Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/init.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'include/linux/init.h') diff --git a/include/linux/init.h b/include/linux/init.h index d82b4b2e1d25..baf0b29a7010 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -320,12 +320,19 @@ struct obs_kernel_param { __aligned(__alignof__(struct obs_kernel_param)) \ = { __setup_str_##unique_id, fn, early } +/* + * NOTE: __setup functions return values: + * @fn returns 1 (or non-zero) if the option argument is "handled" + * and returns 0 if the option argument is "not handled". + */ #define __setup(str, fn) \ __setup_param(str, fn, fn, 0) /* - * NOTE: fn is as per module_param, not __setup! - * Emits warning if fn returns non-zero. + * NOTE: @fn is as per module_param, not __setup! + * I.e., @fn returns 0 for no error or non-zero for error + * (possibly @fn returns a -errno value, but it does not matter). + * Emits warning if @fn returns non-zero. */ #define early_param(str, fn) \ __setup_param(str, fn, fn, 1) -- cgit v1.2.3 From 5dbbb3eaa2a784342f3206b77381b516181d089c Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 8 Sep 2022 14:54:54 -0700 Subject: init: Drop __nocfi from __init It's no longer necessary to disable CFI checking for all __init functions. Drop the __nocfi attribute from __init. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-13-samitolvanen@google.com --- include/linux/init.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/init.h') diff --git a/include/linux/init.h b/include/linux/init.h index baf0b29a7010..88f2964097f5 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -47,7 +47,7 @@ /* These are for everybody (although not all archs will actually discard it in modules) */ -#define __init __section(".init.text") __cold __latent_entropy __noinitretpoline __nocfi +#define __init __section(".init.text") __cold __latent_entropy __noinitretpoline #define __initdata __section(".init.data") #define __initconst __section(".init.rodata") #define __exitdata __section(".exit.data") -- cgit v1.2.3 From 5659b598b4dcb352b1a567c55fc5a658bc80076c Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 8 Sep 2022 14:54:57 -0700 Subject: treewide: Drop __cficanonical CONFIG_CFI_CLANG doesn't use a jump table anymore and therefore, won't change function references to point elsewhere. Remove the __cficanonical attribute and all uses of it. Note that the Clang definition of the attribute was removed earlier, just clean up the no-op definition and users. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-16-samitolvanen@google.com --- include/linux/compiler_types.h | 4 ---- include/linux/init.h | 4 ++-- include/linux/pci.h | 4 ++-- 3 files changed, 4 insertions(+), 8 deletions(-) (limited to 'include/linux/init.h') diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 4f2a819fd60a..6f2ec0976e2d 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -265,10 +265,6 @@ struct ftrace_likely_data { # define __nocfi #endif -#ifndef __cficanonical -# define __cficanonical -#endif - /* * Any place that could be marked with the "alloc_size" attribute is also * a place to be marked with the "malloc" attribute. Do this as part of the diff --git a/include/linux/init.h b/include/linux/init.h index 88f2964097f5..a0a90cd73ebe 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -220,8 +220,8 @@ extern bool initcall_debug; __initcall_name(initstub, __iid, id) #define __define_initcall_stub(__stub, fn) \ - int __init __cficanonical __stub(void); \ - int __init __cficanonical __stub(void) \ + int __init __stub(void); \ + int __init __stub(void) \ { \ return fn(); \ } \ diff --git a/include/linux/pci.h b/include/linux/pci.h index 060af91bafcd..5da0846aa3c1 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2019,8 +2019,8 @@ enum pci_fixup_pass { #ifdef CONFIG_LTO_CLANG #define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \ class_shift, hook, stub) \ - void __cficanonical stub(struct pci_dev *dev); \ - void __cficanonical stub(struct pci_dev *dev) \ + void stub(struct pci_dev *dev); \ + void stub(struct pci_dev *dev) \ { \ hook(dev); \ } \ -- cgit v1.2.3 From 8f824b4abd31c5ea32ae1d6725c47bdb247d18da Mon Sep 17 00:00:00 2001 From: Jiangshan Yi Date: Mon, 5 Sep 2022 10:10:34 +0800 Subject: init.h: fix spelling typo in comment Fix spelling typo in comment. Link: https://lkml.kernel.org/r/20220905021034.947701-1-13667453960@163.com Signed-off-by: Jiangshan Yi Reported-by: k2ci Signed-off-by: Andrew Morton --- include/linux/init.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/init.h') diff --git a/include/linux/init.h b/include/linux/init.h index baf0b29a7010..3254766ebbf2 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -134,7 +134,7 @@ static inline initcall_t initcall_from_entry(initcall_entry_t *entry) extern initcall_entry_t __con_initcall_start[], __con_initcall_end[]; -/* Used for contructor calls. */ +/* Used for constructor calls. */ typedef void (*ctor_fn_t)(void); struct file_system_type; -- cgit v1.2.3