From b4bc842802db3314f9a657094da0450a903ea619 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 7 Feb 2011 16:02:25 -0800 Subject: module: deal with alignment issues in built-in module versions On m68k natural alignment is 2-byte boundary but we are trying to align structures in __modver section on sizeof(void *) boundary. This causes trouble when we try to access elements in this section in array-like fashion when create "version" attributes for built-in modules. Moreover, as DaveM said, we can't reliably put structures into independent objects, put them into a special section, and then expect array access over them (via the section boundaries) after linking the objects together to just "work" due to variable alignment choices in different situations. The only solution that seems to work reliably is to make an array of plain pointers to the objects in question and put those pointers in the special section. Reported-by: Geert Uytterhoeven Signed-off-by: Dmitry Torokhov Signed-off-by: Rusty Russell --- include/linux/module.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 5de42043dff0..4cfebc211695 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -174,10 +174,7 @@ extern struct module __this_module; #define MODULE_VERSION(_version) \ extern ssize_t __modver_version_show(struct module_attribute *, \ struct module *, char *); \ - static struct module_version_attribute __modver_version_attr \ - __used \ - __attribute__ ((__section__ ("__modver"),aligned(sizeof(void *)))) \ - = { \ + static struct module_version_attribute ___modver_attr = { \ .mattr = { \ .attr = { \ .name = "version", \ @@ -187,7 +184,10 @@ extern struct module __this_module; }, \ .module_name = KBUILD_MODNAME, \ .version = _version, \ - } + }; \ + static const struct module_version_attribute \ + __used __attribute__ ((__section__ ("__modver"))) \ + * __moduleparam_const __modver_attr = &___modver_attr #endif /* Optional firmware file (or files) needed by the module -- cgit v1.2.3 From 9b73a5840c7d5f77e5766626716df13787cb258c Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 7 Feb 2011 16:02:27 -0800 Subject: module: do not hide __modver_version_show declaration behind ifdef Doing so prevents the following warning from sparse: CHECK kernel/params.c kernel/params.c:817:9: warning: symbol '__modver_version_show' was not declared. Should it be static? since kernel/params.c is never compiled with MODULE being set. Signed-off-by: Dmitry Torokhov Signed-off-by: Rusty Russell --- include/linux/module.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 4cfebc211695..23996ad147e7 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -64,6 +64,9 @@ struct module_version_attribute { const char *version; } __attribute__ ((__aligned__(sizeof(void *)))); +extern ssize_t __modver_version_show(struct module_attribute *, + struct module *, char *); + struct module_kobject { struct kobject kobj; @@ -172,8 +175,6 @@ extern struct module __this_module; #define MODULE_VERSION(_version) MODULE_INFO(version, _version) #else #define MODULE_VERSION(_version) \ - extern ssize_t __modver_version_show(struct module_attribute *, \ - struct module *, char *); \ static struct module_version_attribute ___modver_attr = { \ .mattr = { \ .attr = { \ -- cgit v1.2.3 From a288bd651f4180c224cfddf837a0416157a36661 Mon Sep 17 00:00:00 2001 From: Richard Kennedy Date: Thu, 19 May 2011 16:55:25 -0600 Subject: module: remove 64 bit alignment padding from struct module with CONFIG_TRACE* Reorder struct module to remove 24 bytes of alignment padding on 64 bit builds when the CONFIG_TRACE options are selected. This allows the structure to fit into one fewer cache lines, and its size drops from 592 to 568 on x86_64. Signed-off-by: Richard Kennedy Signed-off-by: Rusty Russell --- include/linux/module.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 23996ad147e7..65cc6cc73ca8 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -368,34 +368,35 @@ struct module struct module_notes_attrs *notes_attrs; #endif + /* The command line arguments (may be mangled). People like + keeping pointers to this stuff */ + char *args; + #ifdef CONFIG_SMP /* Per-cpu data. */ void __percpu *percpu; unsigned int percpu_size; #endif - /* The command line arguments (may be mangled). People like - keeping pointers to this stuff */ - char *args; #ifdef CONFIG_TRACEPOINTS - struct tracepoint * const *tracepoints_ptrs; unsigned int num_tracepoints; + struct tracepoint * const *tracepoints_ptrs; #endif #ifdef HAVE_JUMP_LABEL struct jump_entry *jump_entries; unsigned int num_jump_entries; #endif #ifdef CONFIG_TRACING - const char **trace_bprintk_fmt_start; unsigned int num_trace_bprintk_fmt; + const char **trace_bprintk_fmt_start; #endif #ifdef CONFIG_EVENT_TRACING struct ftrace_event_call **trace_events; unsigned int num_trace_events; #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD - unsigned long *ftrace_callsites; unsigned int num_ftrace_callsites; + unsigned long *ftrace_callsites; #endif #ifdef CONFIG_MODULE_UNLOAD -- cgit v1.2.3 From de4d8d53465483168d6a627d409ee2d09d8e3308 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 19 Apr 2011 21:49:58 +0200 Subject: module: each_symbol_section instead of each_symbol Instead of having a callback function for each symbol in the kernel, have a callback for each array of symbols. This eases the logic when we move to sorted symbols and binary search. Signed-off-by: Rusty Russell Signed-off-by: Alessio Igor Bogani --- include/linux/module.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 65cc6cc73ca8..49f4ad0ddec2 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -477,8 +477,9 @@ const struct kernel_symbol *find_symbol(const char *name, bool warn); /* Walk the exported symbol table */ -bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, - unsigned int symnum, void *data), void *data); +bool each_symbol_section(bool (*fn)(const struct symsearch *arr, + struct module *owner, + void *data), void *data); /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if symnum out of range. */ -- cgit v1.2.3 From f02e8a6596b7dc9b2171f7ff5654039ef0950cdc Mon Sep 17 00:00:00 2001 From: Alessio Igor Bogani Date: Thu, 14 Apr 2011 14:59:39 +0200 Subject: module: Sort exported symbols This patch places every exported symbol in its own section (i.e. "___ksymtab+printk"). Thus the linker will use its SORT() directive to sort and finally merge all symbol in the right and final section (i.e. "__ksymtab"). The symbol prefixed archs use an underscore as prefix for symbols. To avoid collision we use a different character to create the temporary section names. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani Signed-off-by: Rusty Russell (folded in '+' fixup) Tested-by: Dirk Behme --- include/linux/module.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 49f4ad0ddec2..d9ca2d5dc6d0 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -224,7 +224,7 @@ struct module_use { extern void *__crc_##sym __attribute__((weak)); \ static const unsigned long __kcrctab_##sym \ __used \ - __attribute__((section("__kcrctab" sec), unused)) \ + __attribute__((section("___kcrctab" sec "+" #sym), unused)) \ = (unsigned long) &__crc_##sym; #else #define __CRC_SYMBOL(sym, sec) @@ -239,7 +239,7 @@ struct module_use { = MODULE_SYMBOL_PREFIX #sym; \ static const struct kernel_symbol __ksymtab_##sym \ __used \ - __attribute__((section("__ksymtab" sec), unused)) \ + __attribute__((section("___ksymtab" sec "+" #sym), unused)) \ = { (unsigned long)&sym, __kstrtab_##sym } #define EXPORT_SYMBOL(sym) \ -- cgit v1.2.3