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Commit f91a13bb authored by Linus Torvalds's avatar Linus Torvalds Committed by Rusty Russell
Browse files

module: refactor load_module 



I'd start from the trivial stuff. There's a fair amount of straight-line
code that just makes the function hard to read just because you have to
page up and down so far. Some of it is trivial to just create a helper
function for.

Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 2409e742

kernel/module.c

+69 −61
Original line number Diff line number Diff line
@@ -2107,6 +2107,71 @@ static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr, 
}

#endif



static void find_module_sections(struct module *mod, Elf_Ehdr *hdr,

				 Elf_Shdr *sechdrs, const char *secstrings)

{

	mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",

			       sizeof(*mod->kp), &mod->num_kp);

	mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",

				 sizeof(*mod->syms), &mod->num_syms);

	mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");

	mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",

				     sizeof(*mod->gpl_syms),

				     &mod->num_gpl_syms);

	mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");

	mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,

					    "__ksymtab_gpl_future",

					    sizeof(*mod->gpl_future_syms),

					    &mod->num_gpl_future_syms);

	mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,

					    "__kcrctab_gpl_future");



#ifdef CONFIG_UNUSED_SYMBOLS

	mod->unused_syms = section_objs(hdr, sechdrs, secstrings,

					"__ksymtab_unused",

					sizeof(*mod->unused_syms),

					&mod->num_unused_syms);

	mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,

					"__kcrctab_unused");

	mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,

					    "__ksymtab_unused_gpl",

					    sizeof(*mod->unused_gpl_syms),

					    &mod->num_unused_gpl_syms);

	mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,

					    "__kcrctab_unused_gpl");

#endif

#ifdef CONFIG_CONSTRUCTORS

	mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors",

				  sizeof(*mod->ctors), &mod->num_ctors);

#endif



#ifdef CONFIG_TRACEPOINTS

	mod->tracepoints = section_objs(hdr, sechdrs, secstrings,

					"__tracepoints",

					sizeof(*mod->tracepoints),

					&mod->num_tracepoints);

#endif

#ifdef CONFIG_EVENT_TRACING

	mod->trace_events = section_objs(hdr, sechdrs, secstrings,

					 "_ftrace_events",

					 sizeof(*mod->trace_events),

					 &mod->num_trace_events);

	/*

	 * This section contains pointers to allocated objects in the trace

	 * code and not scanning it leads to false positives.

	 */

	kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *

			   mod->num_trace_events, GFP_KERNEL);

#endif

#ifdef CONFIG_FTRACE_MCOUNT_RECORD

	/* sechdrs[0].sh_size is always zero */

	mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings,

					     "__mcount_loc",

					     sizeof(*mod->ftrace_callsites),

					     &mod->num_ftrace_callsites);

#endif

}



/* Allocate and load the module: note that size of section 0 is always

   zero, and we rely on this for optional sections. */

static noinline struct module *load_module(void __user *umod,
@@ -2326,7 +2391,8 @@ static noinline struct module *load_module(void __user *umod, 
			       sechdrs[i].sh_size);

		/* Update sh_addr to point to copy in image. */

		sechdrs[i].sh_addr = (unsigned long)dest;

		DEBUGP("\t0x%lx %s\n", sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name);

		DEBUGP("\t0x%lx %s\n",

		       sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name);

	}

	/* Module has been moved. */

	mod = (void *)sechdrs[modindex].sh_addr;
@@ -2368,66 +2434,8 @@ static noinline struct module *load_module(void __user *umod, 


	/* Now we've got everything in the final locations, we can

	 * find optional sections. */

	mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",

			       sizeof(*mod->kp), &mod->num_kp);

	mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",

				 sizeof(*mod->syms), &mod->num_syms);

	mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");

	mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",

				     sizeof(*mod->gpl_syms),

				     &mod->num_gpl_syms);

	mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");

	mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,

					    "__ksymtab_gpl_future",

					    sizeof(*mod->gpl_future_syms),

					    &mod->num_gpl_future_syms);

	mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,

					    "__kcrctab_gpl_future");

	find_module_sections(mod, hdr, sechdrs, secstrings);



#ifdef CONFIG_UNUSED_SYMBOLS

	mod->unused_syms = section_objs(hdr, sechdrs, secstrings,

					"__ksymtab_unused",

					sizeof(*mod->unused_syms),

					&mod->num_unused_syms);

	mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,

					"__kcrctab_unused");

	mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,

					    "__ksymtab_unused_gpl",

					    sizeof(*mod->unused_gpl_syms),

					    &mod->num_unused_gpl_syms);

	mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,

					    "__kcrctab_unused_gpl");

#endif

#ifdef CONFIG_CONSTRUCTORS

	mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors",

				  sizeof(*mod->ctors), &mod->num_ctors);

#endif



#ifdef CONFIG_TRACEPOINTS

	mod->tracepoints = section_objs(hdr, sechdrs, secstrings,

					"__tracepoints",

					sizeof(*mod->tracepoints),

					&mod->num_tracepoints);

#endif

#ifdef CONFIG_EVENT_TRACING

	mod->trace_events = section_objs(hdr, sechdrs, secstrings,

					 "_ftrace_events",

					 sizeof(*mod->trace_events),

					 &mod->num_trace_events);

	/*

	 * This section contains pointers to allocated objects in the trace

	 * code and not scanning it leads to false positives.

	 */

	kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *

			   mod->num_trace_events, GFP_KERNEL);

#endif

#ifdef CONFIG_FTRACE_MCOUNT_RECORD

	/* sechdrs[0].sh_size is always zero */

	mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings,

					     "__mcount_loc",

					     sizeof(*mod->ftrace_callsites),

					     &mod->num_ftrace_callsites);

#endif

#ifdef CONFIG_MODVERSIONS

	if ((mod->num_syms && !mod->crcs)

	    || (mod->num_gpl_syms && !mod->gpl_crcs)