Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
module: use kflagstab instead of *_gpl sections
Read kflagstab section for vmlinux and modules to determine whether
kernel symbols are GPL only.
This patch eliminates the need for fragmenting the ksymtab for infering
the value of GPL-only symbol flag, henceforth stop populating *_gpl
versions of the ksymtab and kcrctab in modpost.
Signed-off-by: Siddharth Nayyar <sidnayyar@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
authored by
Siddharth Nayyar
and committed by
Sami Tolvanen
55fcb926
16d0e04f
+46
-40
+11
-10
include/linux/export-internal.h
+11
-10
include/linux/export-internal.h
···
37
37
* section flag requires it. Use '%progbits' instead of '@progbits' since the
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* former apparently works on all arches according to the binutils source.
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*/
40
-
#define __KSYMTAB(name, sym, sec, ns) \
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+
#define __KSYMTAB(name, sym, ns) \
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asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1" "\n" \
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"__kstrtab_" #name ":" "\n" \
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" .asciz \"" #name "\"" "\n" \
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"__kstrtabns_" #name ":" "\n" \
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" .asciz \"" ns "\"" "\n" \
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" .previous" "\n" \
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-
" .section \"___ksymtab" sec "+" #name "\", \"a\"" "\n" \
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+
" .section \"___ksymtab+" #name "\", \"a\"" "\n" \
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__KSYM_ALIGN "\n" \
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"__ksymtab_" #name ":" "\n" \
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__KSYM_REF(sym) "\n" \
···
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#define KSYM_FUNC(name) name
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#endif
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-
#define KSYMTAB_FUNC(name, sec, ns) __KSYMTAB(name, KSYM_FUNC(name), sec, ns)
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-
#define KSYMTAB_DATA(name, sec, ns) __KSYMTAB(name, name, sec, ns)
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+
#define KSYMTAB_FUNC(name, ns) __KSYMTAB(name, KSYM_FUNC(name), ns)
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+
#define KSYMTAB_DATA(name, ns) __KSYMTAB(name, name, ns)
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-
#define SYMBOL_CRC(sym, crc, sec) \
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-
asm(".section \"___kcrctab" sec "+" #sym "\",\"a\"" "\n" \
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-
".balign 4" "\n" \
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-
"__crc_" #sym ":" "\n" \
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-
".long " #crc "\n" \
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-
".previous" "\n")
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+
#define SYMBOL_CRC(sym, crc) \
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+
asm(" .section \"___kcrctab+" #sym "\",\"a\"" "\n" \
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+
" .balign 4" "\n" \
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+
"__crc_" #sym ":" "\n" \
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+
" .long " #crc "\n" \
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+
" .previous" "\n" \
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+
)
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#define SYMBOL_FLAGS(sym, flags) \
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asm(" .section \"___kflagstab+" #sym "\",\"a\"" "\n" \
+1
include/linux/module.h
+1
include/linux/module.h
+1
kernel/module/internal.h
+1
kernel/module/internal.h
+29
-26
kernel/module/main.c
+29
-26
kernel/module/main.c
···
11
11
#include <linux/extable.h>
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#include <linux/moduleloader.h>
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#include <linux/module_signature.h>
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+
#include <linux/module_symbol.h>
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#include <linux/trace_events.h>
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#include <linux/init.h>
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#include <linux/kallsyms.h>
···
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struct symsearch {
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const struct kernel_symbol *start, *stop;
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const u32 *crcs;
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-
enum mod_license license;
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+
const u8 *flagstab;
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};
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/*
···
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struct find_symbol_arg *fsa)
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{
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struct kernel_symbol *sym;
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-
369
-
if (!fsa->gplok && syms->license == GPL_ONLY)
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-
return false;
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+
u8 sym_flags;
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sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
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sizeof(struct kernel_symbol), cmp_name);
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if (!sym)
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return false;
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+
sym_flags = *(syms->flagstab + (sym - syms->start));
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+
if (!fsa->gplok && (sym_flags & KSYM_FLAG_GPL_ONLY))
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+
return false;
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+
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fsa->owner = owner;
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fsa->crc = symversion(syms->crcs, sym - syms->start);
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fsa->sym = sym;
380
-
fsa->license = syms->license;
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+
fsa->license = (sym_flags & KSYM_FLAG_GPL_ONLY) ? GPL_ONLY : NOT_GPL_ONLY;
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return true;
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}
···
390
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*/
391
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bool find_symbol(struct find_symbol_arg *fsa)
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{
393
-
static const struct symsearch arr[] = {
394
-
{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
395
-
NOT_GPL_ONLY },
396
-
{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
397
-
__start___kcrctab_gpl,
398
-
GPL_ONLY },
390
+
const struct symsearch syms = {
391
+
.start = __start___ksymtab,
392
+
.stop = __stop___ksymtab,
393
+
.crcs = __start___kcrctab,
394
+
.flagstab = __start___kflagstab,
399
395
};
400
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struct module *mod;
401
-
unsigned int i;
402
397
403
-
for (i = 0; i < ARRAY_SIZE(arr); i++)
404
-
if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
405
-
return true;
398
+
if (find_exported_symbol_in_section(&syms, NULL, fsa))
399
+
return true;
406
400
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list_for_each_entry_rcu(mod, &modules, list,
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lockdep_is_held(&module_mutex)) {
409
-
struct symsearch arr[] = {
410
-
{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
411
-
NOT_GPL_ONLY },
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-
{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
413
-
mod->gpl_crcs,
414
-
GPL_ONLY },
403
+
const struct symsearch syms = {
404
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.start = mod->syms,
405
+
.stop = mod->syms + mod->num_syms,
406
+
.crcs = mod->crcs,
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+
.flagstab = mod->flagstab,
415
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};
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if (mod->state == MODULE_STATE_UNFORMED)
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continue;
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420
-
for (i = 0; i < ARRAY_SIZE(arr); i++)
421
-
if (find_exported_symbol_in_section(&arr[i], mod, fsa))
422
-
return true;
413
+
if (find_exported_symbol_in_section(&syms, mod, fsa))
414
+
return true;
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415
}
424
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425
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pr_debug("Failed to find symbol %s\n", fsa->name);
···
2679
2681
sizeof(*mod->gpl_syms),
2680
2682
&mod->num_gpl_syms);
2681
2683
mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
2684
+
mod->flagstab = section_addr(info, "__kflagstab");
2682
2685
2683
2686
#ifdef CONFIG_CONSTRUCTORS
2684
2687
mod->ctors = section_objs(info, ".ctors",
···
2883
2884
return ret;
2884
2885
}
2885
2886
2886
-
static int check_export_symbol_versions(struct module *mod)
2887
+
static int check_export_symbol_sections(struct module *mod)
2887
2888
{
2889
+
if (mod->num_syms && !mod->flagstab) {
2890
+
pr_err("%s: no flags for exported symbols\n", mod->name);
2891
+
return -ENOEXEC;
2892
+
}
2888
2893
#ifdef CONFIG_MODVERSIONS
2889
2894
if ((mod->num_syms && !mod->crcs) ||
2890
2895
(mod->num_gpl_syms && !mod->gpl_crcs)) {
···
3504
3501
if (err)
3505
3502
goto free_unload;
3506
3503
3507
-
err = check_export_symbol_versions(mod);
3504
+
err = check_export_symbol_sections(mod);
3508
3505
if (err)
3509
3506
goto free_unload;
3510
3507
+4
-4
scripts/mod/modpost.c
+4
-4
scripts/mod/modpost.c
···
1876
1876
if (trim_unused_exports && !sym->used)
1877
1877
continue;
1878
1878
1879
-
buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1879
+
buf_printf(buf, "KSYMTAB_%s(%s, \"%s\");\n",
1880
1880
sym->is_func ? "FUNC" : "DATA", sym->name,
1881
-
sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1881
+
sym->namespace);
1882
1882
1883
1883
buf_printf(buf, "SYMBOL_FLAGS(%s, 0x%02x);\n",
1884
1884
sym->name, get_symbol_flags(sym));
···
1899
1899
sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1900
1900
sym->name);
1901
1901
1902
-
buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1903
-
sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1902
+
buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x);\n",
1903
+
sym->name, sym->crc);
1904
1904
}
1905
1905
}
1906
1906