| Message ID | 20230608142428.256985-4-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED_KSYMS | expand |
On Thu, Jun 8, 2023 at 7:24 AM Masahiro Yamada <masahiroy@kernel.org> wrote: > > Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing > CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way > whether the EXPORT_SYMBOL() is placed in *.c or *.S. > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Thanks for the patch! Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
On Thu, Jun 8, 2023 at 11:24 PM Masahiro Yamada <masahiroy@kernel.org> wrote: > > Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing > CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way > whether the EXPORT_SYMBOL() is placed in *.c or *.S. > > For further cleanups, this commit applies a similar approach to the > entire data structure of EXPORT_SYMBOL(). > > The EXPORT_SYMBOL() compilation is split into two stages. > > When a source file is compiled, EXPORT_SYMBOL() is converted into a > dummy symbol in the .export_symbol section. > > For example, > > EXPORT_SYMBOL(foo); > EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE); > > will be encoded into the following assembly code: > > .section ".export_symbol","a" > __export_symbol__foo: > .asciz "" > .balign 4 > .long foo - . I hope this will work for all arches, but unfortunately, the 0day bot reported breakages on xtensa. I will restore the code in v6.
On Thu, Jun 08, 2023 at 11:24:20PM +0900, Masahiro Yamada wrote: > Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing > CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way > whether the EXPORT_SYMBOL() is placed in *.c or *.S. > ... > We can do this better now; modpost can selectively emit KSYMTAB entries > that are really used by modules. > This patch results in Building alpha:defconfig ... failed -------------- Error log: <stdin>:1519:2: warning: #warning syscall clone3 not implemented [-Wcpp] WARNING: modpost: "saved_config" [vmlinux] is COMMON symbol ERROR: modpost: vmlinux: page_is_ram: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL. I don't know if other architectures are affected - linux-next is so broken that it is difficult to find root causes for all the breakages. Guenter --- Bisect log: # bad: [15e71592dbae49a674429c618a10401d7f992ac3] Add linux-next specific files for 20230621 # good: [45a3e24f65e90a047bef86f927ebdc4c710edaa1] Linux 6.4-rc7 git bisect start 'HEAD' 'v6.4-rc7' # bad: [e867e67cd55ae460c860ffd896c7fc96add2821c] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git git bisect bad e867e67cd55ae460c860ffd896c7fc96add2821c # bad: [57b289d5b1005a9c39d6d6567e0ef6115bd59cea] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git git bisect bad 57b289d5b1005a9c39d6d6567e0ef6115bd59cea # bad: [dc6399fc9ae6d2530fc38fb3ae96bcc8393bd66f] Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git git bisect bad dc6399fc9ae6d2530fc38fb3ae96bcc8393bd66f # good: [6d366ba598334a0457d917a7bf38efd118c5b7be] Merge branch 'mm-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm git bisect good 6d366ba598334a0457d917a7bf38efd118c5b7be # good: [82fe2e45cdb00de4fa648050ae33bdadf9b3294a] perf pmus: Check if we can encode the PMU number in perf_event_attr.type git bisect good 82fe2e45cdb00de4fa648050ae33bdadf9b3294a # bad: [d2fa756910f88c2f5871775483744407cbf67933] Merge branch 'for-next' of git://git.infradead.org/users/hch/dma-mapping.git git bisect bad d2fa756910f88c2f5871775483744407cbf67933 # good: [1b990bc8edc396a37a3ff1a43f7c329c361ee07c] Merge branch 'mm-nonmm-unstable' into mm-everything git bisect good 1b990bc8edc396a37a3ff1a43f7c329c361ee07c # good: [cff6e7f50bd315e5b39c4e46c704ac587ceb965f] kbuild: Add CLANG_FLAGS to as-instr git bisect good cff6e7f50bd315e5b39c4e46c704ac587ceb965f # bad: [8f3847e175a0044e2212fef772e7fa912270cd6d] ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL* git bisect bad 8f3847e175a0044e2212fef772e7fa912270cd6d # good: [3a3f1e573a105328a2cca45a7cfbebabbf5e3192] modpost: fix off by one in is_executable_section() git bisect good 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 # good: [92e74fb6e6196d642505ae2b74a8e327202afef9] scripts/kallsyms: constify long_options git bisect good 92e74fb6e6196d642505ae2b74a8e327202afef9 # good: [92e2921eeafdfca9acd9b83f07d2b7ca099bac24] ARC: define ASM_NL and __ALIGN(_STR) outside #ifdef __ASSEMBLY__ guard git bisect good 92e2921eeafdfca9acd9b83f07d2b7ca099bac24 # bad: [bb2aa9a94b41b883037a56709d995c269204ade0] kbuild: generate KSYMTAB entries by modpost git bisect bad bb2aa9a94b41b883037a56709d995c269204ade0 # good: [94d6cb68124b7a63f24fcc345795ba5f9a27e694] modpost: pass struct module pointer to check_section_mismatch() git bisect good 94d6cb68124b7a63f24fcc345795ba5f9a27e694 # first bad commit: [bb2aa9a94b41b883037a56709d995c269204ade0] kbuild: generate KSYMTAB entries by modpost
On Thu, Jun 22, 2023 at 1:15 AM Guenter Roeck <linux@roeck-us.net> wrote: > > On Thu, Jun 08, 2023 at 11:24:20PM +0900, Masahiro Yamada wrote: > > Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing > > CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way > > whether the EXPORT_SYMBOL() is placed in *.c or *.S. > > > ... > > > We can do this better now; modpost can selectively emit KSYMTAB entries > > that are really used by modules. > > > > This patch results in > > Building alpha:defconfig ... failed > -------------- > Error log: > <stdin>:1519:2: warning: #warning syscall clone3 not implemented [-Wcpp] > WARNING: modpost: "saved_config" [vmlinux] is COMMON symbol > ERROR: modpost: vmlinux: page_is_ram: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL. > > I don't know if other architectures are affected - linux-next is so broken > that it is difficult to find root causes for all the breakages. Thanks for the comprehensive build tests. If you compare the build log, you will see what has happened. In Linus' tree (without this patch), MODPOST Module.symvers WARNING: modpost: "saved_config" [vmlinux] is COMMON symbol WARNING: modpost: vmlinux.o: EXPORT_SYMBOL used for init/exit symbol: page_is_ram (section: .init.text) In linux-next (with this patch), MODPOST Module.symvers WARNING: modpost: "saved_config" [vmlinux] is COMMON symbol ERROR: modpost: vmlinux: page_is_ram: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL. The change is obvious - I just turned the combination of __init and EXPORT_SYMBOL into an error. But, it seemed too early to do this. I will hold it back as a warning for now, as follows: diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bdf4244da993..412115a8202a 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1239,10 +1239,10 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC); if (match(secname, PATTERNS(INIT_SECTIONS))) - error("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", + warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", mod->name, name); else if (match(secname, PATTERNS(EXIT_SECTIONS))) - error("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", + warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", mod->name, name); } Fixing the alpha code is trivial. diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c index 33bf3a627002..22131e2a9f57 100644 --- a/arch/alpha/kernel/setup.c +++ b/arch/alpha/kernel/setup.c @@ -385,7 +385,7 @@ setup_memory(void *kernel_end) #endif /* CONFIG_BLK_DEV_INITRD */ } -int __init +int page_is_ram(unsigned long pfn) { struct memclust_struct * cluster; I do not know much about the warning for "saved_config". __attribute((common)) was added in the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=3c7940961fbf9f252e20f9c455f2fe63f273294c It was more than 20 years ago, and there is no commit description. I do not know the intention of __attribute((common)). I hope the maintainers will fix the warnings, but I do not know if it is likely to happen. MAINTAINERS says "Odd Fixes" If you find a build regression, please let me know. So far, I did not get new reports from 0day bot. Thanks. > Guenter > > --- > Bisect log: > > # bad: [15e71592dbae49a674429c618a10401d7f992ac3] Add linux-next specific files for 20230621 > # good: [45a3e24f65e90a047bef86f927ebdc4c710edaa1] Linux 6.4-rc7 > git bisect start 'HEAD' 'v6.4-rc7' > # bad: [e867e67cd55ae460c860ffd896c7fc96add2821c] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git > git bisect bad e867e67cd55ae460c860ffd896c7fc96add2821c > # bad: [57b289d5b1005a9c39d6d6567e0ef6115bd59cea] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git > git bisect bad 57b289d5b1005a9c39d6d6567e0ef6115bd59cea > # bad: [dc6399fc9ae6d2530fc38fb3ae96bcc8393bd66f] Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git > git bisect bad dc6399fc9ae6d2530fc38fb3ae96bcc8393bd66f > # good: [6d366ba598334a0457d917a7bf38efd118c5b7be] Merge branch 'mm-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > git bisect good 6d366ba598334a0457d917a7bf38efd118c5b7be > # good: [82fe2e45cdb00de4fa648050ae33bdadf9b3294a] perf pmus: Check if we can encode the PMU number in perf_event_attr.type > git bisect good 82fe2e45cdb00de4fa648050ae33bdadf9b3294a > # bad: [d2fa756910f88c2f5871775483744407cbf67933] Merge branch 'for-next' of git://git.infradead.org/users/hch/dma-mapping.git > git bisect bad d2fa756910f88c2f5871775483744407cbf67933 > # good: [1b990bc8edc396a37a3ff1a43f7c329c361ee07c] Merge branch 'mm-nonmm-unstable' into mm-everything > git bisect good 1b990bc8edc396a37a3ff1a43f7c329c361ee07c > # good: [cff6e7f50bd315e5b39c4e46c704ac587ceb965f] kbuild: Add CLANG_FLAGS to as-instr > git bisect good cff6e7f50bd315e5b39c4e46c704ac587ceb965f > # bad: [8f3847e175a0044e2212fef772e7fa912270cd6d] ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL* > git bisect bad 8f3847e175a0044e2212fef772e7fa912270cd6d > # good: [3a3f1e573a105328a2cca45a7cfbebabbf5e3192] modpost: fix off by one in is_executable_section() > git bisect good 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 > # good: [92e74fb6e6196d642505ae2b74a8e327202afef9] scripts/kallsyms: constify long_options > git bisect good 92e74fb6e6196d642505ae2b74a8e327202afef9 > # good: [92e2921eeafdfca9acd9b83f07d2b7ca099bac24] ARC: define ASM_NL and __ALIGN(_STR) outside #ifdef __ASSEMBLY__ guard > git bisect good 92e2921eeafdfca9acd9b83f07d2b7ca099bac24 > # bad: [bb2aa9a94b41b883037a56709d995c269204ade0] kbuild: generate KSYMTAB entries by modpost > git bisect bad bb2aa9a94b41b883037a56709d995c269204ade0 > # good: [94d6cb68124b7a63f24fcc345795ba5f9a27e694] modpost: pass struct module pointer to check_section_mismatch() > git bisect good 94d6cb68124b7a63f24fcc345795ba5f9a27e694 > # first bad commit: [bb2aa9a94b41b883037a56709d995c269204ade0] kbuild: generate KSYMTAB entries by modpost
On Wed, Jun 21, 2023 at 7:27 PM Masahiro Yamada <masahiroy@kernel.org> wrote: > > On Thu, Jun 22, 2023 at 1:15 AM Guenter Roeck <linux@roeck-us.net> wrote: > > > > On Thu, Jun 08, 2023 at 11:24:20PM +0900, Masahiro Yamada wrote: > > > Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing > > > CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way > > > whether the EXPORT_SYMBOL() is placed in *.c or *.S. > > > > > ... > > > > > We can do this better now; modpost can selectively emit KSYMTAB entries > > > that are really used by modules. > > > > > > > This patch results in > > > > Building alpha:defconfig ... failed > > -------------- > > Error log: > > <stdin>:1519:2: warning: #warning syscall clone3 not implemented [-Wcpp] > > WARNING: modpost: "saved_config" [vmlinux] is COMMON symbol > I do not know much about the warning for "saved_config". > > > > __attribute((common)) was added in the following commit: > > https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=3c7940961fbf9f252e20f9c455f2fe63f273294c > > > It was more than 20 years ago, and there is > no commit description. > I do not know the intention of __attribute((common)). Adding __attribute__((common)) to a variable declaration, the generated assembler will contain a .comm assembler directive. https://godbolt.org/z/6jvoaGs8M https://sourceware.org/binutils/docs/as/Comm.html >>> .comm declares a common symbol named symbol. When linking, a common symbol in one object file may be merged with a defined or common symbol of the same name in another object file. When I see this, I think some kind of ODR tricks are afoot. C doesn't have ODR; C++ does, but this attribute allows for ODR-like linker merging where the linker discards duplicates because "they ought to be the same." IIRC, I think C++ template instantiations are emitted with common linkage. LLVM IR has a linkage type corresponding to this that I initially didn't understand, because without this attribute, I don't think that linkage type is ever emitted for C code. Indeed, for alpha, we can see the same symbol marked common in arch/alpha/: arch/alpha/kernel/core_tsunami.c:36:} saved_config[2] __attribute__((common)); arch/alpha/kernel/sys_sio.c:43:} saved_config __attribute((common)); arch/alpha/kernel/core_cia.c:577:} saved_config __attribute((common)); arch/alpha/kernel/core_titan.c:36:} saved_config[4] __attribute__((common)); All of these have different sizes, so according to the GAS manual, this line comes into play: >>> If ld sees multiple common symbols with the same name, and they do not all have the same size, it will allocate space using the largest size. This kind of smells like some overcomplicating code to save like 30B of static memory. Fixing this requires careful use of enums. For arch/alpha/ not sure such a rework is worth it, given the imminent demise of the architecture I sense looming on the horizon. > > I hope the maintainers will fix the warnings, > but I do not know if it is likely to happen. > > MAINTAINERS says "Odd Fixes" > > If you find a build regression, please let me know. > So far, I did not get new reports from 0day bot. > > > Thanks. > > > > > > Guenter > > > > --- > > Bisect log: > > > > # bad: [15e71592dbae49a674429c618a10401d7f992ac3] Add linux-next specific files for 20230621 > > # good: [45a3e24f65e90a047bef86f927ebdc4c710edaa1] Linux 6.4-rc7 > > git bisect start 'HEAD' 'v6.4-rc7' > > # bad: [e867e67cd55ae460c860ffd896c7fc96add2821c] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git > > git bisect bad e867e67cd55ae460c860ffd896c7fc96add2821c > > # bad: [57b289d5b1005a9c39d6d6567e0ef6115bd59cea] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git > > git bisect bad 57b289d5b1005a9c39d6d6567e0ef6115bd59cea > > # bad: [dc6399fc9ae6d2530fc38fb3ae96bcc8393bd66f] Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git > > git bisect bad dc6399fc9ae6d2530fc38fb3ae96bcc8393bd66f > > # good: [6d366ba598334a0457d917a7bf38efd118c5b7be] Merge branch 'mm-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > > git bisect good 6d366ba598334a0457d917a7bf38efd118c5b7be > > # good: [82fe2e45cdb00de4fa648050ae33bdadf9b3294a] perf pmus: Check if we can encode the PMU number in perf_event_attr.type > > git bisect good 82fe2e45cdb00de4fa648050ae33bdadf9b3294a > > # bad: [d2fa756910f88c2f5871775483744407cbf67933] Merge branch 'for-next' of git://git.infradead.org/users/hch/dma-mapping.git > > git bisect bad d2fa756910f88c2f5871775483744407cbf67933 > > # good: [1b990bc8edc396a37a3ff1a43f7c329c361ee07c] Merge branch 'mm-nonmm-unstable' into mm-everything > > git bisect good 1b990bc8edc396a37a3ff1a43f7c329c361ee07c > > # good: [cff6e7f50bd315e5b39c4e46c704ac587ceb965f] kbuild: Add CLANG_FLAGS to as-instr > > git bisect good cff6e7f50bd315e5b39c4e46c704ac587ceb965f > > # bad: [8f3847e175a0044e2212fef772e7fa912270cd6d] ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL* > > git bisect bad 8f3847e175a0044e2212fef772e7fa912270cd6d > > # good: [3a3f1e573a105328a2cca45a7cfbebabbf5e3192] modpost: fix off by one in is_executable_section() > > git bisect good 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 > > # good: [92e74fb6e6196d642505ae2b74a8e327202afef9] scripts/kallsyms: constify long_options > > git bisect good 92e74fb6e6196d642505ae2b74a8e327202afef9 > > # good: [92e2921eeafdfca9acd9b83f07d2b7ca099bac24] ARC: define ASM_NL and __ALIGN(_STR) outside #ifdef __ASSEMBLY__ guard > > git bisect good 92e2921eeafdfca9acd9b83f07d2b7ca099bac24 > > # bad: [bb2aa9a94b41b883037a56709d995c269204ade0] kbuild: generate KSYMTAB entries by modpost > > git bisect bad bb2aa9a94b41b883037a56709d995c269204ade0 > > # good: [94d6cb68124b7a63f24fcc345795ba5f9a27e694] modpost: pass struct module pointer to check_section_mismatch() > > git bisect good 94d6cb68124b7a63f24fcc345795ba5f9a27e694 > > # first bad commit: [bb2aa9a94b41b883037a56709d995c269204ade0] kbuild: generate KSYMTAB entries by modpost > > > > -- > Best Regards > Masahiro Yamada
diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild index aefae2efde9f..33733245f42b 100644 --- a/arch/ia64/include/asm/Kbuild +++ b/arch/ia64/include/asm/Kbuild @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 generated-y += syscall_table.h generic-y += agp.h +generic-y += export.h generic-y += kvm_para.h generic-y += mcs_spinlock.h generic-y += vtime.h diff --git a/arch/ia64/include/asm/export.h b/arch/ia64/include/asm/export.h deleted file mode 100644 index ad18c6583252..000000000000 --- a/arch/ia64/include/asm/export.h +++ /dev/null @@ -1,3 +0,0 @@ -/* EXPORT_DATA_SYMBOL != EXPORT_SYMBOL here */ -#define KSYM_FUNC(name) @fptr(name) -#include <asm-generic/export.h> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 5e4b1f2369d2..0ae9f38a904c 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -3,86 +3,12 @@ #define __ASM_GENERIC_EXPORT_H /* - * This comment block is used by fixdep. Please do not remove. - * - * When CONFIG_MODVERSIONS is changed from n to y, all source files having - * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a - * side effect of the *.o build rule. + * <asm/export.h> and <asm-generic/export.h> are deprecated. + * Please include <linux/export.h> directly. */ +#include <linux/export.h> -#ifndef KSYM_FUNC -#define KSYM_FUNC(x) x -#endif -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define KSYM_ALIGN 4 -#elif defined(CONFIG_64BIT) -#define KSYM_ALIGN 8 -#else -#define KSYM_ALIGN 4 -#endif - -.macro __put, val, name -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS - .long \val - ., \name - ., 0 -#elif defined(CONFIG_64BIT) - .quad \val, \name, 0 -#else - .long \val, \name, 0 -#endif -.endm - -/* - * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) - * section flag requires it. Use '%progbits' instead of '@progbits' since the - * former apparently works on all arches according to the binutils source. - */ - -.macro ___EXPORT_SYMBOL name,val,sec -#if defined(CONFIG_MODULES) && !defined(__DISABLE_EXPORTS) - .section ___ksymtab\sec+\name,"a" - .balign KSYM_ALIGN -__ksymtab_\name: - __put \val, __kstrtab_\name - .previous - .section __ksymtab_strings,"aMS",%progbits,1 -__kstrtab_\name: - .asciz "\name" - .previous -#endif -.endm - -#if defined(CONFIG_TRIM_UNUSED_KSYMS) - -#include <linux/kconfig.h> -#include <generated/autoksyms.h> - -.macro __ksym_marker sym - .section ".discard.ksym","a" -__ksym_marker_\sym: - .previous -.endm - -#define __EXPORT_SYMBOL(sym, val, sec) \ - __ksym_marker sym; \ - __cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym)) -#define __cond_export_sym(sym, val, sec, conf) \ - ___cond_export_sym(sym, val, sec, conf) -#define ___cond_export_sym(sym, val, sec, enabled) \ - __cond_export_sym_##enabled(sym, val, sec) -#define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec -#define __cond_export_sym_0(sym, val, sec) /* nothing */ - -#else -#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec -#endif - -#define EXPORT_SYMBOL(name) \ - __EXPORT_SYMBOL(name, KSYM_FUNC(name),) -#define EXPORT_SYMBOL_GPL(name) \ - __EXPORT_SYMBOL(name, KSYM_FUNC(name), _gpl) -#define EXPORT_DATA_SYMBOL(name) \ - __EXPORT_SYMBOL(name, name,) -#define EXPORT_DATA_SYMBOL_GPL(name) \ - __EXPORT_SYMBOL(name, name,_gpl) +#define EXPORT_DATA_SYMBOL(name) EXPORT_SYMBOL(name) +#define EXPORT_DATA_SYMBOL_GPL(name) EXPORT_SYMBOL_GPL(name) #endif diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..e65d55e8819c 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -1006,6 +1006,7 @@ PATCHABLE_DISCARDS \ *(.discard) \ *(.discard.*) \ + *(.export_symbol) \ *(.modinfo) \ /* ld.bfd warns about .gnu.version* even when not emitted */ \ *(.gnu.version*) \ diff --git a/include/linux/export-internal.h b/include/linux/export-internal.h index fe7e6ba918f1..1c849db953a5 100644 --- a/include/linux/export-internal.h +++ b/include/linux/export-internal.h @@ -10,6 +10,55 @@ #include <linux/compiler.h> #include <linux/types.h> +#if defined(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS) +/* + * relative reference: this reduces the size by half on 64-bit architectures, + * and eliminates the need for absolute relocations that require runtime + * processing on relocatable kernels. + */ +#define __KSYM_REF(sym) ".long " #sym "- ." +#elif defined(CONFIG_64BIT) +#define __KSYM_REF(sym) ".quad " #sym +#else +#define __KSYM_REF(sym) ".long " #sym +#endif + +/* + * For every exported symbol, do the following: + * + * - Put the name of the symbol and namespace (empty string "" for none) in + * __ksymtab_strings. + * - Place a struct kernel_symbol entry in the __ksymtab section. + * + * Note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) + * section flag requires it. Use '%progbits' instead of '@progbits' since the + * former apparently works on all arches according to the binutils source. + */ +#define __KSYMTAB(name, sym, sec, ns) \ + asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1" "\n" \ + "__kstrtab_" #name ":" "\n" \ + " .asciz \"" #name "\"" "\n" \ + "__kstrtabns_" #name ":" "\n" \ + " .asciz \"" ns "\"" "\n" \ + " .previous" "\n" \ + " .section \"___ksymtab" sec "+" #name "\", \"a\"" "\n" \ + " .balign 4" "\n" \ + "__ksymtab_" #name ":" "\n" \ + __KSYM_REF(sym) "\n" \ + __KSYM_REF(__kstrtab_ ##name) "\n" \ + __KSYM_REF(__kstrtabns_ ##name) "\n" \ + " .previous" "\n" \ + ) + +#ifdef CONFIG_IA64 +#define KSYM_FUNC(name) @fptr(name) +#else +#define KSYM_FUNC(name) name +#endif + +#define KSYMTAB_FUNC(name, sec, ns) __KSYMTAB(name, KSYM_FUNC(name), sec, ns) +#define KSYMTAB_DATA(name, sec, ns) __KSYMTAB(name, name, sec, ns) + #define SYMBOL_CRC(sym, crc, sec) \ asm(".section \"___kcrctab" sec "+" #sym "\",\"a\"" "\n" \ "__crc_" #sym ":" "\n" \ diff --git a/include/linux/export.h b/include/linux/export.h index 3f31ced0d977..529435a821c0 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -2,6 +2,7 @@ #ifndef _LINUX_EXPORT_H #define _LINUX_EXPORT_H +#include <linux/compiler.h> #include <linux/stringify.h> /* @@ -28,72 +29,31 @@ extern struct module __this_module; #else #define THIS_MODULE ((struct module *)0) #endif +#endif /* __ASSEMBLY__ */ -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#include <linux/compiler.h> -/* - * Emit the ksymtab entry as a pair of relative references: this reduces - * the size by half on 64-bit architectures, and eliminates the need for - * absolute relocations that require runtime processing on relocatable - * kernels. - */ -#define __KSYMTAB_ENTRY(sym, sec) \ - __ADDRESSABLE(sym) \ - asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \ - " .balign 4 \n" \ - "__ksymtab_" #sym ": \n" \ - " .long " #sym "- . \n" \ - " .long __kstrtab_" #sym "- . \n" \ - " .long __kstrtabns_" #sym "- . \n" \ - " .previous \n") - -struct kernel_symbol { - int value_offset; - int name_offset; - int namespace_offset; -}; -#else -#define __KSYMTAB_ENTRY(sym, sec) \ - static const struct kernel_symbol __ksymtab_##sym \ - __attribute__((section("___ksymtab" sec "+" #sym), used)) \ - __aligned(sizeof(void *)) \ - = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym } - -struct kernel_symbol { - unsigned long value; - const char *name; - const char *namespace; -}; -#endif +#define ____EXPORT_SYMBOL(sym, license, ns) \ + .section ".export_symbol","a" ; \ + __export_symbol_##license##_##sym: ; \ + .asciz ns ; \ + .balign 4 ; \ + .long sym - . ; \ + .previous #ifdef __GENKSYMS__ #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) +#elif defined(__ASSEMBLY__) + +#define ___EXPORT_SYMBOL(sym, license, ns) \ + ____EXPORT_SYMBOL(sym, license, ns) + #else -/* - * For every exported symbol, do the following: - * - * - Put the name of the symbol and namespace (empty string "" for none) in - * __ksymtab_strings. - * - Place a struct kernel_symbol entry in the __ksymtab section. - * - * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) - * section flag requires it. Use '%progbits' instead of '@progbits' since the - * former apparently works on all arches according to the binutils source. - */ -#define ___EXPORT_SYMBOL(sym, sec, ns) \ - extern typeof(sym) sym; \ - extern const char __kstrtab_##sym[]; \ - extern const char __kstrtabns_##sym[]; \ - asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ - "__kstrtab_" #sym ": \n" \ - " .asciz \"" #sym "\" \n" \ - "__kstrtabns_" #sym ": \n" \ - " .asciz \"" ns "\" \n" \ - " .previous \n"); \ - __KSYMTAB_ENTRY(sym, sec) +#define ___EXPORT_SYMBOL(sym, license, ns) \ + extern typeof(sym) sym; \ + __ADDRESSABLE(sym) \ + asm(__stringify(____EXPORT_SYMBOL(sym, license, ns))) #endif @@ -117,9 +77,21 @@ struct kernel_symbol { * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are * discarded in the final link stage. */ + +#ifdef __ASSEMBLY__ + +#define __ksym_marker(sym) \ + .section ".discard.ksym","a" ; \ +__ksym_marker_##sym: ; \ + .previous + +#else + #define __ksym_marker(sym) \ static int __ksym_marker_##sym[0] __section(".discard.ksym") __used +#endif + #define __EXPORT_SYMBOL(sym, sec, ns) \ __ksym_marker(sym); \ __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) @@ -147,11 +119,9 @@ struct kernel_symbol { #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") #endif -#define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") -#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") -#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", __stringify(ns)) -#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", __stringify(ns)) - -#endif /* !__ASSEMBLY__ */ +#define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym,) +#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym,gpl) +#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym,, __stringify(ns)) +#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym,gpl, __stringify(ns)) #endif /* _LINUX_EXPORT_H */ diff --git a/include/linux/pm.h b/include/linux/pm.h index 035d9649eba4..aabb6bd8f89e 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -388,10 +388,10 @@ const struct dev_pm_ops name = { \ #define EXPORT_PM_FN_NS_GPL(name, ns) #endif -#define EXPORT_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "", "") -#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "_gpl", "") -#define EXPORT_NS_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "", #ns) -#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "_gpl", #ns) +#define EXPORT_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name,, "") +#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name,gpl, "") +#define EXPORT_NS_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name,, #ns) +#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name,gpl, #ns) /* * Use this if you want to use the same suspend and resume callbacks for suspend diff --git a/kernel/module/internal.h b/kernel/module/internal.h index dc7b0160c480..c8b7b4dcf782 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -32,6 +32,18 @@ /* Maximum number of characters written by module_flags() */ #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) +struct kernel_symbol { +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS + int value_offset; + int name_offset; + int namespace_offset; +#else + unsigned long value; + const char *name; + const char *namespace; +#endif +}; + extern struct mutex module_mutex; extern struct list_head modules; diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 9f94fc83f086..6bf026a304e4 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -161,7 +161,7 @@ quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ ifdef CONFIG_MODVERSIONS # When module versioning is enabled the following steps are executed: # o compile a <file>.o from <file>.c -# o if <file>.o doesn't contain a __ksymtab version, i.e. does +# o if <file>.o doesn't contain a __export_symbol*, i.e. does # not export symbols, it's done. # o otherwise, we calculate symbol versions using the good old # genksyms on the preprocessed source and dump them into the .cmd file. @@ -169,7 +169,7 @@ ifdef CONFIG_MODVERSIONS # be compiled and linked to the kernel and/or modules. gen_symversions = \ - if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ + if $(NM) $@ 2>/dev/null | grep -q '__export_symbol_[^_]*_'; then \ $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ >> $(dot-target).cmd; \ fi @@ -340,9 +340,7 @@ $(obj)/%.ll: $(src)/%.rs FORCE cmd_gensymtypes_S = \ { echo "\#include <linux/kernel.h>" ; \ echo "\#include <asm/asm-prototypes.h>" ; \ - $(CPP) $(a_flags) $< | \ - grep "\<___EXPORT_SYMBOL\>" | \ - sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ + $(NM) $@ | sed -n 's/.*__export_symbol_[^_]*_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \ $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ diff --git a/scripts/check-local-export b/scripts/check-local-export index f90b5a9c67b3..969a313b9299 100755 --- a/scripts/check-local-export +++ b/scripts/check-local-export @@ -46,9 +46,9 @@ BEGIN { { symbol_types[$3]=$2 } # append the exported symbol to the array -($3 ~ /^__ksymtab_/) { +($3 ~ /^__export_symbol_(gpl)?_.*/) { export_symbols[i] = $3 - sub(/^__ksymtab_/, "", export_symbols[i]) + sub(/^__export_symbol_(gpl)?_/, "", export_symbols[i]) i++ } diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 403ba4d923f5..0ae6c9c5bdf6 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -217,6 +217,7 @@ struct symbol { unsigned int crc; bool crc_valid; bool weak; + bool is_func; bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ char name[]; }; @@ -533,6 +534,8 @@ static int parse_elf(struct elf_info *info, const char *filename) fatal("%s has NOBITS .modinfo\n", filename); info->modinfo = (void *)hdr + sechdrs[i].sh_offset; info->modinfo_len = sechdrs[i].sh_size; + } else if (!strcmp(secname, ".export_symbol")) { + info->export_symbol_secndx = i; } if (sechdrs[i].sh_type == SHT_SYMTAB) { @@ -655,18 +658,6 @@ static void handle_symbol(struct module *mod, struct elf_info *info, ELF_ST_BIND(sym->st_info) == STB_WEAK); break; default: - /* All exported symbols */ - if (strstarts(symname, "__ksymtab_")) { - const char *name, *secname; - - name = symname + strlen("__ksymtab_"); - secname = sec_name(info, get_secindex(info, sym)); - - if (strstarts(secname, "___ksymtab_gpl+")) - sym_add_exported(name, mod, true); - else if (strstarts(secname, "___ksymtab+")) - sym_add_exported(name, mod, false); - } if (strcmp(symname, "init_module") == 0) mod->has_init = true; if (strcmp(symname, "cleanup_module") == 0) @@ -848,7 +839,6 @@ enum mismatch { XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, - EXPORT_TO_INIT_EXIT, EXTABLE_TO_NON_TEXT, }; @@ -920,12 +910,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, }, -/* Do not export init/exit functions or data */ -{ - .fromsec = { "___ksymtab*", NULL }, - .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, - .mismatch = EXPORT_TO_INIT_EXIT, -}, { .fromsec = { "__ex_table", NULL }, /* If you're adding any new black-listed sections in here, consider @@ -1180,10 +1164,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", modname, fromsym, fromsec, tosym, tosec); break; - case EXPORT_TO_INIT_EXIT: - warn("%s: EXPORT_SYMBOL used for init/exit symbol: %s (section: %s)\n", - modname, tosym, tosec); - break; case EXTABLE_TO_NON_TEXT: warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", modname, fromsec, (long)faddr, tosec, tosym); @@ -1211,14 +1191,69 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } +static void check_export_symbol(struct module *mod, struct elf_info *elf, + Elf_Addr faddr, const char *secname, + Elf_Sym *sym) +{ + const char *label_name, *name, *prefix; + Elf_Sym *label; + struct symbol *s; + bool is_gpl; + + label = find_fromsym(elf, faddr, elf->export_symbol_secndx); + label_name = sym_name(elf, label); + + name = sym_name(elf, sym); + + if (strstarts(label_name, "__export_symbol_gpl_")) { + prefix = "__export_symbol_gpl_"; + is_gpl = true; + } else if (strstarts(label_name, "__export_symbol__")) { + prefix = "__export_symbol__"; + is_gpl = false; + } else { + error("%s: .export_symbol section contains strange symbol '%s'\n", + mod->name, label_name); + return; + } + + if (strcmp(label_name + strlen(prefix), name)) { + error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", + mod->name, name); + return; + } + + s = sym_add_exported(name, mod, is_gpl); + sym_update_namespace(name, sym_get_data(elf, label)); + + /* + * We need to be aware whether we are exporting a function or + * a data on some architectures. + */ + s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC); + + if (match(secname, PATTERNS(INIT_SECTIONS))) + error("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", + mod->name, name); + else if (match(secname, PATTERNS(EXIT_SECTIONS))) + error("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", + mod->name, name); +} + static void check_section_mismatch(struct module *mod, struct elf_info *elf, Elf_Sym *sym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, Elf_Addr taddr) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); - const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); + const struct sectioncheck *mismatch; + if (elf->export_symbol_secndx == fsecndx) { + check_export_symbol(mod, elf, faddr, tosec, sym); + return; + } + + mismatch = section_mismatch(fromsec, tosec); if (!mismatch) return; @@ -1698,15 +1733,6 @@ static void read_symbols(const char *modname) handle_moddevtable(mod, &info, sym, symname); } - for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { - symname = remove_dot(info.strtab + sym->st_name); - - /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */ - if (strstarts(symname, "__kstrtabns_")) - sym_update_namespace(symname + strlen("__kstrtabns_"), - sym_get_data(&info, sym)); - } - check_sec_ref(mod, &info); if (!mod->is_vmlinux) { @@ -1890,6 +1916,14 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) { struct symbol *sym; + /* generate struct for exported symbols */ + buf_printf(buf, "\n"); + list_for_each_entry(sym, &mod->exported_symbols, list) + buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", + sym->is_func ? "FUNC" : "DATA", sym->name, + sym->is_gpl_only ? "_gpl" : "", + sym->namespace ?: ""); + if (!modversions) return; diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index b1e2d95f8047..dfdb9484e325 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -137,6 +137,7 @@ struct elf_info { Elf_Shdr *sechdrs; Elf_Sym *symtab_start; Elf_Sym *symtab_stop; + unsigned int export_symbol_secndx; /* .export_symbol section */ char *strtab; char *modinfo; unsigned int modinfo_len;
Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way whether the EXPORT_SYMBOL() is placed in *.c or *.S. For further cleanups, this commit applies a similar approach to the entire data structure of EXPORT_SYMBOL(). The EXPORT_SYMBOL() compilation is split into two stages. When a source file is compiled, EXPORT_SYMBOL() is converted into a dummy symbol in the .export_symbol section. For example, EXPORT_SYMBOL(foo); EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE); will be encoded into the following assembly code: .section ".export_symbol","a" __export_symbol__foo: .asciz "" .balign 4 .long foo - . .previous .section ".export_symbol","a" __export_symbol_gpl_bar: .asciz "BAR_NAMESPACE" .balign 4 .long bar - . .previous They are mere markers to tell modpost the name, license, and namespace of the symbols. They will be dropped from the final vmlinux and modules because the *(.export_symbol) will go into /DISCARD/ in the linker script. Then, modpost extracts all the information about EXPORT_SYMBOL() from the .export_symbol section, and generates the final C code: KSYMTAB_FUNC(foo, "", ""); KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE"); KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct kernel_symbol that will be linked to the vmlinux or a module. With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S files, providing the following benefits. [1] Deprecate EXPORT_DATA_SYMBOL() In the old days, EXPORT_SYMBOL() was only available in C files. To export a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file. arch/arm/kernel/armksyms.c is one example written in the classic manner. Commit 22823ab419d8 ("EXPORT_SYMBOL() for asm") removed this limitation. Since then, EXPORT_SYMBOL() can be placed close to the symbol definition in *.S files. It was a nice improvement. However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL() for data objects on some architectures. In the new approach, modpost checks symbol's type (STT_FUNC or not), and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly. There are only two users of EXPORT_DATA_SYMBOL: EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S) EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S) They are transformed as follows and output into .vmlinux.export.c KSYMTAB_DATA(empty_zero_page, "_gpl", ""); KSYMTAB_DATA(ia64_ivt, "", ""); The other EXPORT_SYMBOL users in ia64 assembly are output as KSYMTAB_FUNC(). EXPORT_DATA_SYMBOL() is now deprecated. [2] merge <linux/export.h> and <asm-generic/export.h> There are two similar header implementations: include/linux/export.h for .c files include/asm-generic/export.h for .S files Ideally, the functionality should be consistent between them, but they tend to diverge. Commit 8651ec01daed ("module: add support for symbol namespaces.") did not support the namespace for *.S files. This commit shifts the essential implementation part to C, which supports EXPORT_SYMBOL_NS() for *.S files. <asm/export.h> and <asm-generic/export.h> will remain as a wrapper of <linux/export.h> for a while. They will be removed after #include <asm/export.h> directives are all replaced with #include <linux/export.h>. [3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit) When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. We can do this better now; modpost can selectively emit KSYMTAB entries that are really used by modules. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- Changes in v7: - Fix sparse warning reported by 0day bot https://lore.kernel.org/linux-kbuild/202305280830.Rj5ltc9M-lkp@intel.com/ Changes in v6: - Fix build error on UML Changes in v5: - Fix build error on ARM Changes in v4: - Version 3 did not work if a same name symbol exists in a different compilation unit Fix it. Changes in v3: - Move struct kernel_symbol to kernel/module/internal.h Changes in v2: - Use KSYMTAB_FUNC and KSYMTAB_DATA for functions and data, respectively This distinction is needed for ia64. arch/ia64/include/asm/Kbuild | 1 + arch/ia64/include/asm/export.h | 3 - include/asm-generic/export.h | 84 ++----------------------- include/asm-generic/vmlinux.lds.h | 1 + include/linux/export-internal.h | 49 +++++++++++++++ include/linux/export.h | 98 ++++++++++------------------- include/linux/pm.h | 8 +-- kernel/module/internal.h | 12 ++++ scripts/Makefile.build | 8 +-- scripts/check-local-export | 4 +- scripts/mod/modpost.c | 100 ++++++++++++++++++++---------- scripts/mod/modpost.h | 1 + 12 files changed, 179 insertions(+), 190 deletions(-) delete mode 100644 arch/ia64/include/asm/export.h