Re: [PATCH 1/2] modpost: file2alias: go back to simple devtable lookup
From: Masahiro Yamada
Date: Mon Nov 26 2018 - 09:54:08 EST
On Fri, Nov 23, 2018 at 1:52 AM Masahiro Yamada
<yamada.masahiro@xxxxxxxxxxxxx> wrote:
>
> Commit e49ce14150c6 ("modpost: use linker section to generate table.")
> was not so cool as we had expected because it ended up with ugly section
> hacks when commit dd2a3acaecd7 ("mod/file2alias: make modpost compile on
> darwin again") came in.
>
> Given a certain degree of unknowledge about the link stage of host
> programs, I really want to see simple, stupid table lookup so that
> this works in the same way regardless of the underlying executable
> binary format.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
Applied to linux-kbuild.
> scripts/mod/file2alias.c | 144 ++++++++++++++++-------------------------------
> 1 file changed, 49 insertions(+), 95 deletions(-)
>
> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> index 28a6166..7e4aede 100644
> --- a/scripts/mod/file2alias.c
> +++ b/scripts/mod/file2alias.c
> @@ -50,46 +50,6 @@ struct devtable {
> void *function;
> };
>
> -#define ___cat(a,b) a ## b
> -#define __cat(a,b) ___cat(a,b)
> -
> -/* we need some special handling for this host tool running eventually on
> - * Darwin. The Mach-O section handling is a bit different than ELF section
> - * handling. The differnces in detail are:
> - * a) we have segments which have sections
> - * b) we need a API call to get the respective section symbols */
> -#if defined(__MACH__)
> -#include <mach-o/getsect.h>
> -
> -#define INIT_SECTION(name) do { \
> - unsigned long name ## _len; \
> - char *__cat(pstart_,name) = getsectdata("__TEXT", \
> - #name, &__cat(name,_len)); \
> - char *__cat(pstop_,name) = __cat(pstart_,name) + \
> - __cat(name, _len); \
> - __cat(__start_,name) = (void *)__cat(pstart_,name); \
> - __cat(__stop_,name) = (void *)__cat(pstop_,name); \
> - } while (0)
> -#define SECTION(name) __attribute__((section("__TEXT, " #name)))
> -
> -struct devtable **__start___devtable, **__stop___devtable;
> -#else
> -#define INIT_SECTION(name) /* no-op for ELF */
> -#define SECTION(name) __attribute__((section(#name)))
> -
> -/* We construct a table of pointers in an ELF section (pointers generally
> - * go unpadded by gcc). ld creates boundary syms for us. */
> -extern struct devtable *__start___devtable[], *__stop___devtable[];
> -#endif /* __MACH__ */
> -
> -#if !defined(__used)
> -# if __GNUC__ == 3 && __GNUC_MINOR__ < 3
> -# define __used __attribute__((__unused__))
> -# else
> -# define __used __attribute__((__used__))
> -# endif
> -#endif
> -
> /* Define a variable f that holds the value of field f of struct devid
> * based at address m.
> */
> @@ -110,16 +70,6 @@ extern struct devtable *__start___devtable[], *__stop___devtable[];
> #define DEF_FIELD_ADDR(m, devid, f) \
> DEF_FIELD_ADDR_VAR(m, devid, f, f)
>
> -/* Add a table entry. We test function type matches while we're here. */
> -#define ADD_TO_DEVTABLE(device_id, type, function) \
> - static struct devtable __cat(devtable,__LINE__) = { \
> - device_id + 0*sizeof((function)((const char *)NULL, \
> - (void *)NULL, \
> - (char *)NULL)), \
> - SIZE_##type, (function) }; \
> - static struct devtable *SECTION(__devtable) __used \
> - __cat(devtable_ptr,__LINE__) = &__cat(devtable,__LINE__)
> -
> #define ADD(str, sep, cond, field) \
> do { \
> strcat(str, sep); \
> @@ -439,7 +389,6 @@ static int do_hid_entry(const char *filename,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("hid", hid_device_id, do_hid_entry);
>
> /* Looks like: ieee1394:venNmoNspNverN */
> static int do_ieee1394_entry(const char *filename,
> @@ -464,7 +413,6 @@ static int do_ieee1394_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("ieee1394", ieee1394_device_id, do_ieee1394_entry);
>
> /* Looks like: pci:vNdNsvNsdNbcNscNiN. */
> static int do_pci_entry(const char *filename,
> @@ -508,7 +456,6 @@ static int do_pci_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("pci", pci_device_id, do_pci_entry);
>
> /* looks like: "ccw:tNmNdtNdmN" */
> static int do_ccw_entry(const char *filename,
> @@ -532,7 +479,6 @@ static int do_ccw_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("ccw", ccw_device_id, do_ccw_entry);
>
> /* looks like: "ap:tN" */
> static int do_ap_entry(const char *filename,
> @@ -543,7 +489,6 @@ static int do_ap_entry(const char *filename,
> sprintf(alias, "ap:t%02X*", dev_type);
> return 1;
> }
> -ADD_TO_DEVTABLE("ap", ap_device_id, do_ap_entry);
>
> /* looks like: "css:tN" */
> static int do_css_entry(const char *filename,
> @@ -554,7 +499,6 @@ static int do_css_entry(const char *filename,
> sprintf(alias, "css:t%01X", type);
> return 1;
> }
> -ADD_TO_DEVTABLE("css", css_device_id, do_css_entry);
>
> /* Looks like: "serio:tyNprNidNexN" */
> static int do_serio_entry(const char *filename,
> @@ -574,7 +518,6 @@ static int do_serio_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("serio", serio_device_id, do_serio_entry);
>
> /* looks like: "acpi:ACPI0003" or "acpi:PNP0C0B" or "acpi:LNXVIDEO" or
> * "acpi:bbsspp" (bb=base-class, ss=sub-class, pp=prog-if)
> @@ -612,7 +555,6 @@ static int do_acpi_entry(const char *filename,
> }
> return 1;
> }
> -ADD_TO_DEVTABLE("acpi", acpi_device_id, do_acpi_entry);
>
> /* looks like: "pnp:dD" */
> static void do_pnp_device_entry(void *symval, unsigned long size,
> @@ -736,7 +678,6 @@ static int do_pcmcia_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("pcmcia", pcmcia_device_id, do_pcmcia_entry);
>
> static int do_vio_entry(const char *filename, void *symval,
> char *alias)
> @@ -756,7 +697,6 @@ static int do_vio_entry(const char *filename, void *symval,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("vio", vio_device_id, do_vio_entry);
>
> #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
>
> @@ -829,7 +769,6 @@ static int do_input_entry(const char *filename, void *symval,
> do_input(alias, *swbit, 0, INPUT_DEVICE_ID_SW_MAX);
> return 1;
> }
> -ADD_TO_DEVTABLE("input", input_device_id, do_input_entry);
>
> static int do_eisa_entry(const char *filename, void *symval,
> char *alias)
> @@ -841,7 +780,6 @@ static int do_eisa_entry(const char *filename, void *symval,
> strcat(alias, "*");
> return 1;
> }
> -ADD_TO_DEVTABLE("eisa", eisa_device_id, do_eisa_entry);
>
> /* Looks like: parisc:tNhvNrevNsvN */
> static int do_parisc_entry(const char *filename, void *symval,
> @@ -861,7 +799,6 @@ static int do_parisc_entry(const char *filename, void *symval,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("parisc", parisc_device_id, do_parisc_entry);
>
> /* Looks like: sdio:cNvNdN. */
> static int do_sdio_entry(const char *filename,
> @@ -878,7 +815,6 @@ static int do_sdio_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("sdio", sdio_device_id, do_sdio_entry);
>
> /* Looks like: ssb:vNidNrevN. */
> static int do_ssb_entry(const char *filename,
> @@ -895,7 +831,6 @@ static int do_ssb_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("ssb", ssb_device_id, do_ssb_entry);
>
> /* Looks like: bcma:mNidNrevNclN. */
> static int do_bcma_entry(const char *filename,
> @@ -914,7 +849,6 @@ static int do_bcma_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("bcma", bcma_device_id, do_bcma_entry);
>
> /* Looks like: virtio:dNvN */
> static int do_virtio_entry(const char *filename, void *symval,
> @@ -930,7 +864,6 @@ static int do_virtio_entry(const char *filename, void *symval,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("virtio", virtio_device_id, do_virtio_entry);
>
> /*
> * Looks like: vmbus:guid
> @@ -953,7 +886,6 @@ static int do_vmbus_entry(const char *filename, void *symval,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("vmbus", hv_vmbus_device_id, do_vmbus_entry);
>
> /* Looks like: rpmsg:S */
> static int do_rpmsg_entry(const char *filename, void *symval,
> @@ -964,7 +896,6 @@ static int do_rpmsg_entry(const char *filename, void *symval,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("rpmsg", rpmsg_device_id, do_rpmsg_entry);
>
> /* Looks like: i2c:S */
> static int do_i2c_entry(const char *filename, void *symval,
> @@ -975,7 +906,6 @@ static int do_i2c_entry(const char *filename, void *symval,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("i2c", i2c_device_id, do_i2c_entry);
>
> /* Looks like: spi:S */
> static int do_spi_entry(const char *filename, void *symval,
> @@ -986,7 +916,6 @@ static int do_spi_entry(const char *filename, void *symval,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("spi", spi_device_id, do_spi_entry);
>
> static const struct dmifield {
> const char *prefix;
> @@ -1041,7 +970,6 @@ static int do_dmi_entry(const char *filename, void *symval,
> strcat(alias, ":");
> return 1;
> }
> -ADD_TO_DEVTABLE("dmi", dmi_system_id, do_dmi_entry);
>
> static int do_platform_entry(const char *filename,
> void *symval, char *alias)
> @@ -1050,7 +978,6 @@ static int do_platform_entry(const char *filename,
> sprintf(alias, PLATFORM_MODULE_PREFIX "%s", *name);
> return 1;
> }
> -ADD_TO_DEVTABLE("platform", platform_device_id, do_platform_entry);
>
> static int do_mdio_entry(const char *filename,
> void *symval, char *alias)
> @@ -1075,7 +1002,6 @@ static int do_mdio_entry(const char *filename,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("mdio", mdio_device_id, do_mdio_entry);
>
> /* Looks like: zorro:iN. */
> static int do_zorro_entry(const char *filename, void *symval,
> @@ -1086,7 +1012,6 @@ static int do_zorro_entry(const char *filename, void *symval,
> ADD(alias, "i", id != ZORRO_WILDCARD, id);
> return 1;
> }
> -ADD_TO_DEVTABLE("zorro", zorro_device_id, do_zorro_entry);
>
> /* looks like: "pnp:dD" */
> static int do_isapnp_entry(const char *filename,
> @@ -1102,7 +1027,6 @@ static int do_isapnp_entry(const char *filename,
> (function >> 12) & 0x0f, (function >> 8) & 0x0f);
> return 1;
> }
> -ADD_TO_DEVTABLE("isapnp", isapnp_device_id, do_isapnp_entry);
>
> /* Looks like: "ipack:fNvNdN". */
> static int do_ipack_entry(const char *filename,
> @@ -1118,7 +1042,6 @@ static int do_ipack_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("ipack", ipack_device_id, do_ipack_entry);
>
> /*
> * Append a match expression for a single masked hex digit.
> @@ -1189,7 +1112,6 @@ static int do_amba_entry(const char *filename,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("amba", amba_id, do_amba_entry);
>
> /*
> * looks like: "mipscdmm:tN"
> @@ -1205,7 +1127,6 @@ static int do_mips_cdmm_entry(const char *filename,
> sprintf(alias, "mipscdmm:t%02X*", type);
> return 1;
> }
> -ADD_TO_DEVTABLE("mipscdmm", mips_cdmm_device_id, do_mips_cdmm_entry);
>
> /* LOOKS like cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:*,FEAT,*
> * All fields are numbers. It would be nicer to use strings for vendor
> @@ -1230,7 +1151,6 @@ static int do_x86cpu_entry(const char *filename, void *symval,
> sprintf(alias + strlen(alias), "%04X*", feature);
> return 1;
> }
> -ADD_TO_DEVTABLE("x86cpu", x86_cpu_id, do_x86cpu_entry);
>
> /* LOOKS like cpu:type:*:feature:*FEAT* */
> static int do_cpu_entry(const char *filename, void *symval, char *alias)
> @@ -1240,7 +1160,6 @@ static int do_cpu_entry(const char *filename, void *symval, char *alias)
> sprintf(alias, "cpu:type:*:feature:*%04X*", feature);
> return 1;
> }
> -ADD_TO_DEVTABLE("cpu", cpu_feature, do_cpu_entry);
>
> /* Looks like: mei:S:uuid:N:* */
> static int do_mei_entry(const char *filename, void *symval,
> @@ -1259,7 +1178,6 @@ static int do_mei_entry(const char *filename, void *symval,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("mei", mei_cl_device_id, do_mei_entry);
>
> /* Looks like: rapidio:vNdNavNadN */
> static int do_rio_entry(const char *filename,
> @@ -1279,7 +1197,6 @@ static int do_rio_entry(const char *filename,
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("rapidio", rio_device_id, do_rio_entry);
>
> /* Looks like: ulpi:vNpN */
> static int do_ulpi_entry(const char *filename, void *symval,
> @@ -1292,7 +1209,6 @@ static int do_ulpi_entry(const char *filename, void *symval,
>
> return 1;
> }
> -ADD_TO_DEVTABLE("ulpi", ulpi_device_id, do_ulpi_entry);
>
> /* Looks like: hdaudio:vNrNaN */
> static int do_hda_entry(const char *filename, void *symval, char *alias)
> @@ -1309,7 +1225,6 @@ static int do_hda_entry(const char *filename, void *symval, char *alias)
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("hdaudio", hda_device_id, do_hda_entry);
>
> /* Looks like: sdw:mNpN */
> static int do_sdw_entry(const char *filename, void *symval, char *alias)
> @@ -1324,7 +1239,6 @@ static int do_sdw_entry(const char *filename, void *symval, char *alias)
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("sdw", sdw_device_id, do_sdw_entry);
>
> /* Looks like: fsl-mc:vNdN */
> static int do_fsl_mc_entry(const char *filename, void *symval,
> @@ -1336,7 +1250,6 @@ static int do_fsl_mc_entry(const char *filename, void *symval,
> sprintf(alias, "fsl-mc:v%08Xd%s", vendor, *obj_type);
> return 1;
> }
> -ADD_TO_DEVTABLE("fslmc", fsl_mc_device_id, do_fsl_mc_entry);
>
> /* Looks like: tbsvc:kSpNvNrN */
> static int do_tbsvc_entry(const char *filename, void *symval, char *alias)
> @@ -1361,7 +1274,6 @@ static int do_tbsvc_entry(const char *filename, void *symval, char *alias)
> add_wildcard(alias);
> return 1;
> }
> -ADD_TO_DEVTABLE("tbsvc", tb_service_id, do_tbsvc_entry);
>
> /* Looks like: typec:idNmN */
> static int do_typec_entry(const char *filename, void *symval, char *alias)
> @@ -1374,7 +1286,6 @@ static int do_typec_entry(const char *filename, void *symval, char *alias)
>
> return 1;
> }
> -ADD_TO_DEVTABLE("typec", typec_device_id, do_typec_entry);
>
> /* Does namelen bytes of name exactly match the symbol? */
> static bool sym_is(const char *name, unsigned namelen, const char *symbol)
> @@ -1407,6 +1318,48 @@ static void do_table(void *symval, unsigned long size,
> }
> }
>
> +static const struct devtable devtable[] = {
> + {"hid", SIZE_hid_device_id, do_hid_entry},
> + {"ieee1394", SIZE_ieee1394_device_id, do_ieee1394_entry},
> + {"pci", SIZE_pci_device_id, do_pci_entry},
> + {"ccw", SIZE_ccw_device_id, do_ccw_entry},
> + {"ap", SIZE_ap_device_id, do_ap_entry},
> + {"css", SIZE_css_device_id, do_css_entry},
> + {"serio", SIZE_serio_device_id, do_serio_entry},
> + {"acpi", SIZE_acpi_device_id, do_acpi_entry},
> + {"pcmcia", SIZE_pcmcia_device_id, do_pcmcia_entry},
> + {"vio", SIZE_vio_device_id, do_vio_entry},
> + {"input", SIZE_input_device_id, do_input_entry},
> + {"eisa", SIZE_eisa_device_id, do_eisa_entry},
> + {"parisc", SIZE_parisc_device_id, do_parisc_entry},
> + {"sdio", SIZE_sdio_device_id, do_sdio_entry},
> + {"ssb", SIZE_ssb_device_id, do_ssb_entry},
> + {"bcma", SIZE_bcma_device_id, do_bcma_entry},
> + {"virtio", SIZE_virtio_device_id, do_virtio_entry},
> + {"vmbus", SIZE_hv_vmbus_device_id, do_vmbus_entry},
> + {"rpmsg", SIZE_rpmsg_device_id, do_rpmsg_entry},
> + {"i2c", SIZE_i2c_device_id, do_i2c_entry},
> + {"spi", SIZE_spi_device_id, do_spi_entry},
> + {"dmi", SIZE_dmi_system_id, do_dmi_entry},
> + {"platform", SIZE_platform_device_id, do_platform_entry},
> + {"mdio", SIZE_mdio_device_id, do_mdio_entry},
> + {"zorro", SIZE_zorro_device_id, do_zorro_entry},
> + {"isapnp", SIZE_isapnp_device_id, do_isapnp_entry},
> + {"ipack", SIZE_ipack_device_id, do_ipack_entry},
> + {"amba", SIZE_amba_id, do_amba_entry},
> + {"mipscdmm", SIZE_mips_cdmm_device_id, do_mips_cdmm_entry},
> + {"x86cpu", SIZE_x86_cpu_id, do_x86cpu_entry},
> + {"cpu", SIZE_cpu_feature, do_cpu_entry},
> + {"mei", SIZE_mei_cl_device_id, do_mei_entry},
> + {"rapidio", SIZE_rio_device_id, do_rio_entry},
> + {"ulpi", SIZE_ulpi_device_id, do_ulpi_entry},
> + {"hdaudio", SIZE_hda_device_id, do_hda_entry},
> + {"sdw", SIZE_sdw_device_id, do_sdw_entry},
> + {"fslmc", SIZE_fsl_mc_device_id, do_fsl_mc_entry},
> + {"tbsvc", SIZE_tb_service_id, do_tbsvc_entry},
> + {"typec", SIZE_typec_device_id, do_typec_entry},
> +};
> +
> /* Create MODULE_ALIAS() statements.
> * At this time, we cannot write the actual output C source yet,
> * so we write into the mod->dev_table_buf buffer. */
> @@ -1460,13 +1413,14 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
> else if (sym_is(name, namelen, "pnp_card"))
> do_pnp_card_entries(symval, sym->st_size, mod);
> else {
> - struct devtable **p;
> - INIT_SECTION(__devtable);
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(devtable); i++) {
> + const struct devtable *p = &devtable[i];
>
> - for (p = __start___devtable; p < __stop___devtable; p++) {
> - if (sym_is(name, namelen, (*p)->device_id)) {
> - do_table(symval, sym->st_size, (*p)->id_size,
> - (*p)->device_id, (*p)->function, mod);
> + if (sym_is(name, namelen, p->device_id)) {
> + do_table(symval, sym->st_size, p->id_size,
> + p->device_id, p->function, mod);
> break;
> }
> }
> --
> 2.7.4
>
--
Best Regards
Masahiro Yamada