Re: [PATCH -next] modpost: move some defines to the file head

From: Kefeng Wang
Date: Fri Jul 21 2023 - 05:12:12 EST


Hi, kindly ping, the build issue still exist in Linux-next.

On 2023/7/13 0:28, Palmer Dabbelt wrote:
On Wed, 12 Jul 2023 08:55:23 PDT (-0700), masahiroy@xxxxxxxxxx wrote:
+To: Luis Chamberlain, the commiter of the breakage



On Wed, Jul 12, 2023 at 10:44 AM Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:

with "module: Ignore RISC-V mapping symbols too", build error occurs,

scripts/mod/modpost.c: In function ‘is_valid_name’:
scripts/mod/modpost.c:1055:57: error: ‘EM_RISCV’ undeclared (first use in this function)
  return !is_mapping_symbol(name, elf->hdr->e_machine == EM_RISCV);

Fix it by moving the EM_RISCV to the file head, also some other
defines in case of similar problem in the future.



BTW, why is the flag 'is_riscv' needed?


All symbols starting with '$' look special to me.



Why not like this?


       if (str[0] == '$')
                 return true;

       return false;

There's a bit of commentary in the v1 <https://lore.kernel.org/all/20230707054007.32591-1-palmer@xxxxxxxxxxxx/>, but essentially it's not necessary.  I just wanted to play things safe and avoid changing the mapping symbol detection elsewhere in order to deal with RISC-V.

IIRC we decided $ was special in RISC-V because there were some other ports that behaved that way, but it wasn't universal.  If folks are OK treating $-prefixed symbols as special everywhere that's fine with me, I just wasn't sure what the right answer was.
There's also some similar arch-specific-ness with the labels and such in here.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
 scripts/mod/modpost.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 7c71429d6502..885cca272eb8 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -60,6 +60,22 @@ static unsigned int nr_unresolved;

 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))

+#ifndef EM_RISCV
+#define EM_RISCV               243
+#endif
+
+#ifndef R_RISCV_SUB32
+#define R_RISCV_SUB32          39
+#endif
+
+#ifndef EM_LOONGARCH
+#define EM_LOONGARCH           258
+#endif
+
+#ifndef R_LARCH_SUB32
+#define R_LARCH_SUB32          55
+#endif
+
 void __attribute__((format(printf, 2, 3)))
 modpost_log(enum loglevel loglevel, const char *fmt, ...)
 {
@@ -1428,22 +1444,6 @@ static int addend_mips_rel(uint32_t *location, Elf_Rela *r)
        return 0;
 }

-#ifndef EM_RISCV
-#define EM_RISCV               243
-#endif
-
-#ifndef R_RISCV_SUB32
-#define R_RISCV_SUB32          39
-#endif
-
-#ifndef EM_LOONGARCH
-#define EM_LOONGARCH           258
-#endif
-
-#ifndef R_LARCH_SUB32
-#define R_LARCH_SUB32          55
-#endif
-
 static void section_rela(struct module *mod, struct elf_info *elf,
                         Elf_Shdr *sechdr)
 {
--
2.41.0