scripts/sortextable: Refactor the do_func() function

Refine the loop, naming and code structure, make the code more readable
and extendable. No functional changes intended.

Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-5-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/scripts/sortextable.c b/scripts/sortextable.c
index e5384e86b58c58fbf2bb600bbd1d2a37ae0ffc64..efa2839865cdb09b5f3deb9e105746efb12defa0 100644 (file)
--- a/scripts/sortextable.c
+++ b/scripts/sortextable.c
@@ -320,7 +320,7 @@ static int do_file(char const *const fname, void *addr)
                                "unrecognized ET_EXEC/ET_DYN file: %s\n", fname);
                        break;
                }
-               rc = do32(ehdr, fname, custom_sort);
+               rc = do_sort_32(ehdr, fname, custom_sort);
                break;
        case ELFCLASS64:
                {
@@ -332,7 +332,7 @@ static int do_file(char const *const fname, void *addr)
                                fname);
                        break;
                }
-               rc = do64(ghdr, fname, custom_sort);
+               rc = do_sort_64(ghdr, fname, custom_sort);
                }
                break;
        default:

diff --git a/scripts/sortextable.h b/scripts/sortextable.h
index a2e3af7bf2119c6fe60d1f9ea42aacce4638d645..6485513f7caebe264c68046599f8ad86c4299e83 100644 (file)
--- a/scripts/sortextable.h
+++ b/scripts/sortextable.h
@@ -12,7 +12,7 @@
 
 #undef extable_ent_size
 #undef compare_extable
-#undef do_func
+#undef do_sort
 #undef Elf_Addr
 #undef Elf_Ehdr
 #undef Elf_Shdr
@@ -34,7 +34,7 @@
 #ifdef SORTEXTABLE_64
 # define extable_ent_size      16
 # define compare_extable       compare_extable_64
-# define do_func               do64
+# define do_sort               do_sort_64
 # define Elf_Addr              Elf64_Addr
 # define Elf_Ehdr              Elf64_Ehdr
 # define Elf_Shdr              Elf64_Shdr
@@ -55,7 +55,7 @@
 #else
 # define extable_ent_size      8
 # define compare_extable       compare_extable_32
-# define do_func               do32
+# define do_sort               do_sort_32
 # define Elf_Addr              Elf32_Addr
 # define Elf_Ehdr              Elf32_Ehdr
 # define Elf_Shdr              Elf32_Shdr
@@ -87,81 +87,81 @@ static int compare_extable(const void *a, const void *b)
        return 0;
 }
 
-static int do_func(Elf_Ehdr *ehdr,
+static int do_sort(Elf_Ehdr *ehdr,
                   char const *const fname,
                   table_sort_t custom_sort)
 {
-       Elf_Shdr *shdr;
-       Elf_Shdr *shstrtab_sec;
+       Elf_Shdr *s, *shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
        Elf_Shdr *strtab_sec = NULL;
        Elf_Shdr *symtab_sec = NULL;
        Elf_Shdr *extab_sec = NULL;
        Elf_Sym *sym;
        const Elf_Sym *symtab;
-       Elf32_Word *symtab_shndx_start = NULL;
-       Elf_Sym *sort_needed_sym;
+       Elf32_Word *symtab_shndx = NULL;
+       Elf_Sym *sort_needed_sym = NULL;
        Elf_Shdr *sort_needed_sec;
        Elf_Rel *relocs = NULL;
        int relocs_size = 0;
-       uint32_t *sort_done_location;
-       const char *secstrtab;
+       uint32_t *sort_needed_loc;
+       const char *secstrings;
        const char *strtab;
        char *extab_image;
        int extab_index = 0;
        int i;
        int idx;
-       unsigned int num_sections;
-       unsigned int secindex_strings;
+       unsigned int shnum;
+       unsigned int shstrndx;
 
-       shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
+       shstrndx = r2(&ehdr->e_shstrndx);
+       if (shstrndx == SHN_XINDEX)
+               shstrndx = r(&shdr[0].sh_link);
+       secstrings = (const char *)ehdr + _r(&shdr[shstrndx].sh_offset);
 
-       num_sections = r2(&ehdr->e_shnum);
-       if (num_sections == SHN_UNDEF)
-               num_sections = _r(&shdr[0].sh_size);
+       shnum = r2(&ehdr->e_shnum);
+       if (shnum == SHN_UNDEF)
+               shnum = _r(&shdr[0].sh_size);
 
-       secindex_strings = r2(&ehdr->e_shstrndx);
-       if (secindex_strings == SHN_XINDEX)
-               secindex_strings = r(&shdr[0].sh_link);
-
-       shstrtab_sec = shdr + secindex_strings;
-       secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
-       for (i = 0; i < num_sections; i++) {
-               idx = r(&shdr[i].sh_name);
-               if (!strcmp(secstrtab + idx, "__ex_table")) {
-                       extab_sec = shdr + i;
+       for (i = 0, s = shdr; s < shdr + shnum; i++, s++) {
+               idx = r(&s->sh_name);
+               if (!strcmp(secstrings + idx, "__ex_table")) {
+                       extab_sec = s;
                        extab_index = i;
                }
-               if ((r(&shdr[i].sh_type) == SHT_REL ||
-                    r(&shdr[i].sh_type) == SHT_RELA) &&
-                   r(&shdr[i].sh_info) == extab_index) {
-                       relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
-                       relocs_size = _r(&shdr[i].sh_size);
+               if (!strcmp(secstrings + idx, ".symtab"))
+                       symtab_sec = s;
+               if (!strcmp(secstrings + idx, ".strtab"))
+                       strtab_sec = s;
+
+               if ((r(&s->sh_type) == SHT_REL ||
+                    r(&s->sh_type) == SHT_RELA) &&
+                   r(&s->sh_info) == extab_index) {
+                       relocs = (void *)ehdr + _r(&s->sh_offset);
+                       relocs_size = _r(&s->sh_size);
                }
-               if (!strcmp(secstrtab + idx, ".symtab"))
-                       symtab_sec = shdr + i;
-               if (!strcmp(secstrtab + idx, ".strtab"))
-                       strtab_sec = shdr + i;
-               if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX)
-                       symtab_shndx_start = (Elf32_Word *)(
-                               (const char *)ehdr + _r(&shdr[i].sh_offset));
+               if (r(&s->sh_type) == SHT_SYMTAB_SHNDX)
+                       symtab_shndx = (Elf32_Word *)((const char *)ehdr +
+                                                     _r(&s->sh_offset));
        }
-       if (!strtab_sec) {
-               fprintf(stderr, "no .strtab in file: %s\n", fname);
+
+       if (!extab_sec) {
+               fprintf(stderr, "no __ex_table in file: %s\n", fname);
                return -1;
        }
+
        if (!symtab_sec) {
                fprintf(stderr, "no .symtab in file: %s\n", fname);
                return -1;
        }
-       symtab = (const Elf_Sym *)((const char *)ehdr +
-                                  _r(&symtab_sec->sh_offset));
-       if (!extab_sec) {
-               fprintf(stderr, "no __ex_table in file: %s\n", fname);
+
+       if (!strtab_sec) {
+               fprintf(stderr, "no .strtab in file: %s\n", fname);
                return -1;
        }
-       strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
 
        extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
+       strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
+       symtab = (const Elf_Sym *)((const char *)ehdr +
+                                                 _r(&symtab_sec->sh_offset));
 
        if (custom_sort) {
                custom_sort(extab_image, _r(&extab_sec->sh_size));
@@ -170,38 +170,41 @@ static int do_func(Elf_Ehdr *ehdr,
                qsort(extab_image, num_entries,
                      extable_ent_size, compare_extable);
        }
+
        /* If there were relocations, we no longer need them. */
        if (relocs)
                memset(relocs, 0, relocs_size);
 
-       /* find main_extable_sort_needed */
-       sort_needed_sym = NULL;
-       for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
-               sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
-               sym += i;
+       /* find the flag main_extable_sort_needed */
+       for (sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
+            sym < sym + _r(&symtab_sec->sh_size) / sizeof(Elf_Sym);
+            sym++) {
                if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
                        continue;
-               idx = r(&sym->st_name);
-               if (!strcmp(strtab + idx, "main_extable_sort_needed")) {
+               if (!strcmp(strtab + r(&sym->st_name),
+                           "main_extable_sort_needed")) {
                        sort_needed_sym = sym;
                        break;
                }
        }
+
        if (!sort_needed_sym) {
                fprintf(stderr,
                        "no main_extable_sort_needed symbol in file: %s\n",
                        fname);
                return -1;
        }
+
        sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
                                             sort_needed_sym - symtab,
-                                            symtab_shndx_start)];
-       sort_done_location = (void *)ehdr +
+                                            symtab_shndx)];
+       sort_needed_loc = (void *)ehdr +
                _r(&sort_needed_sec->sh_offset) +
                _r(&sort_needed_sym->st_value) -
                _r(&sort_needed_sec->sh_addr);
 
-       /* We sorted it, clear the flag. */
-       w(0, sort_done_location);
+       /* extable has been sorted, clear the flag */
+       w(0, sort_needed_loc);
+
        return 0;
 }