objtool: Fix reloc_hash size

With CONFIG_DEBUG_INFO, DWARF creates a lot of relocations and
reloc_hash is woefully undersized, which can affect performance
significantly.  Fix that.

Link: https://lore.kernel.org/r/38ef60dc8043270bf3b9dfd139ae2a30ca3f75cc.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 4bbdd8e6df2cf5cd672a4823789196f2ceee383e..f72ec6d8fb14f2013843a6283848cdcc260a56ab 100644 (file)
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -328,12 +328,12 @@ static int read_sections(struct elf *elf)
                        }
                }
 
-               if (sec->sh.sh_flags & SHF_EXECINSTR)
-                       elf->text_size += sec->sh.sh_size;
-
                list_add_tail(&sec->list, &elf->sections);
                elf_hash_add(section, &sec->hash, sec->idx);
                elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
+
+               if (is_reloc_sec(sec))
+                       elf->num_relocs += sec->sh.sh_size / sec->sh.sh_entsize;
        }
 
        if (opts.stats) {
@@ -888,19 +888,18 @@ static int read_reloc(struct section *rsec, int i, struct reloc *reloc)
 
 static int read_relocs(struct elf *elf)
 {
-       unsigned long nr_reloc, max_reloc = 0, tot_reloc = 0;
+       unsigned long nr_reloc, max_reloc = 0;
        struct section *rsec;
        struct reloc *reloc;
        unsigned int symndx;
        struct symbol *sym;
        int i;
 
-       if (!elf_alloc_hash(reloc, elf->text_size / 16))
+       if (!elf_alloc_hash(reloc, elf->num_relocs))
                return -1;
 
        list_for_each_entry(rsec, &elf->sections, list) {
-               if ((rsec->sh.sh_type != SHT_RELA) &&
-                   (rsec->sh.sh_type != SHT_REL))
+               if (!is_reloc_sec(rsec))
                        continue;
 
                rsec->base = find_section_by_index(elf, rsec->sh.sh_info);
@@ -942,12 +941,11 @@ static int read_relocs(struct elf *elf)
                        nr_reloc++;
                }
                max_reloc = max(max_reloc, nr_reloc);
-               tot_reloc += nr_reloc;
        }
 
        if (opts.stats) {
                printf("max_reloc: %lu\n", max_reloc);
-               printf("tot_reloc: %lu\n", tot_reloc);
+               printf("num_relocs: %lu\n", elf->num_relocs);
                printf("reloc_bits: %d\n", elf->reloc_bits);
        }
 

diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 6f82f2515d6b13cba53818ee7233b08534337b89..b81d78b3512614cff7fc8de6c9c4cd30daae95f8 100644 (file)
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -90,8 +90,9 @@ struct elf {
        int fd;
        bool changed;
        char *name;
-       unsigned int text_size, num_files;
+       unsigned int num_files;
        struct list_head sections;
+       unsigned long num_relocs;
 
        int symbol_bits;
        int symbol_name_bits;
@@ -158,6 +159,11 @@ static inline size_t elf_rela_size(struct elf *elf)
        return elf_addr_size(elf) == 4 ? sizeof(Elf32_Rela) : sizeof(Elf64_Rela);
 }
 
+static inline bool is_reloc_sec(struct section *sec)
+{
+       return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL;
+}
+
 #define for_each_sec(file, sec)                                                \
        list_for_each_entry(sec, &file->elf->sections, list)