[PATCH 20/22] objtool: Get rid of reloc->rel[a]

From: Josh Poimboeuf
Date: Tue May 30 2023 - 13:22:59 EST

Next message: Bjorn Helgaas: "Re: [PATCH v3] PCI: Add suspend fixup for SSD on sc7280"
Previous message: Josh Poimboeuf: "[PATCH 22/22] objtool: Skip reading DWARF section data"
In reply to: Josh Poimboeuf: "[PATCH 22/22] objtool: Skip reading DWARF section data"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Get the relocation entry info from the underlying rsec->data.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 35.12G
- After: peak heap memory consumption: 29.93G

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
tools/objtool/check.c | 20 +++---
tools/objtool/elf.c | 60 +++---------------
tools/objtool/include/objtool/elf.h | 94 +++++++++++++++++++++++++----
3 files changed, 96 insertions(+), 78 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 3fe6b3657e22..65c59b0b1e96 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -967,7 +967,7 @@ static int create_mcount_loc_sections(struct objtool_file *file)
if (!reloc)
return -1;

- set_reloc_type(reloc, addr_size == 8 ? R_ABS64 : R_ABS32);
+ set_reloc_type(file->elf, reloc, addr_size == 8 ? R_ABS64 : R_ABS32);

idx++;
}
@@ -1362,10 +1362,8 @@ static void annotate_call_site(struct objtool_file *file,
* noinstr text.
*/
if (opts.hack_noinstr && insn->sec->noinstr && sym->profiling_func) {
- if (reloc) {
- set_reloc_type(reloc, R_NONE);
- elf_write_reloc(file->elf, reloc);
- }
+ if (reloc)
+ set_reloc_type(file->elf, reloc, R_NONE);

elf_write_insn(file->elf, insn->sec,
insn->offset, insn->len,
@@ -1391,10 +1389,8 @@ static void annotate_call_site(struct objtool_file *file,
if (sibling)
WARN_INSN(insn, "tail call to __fentry__ !?!?");
if (opts.mnop) {
- if (reloc) {
- set_reloc_type(reloc, R_NONE);
- elf_write_reloc(file->elf, reloc);
- }
+ if (reloc)
+ set_reloc_type(file->elf, reloc, R_NONE);

elf_write_insn(file->elf, insn->sec,
insn->offset, insn->len,
@@ -1873,10 +1869,8 @@ static int handle_jump_alt(struct objtool_file *file,
if (opts.hack_jump_label && special_alt->key_addend & 2) {
struct reloc *reloc = insn_reloc(file, orig_insn);

- if (reloc) {
- set_reloc_type(reloc, R_NONE);
- elf_write_reloc(file->elf, reloc);
- }
+ if (reloc)
+ set_reloc_type(file->elf, reloc, R_NONE);
elf_write_insn(file->elf, orig_insn->sec,
orig_insn->offset, orig_insn->len,
arch_nop_insn(orig_insn->len));
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 04038b1324cf..54d182ddc4bb 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -575,11 +575,8 @@ static int elf_update_sym_relocs(struct elf *elf, struct symbol *sym)
{
struct reloc *reloc;

- for (reloc = sym->relocs; reloc; reloc = reloc->sym_next_reloc) {
- reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc_type(reloc));
- if (elf_write_reloc(elf, reloc))
- return -1;
- }
+ for (reloc = sym->relocs; reloc; reloc = reloc->sym_next_reloc)
+ set_reloc_sym(elf, reloc, reloc->sym->idx);

return 0;
}
@@ -869,12 +866,10 @@ static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
reloc->sec = rsec;
reloc->sym = sym;

- reloc->rel.r_offset = offset;
- reloc->rel.r_info = GELF_R_INFO(sym->idx, type);
- reloc->rela.r_addend = addend;
-
- if (elf_write_reloc(elf, reloc))
- return NULL;
+ set_reloc_offset(elf, reloc, offset);
+ set_reloc_sym(elf, reloc, sym->idx);
+ set_reloc_type(elf, reloc, type);
+ set_reloc_addend(elf, reloc, addend);

elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));
reloc->sym_next_reloc = sym->relocs;
@@ -932,24 +927,6 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
elf_data_rela_type(elf));
}

-static int read_reloc(struct section *rsec, int i, struct reloc *reloc)
-{
- bool rela = rsec->sh.sh_type == SHT_RELA;
- void *retp;
-
- if (rela)
- retp = gelf_getrela(rsec->data, i, &reloc->rela);
- else
- retp = gelf_getrel(rsec->data, i, &reloc->rel);
-
- if (!retp) {
- WARN_ELF("gelf_getrela");
- return -1;
- }
-
- return 0;
-}
-
static int read_relocs(struct elf *elf)
{
unsigned long nr_reloc, max_reloc = 0;
@@ -984,11 +961,8 @@ static int read_relocs(struct elf *elf)
for (i = 0; i < sec_num_entries(rsec); i++) {
reloc = &rsec->relocs[i];

- if (read_reloc(rsec, i, reloc))
- return -1;
-
reloc->sec = rsec;
- symndx = GELF_R_SYM(reloc->rel.r_info);
+ symndx = reloc_sym(reloc);
reloc->sym = sym = find_symbol_by_index(elf, symndx);
if (!reloc->sym) {
WARN("can't find reloc entry symbol %d for %s",
@@ -1261,26 +1235,6 @@ int elf_write_insn(struct elf *elf, struct section *sec,
return 0;
}

-int elf_write_reloc(struct elf *elf, struct reloc *reloc)
-{
- struct section *rsec = reloc->sec;
- int ret;
-
- if (rsec->sh.sh_type == SHT_RELA)
- ret = gelf_update_rela(rsec->data, reloc_idx(reloc), &reloc->rela);
- else
- ret = gelf_update_rel(rsec->data, reloc_idx(reloc), &reloc->rel);
-
- if (!ret) {
- WARN_ELF("gelf_update_rela");
- return -1;
- }
-
- mark_sec_changed(elf, rsec, true);
-
- return 0;
-}
-
/*
* When Elf_Scn::sh_size is smaller than the combined Elf_Data::d_size
* do you:
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 03a9040f696c..c532d70864dc 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -72,10 +72,6 @@ struct symbol {

struct reloc {
struct elf_hash_node hash;
- union {
- GElf_Rela rela;
- GElf_Rel rel;
- };
struct section *sec;
struct symbol *sym;
struct reloc *sym_next_reloc;
@@ -132,7 +128,6 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
int elf_write_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len,
const char *insn);
-int elf_write_reloc(struct elf *elf, struct reloc *reloc);
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);

@@ -204,24 +199,99 @@ static inline unsigned int reloc_idx(struct reloc *reloc)
return reloc - reloc->sec->relocs;
}

-static inline unsigned long reloc_offset(struct reloc *reloc)
+static inline void *reloc_rel(struct reloc *reloc)
{
- return reloc->rel.r_offset;
+ struct section *rsec = reloc->sec;
+
+ return rsec->data->d_buf + (reloc_idx(reloc) * rsec->sh.sh_entsize);
}

-static inline unsigned int reloc_type(struct reloc *reloc)
+static inline bool is_32bit_reloc(struct reloc *reloc)
{
- return GELF_R_TYPE(reloc->rel.r_info);
+ /*
+ * Elf32_Rel: 8 bytes
+ * Elf32_Rela: 12 bytes
+ * Elf64_Rel: 16 bytes
+ * Elf64_Rela: 24 bytes
+ */
+ return reloc->sec->sh.sh_entsize < 16;
}

-static inline void set_reloc_type(struct reloc *reloc, int type)
+#define __get_reloc_field(reloc, field) \
+({ \
+ is_32bit_reloc(reloc) ? \
+ ((Elf32_Rela *)reloc_rel(reloc))->field : \
+ ((Elf64_Rela *)reloc_rel(reloc))->field; \
+})
+
+#define __set_reloc_field(reloc, field, val) \
+({ \
+ if (is_32bit_reloc(reloc)) \
+ ((Elf32_Rela *)reloc_rel(reloc))->field = val; \
+ else \
+ ((Elf64_Rela *)reloc_rel(reloc))->field = val; \
+})
+
+static inline u64 reloc_offset(struct reloc *reloc)
{
- reloc->rel.r_info = GELF_R_INFO(GELF_R_SYM(reloc->rel.r_info), type);
+ return __get_reloc_field(reloc, r_offset);
+}
+
+static inline void set_reloc_offset(struct elf *elf, struct reloc *reloc, u64 offset)
+{
+ __set_reloc_field(reloc, r_offset, offset);
+ mark_sec_changed(elf, reloc->sec, true);
}

static inline s64 reloc_addend(struct reloc *reloc)
{
- return reloc->rela.r_addend;
+ return __get_reloc_field(reloc, r_addend);
+}
+
+static inline void set_reloc_addend(struct elf *elf, struct reloc *reloc, s64 addend)
+{
+ __set_reloc_field(reloc, r_addend, addend);
+ mark_sec_changed(elf, reloc->sec, true);
+}
+
+
+static inline unsigned int reloc_sym(struct reloc *reloc)
+{
+ u64 info = __get_reloc_field(reloc, r_info);
+
+ return is_32bit_reloc(reloc) ?
+ ELF32_R_SYM(info) :
+ ELF64_R_SYM(info);
+}
+
+static inline unsigned int reloc_type(struct reloc *reloc)
+{
+ u64 info = __get_reloc_field(reloc, r_info);
+
+ return is_32bit_reloc(reloc) ?
+ ELF32_R_TYPE(info) :
+ ELF64_R_TYPE(info);
+}
+
+static inline void set_reloc_sym(struct elf *elf, struct reloc *reloc, unsigned int sym)
+{
+ u64 info = is_32bit_reloc(reloc) ?
+ ELF32_R_INFO(sym, reloc_type(reloc)) :
+ ELF64_R_INFO(sym, reloc_type(reloc));
+
+ __set_reloc_field(reloc, r_info, info);
+
+ mark_sec_changed(elf, reloc->sec, true);
+}
+static inline void set_reloc_type(struct elf *elf, struct reloc *reloc, unsigned int type)
+{
+ u64 info = is_32bit_reloc(reloc) ?
+ ELF32_R_INFO(reloc_sym(reloc), type) :
+ ELF64_R_INFO(reloc_sym(reloc), type);
+
+ __set_reloc_field(reloc, r_info, info);
+
+ mark_sec_changed(elf, reloc->sec, true);
}

#define for_each_sec(file, sec) \
--
2.40.1

Next message: Bjorn Helgaas: "Re: [PATCH v3] PCI: Add suspend fixup for SSD on sc7280"
Previous message: Josh Poimboeuf: "[PATCH 22/22] objtool: Skip reading DWARF section data"
In reply to: Josh Poimboeuf: "[PATCH 22/22] objtool: Skip reading DWARF section data"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]