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[PATCH 1/3] objtool: Refactor ORC section generation



Decouple ORC entries from instructions.  This simplifies the
control/data flow, and is going to make it easier to support alternative
instructions which change the stack layout.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 tools/objtool/Makefile      |   4 -
 tools/objtool/arch.h        |   4 -
 tools/objtool/builtin-orc.c |   6 +-
 tools/objtool/check.h       |   3 -
 tools/objtool/objtool.h     |   3 +-
 tools/objtool/orc_gen.c     | 272 ++++++++++++++++++------------------
 tools/objtool/weak.c        |   7 +-
 7 files changed, 140 insertions(+), 159 deletions(-)

diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 5cdb19036d7f..a43096f713c7 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -46,10 +46,6 @@ ifeq ($(SRCARCH),x86)
        SUBCMD_ORC := y
 endif
 
-ifeq ($(SUBCMD_ORC),y)
-       CFLAGS += -DINSN_USE_ORC
-endif
-
 export SUBCMD_CHECK SUBCMD_ORC
 export srctree OUTPUT CFLAGS SRCARCH AWK
 include $(srctree)/tools/build/Makefile.include
diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index 4a84c3081b8e..5e3f3ea8bb89 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -11,10 +11,6 @@
 #include "objtool.h"
 #include "cfi.h"
 
-#ifdef INSN_USE_ORC
-#include <asm/orc_types.h>
-#endif
-
 enum insn_type {
        INSN_JUMP_CONDITIONAL,
        INSN_JUMP_UNCONDITIONAL,
diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c
index 7b31121fa60b..508bdf6ae8dc 100644
--- a/tools/objtool/builtin-orc.c
+++ b/tools/objtool/builtin-orc.c
@@ -51,11 +51,7 @@ int cmd_orc(int argc, const char **argv)
                if (list_empty(&file->insn_list))
                        return 0;
 
-               ret = create_orc(file);
-               if (ret)
-                       return ret;
-
-               ret = create_orc_sections(file);
+               ret = orc_create(file);
                if (ret)
                        return ret;
 
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 5ec00a4b891b..4c10916ff1cf 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -43,9 +43,6 @@ struct instruction {
        struct symbol *func;
        struct list_head stack_ops;
        struct cfi_state cfi;
-#ifdef INSN_USE_ORC
-       struct orc_entry orc;
-#endif
 };
 
 static inline bool is_static_jump(struct instruction *insn)
diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h
index 4125d4578b23..5e58d3537e2f 100644
--- a/tools/objtool/objtool.h
+++ b/tools/objtool/objtool.h
@@ -26,7 +26,6 @@ struct objtool_file *objtool_open_read(const char *_objname);
 
 int check(struct objtool_file *file);
 int orc_dump(const char *objname);
-int create_orc(struct objtool_file *file);
-int create_orc_sections(struct objtool_file *file);
+int orc_create(struct objtool_file *file);
 
 #endif /* _OBJTOOL_H */
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 235663b96adc..73efba2bfa72 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -12,89 +12,84 @@
 #include "check.h"
 #include "warn.h"
 
-int create_orc(struct objtool_file *file)
+static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi)
 {
-       struct instruction *insn;
+       struct instruction *insn = container_of(cfi, struct instruction, cfi);
+       struct cfi_reg *bp = &cfi->regs[CFI_BP];
 
-       for_each_insn(file, insn) {
-               struct orc_entry *orc = &insn->orc;
-               struct cfi_reg *cfa = &insn->cfi.cfa;
-               struct cfi_reg *bp = &insn->cfi.regs[CFI_BP];
+       memset(orc, 0, sizeof(*orc));
 
-               if (!insn->sec->text)
-                       continue;
-
-               orc->end = insn->cfi.end;
+       orc->end = cfi->end;
 
-               if (cfa->base == CFI_UNDEFINED) {
-                       orc->sp_reg = ORC_REG_UNDEFINED;
-                       continue;
-               }
-
-               switch (cfa->base) {
-               case CFI_SP:
-                       orc->sp_reg = ORC_REG_SP;
-                       break;
-               case CFI_SP_INDIRECT:
-                       orc->sp_reg = ORC_REG_SP_INDIRECT;
-                       break;
-               case CFI_BP:
-                       orc->sp_reg = ORC_REG_BP;
-                       break;
-               case CFI_BP_INDIRECT:
-                       orc->sp_reg = ORC_REG_BP_INDIRECT;
-                       break;
-               case CFI_R10:
-                       orc->sp_reg = ORC_REG_R10;
-                       break;
-               case CFI_R13:
-                       orc->sp_reg = ORC_REG_R13;
-                       break;
-               case CFI_DI:
-                       orc->sp_reg = ORC_REG_DI;
-                       break;
-               case CFI_DX:
-                       orc->sp_reg = ORC_REG_DX;
-                       break;
-               default:
-                       WARN_FUNC("unknown CFA base reg %d",
-                                 insn->sec, insn->offset, cfa->base);
-                       return -1;
-               }
+       if (cfi->cfa.base == CFI_UNDEFINED) {
+               orc->sp_reg = ORC_REG_UNDEFINED;
+               return 0;
+       }
 
-               switch(bp->base) {
-               case CFI_UNDEFINED:
-                       orc->bp_reg = ORC_REG_UNDEFINED;
-                       break;
-               case CFI_CFA:
-                       orc->bp_reg = ORC_REG_PREV_SP;
-                       break;
-               case CFI_BP:
-                       orc->bp_reg = ORC_REG_BP;
-                       break;
-               default:
-                       WARN_FUNC("unknown BP base reg %d",
-                                 insn->sec, insn->offset, bp->base);
-                       return -1;
-               }
+       switch (cfi->cfa.base) {
+       case CFI_SP:
+               orc->sp_reg = ORC_REG_SP;
+               break;
+       case CFI_SP_INDIRECT:
+               orc->sp_reg = ORC_REG_SP_INDIRECT;
+               break;
+       case CFI_BP:
+               orc->sp_reg = ORC_REG_BP;
+               break;
+       case CFI_BP_INDIRECT:
+               orc->sp_reg = ORC_REG_BP_INDIRECT;
+               break;
+       case CFI_R10:
+               orc->sp_reg = ORC_REG_R10;
+               break;
+       case CFI_R13:
+               orc->sp_reg = ORC_REG_R13;
+               break;
+       case CFI_DI:
+               orc->sp_reg = ORC_REG_DI;
+               break;
+       case CFI_DX:
+               orc->sp_reg = ORC_REG_DX;
+               break;
+       default:
+               WARN_FUNC("unknown CFA base reg %d",
+                         insn->sec, insn->offset, cfi->cfa.base);
+               return -1;
+       }
 
-               orc->sp_offset = cfa->offset;
-               orc->bp_offset = bp->offset;
-               orc->type = insn->cfi.type;
+       switch (bp->base) {
+       case CFI_UNDEFINED:
+               orc->bp_reg = ORC_REG_UNDEFINED;
+               break;
+       case CFI_CFA:
+               orc->bp_reg = ORC_REG_PREV_SP;
+               break;
+       case CFI_BP:
+               orc->bp_reg = ORC_REG_BP;
+               break;
+       default:
+               WARN_FUNC("unknown BP base reg %d",
+                         insn->sec, insn->offset, bp->base);
+               return -1;
        }
 
+       orc->sp_offset = cfi->cfa.offset;
+       orc->bp_offset = bp->offset;
+       orc->type = cfi->type;
+
        return 0;
 }
 
-static int create_orc_entry(struct elf *elf, struct section *u_sec, struct 
section *ip_relocsec,
-                               unsigned int idx, struct section *insn_sec,
-                               unsigned long insn_off, struct orc_entry *o)
+static int write_orc_entry(struct elf *elf, struct section *orc_sec,
+                          struct section *ip_rsec, unsigned int idx,
+                          struct section *insn_sec, unsigned long insn_off,
+                          struct orc_entry *o)
 {
        struct orc_entry *orc;
        struct reloc *reloc;
 
        /* populate ORC data */
-       orc = (struct orc_entry *)u_sec->data->d_buf + idx;
+       orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
        memcpy(orc, o, sizeof(*orc));
 
        /* populate reloc for ip */
@@ -133,102 +128,109 @@ static int create_orc_entry(struct elf *elf, struct 
section *u_sec, struct secti
 
        reloc->type = R_X86_64_PC32;
        reloc->offset = idx * sizeof(int);
-       reloc->sec = ip_relocsec;
+       reloc->sec = ip_rsec;
 
        elf_add_reloc(elf, reloc);
 
        return 0;
 }
 
-int create_orc_sections(struct objtool_file *file)
+struct orc_list_entry {
+       struct list_head list;
+       struct orc_entry orc;
+       struct section *insn_sec;
+       unsigned long insn_off;
+};
+
+static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
+                       struct section *sec, unsigned long offset)
+{
+       struct orc_list_entry *entry = malloc(sizeof(*entry));
+
+       if (!entry) {
+               WARN("malloc failed");
+               return -1;
+       }
+
+       entry->orc      = *orc;
+       entry->insn_sec = sec;
+       entry->insn_off = offset;
+
+       list_add_tail(&entry->list, orc_list);
+       return 0;
+}
+
+int orc_create(struct objtool_file *file)
 {
-       struct instruction *insn, *prev_insn;
-       struct section *sec, *u_sec, *ip_relocsec;
-       unsigned int idx;
+       struct section *sec, *ip_rsec, *orc_sec;
+       unsigned int nr = 0, idx = 0;
+       struct orc_list_entry *entry;
+       struct list_head orc_list;
 
-       struct orc_entry empty = {
-               .sp_reg = ORC_REG_UNDEFINED,
+       struct orc_entry null = {
+               .sp_reg  = ORC_REG_UNDEFINED,
                .bp_reg  = ORC_REG_UNDEFINED,
                .type    = UNWIND_HINT_TYPE_CALL,
        };
 
-       sec = find_section_by_name(file->elf, ".orc_unwind");
-       if (sec) {
-               WARN("file already has .orc_unwind section, skipping");
-               return -1;
-       }
-
-       /* count the number of needed orcs */
-       idx = 0;
+       /* Build a deduplicated list of ORC entries: */
+       INIT_LIST_HEAD(&orc_list);
        for_each_sec(file, sec) {
+               struct orc_entry orc, prev_orc = {0};
+               struct instruction *insn;
+               bool empty = true;
+
                if (!sec->text)
                        continue;
 
-               prev_insn = NULL;
                sec_for_each_insn(file, sec, insn) {
-                       if (!prev_insn ||
-                           memcmp(&insn->orc, &prev_insn->orc,
-                                  sizeof(struct orc_entry))) {
-                               idx++;
-                       }
-                       prev_insn = insn;
+                       if (init_orc_entry(&orc, &insn->cfi))
+                               return -1;
+                       if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+                               continue;
+                       if (orc_list_add(&orc_list, &orc, sec, insn->offset))
+                               return -1;
+                       nr++;
+                       prev_orc = orc;
+                       empty = false;
                }
 
-               /* section terminator */
-               if (prev_insn)
-                       idx++;
+               /* Add a section terminator */
+               if (!empty) {
+                       orc_list_add(&orc_list, &null, sec, sec->len);
+                       nr++;
+               }
        }
-       if (!idx)
-               return -1;
+       if (!nr)
+               return 0;
 
+       /* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: 
*/
+       sec = find_section_by_name(file->elf, ".orc_unwind");
+       if (sec) {
+               WARN("file already has .orc_unwind section, skipping");
+               return -1;
+       }
+       orc_sec = elf_create_section(file->elf, ".orc_unwind", 0,
+                                    sizeof(struct orc_entry), nr);
+       if (!orc_sec)
+               return -1;
 
-       /* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
-       sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), 
idx);
+       sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), 
nr);
        if (!sec)
                return -1;
-
-       ip_relocsec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
-       if (!ip_relocsec)
+       ip_rsec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
+       if (!ip_rsec)
                return -1;
 
-       /* create .orc_unwind section */
-       u_sec = elf_create_section(file->elf, ".orc_unwind", 0,
-                                  sizeof(struct orc_entry), idx);
-
-       /* populate sections */
-       idx = 0;
-       for_each_sec(file, sec) {
-               if (!sec->text)
-                       continue;
-
-               prev_insn = NULL;
-               sec_for_each_insn(file, sec, insn) {
-                       if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
-                                                sizeof(struct orc_entry))) {
-
-                               if (create_orc_entry(file->elf, u_sec, 
ip_relocsec, idx,
-                                                    insn->sec, insn->offset,
-                                                    &insn->orc))
-                                       return -1;
-
-                               idx++;
-                       }
-                       prev_insn = insn;
-               }
-
-               /* section terminator */
-               if (prev_insn) {
-                       if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx,
-                                            prev_insn->sec,
-                                            prev_insn->offset + prev_insn->len,
-                                            &empty))
-                               return -1;
-
-                       idx++;
-               }
+       /* Write ORC entries to sections: */
+       list_for_each_entry(entry, &orc_list, list) {
+               if (write_orc_entry(file->elf, orc_sec, ip_rsec, idx++,
+                                   entry->insn_sec, entry->insn_off,
+                                   &entry->orc))
+                       return -1;
        }
 
-       if (elf_rebuild_reloc_section(file->elf, ip_relocsec))
+       if (elf_rebuild_reloc_section(file->elf, ip_rsec))
                return -1;
 
        return 0;
diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c
index 7843e9a7a72f..553ec9ce51ba 100644
--- a/tools/objtool/weak.c
+++ b/tools/objtool/weak.c
@@ -25,12 +25,7 @@ int __weak orc_dump(const char *_objname)
        UNSUPPORTED("orc");
 }
 
-int __weak create_orc(struct objtool_file *file)
-{
-       UNSUPPORTED("orc");
-}
-
-int __weak create_orc_sections(struct objtool_file *file)
+int __weak orc_create(struct objtool_file *file)
 {
        UNSUPPORTED("orc");
 }
-- 
2.29.2




 


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