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Subject[PATCH v2 9/9] objtool: Abstract unwind hint reading
Date
The type of unwind hints and the semantics associated with them depend
on the architecture. Let arch specific code convert unwind hints into
objtool stack state descriptions.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
tools/objtool/arch.h | 5 +--
tools/objtool/arch/x86/decode.c | 54 ++++++++++++++++++++++++++++++
tools/objtool/cfi.h | 3 +-
tools/objtool/check.c | 58 +++++----------------------------
tools/objtool/orc_gen.c | 4 ++-
5 files changed, 71 insertions(+), 53 deletions(-)

diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index 2e2ce089b0e9..44107e9aab71 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -7,12 +7,11 @@
#define _ARCH_H

#include <stdbool.h>
+#include <linux/frame.h>
#include <linux/list.h>
#include "objtool.h"
#include "cfi.h"

-#include <asm/orc_types.h>
-
enum insn_type {
INSN_JUMP_CONDITIONAL,
INSN_JUMP_UNCONDITIONAL,
@@ -86,4 +85,6 @@ unsigned long arch_dest_reloc_offset(int addend);

const char *arch_nop_insn(int len);

+int arch_decode_insn_hint(struct instruction *insn, struct unwind_hint *hint);
+
#endif /* _ARCH_H */
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 1967370440b3..2099809925af 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -6,6 +6,8 @@
#include <stdio.h>
#include <stdlib.h>

+#include <linux/frame.h>
+
#define unlikely(cond) (cond)
#include <asm/insn.h>
#include "../../../arch/x86/lib/inat.c"
@@ -15,6 +17,7 @@
#include "../../elf.h"
#include "../../arch.h"
#include "../../warn.h"
+#include <asm/orc_types.h>

static unsigned char op_to_cfi_reg[][2] = {
{CFI_AX, CFI_R8},
@@ -583,3 +586,54 @@ const char *arch_nop_insn(int len)

return nops[len-1];
}
+
+int arch_decode_insn_hint(struct instruction *insn, struct unwind_hint *hint)
+{
+ struct cfi_reg *cfa = &insn->cfi.cfa;
+
+ if (hint->type == UNWIND_HINT_TYPE_RET_OFFSET) {
+ insn->ret_offset = hint->sp_offset;
+ return 0;
+ }
+
+ insn->hint = true;
+
+ switch (hint->sp_reg) {
+ case ORC_REG_UNDEFINED:
+ cfa->base = CFI_UNDEFINED;
+ break;
+ case ORC_REG_SP:
+ cfa->base = CFI_SP;
+ break;
+ case ORC_REG_BP:
+ cfa->base = CFI_BP;
+ break;
+ case ORC_REG_SP_INDIRECT:
+ cfa->base = CFI_SP_INDIRECT;
+ break;
+ case ORC_REG_R10:
+ cfa->base = CFI_R10;
+ break;
+ case ORC_REG_R13:
+ cfa->base = CFI_R13;
+ break;
+ case ORC_REG_DI:
+ cfa->base = CFI_DI;
+ break;
+ case ORC_REG_DX:
+ cfa->base = CFI_DX;
+ break;
+ default:
+ WARN_FUNC("unsupported unwind_hint sp base reg %d",
+ insn->sec, insn->offset, hint->sp_reg);
+ return -1;
+ }
+
+ cfa->offset = hint->sp_offset;
+ insn->cfi.hint_type = hint->type;
+ insn->cfi.end = hint->end;
+
+ insn->cfi.sp_only = hint->type == ORC_TYPE_REGS || hint->type == ORC_TYPE_REGS_IRET;
+
+ return 0;
+}
diff --git a/tools/objtool/cfi.h b/tools/objtool/cfi.h
index c7c59c6a44ee..f5aeca023133 100644
--- a/tools/objtool/cfi.h
+++ b/tools/objtool/cfi.h
@@ -29,10 +29,11 @@ struct cfi_state {
struct cfi_reg cfa;
int stack_size;
int drap_reg, drap_offset;
- unsigned char type;
+ unsigned char hint_type;
bool bp_scratch;
bool drap;
bool end;
+ bool sp_only;
};

#endif /* _OBJTOOL_CFI_H */
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d6731e88259d..d856580369dd 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1217,7 +1217,6 @@ static int read_unwind_hints(struct objtool_file *file)
struct reloc *reloc;
struct unwind_hint *hint;
struct instruction *insn;
- struct cfi_reg *cfa;
int i;

sec = find_section_by_name(file->elf, ".discard.unwind_hints");
@@ -1252,49 +1251,10 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}

- cfa = &insn->cfi.cfa;
-
- if (hint->type == UNWIND_HINT_TYPE_RET_OFFSET) {
- insn->ret_offset = hint->sp_offset;
- continue;
- }
-
- insn->hint = true;
-
- switch (hint->sp_reg) {
- case ORC_REG_UNDEFINED:
- cfa->base = CFI_UNDEFINED;
- break;
- case ORC_REG_SP:
- cfa->base = CFI_SP;
- break;
- case ORC_REG_BP:
- cfa->base = CFI_BP;
- break;
- case ORC_REG_SP_INDIRECT:
- cfa->base = CFI_SP_INDIRECT;
- break;
- case ORC_REG_R10:
- cfa->base = CFI_R10;
- break;
- case ORC_REG_R13:
- cfa->base = CFI_R13;
- break;
- case ORC_REG_DI:
- cfa->base = CFI_DI;
- break;
- case ORC_REG_DX:
- cfa->base = CFI_DX;
- break;
- default:
- WARN_FUNC("unsupported unwind_hint sp base reg %d",
- insn->sec, insn->offset, hint->sp_reg);
+ if (arch_decode_insn_hint(insn, hint)) {
+ WARN_FUNC("Bad unwind hint", insn->sec, insn->offset);
return -1;
}
-
- cfa->offset = hint->sp_offset;
- insn->cfi.type = hint->type;
- insn->cfi.end = hint->end;
}

return 0;
@@ -1571,9 +1531,9 @@ static bool has_valid_stack_frame(struct insn_state *state)
return false;
}

-static int update_cfi_state_regs(struct instruction *insn,
- struct cfi_state *cfi,
- struct stack_op *op)
+static int update_sp_only_cfi_state(struct instruction *insn,
+ struct cfi_state *cfi,
+ struct stack_op *op)
{
struct cfi_reg *cfa = &cfi->cfa;

@@ -1679,8 +1639,8 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi,
return 0;
}

- if (cfi->type == ORC_TYPE_REGS || cfi->type == ORC_TYPE_REGS_IRET)
- return update_cfi_state_regs(insn, cfi, op);
+ if (cfi->sp_only)
+ return update_sp_only_cfi_state(insn, cfi, op);

switch (op->dest.type) {

@@ -2084,10 +2044,10 @@ static bool insn_cfi_match(struct instruction *insn, struct cfi_state *cfi2)
break;
}

- } else if (cfi1->type != cfi2->type) {
+ } else if (cfi1->hint_type != cfi2->hint_type) {

WARN_FUNC("stack state mismatch: type1=%d type2=%d",
- insn->sec, insn->offset, cfi1->type, cfi2->type);
+ insn->sec, insn->offset, cfi1->hint_type, cfi2->hint_type);

} else if (cfi1->drap != cfi2->drap ||
(cfi1->drap && cfi1->drap_reg != cfi2->drap_reg) ||
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 00f1efd05653..a36aee98bed0 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -9,6 +9,8 @@
#include "check.h"
#include "warn.h"

+#include <asm/orc_types.h>
+
struct orc_data {
struct list_head list;
struct instruction *insn;
@@ -92,7 +94,7 @@ int create_orc(struct objtool_file *file)

orc->sp_offset = cfa->offset;
orc->bp_offset = bp->offset;
- orc->type = insn->cfi.type;
+ orc->type = insn->cfi.hint_type;
}

return 0;
--
2.21.3
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