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objtool: Make unwind hint definitions available to other architectures

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Unwind hints are useful to provide objtool with information about stack
states in non-standard functions/code.

While the type of information being provided might be very arch
specific, the mechanism to provide the information can be useful for
other architectures.

Move the relevant unwint hint definitions for all architectures to
see.

[ jpoimboe: REGS_IRET -> REGS_PARTIAL ]

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Julien Thierry
2020-09-04 16:30:27 +01:00
committed by Josh Poimboeuf
parent 5567c6c39f
commit ee819aedf3
10 changed files with 249 additions and 125 deletions
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56
arch/x86/include/asm/unwind_hints.h
View File

@ -1,51 +1,17 @@
#ifndef _ASM_X86_UNWIND_HINTS_H
#define _ASM_X86_UNWIND_HINTS_H
#include <linux/objtool.h>
#include "orc_types.h"
#ifdef __ASSEMBLY__
/*
* In asm, there are two kinds of code: normal C-type callable functions and
* the rest. The normal callable functions can be called by other code, and
* don't do anything unusual with the stack. Such normal callable functions
* are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
* category. In this case, no special debugging annotations are needed because
* objtool can automatically generate the ORC data for the ORC unwinder to read
* at runtime.
*
* Anything which doesn't fall into the above category, such as syscall and
* interrupt handlers, tends to not be called directly by other functions, and
* often does unusual non-C-function-type things with the stack pointer. Such
* code needs to be annotated such that objtool can understand it. The
* following CFI hint macros are for this type of code.
*
* These macros provide hints to objtool about the state of the stack at each
* instruction. Objtool starts from the hints and follows the code flow,
* making automatic CFI adjustments when it sees pushes and pops, filling out
* the debuginfo as necessary. It will also warn if it sees any
* inconsistencies.
*/
.macro UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL end=0
#ifdef CONFIG_STACK_VALIDATION
.Lunwind_hint_ip_\@:
.pushsection .discard.unwind_hints
/* struct unwind_hint */
.long .Lunwind_hint_ip_\@ - .
.short \sp_offset
.byte \sp_reg
.byte \type
.byte \end
.balign 4
.popsection
#endif
.endm
.macro UNWIND_HINT_EMPTY
UNWIND_HINT sp_reg=ORC_REG_UNDEFINED end=1
UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1
.endm
.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0
.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
.if \base == %rsp
.if \indirect
.set sp_reg, ORC_REG_SP_INDIRECT
@ -66,24 +32,24 @@
.set sp_offset, \offset
.if \iret
.set type, ORC_TYPE_REGS_IRET
.if \partial
.set type, UNWIND_HINT_TYPE_REGS_PARTIAL
.elseif \extra == 0
.set type, ORC_TYPE_REGS_IRET
.set type, UNWIND_HINT_TYPE_REGS_PARTIAL
.set sp_offset, \offset + (16*8)
.else
.set type, ORC_TYPE_REGS
.set type, UNWIND_HINT_TYPE_REGS
.endif
UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
.endm
.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
UNWIND_HINT_REGS base=\base offset=\offset iret=1
UNWIND_HINT_REGS base=\base offset=\offset partial=1
.endm
.macro UNWIND_HINT_FUNC sp_offset=8
UNWIND_HINT sp_offset=\sp_offset
UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=\sp_offset type=UNWIND_HINT_TYPE_CALL
.endm
/*
@ -92,7 +58,7 @@
* initial_func_cfi.
*/
.macro UNWIND_HINT_RET_OFFSET sp_offset=8
UNWIND_HINT type=UNWIND_HINT_TYPE_RET_OFFSET sp_offset=\sp_offset
UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_RET_OFFSET sp_offset=\sp_offset
.endm
#endif /* __ASSEMBLY__ */