/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_OBJTOOL_H
#define _LINUX_OBJTOOL_H

#include <linux/objtool_types.h>
#include <linux/annotate.h>

#ifdef CONFIG_OBJTOOL

#ifndef __ASSEMBLY__

#define UNWIND_HINT(type, sp_reg, sp_offset, signal)            \
        "987: \n\t"                                             \
        ".pushsection .discard.unwind_hints\n\t"                \
        ANNOTATE_DATA_SPECIAL "\n\t"                            \
        /* struct unwind_hint */                                \
        ".long 987b - .\n\t"                                    \
        ".short " __stringify(sp_offset) "\n\t"                 \
        ".byte " __stringify(sp_reg) "\n\t"                     \
        ".byte " __stringify(type) "\n\t"                       \
        ".byte " __stringify(signal) "\n\t"                     \
        ".balign 4 \n\t"                                        \
        ".popsection\n\t"

/*
 * This macro marks the given function's stack frame as "non-standard", which
 * tells objtool to ignore the function when doing stack metadata validation.
 * It should only be used in special cases where you're 100% sure it won't
 * affect the reliability of frame pointers and kernel stack traces.
 *
 * For more information, see tools/objtool/Documentation/objtool.txt.
 */
#define STACK_FRAME_NON_STANDARD(func) \
        static void __used __section(".discard.func_stack_frame_non_standard") \
                *__func_stack_frame_non_standard_##func = func

/*
 * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
 * for the case where a function is intentionally missing frame pointer setup,
 * but otherwise needs objtool/ORC coverage when frame pointers are disabled.
 */
#ifdef CONFIG_FRAME_POINTER
#define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
#else
#define STACK_FRAME_NON_STANDARD_FP(func)
#endif

#define ASM_REACHABLE                                                   \
        "998:\n\t"                                                      \
        ".pushsection .discard.reachable\n\t"                           \
        ".long 998b\n\t"                                                \
        ".popsection\n\t"

#define __ASM_BREF(label)       label ## b

#else /* __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 SYM_FUNC_{START,END}.  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 type:req sp_reg=0 sp_offset=0 signal=0
.Lhere_\@:
        .pushsection .discard.unwind_hints
                ANNOTATE_DATA_SPECIAL
                /* struct unwind_hint */
                .long .Lhere_\@ - .
                .short \sp_offset
                .byte \sp_reg
                .byte \type
                .byte \signal
                .balign 4
        .popsection
.endm

.macro STACK_FRAME_NON_STANDARD func:req
        .pushsection .discard.func_stack_frame_non_standard, "aw"
        .quad \func
        .popsection
.endm

.macro STACK_FRAME_NON_STANDARD_FP func:req
#ifdef CONFIG_FRAME_POINTER
        STACK_FRAME_NON_STANDARD \func
#endif
.endm

#endif /* __ASSEMBLY__ */

#else /* !CONFIG_OBJTOOL */

#ifndef __ASSEMBLY__

#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t"
#define STACK_FRAME_NON_STANDARD(func)
#define STACK_FRAME_NON_STANDARD_FP(func)
#else
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
#endif

#endif /* CONFIG_OBJTOOL */

#if defined(CONFIG_NOINSTR_VALIDATION) && \
        (defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
#define VALIDATE_UNRET_BEGIN    ANNOTATE_UNRET_BEGIN
#else
#define VALIDATE_UNRET_BEGIN
#endif

#endif /* _LINUX_OBJTOOL_H */