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ffb1b4a410
Add a 'signal' field which allows unwind hints to specify whether the instruction pointer should be taken literally (like for most interrupts and exceptions) rather than decremented (like for call stack return addresses) when used to find the next ORC entry. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/d2c5ec4d83a45b513d8fd72fab59f1a8cfa46871.1676068346.git.jpoimboe@kernel.org
200 lines
5.7 KiB
C
200 lines
5.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_OBJTOOL_H
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#define _LINUX_OBJTOOL_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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/*
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* This struct is used by asm and inline asm code to manually annotate the
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* location of registers on the stack.
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*/
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struct unwind_hint {
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u32 ip;
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s16 sp_offset;
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u8 sp_reg;
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u8 type;
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u8 signal;
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u8 end;
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};
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#endif
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/*
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* UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
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* (the caller's SP right before it made the call). Used for all callable
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* functions, i.e. all C code and all callable asm functions.
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*
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* UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
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* points to a fully populated pt_regs from a syscall, interrupt, or exception.
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*
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* UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
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* sp_reg+sp_offset points to the iret return frame.
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*
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* UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function.
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* Useful for code which doesn't have an ELF function annotation.
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*
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* UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
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*/
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#define UNWIND_HINT_TYPE_CALL 0
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#define UNWIND_HINT_TYPE_REGS 1
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#define UNWIND_HINT_TYPE_REGS_PARTIAL 2
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#define UNWIND_HINT_TYPE_FUNC 3
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#define UNWIND_HINT_TYPE_ENTRY 4
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#define UNWIND_HINT_TYPE_SAVE 5
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#define UNWIND_HINT_TYPE_RESTORE 6
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#ifdef CONFIG_OBJTOOL
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#include <asm/asm.h>
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#ifndef __ASSEMBLY__
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#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
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"987: \n\t" \
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".pushsection .discard.unwind_hints\n\t" \
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/* struct unwind_hint */ \
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".long 987b - .\n\t" \
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".short " __stringify(sp_offset) "\n\t" \
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".byte " __stringify(sp_reg) "\n\t" \
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".byte " __stringify(type) "\n\t" \
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".byte " __stringify(signal) "\n\t" \
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".byte " __stringify(end) "\n\t" \
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".balign 4 \n\t" \
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".popsection\n\t"
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/*
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* This macro marks the given function's stack frame as "non-standard", which
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* tells objtool to ignore the function when doing stack metadata validation.
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* It should only be used in special cases where you're 100% sure it won't
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* affect the reliability of frame pointers and kernel stack traces.
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*
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* For more information, see tools/objtool/Documentation/objtool.txt.
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*/
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#define STACK_FRAME_NON_STANDARD(func) \
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static void __used __section(".discard.func_stack_frame_non_standard") \
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*__func_stack_frame_non_standard_##func = func
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/*
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* STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
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* for the case where a function is intentionally missing frame pointer setup,
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* but otherwise needs objtool/ORC coverage when frame pointers are disabled.
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*/
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#ifdef CONFIG_FRAME_POINTER
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#define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
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#else
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#define STACK_FRAME_NON_STANDARD_FP(func)
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#endif
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#define ANNOTATE_NOENDBR \
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"986: \n\t" \
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".pushsection .discard.noendbr\n\t" \
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_ASM_PTR " 986b\n\t" \
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".popsection\n\t"
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#define ASM_REACHABLE \
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"998:\n\t" \
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".pushsection .discard.reachable\n\t" \
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".long 998b - .\n\t" \
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".popsection\n\t"
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#else /* __ASSEMBLY__ */
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/*
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* This macro indicates that the following intra-function call is valid.
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* Any non-annotated intra-function call will cause objtool to issue a warning.
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*/
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#define ANNOTATE_INTRA_FUNCTION_CALL \
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999: \
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.pushsection .discard.intra_function_calls; \
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.long 999b; \
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.popsection;
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/*
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* In asm, there are two kinds of code: normal C-type callable functions and
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* the rest. The normal callable functions can be called by other code, and
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* don't do anything unusual with the stack. Such normal callable functions
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* are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
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* category. In this case, no special debugging annotations are needed because
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* objtool can automatically generate the ORC data for the ORC unwinder to read
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* at runtime.
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*
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* Anything which doesn't fall into the above category, such as syscall and
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* interrupt handlers, tends to not be called directly by other functions, and
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* often does unusual non-C-function-type things with the stack pointer. Such
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* code needs to be annotated such that objtool can understand it. The
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* following CFI hint macros are for this type of code.
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*
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* These macros provide hints to objtool about the state of the stack at each
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* instruction. Objtool starts from the hints and follows the code flow,
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* making automatic CFI adjustments when it sees pushes and pops, filling out
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* the debuginfo as necessary. It will also warn if it sees any
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* inconsistencies.
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*/
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.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
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.Lunwind_hint_ip_\@:
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.pushsection .discard.unwind_hints
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/* struct unwind_hint */
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.long .Lunwind_hint_ip_\@ - .
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.short \sp_offset
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.byte \sp_reg
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.byte \type
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.byte \signal
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.byte \end
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.balign 4
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.popsection
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.endm
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.macro STACK_FRAME_NON_STANDARD func:req
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.pushsection .discard.func_stack_frame_non_standard, "aw"
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_ASM_PTR \func
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.popsection
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.endm
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.macro STACK_FRAME_NON_STANDARD_FP func:req
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#ifdef CONFIG_FRAME_POINTER
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STACK_FRAME_NON_STANDARD \func
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#endif
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.endm
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.macro ANNOTATE_NOENDBR
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.Lhere_\@:
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.pushsection .discard.noendbr
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.quad .Lhere_\@
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.popsection
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.endm
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.macro REACHABLE
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.Lhere_\@:
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.pushsection .discard.reachable
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.long .Lhere_\@ - .
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.popsection
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.endm
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#endif /* __ASSEMBLY__ */
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#else /* !CONFIG_OBJTOOL */
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#ifndef __ASSEMBLY__
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#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
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"\n\t"
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#define STACK_FRAME_NON_STANDARD(func)
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#define STACK_FRAME_NON_STANDARD_FP(func)
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#define ANNOTATE_NOENDBR
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#define ASM_REACHABLE
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#else
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#define ANNOTATE_INTRA_FUNCTION_CALL
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.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
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.endm
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.macro STACK_FRAME_NON_STANDARD func:req
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.endm
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.macro ANNOTATE_NOENDBR
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.endm
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.macro REACHABLE
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.endm
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#endif
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#endif /* CONFIG_OBJTOOL */
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#endif /* _LINUX_OBJTOOL_H */
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