freebsd-skq/sys/riscv/include/elf.h
mhorne 50a7855ac2 RISC-V: expose extension bits in AT_HWCAP
AT_HWCAP is a field in the elf auxiliary vector meant to describe
cpu-specific hardware features. For RISC-V we want to use this to
indicate the presence of any standard extensions supported by the CPU.
This allows userland applications to query the system for supported
extensions using elf_aux_info(3).

Support for an extension is indicated by the presence of its
corresponding bit in AT_HWCAP -- e.g. systems supporting the 'c'
extension (compressed instructions) will have the second bit set.

Extensions advertised through AT_HWCAP are only those that are supported
by all harts in the system.

Reviewed by:	jhb, markj
Approved by:	markj (mentor)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D20493
2019-06-11 00:55:54 +00:00

89 lines
2.9 KiB
C

/*-
* Copyright (c) 1996-1997 John D. Polstra.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE_ELF_H_
#define _MACHINE_ELF_H_
/*
* ELF definitions for the RISC-V architecture.
*/
#include <sys/elf32.h> /* Definitions common to all 32 bit architectures. */
#include <sys/elf64.h> /* Definitions common to all 64 bit architectures. */
#define __ELF_WORD_SIZE 64 /* Used by <sys/elf_generic.h> */
#include <sys/elf_generic.h>
/*
* Auxiliary vector entries for passing information to the interpreter.
*/
typedef struct { /* Auxiliary vector entry on initial stack */
int a_type; /* Entry type. */
union {
int a_val; /* Integer value. */
} a_un;
} Elf32_Auxinfo;
typedef struct { /* Auxiliary vector entry on initial stack */
long a_type; /* Entry type. */
union {
long a_val; /* Integer value. */
void *a_ptr; /* Address. */
void (*a_fcn)(void); /* Function pointer (not used). */
} a_un;
} Elf64_Auxinfo;
__ElfType(Auxinfo);
#define ELF_ARCH EM_RISCV
#define ELF_MACHINE_OK(x) ((x) == (ELF_ARCH))
/* Define "machine" characteristics */
#define ELF_TARG_CLASS ELFCLASS64
#define ELF_TARG_DATA ELFDATA2LSB
#define ELF_TARG_MACH EM_RISCV
#define ELF_TARG_VER 1
/* TODO: set correct value */
#define ET_DYN_LOAD_ADDR 0x100000
/* Flags passed in AT_HWCAP */
#define HWCAP_ISA_BIT(c) (1 << ((c) - 'A'))
#define HWCAP_ISA_I HWCAP_ISA_BIT('I')
#define HWCAP_ISA_M HWCAP_ISA_BIT('M')
#define HWCAP_ISA_A HWCAP_ISA_BIT('A')
#define HWCAP_ISA_F HWCAP_ISA_BIT('F')
#define HWCAP_ISA_D HWCAP_ISA_BIT('D')
#define HWCAP_ISA_C HWCAP_ISA_BIT('C')
#define HWCAP_ISA_G \
(HWCAP_ISA_I | HWCAP_ISA_M | HWCAP_ISA_A | HWCAP_ISA_F | HWCAP_ISA_D)
#endif /* !_MACHINE_ELF_H_ */