linux/arch/riscv/include/asm/vdso.h
Guo Ren 0715372a06
riscv: compat: vdso: Add COMPAT_VDSO base code implementation
There is no vgettimeofday supported in rv32 that makes simple to
generate rv32 vdso code which only needs riscv64 compiler. Other
architectures need change compiler or -m (machine parameter) to
support vdso32 compiling. If rv32 support vgettimeofday (which
cause C compile) in future, we would add CROSS_COMPILE to support
that makes more requirement on compiler enviornment.

linux-rv64/arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg:
file format elf64-littleriscv

Disassembly of section .text:

0000000000000800 <__vdso_rt_sigreturn>:
 800:   08b00893                li      a7,139
 804:   00000073                ecall
 808:   0000                    unimp
        ...

000000000000080c <__vdso_getcpu>:
 80c:   0a800893                li      a7,168
 810:   00000073                ecall
 814:   8082                    ret
        ...

0000000000000818 <__vdso_flush_icache>:
 818:   10300893                li      a7,259
 81c:   00000073                ecall
 820:   8082                    ret

linux-rv32/arch/riscv/kernel/vdso/vdso.so.dbg:
file format elf32-littleriscv

Disassembly of section .text:

00000800 <__vdso_rt_sigreturn>:
 800:   08b00893                li      a7,139
 804:   00000073                ecall
 808:   0000                    unimp
        ...

0000080c <__vdso_getcpu>:
 80c:   0a800893                li      a7,168
 810:   00000073                ecall
 814:   8082                    ret
        ...

00000818 <__vdso_flush_icache>:
 818:   10300893                li      a7,259
 81c:   00000073                ecall
 820:   8082                    ret

Finally, reuse all *.S from vdso in compat_vdso that makes
implementation clear and readable.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-17-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-04-26 13:36:53 -07:00

38 lines
872 B
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 ARM Limited
* Copyright (C) 2014 Regents of the University of California
* Copyright (C) 2017 SiFive
*/
#ifndef _ASM_RISCV_VDSO_H
#define _ASM_RISCV_VDSO_H
/*
* All systems with an MMU have a VDSO, but systems without an MMU don't
* support shared libraries and therefor don't have one.
*/
#ifdef CONFIG_MMU
#define __VVAR_PAGES 2
#ifndef __ASSEMBLY__
#include <generated/vdso-offsets.h>
#define VDSO_SYMBOL(base, name) \
(void __user *)((unsigned long)(base) + __vdso_##name##_offset)
#ifdef CONFIG_COMPAT
#include <generated/compat_vdso-offsets.h>
#define COMPAT_VDSO_SYMBOL(base, name) \
(void __user *)((unsigned long)(base) + compat__vdso_##name##_offset)
#endif /* CONFIG_COMPAT */
#endif /* !__ASSEMBLY__ */
#endif /* CONFIG_MMU */
#endif /* _ASM_RISCV_VDSO_H */