Re: [PATCH 10/18] bsd-user: Add RISC-V thread setup and initialization support

[Richard Henderson <richard.henderson@linaro.org>]

On 8/2/24 18:34, Ajeet Singh wrote:
> From: Mark Corbin <mark.corbin@embecsom.com>
> 
> Implemented functions for setting up and initializing threads in the
> RISC-V architecture.
> The 'target_thread_set_upcall' function sets up the stack pointer,
> program counter, and function argument for new threads.
> The 'target_thread_init' function initializes thread registers based on
> the provided image information.
> 
> Signed-off-by: Mark Corbin <mark.corbin@embecsom.com>
> Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
> Co-authored-by: Jessica Clarke <jrtc27@jrtc27.com>
> Co-authored-by: Kyle Evans <kevans@FreeBSD.org>
> ---
>   bsd-user/riscv/target_arch_thread.h | 47 +++++++++++++++++++++++++++++
>   1 file changed, 47 insertions(+)
>   create mode 100644 bsd-user/riscv/target_arch_thread.h
> 
> diff --git a/bsd-user/riscv/target_arch_thread.h b/bsd-user/riscv/target_arch_thread.h
> new file mode 100644
> index 0000000000..faabb9fb45
> --- /dev/null
> +++ b/bsd-user/riscv/target_arch_thread.h
> @@ -0,0 +1,47 @@
> +/*
> + *  RISC-V thread support
> + *
> + *  Copyright (c) 2019 Mark Corbin
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef TARGET_ARCH_THREAD_H
> +#define TARGET_ARCH_THREAD_H
> +
> +/* Compare with cpu_set_upcall() in riscv/riscv/vm_machdep.c */
> +static inline void target_thread_set_upcall(CPURISCVState *regs,
> +    abi_ulong entry, abi_ulong arg, abi_ulong stack_base,
> +    abi_ulong stack_size)
> +{
> +    abi_ulong sp;
> +
> +    sp = (abi_ulong)(stack_base + stack_size) & ~(16 - 1);
> +
> +    regs->gpr[xSP] = sp;
> +    regs->pc = entry;
> +    regs->gpr[xA0] = arg;
> +}
> +
> +/* Compare with exec_setregs() in riscv/riscv/machdep.c */

exec_machdep.c.

> +static inline void target_thread_init(struct target_pt_regs *regs,
> +    struct image_info *infop)
> +{
> +    regs->sepc = infop->entry;
> +    regs->regs[xRA] = infop->entry;
> +    regs->regs[10] = infop->start_stack;               /* a0 */

xA0

> +    regs->regs[xSP] = infop->start_stack & ~(16 - 1);

ROUND_DOWN.


r~