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From: Kyle Evans <kevans@freebsd.org>
To: Warner Losh <imp@bsdimp.com>
Cc: Stacey Son <sson@freebsd.org>,
	qemu-trivial@nongnu.org, Kyle Evans <kevans@freebsd.org>,
	Michael Tokarev <mjt@tls.msk.ru>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Laurent Vivier <laurent@vivier.eu>
Subject: Re: [PATCH 13/24] bsd-user/arm/target_arch_thread.h: Routines to create and switch to a thread
Date: Tue, 26 Oct 2021 01:01:11 -0500	[thread overview]
Message-ID: <CACNAnaHUq==anp0uQhxk3o=MuLeyaii+MsMPZc3_pBnuS-wCag@mail.gmail.com> (raw)
In-Reply-To: <20211019164447.16359-14-imp@bsdimp.com>

On Tue, Oct 19, 2021 at 11:45 AM Warner Losh <imp@bsdimp.com> wrote:
>
> Implement target_thread_init (to create a thread) and target_set_upcall
> (to switch to a thread) for arm.
>
> Signed-off-by: Stacey Son <sson@FreeBSD.org>
> Signed-off-by: Klye Evans <kevans@FreeBSD.org>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>  bsd-user/arm/target_arch_thread.h | 71 +++++++++++++++++++++++++++++++
>  1 file changed, 71 insertions(+)
>  create mode 100644 bsd-user/arm/target_arch_thread.h
>
> diff --git a/bsd-user/arm/target_arch_thread.h b/bsd-user/arm/target_arch_thread.h
> new file mode 100644
> index 0000000000..317364bb84
> --- /dev/null
> +++ b/bsd-user/arm/target_arch_thread.h
> @@ -0,0 +1,71 @@
> +/*
> + *  arm thread support
> + *
> + *  Copyright (c) 2013 Stacey D. Son
> + *
> + *  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 to arm/arm/vm_machdep.c cpu_set_upcall_kse() */
> +static inline void target_thread_set_upcall(CPUARMState *regs, abi_ulong entry,
> +    abi_ulong arg, abi_ulong stack_base, abi_ulong stack_size)
> +{
> +    abi_ulong sp;
> +
> +    /*
> +     * Make sure the stack is properly aligned.
> +     * arm/include/param.h (STACKLIGN() macro)
> +     */
> +    sp = (u_int)((stack_base + stack_size) -
> +        sizeof(struct target_trapframe)) & ~0x7;
> +
> +    /* sp = stack base */
> +    regs->regs[13] = sp;
> +    /* pc = start function entry */
> +    regs->regs[15] = entry & 0xfffffffe;
> +    /* r0 = arg */
> +    regs->regs[0] = arg;
> +    regs->spsr = ARM_CPU_MODE_USR;
> +    if (entry & 0x1) {
> +        regs->spsr |= CPSR_T;
> +    }
> +}
> +
> +static inline void target_thread_init(struct target_pt_regs *regs,
> +        struct image_info *infop)
> +{
> +    abi_long stack = infop->start_stack;
> +    memset(regs, 0, sizeof(*regs));
> +    regs->ARM_cpsr = 0x10;
> +    if (infop->entry & 1) {
> +        regs->ARM_cpsr |= CPSR_T;
> +    }
> +    regs->ARM_pc = infop->entry & 0xfffffffe;
> +    regs->ARM_sp = infop->start_stack;
> +    if (bsd_type == target_freebsd) {
> +        regs->ARM_lr = infop->entry & 0xfffffffe;
> +    }
> +    /* FIXME - what to for failure of get_user()? */
> +    get_user_ual(regs->ARM_r2, stack + 8); /* envp */
> +    get_user_ual(regs->ARM_r1, stack + 4); /* envp */
> +    /* XXX: it seems that r0 is zeroed after ! */
> +    regs->ARM_r0 = 0;
> +    /* For uClinux PIC binaries.  */
> +    /* XXX: Linux does this only on ARM with no MMU (do we care ?) */
> +    regs->ARM_r10 = infop->start_data;
> +}
> +
> +#endif /* !_TARGET_ARCH_THREAD_H_ */
> --
> 2.32.0
>

I think it's obvious enough to folks already familiar with ARM, but I
wonder if we shouldn't add in some basic commentary about the thumb
bits above. Something like:

/*
 * The low bit in an entry point indicates a thumb instruction; the entry point
 * can't actually exist at this address because it must be 16- or 32-
bit aligned.
 * The low bit gets masked off and the T bit in CSPR is twiddled to
indicate thumb.
 */


  reply	other threads:[~2021-10-26  6:18 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-19 16:44 [PATCH 00/24] bsd-user: arm (32-bit) support Warner Losh
2021-10-19 16:44 ` [PATCH 01/24] bsd-user/arm/target_arch_sysarch.h: Use consistent include guards Warner Losh
2021-10-23  7:29   ` Kyle Evans
2021-10-28 15:08   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 02/24] bsd-user/arm/target_syscall.h: Add copyright and update name Warner Losh
2021-10-23  7:30   ` Kyle Evans
2021-10-28 15:08   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 03/24] bsd-user/arm/target_arch_cpu.c: Target specific TLS routines Warner Losh
2021-10-23  7:30   ` Kyle Evans
2021-10-28 15:08   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 04/24] bsd-user/arm/target_arch_cpu.h: CPU Loop definitions Warner Losh
2021-10-23  7:31   ` Kyle Evans
2021-10-28 15:14   ` Richard Henderson
2021-10-28 17:36     ` Warner Losh
2021-10-19 16:44 ` [PATCH 05/24] bsd-user/arm/target_arch_cpu.h: Implement target_cpu_clone_regs Warner Losh
2021-10-23  7:31   ` Kyle Evans
2021-10-28 15:15   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 06/24] bsd-user/arm/target_arch_cpu.h: Dummy target_cpu_loop implementation Warner Losh
2021-10-23  7:32   ` Kyle Evans
2021-10-28 15:15   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 07/24] bsd-user/arm/target_arch_cpu.h: Implment trivial EXCP exceptions Warner Losh
2021-10-26  5:52   ` Kyle Evans
2021-10-28 15:19   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 08/24] bsd-user/arm/target_arch_cpu.h: Implement data abort exceptions Warner Losh
2021-10-26  5:47   ` Kyle Evans
2021-10-28 15:29   ` Richard Henderson
2021-10-28 16:56     ` Warner Losh
2021-10-19 16:44 ` [PATCH 09/24] bsd-user/arm/target_arch_cpu.h: Implement system call dispatch Warner Losh
2021-10-23  7:33   ` Kyle Evans
2021-10-23 15:17     ` Warner Losh
2021-10-28 15:35   ` Richard Henderson
2021-10-28 17:56     ` Warner Losh
2021-10-19 16:44 ` [PATCH 10/24] bsd-user/arm/target_arch_reg.h: Implement core dump register copying Warner Losh
2021-10-26  5:48   ` Kyle Evans
2021-10-28 15:36   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 11/24] bsd-user/arm/target_arch_vmparam.h: Parameters for arm address space Warner Losh
2021-10-26  5:52   ` Kyle Evans
2021-10-28 15:37   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 12/24] bsd-user/arm/target_arch_sigtramp.h: Signal Trampoline for arm Warner Losh
2021-10-26  5:51   ` Kyle Evans
2021-10-28 15:42   ` Richard Henderson
2021-10-28 19:35     ` Warner Losh
2021-10-19 16:44 ` [PATCH 13/24] bsd-user/arm/target_arch_thread.h: Routines to create and switch to a thread Warner Losh
2021-10-26  6:01   ` Kyle Evans [this message]
2021-10-26  6:11     ` Kyle Evans
2021-10-27 15:35       ` Warner Losh
2021-10-27 15:40         ` Kyle Evans
2021-10-28 15:57   ` Richard Henderson
2021-10-28 19:45     ` Warner Losh
2021-10-29 16:06       ` Richard Henderson
2021-10-19 16:44 ` [PATCH 14/24] bsd-user/arm/target_arch_elf.h: arm defines for ELF Warner Losh
2021-10-26  6:07   ` Kyle Evans
2021-10-28 16:02   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 15/24] bsd-user/arm/target_arch_elf.h: arm get hwcap Warner Losh
2021-10-26  6:02   ` Kyle Evans
2021-10-28 16:06   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 16/24] bsd-user/arm/target_arch_elf.h: arm get_hwcap2 impl Warner Losh
2021-10-26  6:02   ` Kyle Evans
2021-10-28 16:08   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 17/24] bsd-user/arm/target_arch_signal.h: arm specific signal registers and stack Warner Losh
2021-10-26  6:03   ` Kyle Evans
2021-10-28 16:18   ` Richard Henderson
2021-10-28 16:48     ` Warner Losh
2021-10-19 16:44 ` [PATCH 18/24] bsd-user/arm/target_arch_signal.h: arm machine context for signals Warner Losh
2021-10-26  6:03   ` Kyle Evans
2021-10-28 17:04   ` Richard Henderson
2021-10-28 17:18   ` Richard Henderson
2021-10-28 20:16     ` Warner Losh
2021-10-19 16:44 ` [PATCH 19/24] bsd-user/arm/target_arch_signal.h: arm user context and trapframe " Warner Losh
2021-10-26  6:07   ` Kyle Evans
2021-10-27 15:48     ` Warner Losh
2021-10-28 17:22   ` Richard Henderson
2021-10-30  2:44     ` Warner Losh
2021-10-19 16:44 ` [PATCH 20/24] bsd-user/arm/target_arch_signal.h: arm set_sigtramp_args Warner Losh
2021-10-26  6:10   ` Kyle Evans
2021-10-28 17:25   ` Richard Henderson
2021-10-28 17:35     ` Kyle Evans
2021-10-28 22:22       ` Warner Losh
2021-10-28 22:41     ` Warner Losh
2021-10-30  2:47       ` Warner Losh
2021-10-19 16:44 ` [PATCH 21/24] bsd-user/arm/target_arch_signal.h: arm get_mcontext Warner Losh
2021-10-26  6:08   ` Kyle Evans
2021-10-28 17:27   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 22/24] bsd-user/arm/target_arch_signal.h: arm set_mcontext Warner Losh
2021-10-26  6:12   ` Kyle Evans
2021-10-28 17:53   ` Richard Henderson
2021-10-29  0:07     ` Warner Losh
2021-10-29  4:34       ` Warner Losh
2021-10-28 17:57   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 23/24] bsd-user/arm/target_arch_signal.h: arm get_ucontext_sigreturn Warner Losh
2021-10-26  6:12   ` Kyle Evans
2021-10-28 17:59   ` Richard Henderson
2021-10-19 16:44 ` [PATCH 24/24] bsd-user: add arm target build Warner Losh
2021-10-26  6:21   ` Kyle Evans
2021-10-28 18:02     ` Richard Henderson

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