Re: [PATCH V5 09/21] riscv: compat: Add basic compat data type implementation

Palmer Dabbelt
2022-02-23T01:42:55Z

On Tue, 01 Feb 2022 07:05:33 PST (-0800), guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Implement riscv asm/compat.h for struct compat_xxx,
> is_compat_task, compat_user_regset, regset convert.
>
> The rv64 compat.h has inherited most of the structs
> from the generic one.
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> ---
> arch/riscv/include/asm/compat.h | 129 +++++++++++++++++++++++++++
> arch/riscv/include/asm/thread_info.h | 1 +
> 2 files changed, 130 insertions(+)
> create mode 100644 arch/riscv/include/asm/compat.h
>
> diff --git a/arch/riscv/include/asm/compat.h b/arch/riscv/include/asm/compat.h
> new file mode 100644
> index 000000000000..2ac955b51148
> --- /dev/null
> +++ b/arch/riscv/include/asm/compat.h
> @@ -0,0 +1,129 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef __ASM_COMPAT_H
> +#define __ASM_COMPAT_H
> +
> +#define COMPAT_UTS_MACHINE "riscv\0\0"
> +
> +/*
> + * Architecture specific compatibility types
> + */
> +#include <linux/types.h>
> +#include <linux/sched.h>
> +#include <linux/sched/task_stack.h>
> +#include <asm-generic/compat.h>
> +
> +static inline int is_compat_task(void)
> +{
> + return test_thread_flag(TIF_32BIT);
> +}
> +
> +struct compat_user_regs_struct {
> + compat_ulong_t pc;
> + compat_ulong_t ra;
> + compat_ulong_t sp;
> + compat_ulong_t gp;
> + compat_ulong_t tp;
> + compat_ulong_t t0;
> + compat_ulong_t t1;
> + compat_ulong_t t2;
> + compat_ulong_t s0;
> + compat_ulong_t s1;
> + compat_ulong_t a0;
> + compat_ulong_t a1;
> + compat_ulong_t a2;
> + compat_ulong_t a3;
> + compat_ulong_t a4;
> + compat_ulong_t a5;
> + compat_ulong_t a6;
> + compat_ulong_t a7;
> + compat_ulong_t s2;
> + compat_ulong_t s3;
> + compat_ulong_t s4;
> + compat_ulong_t s5;
> + compat_ulong_t s6;
> + compat_ulong_t s7;
> + compat_ulong_t s8;
> + compat_ulong_t s9;
> + compat_ulong_t s10;
> + compat_ulong_t s11;
> + compat_ulong_t t3;
> + compat_ulong_t t4;
> + compat_ulong_t t5;
> + compat_ulong_t t6;
> +};
> +
> +static inline void regs_to_cregs(struct compat_user_regs_struct *cregs,
> + struct pt_regs *regs)
> +{
> + cregs->pc = (compat_ulong_t) regs->epc;
> + cregs->ra = (compat_ulong_t) regs->ra;
> + cregs->sp = (compat_ulong_t) regs->sp;
> + cregs->gp = (compat_ulong_t) regs->gp;
> + cregs->tp = (compat_ulong_t) regs->tp;
> + cregs->t0 = (compat_ulong_t) regs->t0;
> + cregs->t1 = (compat_ulong_t) regs->t1;
> + cregs->t2 = (compat_ulong_t) regs->t2;
> + cregs->s0 = (compat_ulong_t) regs->s0;
> + cregs->s1 = (compat_ulong_t) regs->s1;
> + cregs->a0 = (compat_ulong_t) regs->a0;
> + cregs->a1 = (compat_ulong_t) regs->a1;
> + cregs->a2 = (compat_ulong_t) regs->a2;
> + cregs->a3 = (compat_ulong_t) regs->a3;
> + cregs->a4 = (compat_ulong_t) regs->a4;
> + cregs->a5 = (compat_ulong_t) regs->a5;
> + cregs->a6 = (compat_ulong_t) regs->a6;
> + cregs->a7 = (compat_ulong_t) regs->a7;
> + cregs->s2 = (compat_ulong_t) regs->s2;
> + cregs->s3 = (compat_ulong_t) regs->s3;
> + cregs->s4 = (compat_ulong_t) regs->s4;
> + cregs->s5 = (compat_ulong_t) regs->s5;
> + cregs->s6 = (compat_ulong_t) regs->s6;
> + cregs->s7 = (compat_ulong_t) regs->s7;
> + cregs->s8 = (compat_ulong_t) regs->s8;
> + cregs->s9 = (compat_ulong_t) regs->s9;
> + cregs->s10 = (compat_ulong_t) regs->s10;
> + cregs->s11 = (compat_ulong_t) regs->s11;
> + cregs->t3 = (compat_ulong_t) regs->t3;
> + cregs->t4 = (compat_ulong_t) regs->t4;
> + cregs->t5 = (compat_ulong_t) regs->t5;
> + cregs->t6 = (compat_ulong_t) regs->t6;
> +};
> +
> +static inline void cregs_to_regs(struct compat_user_regs_struct *cregs,
> + struct pt_regs *regs)
> +{
> + regs->epc = (unsigned long) cregs->pc;
> + regs->ra = (unsigned long) cregs->ra;
> + regs->sp = (unsigned long) cregs->sp;
> + regs->gp = (unsigned long) cregs->gp;
> + regs->tp = (unsigned long) cregs->tp;
> + regs->t0 = (unsigned long) cregs->t0;
> + regs->t1 = (unsigned long) cregs->t1;
> + regs->t2 = (unsigned long) cregs->t2;
> + regs->s0 = (unsigned long) cregs->s0;
> + regs->s1 = (unsigned long) cregs->s1;
> + regs->a0 = (unsigned long) cregs->a0;
> + regs->a1 = (unsigned long) cregs->a1;
> + regs->a2 = (unsigned long) cregs->a2;
> + regs->a3 = (unsigned long) cregs->a3;
> + regs->a4 = (unsigned long) cregs->a4;
> + regs->a5 = (unsigned long) cregs->a5;
> + regs->a6 = (unsigned long) cregs->a6;
> + regs->a7 = (unsigned long) cregs->a7;
> + regs->s2 = (unsigned long) cregs->s2;
> + regs->s3 = (unsigned long) cregs->s3;
> + regs->s4 = (unsigned long) cregs->s4;
> + regs->s5 = (unsigned long) cregs->s5;
> + regs->s6 = (unsigned long) cregs->s6;
> + regs->s7 = (unsigned long) cregs->s7;
> + regs->s8 = (unsigned long) cregs->s8;
> + regs->s9 = (unsigned long) cregs->s9;
> + regs->s10 = (unsigned long) cregs->s10;
> + regs->s11 = (unsigned long) cregs->s11;
> + regs->t3 = (unsigned long) cregs->t3;
> + regs->t4 = (unsigned long) cregs->t4;
> + regs->t5 = (unsigned long) cregs->t5;
> + regs->t6 = (unsigned long) cregs->t6;
> +};
> +
> +#endif /* __ASM_COMPAT_H */
> diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
> index 60da0dcacf14..9392e35c689d 100644
> --- a/arch/riscv/include/asm/thread_info.h
> +++ b/arch/riscv/include/asm/thread_info.h
> @@ -91,6 +91,7 @@ struct thread_info {
> #define TIF_SECCOMP 8 /* syscall secure computing */
> #define TIF_NOTIFY_SIGNAL 9 /* signal notifications exist */
> #define TIF_UPROBE 10 /* uprobe breakpoint or singlestep */
> +#define TIF_32BIT 11 /* 32bit process */

Presumably that's just meant for 32-bit processes on rv64? Probably
best to have the comment say that explicitly.

> #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
> #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)