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

[Palmer Dabbelt]

On Tue, 01 Feb 2022 07:05:33 PST (-0800), guoren at kernel.org wrote:
> From: Guo Ren <guoren at 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 at linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren at kernel.org>
> Cc: Arnd Bergmann <arnd at arndb.de>
> Cc: Palmer Dabbelt <palmer at 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)