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

From: Palmer Dabbelt
Date: Tue Feb 22 2022 - 20:42:55 EST

On Tue, 01 Feb 2022 07:05:33 PST (-0800), guoren@xxxxxxxxxx wrote:
From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
---
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)