1 files changed, 178 insertions, 0 deletions
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
new file mode 100644
index 000000000..69678ab64
--- /dev/null
+++ b/arch/riscv/kernel/ptrace.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ * Copyright 2015 Regents of the University of California
+ * Copyright 2017 SiFive
+ *
+ * Copied from arch/tile/kernel/ptrace.c
+ */
+
+#include <asm/ptrace.h>
+#include <asm/syscall.h>
+#include <asm/thread_info.h>
+#include <asm/switch_to.h>
+#include <linux/audit.h>
+#include <linux/ptrace.h>
+#include <linux/elf.h>
+#include <linux/regset.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/tracehook.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
+enum riscv_regset {
+	REGSET_X,
+#ifdef CONFIG_FPU
+	REGSET_F,
+#endif
+};
+
+static int riscv_gpr_get(struct task_struct *target,
+			 const struct user_regset *regset,
+			 struct membuf to)
+{
+	return membuf_write(&to, task_pt_regs(target),
+			    sizeof(struct user_regs_struct));
+}
+
+static int riscv_gpr_set(struct task_struct *target,
+			 const struct user_regset *regset,
+			 unsigned int pos, unsigned int count,
+			 const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	struct pt_regs *regs;
+
+	regs = task_pt_regs(target);
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+	return ret;
+}
+
+#ifdef CONFIG_FPU
+static int riscv_fpr_get(struct task_struct *target,
+			 const struct user_regset *regset,
+			 struct membuf to)
+{
+	struct __riscv_d_ext_state *fstate = &target->thread.fstate;
+
+	if (target == current)
+		fstate_save(current, task_pt_regs(current));
+
+	membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
+	membuf_store(&to, fstate->fcsr);
+	return membuf_zero(&to, 4);	// explicitly pad
+}
+
+static int riscv_fpr_set(struct task_struct *target,
+			 const struct user_regset *regset,
+			 unsigned int pos, unsigned int count,
+			 const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	struct __riscv_d_ext_state *fstate = &target->thread.fstate;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
+				 offsetof(struct __riscv_d_ext_state, fcsr));
+	if (!ret) {
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
+					 offsetof(struct __riscv_d_ext_state, fcsr) +
+					 sizeof(fstate->fcsr));
+	}
+
+	return ret;
+}
+#endif
+
+static const struct user_regset riscv_user_regset[] = {
+	[REGSET_X] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = ELF_NGREG,
+		.size = sizeof(elf_greg_t),
+		.align = sizeof(elf_greg_t),
+		.regset_get = riscv_gpr_get,
+		.set = riscv_gpr_set,
+	},
+#ifdef CONFIG_FPU
+	[REGSET_F] = {
+		.core_note_type = NT_PRFPREG,
+		.n = ELF_NFPREG,
+		.size = sizeof(elf_fpreg_t),
+		.align = sizeof(elf_fpreg_t),
+		.regset_get = riscv_fpr_get,
+		.set = riscv_fpr_set,
+	},
+#endif
+};
+
+static const struct user_regset_view riscv_user_native_view = {
+	.name = "riscv",
+	.e_machine = EM_RISCV,
+	.regsets = riscv_user_regset,
+	.n = ARRAY_SIZE(riscv_user_regset),
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &riscv_user_native_view;
+}
+
+void ptrace_disable(struct task_struct *child)
+{
+	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	long ret = -EIO;
+
+	switch (request) {
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
+ * {handle,ret_from}_syscall.
+ */
+__visible int do_syscall_trace_enter(struct pt_regs *regs)
+{
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		if (tracehook_report_syscall_entry(regs))
+			return -1;
+
+	/*
+	 * Do the secure computing after ptrace; failures should be fast.
+	 * If this fails we might have return value in a0 from seccomp
+	 * (via SECCOMP_RET_ERRNO/TRACE).
+	 */
+	if (secure_computing() == -1)
+		return -1;
+
+#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
+	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+		trace_sys_enter(regs, syscall_get_nr(current, regs));
+#endif
+
+	audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
+	return 0;
+}
+
+__visible void do_syscall_trace_exit(struct pt_regs *regs)
+{
+	audit_syscall_exit(regs);
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(regs, 0);
+
+#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
+	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+		trace_sys_exit(regs, regs_return_value(regs));
+#endif
+}