C6X: ptrace support

Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 187 insertions, 0 deletions

diff --git a/arch/c6x/kernel/ptrace.c b/arch/c6x/kernel/ptrace.c
new file mode 100644
index 00000000000..3c494e84444
--- /dev/null
+++ b/arch/c6x/kernel/ptrace.c
@@ -0,0 +1,187 @@
+/*
+ *  Port on Texas Instruments TMS320C6x architecture
+ *
+ *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
+ *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
+ *
+ *  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+#include <linux/regset.h>
+#include <linux/elf.h>
+
+#include <asm/cacheflush.h>
+
+#define PT_REG_SIZE	  (sizeof(struct pt_regs))
+
+/*
+ * Called by kernel/ptrace.c when detaching.
+ */
+void ptrace_disable(struct task_struct *child)
+{
+	/* nothing to do */
+}
+
+/*
+ * Get a register number from live pt_regs for the specified task.
+ */
+static inline long get_reg(struct task_struct *task, int regno)
+{
+	long *addr = (long *)task_pt_regs(task);
+
+	if (regno == PT_TSR || regno == PT_CSR)
+		return 0;
+
+	return addr[regno];
+}
+
+/*
+ * Write contents of register REGNO in task TASK.
+ */
+static inline int put_reg(struct task_struct *task,
+			  int regno,
+			  unsigned long data)
+{
+	unsigned long *addr = (unsigned long *)task_pt_regs(task);
+
+	if (regno != PT_TSR && regno != PT_CSR)
+		addr[regno] = data;
+
+	return 0;
+}
+
+/* regset get/set implementations */
+
+static int gpr_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   void *kbuf, void __user *ubuf)
+{
+	struct pt_regs *regs = task_pt_regs(target);
+
+	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				   regs,
+				   0, sizeof(*regs));
+}
+
+static int 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 = task_pt_regs(target);
+
+	/* Don't copyin TSR or CSR */
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &regs,
+				 0, PT_TSR * sizeof(long));
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+					PT_TSR * sizeof(long),
+					(PT_TSR + 1) * sizeof(long));
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &regs,
+				 (PT_TSR + 1) * sizeof(long),
+				 PT_CSR * sizeof(long));
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+					PT_CSR * sizeof(long),
+					(PT_CSR + 1) * sizeof(long));
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &regs,
+				 (PT_CSR + 1) * sizeof(long), -1);
+	return ret;
+}
+
+enum c6x_regset {
+	REGSET_GPR,
+};
+
+static const struct user_regset c6x_regsets[] = {
+	[REGSET_GPR] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = ELF_NGREG,
+		.size = sizeof(u32),
+		.align = sizeof(u32),
+		.get = gpr_get,
+		.set = gpr_set
+	},
+};
+
+static const struct user_regset_view user_c6x_native_view = {
+	.name		= "tic6x",
+	.e_machine	= EM_TI_C6000,
+	.regsets	= c6x_regsets,
+	.n		= ARRAY_SIZE(c6x_regsets),
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &user_c6x_native_view;
+}
+
+/*
+ * Perform ptrace request
+ */
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	int ret = 0;
+
+	switch (request) {
+		/*
+		 * write the word at location addr.
+		 */
+	case PTRACE_POKETEXT:
+		ret = generic_ptrace_pokedata(child, addr, data);
+		if (ret == 0 && request == PTRACE_POKETEXT)
+			flush_icache_range(addr, addr + 4);
+		break;
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * handle tracing of system call entry
+ * - return the revised system call number or ULONG_MAX to cause ENOSYS
+ */
+asmlinkage unsigned long syscall_trace_entry(struct pt_regs *regs)
+{
+	if (tracehook_report_syscall_entry(regs))
+		/* tracing decided this syscall should not happen, so
+		 * We'll return a bogus call number to get an ENOSYS
+		 * error, but leave the original number in
+		 * regs->orig_a4
+		 */
+		return ULONG_MAX;
+
+	return regs->b0;
+}
+
+/*
+ * handle tracing of system call exit
+ */
+asmlinkage void syscall_trace_exit(struct pt_regs *regs)
+{
+	tracehook_report_syscall_exit(regs, 0);
+}