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>

arch/c6x/include/asm/ptrace.h

+/*
+ *  Copyright (C) 2004, 2006, 2009, 2010 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.
+ */
+#ifndef _ASM_C6X_PTRACE_H
+#define _ASM_C6X_PTRACE_H
+
+#define BKPT_OPCODE	0x56454314	/* illegal opcode */
+
+#ifdef _BIG_ENDIAN
+#define PT_LO(odd, even)  odd
+#define PT_HI(odd, even)  even
+#else
+#define PT_LO(odd, even)  even
+#define PT_HI(odd, even)  odd
+#endif
+
+#define PT_A4_ORG  PT_LO(1, 0)
+#define PT_TSR	   PT_HI(1, 0)
+#define PT_ILC	   PT_LO(3, 2)
+#define PT_RILC    PT_HI(3, 2)
+#define PT_CSR	   PT_LO(5, 4)
+#define PT_PC	   PT_HI(5, 4)
+#define PT_B16	   PT_LO(7, 6)
+#define PT_B17	   PT_HI(7, 6)
+#define PT_B18	   PT_LO(9, 8)
+#define PT_B19	   PT_HI(9, 8)
+#define PT_B20	   PT_LO(11, 10)
+#define PT_B21	   PT_HI(11, 10)
+#define PT_B22	   PT_LO(13, 12)
+#define PT_B23	   PT_HI(13, 12)
+#define PT_B24	   PT_LO(15, 14)
+#define PT_B25	   PT_HI(15, 14)
+#define PT_B26	   PT_LO(17, 16)
+#define PT_B27	   PT_HI(17, 16)
+#define PT_B28	   PT_LO(19, 18)
+#define PT_B29	   PT_HI(19, 18)
+#define PT_B30	   PT_LO(21, 20)
+#define PT_B31	   PT_HI(21, 20)
+#define PT_B0	   PT_LO(23, 22)
+#define PT_B1	   PT_HI(23, 22)
+#define PT_B2	   PT_LO(25, 24)
+#define PT_B3	   PT_HI(25, 24)
+#define PT_B4	   PT_LO(27, 26)
+#define PT_B5	   PT_HI(27, 26)
+#define PT_B6	   PT_LO(29, 28)
+#define PT_B7	   PT_HI(29, 28)
+#define PT_B8	   PT_LO(31, 30)
+#define PT_B9	   PT_HI(31, 30)
+#define PT_B10	   PT_LO(33, 32)
+#define PT_B11	   PT_HI(33, 32)
+#define PT_B12	   PT_LO(35, 34)
+#define PT_B13	   PT_HI(35, 34)
+#define PT_A16	   PT_LO(37, 36)
+#define PT_A17	   PT_HI(37, 36)
+#define PT_A18	   PT_LO(39, 38)
+#define PT_A19	   PT_HI(39, 38)
+#define PT_A20	   PT_LO(41, 40)
+#define PT_A21	   PT_HI(41, 40)
+#define PT_A22	   PT_LO(43, 42)
+#define PT_A23	   PT_HI(43, 42)
+#define PT_A24	   PT_LO(45, 44)
+#define PT_A25	   PT_HI(45, 44)
+#define PT_A26	   PT_LO(47, 46)
+#define PT_A27	   PT_HI(47, 46)
+#define PT_A28	   PT_LO(49, 48)
+#define PT_A29	   PT_HI(49, 48)
+#define PT_A30	   PT_LO(51, 50)
+#define PT_A31	   PT_HI(51, 50)
+#define PT_A0	   PT_LO(53, 52)
+#define PT_A1	   PT_HI(53, 52)
+#define PT_A2	   PT_LO(55, 54)
+#define PT_A3	   PT_HI(55, 54)
+#define PT_A4	   PT_LO(57, 56)
+#define PT_A5	   PT_HI(57, 56)
+#define PT_A6	   PT_LO(59, 58)
+#define PT_A7	   PT_HI(59, 58)
+#define PT_A8	   PT_LO(61, 60)
+#define PT_A9	   PT_HI(61, 60)
+#define PT_A10	   PT_LO(63, 62)
+#define PT_A11	   PT_HI(63, 62)
+#define PT_A12	   PT_LO(65, 64)
+#define PT_A13	   PT_HI(65, 64)
+#define PT_A14	   PT_LO(67, 66)
+#define PT_A15	   PT_HI(67, 66)
+#define PT_B14	   PT_LO(69, 68)
+#define PT_B15	   PT_HI(69, 68)
+
+#define NR_PTREGS  70
+
+#define PT_DP	   PT_B14  /* Data Segment Pointer (B14) */
+#define PT_SP	   PT_B15  /* Stack Pointer (B15)  */
+
+#ifndef __ASSEMBLY__
+
+#ifdef _BIG_ENDIAN
+#define REG_PAIR(odd, even) unsigned long odd; unsigned long even
+#else
+#define REG_PAIR(odd, even) unsigned long even; unsigned long odd
+#endif
+
+/*
+ * this struct defines the way the registers are stored on the
+ * stack during a system call. fields defined with REG_PAIR
+ * are saved and restored using double-word memory operations
+ * which means the word ordering of the pair depends on endianess.
+ */
+struct pt_regs {
+	REG_PAIR(tsr, orig_a4);
+	REG_PAIR(rilc, ilc);
+	REG_PAIR(pc, csr);
+
+	REG_PAIR(b17, b16);
+	REG_PAIR(b19, b18);
+	REG_PAIR(b21, b20);
+	REG_PAIR(b23, b22);
+	REG_PAIR(b25, b24);
+	REG_PAIR(b27, b26);
+	REG_PAIR(b29, b28);
+	REG_PAIR(b31, b30);
+
+	REG_PAIR(b1, b0);
+	REG_PAIR(b3, b2);
+	REG_PAIR(b5, b4);
+	REG_PAIR(b7, b6);
+	REG_PAIR(b9, b8);
+	REG_PAIR(b11, b10);
+	REG_PAIR(b13, b12);
+
+	REG_PAIR(a17, a16);
+	REG_PAIR(a19, a18);
+	REG_PAIR(a21, a20);
+	REG_PAIR(a23, a22);
+	REG_PAIR(a25, a24);
+	REG_PAIR(a27, a26);
+	REG_PAIR(a29, a28);
+	REG_PAIR(a31, a30);
+
+	REG_PAIR(a1, a0);
+	REG_PAIR(a3, a2);
+	REG_PAIR(a5, a4);
+	REG_PAIR(a7, a6);
+	REG_PAIR(a9, a8);
+	REG_PAIR(a11, a10);
+	REG_PAIR(a13, a12);
+
+	REG_PAIR(a15, a14);
+	REG_PAIR(sp, dp);
+};
+
+#ifdef __KERNEL__
+
+#include <linux/linkage.h>
+
+#define user_mode(regs)	((((regs)->tsr) & 0x40) != 0)
+
+#define instruction_pointer(regs) ((regs)->pc)
+#define profile_pc(regs) instruction_pointer(regs)
+#define user_stack_pointer(regs) ((regs)->sp)
+
+extern void show_regs(struct pt_regs *);
+
+extern asmlinkage unsigned long syscall_trace_entry(struct pt_regs *regs);
+extern asmlinkage void syscall_trace_exit(struct pt_regs *regs);
+
+#endif /* __KERNEL__ */
+#endif /* __ASSEMBLY__ */
+#endif /* _ASM_C6X_PTRACE_H */

arch/c6x/kernel/ptrace.c

+/*
+ *  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);
+}