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>

2 files changed, 361 insertions, 0 deletions

diff --git a/arch/c6x/include/asm/ptrace.h b/arch/c6x/include/asm/ptrace.h
new file mode 100644
index 000000000000..21e8d7931fe7
--- /dev/null
+++ b/arch/c6x/include/asm/ptrace.h
@@ -0,0 +1,174 @@
+/*
+ *  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 */
diff --git a/arch/c6x/kernel/ptrace.c b/arch/c6x/kernel/ptrace.c
new file mode 100644
index 000000000000..3c494e84444d
--- /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);
+}