unicore32 additional architecture files: ptrace handling

This patch adds ptrace support.

Changed from previous version:
    1. disable arch_has_single_step and remove single-step instruction handler
    2. add 'Ross Biro 1/23/92' contributor information
    3. clean unused codes

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/arch/unicore32/include/asm/ptrace.h b/arch/unicore32/include/asm/ptrace.h
new file mode 100644 (file)
index 0000000..b9caf9b
--- /dev/null
+++ b/arch/unicore32/include/asm/ptrace.h
@@ -0,0 +1,133 @@
+/*
+ * linux/arch/unicore32/include/asm/ptrace.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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 __UNICORE_PTRACE_H__
+#define __UNICORE_PTRACE_H__
+
+#define PTRACE_GET_THREAD_AREA 22
+
+/*
+ * PSR bits
+ */
+#define USER_MODE      0x00000010
+#define REAL_MODE      0x00000011
+#define INTR_MODE      0x00000012
+#define PRIV_MODE      0x00000013
+#define ABRT_MODE      0x00000017
+#define EXTN_MODE      0x0000001b
+#define SUSR_MODE      0x0000001f
+#define MODE_MASK      0x0000001f
+#define PSR_R_BIT      0x00000040
+#define PSR_I_BIT      0x00000080
+#define PSR_V_BIT      0x10000000
+#define PSR_C_BIT      0x20000000
+#define PSR_Z_BIT      0x40000000
+#define PSR_S_BIT      0x80000000
+
+/*
+ * Groups of PSR bits
+ */
+#define PSR_f          0xff000000      /* Flags                */
+#define PSR_c          0x000000ff      /* Control              */
+
+#ifndef __ASSEMBLY__
+
+/*
+ * This struct defines the way the registers are stored on the
+ * stack during a system call.  Note that sizeof(struct pt_regs)
+ * has to be a multiple of 8.
+ */
+struct pt_regs {
+       unsigned long uregs[34];
+};
+
+#define UCreg_asr              uregs[32]
+#define UCreg_pc               uregs[31]
+#define UCreg_lr               uregs[30]
+#define UCreg_sp               uregs[29]
+#define UCreg_ip               uregs[28]
+#define UCreg_fp               uregs[27]
+#define UCreg_26               uregs[26]
+#define UCreg_25               uregs[25]
+#define UCreg_24               uregs[24]
+#define UCreg_23               uregs[23]
+#define UCreg_22               uregs[22]
+#define UCreg_21               uregs[21]
+#define UCreg_20               uregs[20]
+#define UCreg_19               uregs[19]
+#define UCreg_18               uregs[18]
+#define UCreg_17               uregs[17]
+#define UCreg_16               uregs[16]
+#define UCreg_15               uregs[15]
+#define UCreg_14               uregs[14]
+#define UCreg_13               uregs[13]
+#define UCreg_12               uregs[12]
+#define UCreg_11               uregs[11]
+#define UCreg_10               uregs[10]
+#define UCreg_09               uregs[9]
+#define UCreg_08               uregs[8]
+#define UCreg_07               uregs[7]
+#define UCreg_06               uregs[6]
+#define UCreg_05               uregs[5]
+#define UCreg_04               uregs[4]
+#define UCreg_03               uregs[3]
+#define UCreg_02               uregs[2]
+#define UCreg_01               uregs[1]
+#define UCreg_00               uregs[0]
+#define UCreg_ORIG_00          uregs[33]
+
+#ifdef __KERNEL__
+
+#define user_mode(regs)        \
+       (processor_mode(regs) == USER_MODE)
+
+#define processor_mode(regs) \
+       ((regs)->UCreg_asr & MODE_MASK)
+
+#define interrupts_enabled(regs) \
+       (!((regs)->UCreg_asr & PSR_I_BIT))
+
+#define fast_interrupts_enabled(regs) \
+       (!((regs)->UCreg_asr & PSR_R_BIT))
+
+/* Are the current registers suitable for user mode?
+ * (used to maintain security in signal handlers)
+ */
+static inline int valid_user_regs(struct pt_regs *regs)
+{
+       unsigned long mode = regs->UCreg_asr & MODE_MASK;
+
+       /*
+        * Always clear the R (REAL) bits
+        */
+       regs->UCreg_asr &= ~(PSR_R_BIT);
+
+       if ((regs->UCreg_asr & PSR_I_BIT) == 0) {
+               if (mode == USER_MODE)
+                       return 1;
+       }
+
+       /*
+        * Force ASR to something logical...
+        */
+       regs->UCreg_asr &= PSR_f | USER_MODE;
+
+       return 0;
+}
+
+#define instruction_pointer(regs)      ((regs)->UCreg_pc)
+
+#endif /* __KERNEL__ */
+
+#endif /* __ASSEMBLY__ */
+
+#endif
+

diff --git a/arch/unicore32/kernel/ptrace.c b/arch/unicore32/kernel/ptrace.c
new file mode 100644 (file)
index 0000000..9f07c08
--- /dev/null
+++ b/arch/unicore32/kernel/ptrace.c
@@ -0,0 +1,149 @@
+/*
+ * linux/arch/unicore32/kernel/ptrace.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * By Ross Biro 1/23/92
+ *
+ * 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/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/signal.h>
+#include <linux/uaccess.h>
+
+/*
+ * this routine will get a word off of the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline long get_user_reg(struct task_struct *task, int offset)
+{
+       return task_pt_regs(task)->uregs[offset];
+}
+
+/*
+ * this routine will put a word on the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline int
+put_user_reg(struct task_struct *task, int offset, long data)
+{
+       struct pt_regs newregs, *regs = task_pt_regs(task);
+       int ret = -EINVAL;
+
+       newregs = *regs;
+       newregs.uregs[offset] = data;
+
+       if (valid_user_regs(&newregs)) {
+               regs->uregs[offset] = data;
+               ret = 0;
+       }
+
+       return ret;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ */
+void ptrace_disable(struct task_struct *child)
+{
+}
+
+/*
+ * We actually access the pt_regs stored on the kernel stack.
+ */
+static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
+                           unsigned long __user *ret)
+{
+       unsigned long tmp;
+
+       tmp = 0;
+       if (off < sizeof(struct pt_regs))
+               tmp = get_user_reg(tsk, off >> 2);
+
+       return put_user(tmp, ret);
+}
+
+/*
+ * We actually access the pt_regs stored on the kernel stack.
+ */
+static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
+                            unsigned long val)
+{
+       if (off >= sizeof(struct pt_regs))
+               return 0;
+
+       return put_user_reg(tsk, off >> 2, val);
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+                unsigned long addr, unsigned long data)
+{
+       int ret;
+       unsigned long __user *datap = (unsigned long __user *) data;
+
+       switch (request) {
+       case PTRACE_PEEKUSR:
+               ret = ptrace_read_user(child, addr, datap);
+               break;
+
+       case PTRACE_POKEUSR:
+               ret = ptrace_write_user(child, addr, data);
+               break;
+
+       case PTRACE_GET_THREAD_AREA:
+               ret = put_user(task_pt_regs(child)->UCreg_16,
+                              datap);
+               break;
+
+       default:
+               ret = ptrace_request(child, request, addr, data);
+               break;
+       }
+
+       return ret;
+}
+
+asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
+{
+       unsigned long ip;
+
+       if (!test_thread_flag(TIF_SYSCALL_TRACE))
+               return scno;
+       if (!(current->ptrace & PT_PTRACED))
+               return scno;
+
+       /*
+        * Save IP.  IP is used to denote syscall entry/exit:
+        *  IP = 0 -> entry, = 1 -> exit
+        */
+       ip = regs->UCreg_ip;
+       regs->UCreg_ip = why;
+
+       current_thread_info()->syscall = scno;
+
+       /* the 0x80 provides a way for the tracing parent to distinguish
+          between a syscall stop and SIGTRAP delivery */
+       ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+                                ? 0x80 : 0));
+       /*
+        * this isn't the same as continuing with a signal, but it will do
+        * for normal use.  strace only continues with a signal if the
+        * stopping signal is not SIGTRAP.  -brl
+        */
+       if (current->exit_code) {
+               send_sig(current->exit_code, current, 1);
+               current->exit_code = 0;
+       }
+       regs->UCreg_ip = ip;
+
+       return current_thread_info()->syscall;
+}