Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * arch/arm/kernel/kgdb.c
  3  *
  4  * ARM KGDB support
  5  *
  6  * Copyright (c) 2002-2004 MontaVista Software, Inc
  7  * Copyright (c) 2008 Wind River Systems, Inc.
  8  *
  9  * Authors:  George Davis <davis_g@mvista.com>
 10  *           Deepak Saxena <dsaxena@plexity.net>
 11  */
 12 #include <linux/kgdb.h>
 13 #include <asm/traps.h>
 14 
 15 /* Make a local copy of the registers passed into the handler (bletch) */
 16 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
 17 {
 18         int regno;
 19 
 20         /* Initialize all to zero. */
 21         for (regno = 0; regno < GDB_MAX_REGS; regno++)
 22                 gdb_regs[regno] = 0;
 23 
 24         gdb_regs[_R0]           = kernel_regs->ARM_r0;
 25         gdb_regs[_R1]           = kernel_regs->ARM_r1;
 26         gdb_regs[_R2]           = kernel_regs->ARM_r2;
 27         gdb_regs[_R3]           = kernel_regs->ARM_r3;
 28         gdb_regs[_R4]           = kernel_regs->ARM_r4;
 29         gdb_regs[_R5]           = kernel_regs->ARM_r5;
 30         gdb_regs[_R6]           = kernel_regs->ARM_r6;
 31         gdb_regs[_R7]           = kernel_regs->ARM_r7;
 32         gdb_regs[_R8]           = kernel_regs->ARM_r8;
 33         gdb_regs[_R9]           = kernel_regs->ARM_r9;
 34         gdb_regs[_R10]          = kernel_regs->ARM_r10;
 35         gdb_regs[_FP]           = kernel_regs->ARM_fp;
 36         gdb_regs[_IP]           = kernel_regs->ARM_ip;
 37         gdb_regs[_SPT]          = kernel_regs->ARM_sp;
 38         gdb_regs[_LR]           = kernel_regs->ARM_lr;
 39         gdb_regs[_PC]           = kernel_regs->ARM_pc;
 40         gdb_regs[_CPSR]         = kernel_regs->ARM_cpsr;
 41 }
 42 
 43 /* Copy local gdb registers back to kgdb regs, for later copy to kernel */
 44 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
 45 {
 46         kernel_regs->ARM_r0     = gdb_regs[_R0];
 47         kernel_regs->ARM_r1     = gdb_regs[_R1];
 48         kernel_regs->ARM_r2     = gdb_regs[_R2];
 49         kernel_regs->ARM_r3     = gdb_regs[_R3];
 50         kernel_regs->ARM_r4     = gdb_regs[_R4];
 51         kernel_regs->ARM_r5     = gdb_regs[_R5];
 52         kernel_regs->ARM_r6     = gdb_regs[_R6];
 53         kernel_regs->ARM_r7     = gdb_regs[_R7];
 54         kernel_regs->ARM_r8     = gdb_regs[_R8];
 55         kernel_regs->ARM_r9     = gdb_regs[_R9];
 56         kernel_regs->ARM_r10    = gdb_regs[_R10];
 57         kernel_regs->ARM_fp     = gdb_regs[_FP];
 58         kernel_regs->ARM_ip     = gdb_regs[_IP];
 59         kernel_regs->ARM_sp     = gdb_regs[_SPT];
 60         kernel_regs->ARM_lr     = gdb_regs[_LR];
 61         kernel_regs->ARM_pc     = gdb_regs[_PC];
 62         kernel_regs->ARM_cpsr   = gdb_regs[_CPSR];
 63 }
 64 
 65 void
 66 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
 67 {
 68         struct pt_regs *thread_regs;
 69         int regno;
 70 
 71         /* Just making sure... */
 72         if (task == NULL)
 73                 return;
 74 
 75         /* Initialize to zero */
 76         for (regno = 0; regno < GDB_MAX_REGS; regno++)
 77                 gdb_regs[regno] = 0;
 78 
 79         /* Otherwise, we have only some registers from switch_to() */
 80         thread_regs             = task_pt_regs(task);
 81         gdb_regs[_R0]           = thread_regs->ARM_r0;
 82         gdb_regs[_R1]           = thread_regs->ARM_r1;
 83         gdb_regs[_R2]           = thread_regs->ARM_r2;
 84         gdb_regs[_R3]           = thread_regs->ARM_r3;
 85         gdb_regs[_R4]           = thread_regs->ARM_r4;
 86         gdb_regs[_R5]           = thread_regs->ARM_r5;
 87         gdb_regs[_R6]           = thread_regs->ARM_r6;
 88         gdb_regs[_R7]           = thread_regs->ARM_r7;
 89         gdb_regs[_R8]           = thread_regs->ARM_r8;
 90         gdb_regs[_R9]           = thread_regs->ARM_r9;
 91         gdb_regs[_R10]          = thread_regs->ARM_r10;
 92         gdb_regs[_FP]           = thread_regs->ARM_fp;
 93         gdb_regs[_IP]           = thread_regs->ARM_ip;
 94         gdb_regs[_SPT]          = thread_regs->ARM_sp;
 95         gdb_regs[_LR]           = thread_regs->ARM_lr;
 96         gdb_regs[_PC]           = thread_regs->ARM_pc;
 97         gdb_regs[_CPSR]         = thread_regs->ARM_cpsr;
 98 }
 99 
100 static int compiled_break;
101 
102 int kgdb_arch_handle_exception(int exception_vector, int signo,
103                                int err_code, char *remcom_in_buffer,
104                                char *remcom_out_buffer,
105                                struct pt_regs *linux_regs)
106 {
107         unsigned long addr;
108         char *ptr;
109 
110         switch (remcom_in_buffer[0]) {
111         case 'D':
112         case 'k':
113         case 'c':
114                 /*
115                  * Try to read optional parameter, pc unchanged if no parm.
116                  * If this was a compiled breakpoint, we need to move
117                  * to the next instruction or we will just breakpoint
118                  * over and over again.
119                  */
120                 ptr = &remcom_in_buffer[1];
121                 if (kgdb_hex2long(&ptr, &addr))
122                         linux_regs->ARM_pc = addr;
123                 else if (compiled_break == 1)
124                         linux_regs->ARM_pc += 4;
125 
126                 compiled_break = 0;
127 
128                 return 0;
129         }
130 
131         return -1;
132 }
133 
134 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
135 {
136         kgdb_handle_exception(1, SIGTRAP, 0, regs);
137 
138         return 0;
139 }
140 
141 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
142 {
143         compiled_break = 1;
144         kgdb_handle_exception(1, SIGTRAP, 0, regs);
145 
146         return 0;
147 }
148 
149 static struct undef_hook kgdb_brkpt_hook = {
150         .instr_mask             = 0xffffffff,
151         .instr_val              = KGDB_BREAKINST,
152         .fn                     = kgdb_brk_fn
153 };
154 
155 static struct undef_hook kgdb_compiled_brkpt_hook = {
156         .instr_mask             = 0xffffffff,
157         .instr_val              = KGDB_COMPILED_BREAK,
158         .fn                     = kgdb_compiled_brk_fn
159 };
160 
161 /**
162  *      kgdb_arch_init - Perform any architecture specific initalization.
163  *
164  *      This function will handle the initalization of any architecture
165  *      specific callbacks.
166  */
167 int kgdb_arch_init(void)
168 {
169         register_undef_hook(&kgdb_brkpt_hook);
170         register_undef_hook(&kgdb_compiled_brkpt_hook);
171 
172         return 0;
173 }
174 
175 /**
176  *      kgdb_arch_exit - Perform any architecture specific uninitalization.
177  *
178  *      This function will handle the uninitalization of any architecture
179  *      specific callbacks, for dynamic registration and unregistration.
180  */
181 void kgdb_arch_exit(void)
182 {
183         unregister_undef_hook(&kgdb_brkpt_hook);
184         unregister_undef_hook(&kgdb_compiled_brkpt_hook);
185 }
186 
187 /*
188  * Register our undef instruction hooks with ARM undef core.
189  * We regsiter a hook specifically looking for the KGB break inst
190  * and we handle the normal undef case within the do_undefinstr
191  * handler.
192  */
193 struct kgdb_arch arch_kgdb_ops = {
194 #ifndef __ARMEB__
195         .gdb_bpt_instr          = {0xfe, 0xde, 0xff, 0xe7}
196 #else /* ! __ARMEB__ */
197         .gdb_bpt_instr          = {0xe7, 0xff, 0xde, 0xfe}
198 #endif
199 };
200 
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