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/*
 * Low level exception handling
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994, 1995 by Ralf Baechle
 */
 
/*
 * entry.S contains the system-call and fault low-level handling routines.
 * This also contains the timer-interrupt handler, as well as all interrupts
 * and faults that can result in a task-switch. The ISA dependent TLB
 * code is in arch/mips/kernel/.S
 */
#include 
 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
 
/*
 * These are offsets into the task-struct.
 */
state           =  0
counter         =  4
priority        =  8
signal          = 12
blocked         = 16
flags           = 20
errno           = 24
exec_domain     = 60
 
#ifdef __SMP__
#error "Fix this for SMP"
#else
#define current current_set
#endif
 
/*
 * Heia ...  The %lo, %hi and %HI stuff is too strong for the ELF assembler
 * and the ABI to cope with ...
 */
                .text
                .set    noreorder
                .align 4
handle_bottom_half:
                lui     s0,%hi(intr_count)
                lw      s1,%lo(intr_count)(s0)
                mfc0    s3,CP0_STATUS           # Enable IRQs
                addiu   s2,s1,1
                sw      s2,%lo(intr_count)(s0)
                ori     t0,s3,0x1f
                xori    t0,0x1e
                jal     do_bottom_half
                mtc0    t0,CP0_STATUS           # delay slot
                mtc0    s3,CP0_STATUS           # Restore old IRQ state
                b       9f
                sw      s1,%lo(intr_count)(s0)  # delay slot
 
reschedule:     jal     schedule
                nop                             # delay slot
EXPORT(ret_from_sys_call)
                lw      t0,intr_count           # bottom half
                bnez    t0,return
 
9:              lw      t0,bh_mask              # delay slot
                lw      t1,bh_active            # unused delay slot
                and     t0,t1
                bnez    t0,handle_bottom_half
 
                lw      t0,FR_STATUS(sp)        # returning to kernel mode?
                andi    t1,t0,0x10
                beqz    t1,return               # -> yes
 
                mfc0    t0,CP0_STATUS           # delay slot
                lw      t1,need_resched
                ori     t0,0x1f                 # enable irqs
                xori    t0,0x1e
                bnez    t1,reschedule
                mtc0    t0,CP0_STATUS           # delay slot
 
                lw      s0,current
                lw      t0,task
                lw      a0,blocked(s0)
                beq     s0,t0,return            # task[0] cannot have signals
                                                # save blocked in a0 for
                                                # signal handling
                lw      t0,signal(s0)
                nor     t1,zero,a0
                and     t1,t0,t1
                beqz    t1,return
                nop
 
                jal     do_signal
                move    a1,sp                   # delay slot
 
                .set    noat
EXPORT(return)  RESTORE_ALL
                ERET
                .set    at
 
/*
 * Beware: interrupt, fast_interrupt and bad_interrupt have unusual
 * calling conventions to speedup the mess.
 *
 * t1 - interrupt number
 * s2 - destroyed
 * return values:
 * v0 - return routine
 */
                .text
                .set    at
                .align  5
NESTED(interrupt, FR_SIZE, sp)
                move    s2,ra
                mfc0    t0,CP0_STATUS                   # enable IRQs
                ori     t0,0x1f
                xori    t0,0x1e
                mtc0    t0,CP0_STATUS
                move    a0,t1
                jal     do_IRQ
                move    a1,sp                           # delay slot
                mfc0    t0,CP0_STATUS                   # disable IRQs
                ori     t0,1
                xori    t0,1
                la      v0,ret_from_sys_call
                jr      s2
                mtc0    t0,CP0_STATUS                   # delay slot
                END(interrupt)
 
                .align  5
NESTED(fast_interrupt, FR_SIZE, sp)
                move    s2,ra
                move    a0,t1
                jal     do_fast_IRQ
                move    a1,sp                           # delay slot
                lui     v0,%hi(return)
                jr      s2
                addiu   v0,%lo(return)                  # delay slot
                END(fast_interrupt)
 
LEAF(bad_interrupt)
                /*
                 * Don't return & unblock the pic
                 */
                j       return
                nop
                END(bad_interrupt)
 
/*
 * do_syscall calls the function in a1 with upto 7 arguments.  If over
 * four arguments are being requested, the additional arguments will
 * be copied from the user stack pointed to by a0->reg29.
 * Note that this routine relies on the GNU assemblers weak instruction
 * scheduling abilities to generate the best possible code for all MIPS CPUs.
 *
 * a0 (struct pt_regs *)  pointer to user registers
 * a1 (syscall_t)         pointer to syscall to do
 * a2 (int)               number of arguments to syscall
 */
                .set    noreorder
                .text
NESTED(do_syscalls, 32, sp)
                subu    sp,32
                sw      ra,28(sp)
                sll     a2,a2,PTRLOG
                lw      t0,dst(a2)
                move    t2,a1
                jalr    t0
                lw      t0,FR_REG29(a0)         # get old user stack pointer
 
                .set    reorder                 # for sake of R3000
7:              lw      t1,24(t0)               # parameter #7 from usp
                sw      t1,24(t0)
6:              lw      t1,20(t0)               # parameter #6 from usp
                sw      t1,20(t0)
5:              lw      t1,16(t0)               # parameter #5 from usp
                sw      t1,16(t0)
                .set    noreorder
4:              lw      a3,FR_REG7(a0)          # 4 args
3:              lw      a2,FR_REG6(a0)          # 3 args
2:              lw      a1,FR_REG5(a0)          # 2 args
1:              jalr    t2                      # 1 args
                lw      a0,FR_REG4(a0)          # delay slot
                .set    reorder
                lw      ra,28(sp)
                addiu   sp,32
                jr      ra
0:              jalr    t2                      # 0 args, just pass a0
                lw      ra,28(sp)
                addiu   sp,32
                jr      ra
                END(do_syscalls)
                .set    noreorder
 
                .rdata
                .align  PTRLOG
dst:            PTR     0b, 1b, 2b, 3b, 4b, 5b, 6b, 7b
 
/*
 * Build a default exception handler for the exceptions that don't need
 * special handlers.  If you didn't know yet - I *like* playing games with
 * the C preprocessor ...
 */
#define __BUILD_silent(exception)
#define __BUILD_verbose(exception)                                      \
                la      a1,8f;                                          \
                TEXT    (#exception);                                   \
                lw      a2,FR_EPC(sp);                                  \
                PRINT("Got %s at %08x.\n")
#define __BUILD_count(exception)                                        \
                .set    reorder;                                        \
                lw      t0,exception_count_##exception;                 \
                addiu   t0,1;                                           \
                sw      t0,exception_count_##exception;                 \
                .set    noreorder;                                      \
                .data;                                                  \
EXPORT(exception_count_##exception);                                    \
                .word   0;                                              \
                .text;
#define BUILD_HANDLER(exception,verbose)                                \
                .text;                                                  \
                .align  5;                                              \
                NESTED(handle_##exception, FR_SIZE, sp);                \
                .set    noat;                                           \
                SAVE_ALL;                                               \
                STI;                                                    \
                .set    at;                                             \
                __BUILD_##verbose(exception);                           \
                li      t0,-1;                   /* not a sys call */   \
                sw      t0,FR_ORIG_REG2(sp);                            \
                jal     do_##exception;                                 \
                move    a0,sp;                   /* delay slot */       \
                j       ret_from_sys_call;                              \
                nop;                             /* delay slot */       \
                END(handle_##exception)
 
                BUILD_HANDLER(adel,verbose)             /* #4  */
                BUILD_HANDLER(ades,verbose)             /* #5  */
                BUILD_HANDLER(ibe,verbose)              /* #6  */
                BUILD_HANDLER(dbe,verbose)              /* #7  */
                BUILD_HANDLER(sys,silent)               /* #8  */
                BUILD_HANDLER(bp,verbose)               /* #9  */
                BUILD_HANDLER(ri,verbose)               /* #10 */
                BUILD_HANDLER(cpu,silent)               /* #11 */
                BUILD_HANDLER(ov,verbose)               /* #12 */
                BUILD_HANDLER(tr,verbose)               /* #13 */
                BUILD_HANDLER(vcei,verbose)             /* #14 */
                BUILD_HANDLER(fpe,verbose)              /* #15 */
                BUILD_HANDLER(watch,verbose)            /* #23 */
                BUILD_HANDLER(vced,verbose)             /* #31 */
                BUILD_HANDLER(reserved,verbose)         /* others */
 
/*
 * Exception handler table with 32 entries.
 * This might be extended to handle software exceptions
 */
                .bss
                .align  PTRLOG
EXPORT(exception_handlers)
                .fill   32,PTRSIZE,0
 
/*
 * Interrupt handler table with 16 entries.
 */
EXPORT(IRQ_vectors)
                .fill   16,PTRSIZE,0
 
/*
 * Table of syscalls
 */
                .data
                .align  PTRLOG
EXPORT(sys_call_table)
                /*
                 * Reserved space for all the SVR4, SVR, BSD43 and POSIX
                 * flavoured syscalls.
                 */
                .space  (__NR_Linux)*PTRSIZE
 
                /*
                 * Linux flavoured syscalls.
                 */
#define SYS(call, narg) PTR call
#include "syscalls.h"
 
/*
 * Number of arguments of each syscall
 */
EXPORT(sys_narg_table)
                /*
                 * Reserved space for all the SVR4, SVR, BSD43 and POSIX
                 * flavoured syscalls.
                 */
                .space  (__NR_Linux)
 
                /*
                 * Linux flavoured syscalls.
                 */
#undef SYS
#define SYS(call, narg) .byte narg
#include "syscalls.h"

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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [mips/] [kernel/] [entry.S] - Blame information for rev 1777

Line No.	Rev	Author	Line
1	1624	jcastillo	`/*`
2			`* Low level exception handling`
3			`*`
4			`* This file is subject to the terms and conditions of the GNU General Public`
5			`* License. See the file "COPYING" in the main directory of this archive`
6			`* for more details.`
7			`*`
8			`* Copyright (C) 1994, 1995 by Ralf Baechle`
9			`*/`
10
11			`/*`
12			`* entry.S contains the system-call and fault low-level handling routines.`
13			`* This also contains the timer-interrupt handler, as well as all interrupts`
14			`* and faults that can result in a task-switch. The ISA dependent TLB`
15			`* code is in arch/mips/kernel/.S`
16			`*/`
17			`#include`
18
19			`#include`
20			`#include`
21			`#include`
22			`#include`
23			`#include`
24			`#include`
25			`#include`
26			`#include`
27			`#include`
28			`#include`
29
30			`/*`
31			`* These are offsets into the task-struct.`
32			`*/`
33			`state = 0`
34			`counter = 4`
35			`priority = 8`
36			`signal = 12`
37			`blocked = 16`
38			`flags = 20`
39			`errno = 24`
40			`exec_domain = 60`
41
42			`#ifdef __SMP__`
43			`#error "Fix this for SMP"`
44			`#else`
45			`#define current current_set`
46			`#endif`
47
48			`/*`
49			`* Heia ... The %lo, %hi and %HI stuff is too strong for the ELF assembler`
50			`* and the ABI to cope with ...`
51			`*/`
52			`.text`
53			`.set noreorder`
54			`.align 4`
55			`handle_bottom_half:`
56			`lui s0,%hi(intr_count)`
57			`lw s1,%lo(intr_count)(s0)`
58			`mfc0 s3,CP0_STATUS # Enable IRQs`
59			`addiu s2,s1,1`
60			`sw s2,%lo(intr_count)(s0)`
61			`ori t0,s3,0x1f`
62			`xori t0,0x1e`
63			`jal do_bottom_half`
64			`mtc0 t0,CP0_STATUS # delay slot`
65			`mtc0 s3,CP0_STATUS # Restore old IRQ state`
66			`b 9f`
67			`sw s1,%lo(intr_count)(s0) # delay slot`
68
69			`reschedule: jal schedule`
70			`nop # delay slot`
71			`EXPORT(ret_from_sys_call)`
72			`lw t0,intr_count # bottom half`
73			`bnez t0,return`
74
75			`9: lw t0,bh_mask # delay slot`
76			`lw t1,bh_active # unused delay slot`
77			`and t0,t1`
78			`bnez t0,handle_bottom_half`
79
80			`lw t0,FR_STATUS(sp) # returning to kernel mode?`
81			`andi t1,t0,0x10`
82			`beqz t1,return # -> yes`
83
84			`mfc0 t0,CP0_STATUS # delay slot`
85			`lw t1,need_resched`
86			`ori t0,0x1f # enable irqs`
87			`xori t0,0x1e`
88			`bnez t1,reschedule`
89			`mtc0 t0,CP0_STATUS # delay slot`
90
91			`lw s0,current`
92			`lw t0,task`
93			`lw a0,blocked(s0)`
94			`beq s0,t0,return # task[0] cannot have signals`
95			`# save blocked in a0 for`
96			`# signal handling`
97			`lw t0,signal(s0)`
98			`nor t1,zero,a0`
99			`and t1,t0,t1`
100			`beqz t1,return`
101			`nop`
102
103			`jal do_signal`
104			`move a1,sp # delay slot`
105
106			`.set noat`
107			`EXPORT(return) RESTORE_ALL`
108			`ERET`
109			`.set at`
110
111			`/*`
112			`* Beware: interrupt, fast_interrupt and bad_interrupt have unusual`
113			`* calling conventions to speedup the mess.`
114			`*`
115			`* t1 - interrupt number`
116			`* s2 - destroyed`
117			`* return values:`
118			`* v0 - return routine`
119			`*/`
120			`.text`
121			`.set at`
122			`.align 5`
123			`NESTED(interrupt, FR_SIZE, sp)`
124			`move s2,ra`
125			`mfc0 t0,CP0_STATUS # enable IRQs`
126			`ori t0,0x1f`
127			`xori t0,0x1e`
128			`mtc0 t0,CP0_STATUS`
129			`move a0,t1`
130			`jal do_IRQ`
131			`move a1,sp # delay slot`
132			`mfc0 t0,CP0_STATUS # disable IRQs`
133			`ori t0,1`
134			`xori t0,1`
135			`la v0,ret_from_sys_call`
136			`jr s2`
137			`mtc0 t0,CP0_STATUS # delay slot`
138			`END(interrupt)`
139
140			`.align 5`
141			`NESTED(fast_interrupt, FR_SIZE, sp)`
142			`move s2,ra`
143			`move a0,t1`
144			`jal do_fast_IRQ`
145			`move a1,sp # delay slot`
146			`lui v0,%hi(return)`
147			`jr s2`
148			`addiu v0,%lo(return) # delay slot`
149			`END(fast_interrupt)`
150
151			`LEAF(bad_interrupt)`
152			`/*`
153			`* Don't return & unblock the pic`
154			`*/`
155			`j return`
156			`nop`
157			`END(bad_interrupt)`
158
159			`/*`
160			`* do_syscall calls the function in a1 with upto 7 arguments. If over`
161			`* four arguments are being requested, the additional arguments will`
162			`* be copied from the user stack pointed to by a0->reg29.`
163			`* Note that this routine relies on the GNU assemblers weak instruction`
164			`* scheduling abilities to generate the best possible code for all MIPS CPUs.`
165			`*`
166			`* a0 (struct pt_regs *) pointer to user registers`
167			`* a1 (syscall_t) pointer to syscall to do`
168			`* a2 (int) number of arguments to syscall`
169			`*/`
170			`.set noreorder`
171			`.text`
172			`NESTED(do_syscalls, 32, sp)`
173			`subu sp,32`
174			`sw ra,28(sp)`
175			`sll a2,a2,PTRLOG`
176			`lw t0,dst(a2)`
177			`move t2,a1`
178			`jalr t0`
179			`lw t0,FR_REG29(a0) # get old user stack pointer`
180
181			`.set reorder # for sake of R3000`
182			`7: lw t1,24(t0) # parameter #7 from usp`
183			`sw t1,24(t0)`
184			`6: lw t1,20(t0) # parameter #6 from usp`
185			`sw t1,20(t0)`
186			`5: lw t1,16(t0) # parameter #5 from usp`
187			`sw t1,16(t0)`
188			`.set noreorder`
189			`4: lw a3,FR_REG7(a0) # 4 args`
190			`3: lw a2,FR_REG6(a0) # 3 args`
191			`2: lw a1,FR_REG5(a0) # 2 args`
192			`1: jalr t2 # 1 args`
193			`lw a0,FR_REG4(a0) # delay slot`
194			`.set reorder`
195			`lw ra,28(sp)`
196			`addiu sp,32`
197			`jr ra`
198			`0: jalr t2 # 0 args, just pass a0`
199			`lw ra,28(sp)`
200			`addiu sp,32`
201			`jr ra`
202			`END(do_syscalls)`
203			`.set noreorder`
204
205			`.rdata`
206			`.align PTRLOG`
207			`dst: PTR 0b, 1b, 2b, 3b, 4b, 5b, 6b, 7b`
208
209			`/*`
210			`* Build a default exception handler for the exceptions that don't need`
211			`* special handlers. If you didn't know yet - I like playing games with`
212			`* the C preprocessor ...`
213			`*/`
214			`#define __BUILD_silent(exception)`
215			`#define __BUILD_verbose(exception) \`
216			`la a1,8f; \`
217			`TEXT (#exception); \`
218			`lw a2,FR_EPC(sp); \`
219			`PRINT("Got %s at %08x.\n")`
220			`#define __BUILD_count(exception) \`
221			`.set reorder; \`
222			`lw t0,exception_count_##exception; \`
223			`addiu t0,1; \`
224			`sw t0,exception_count_##exception; \`
225			`.set noreorder; \`
226			`.data; \`
227			`EXPORT(exception_count_##exception); \`
228			`.word 0; \`
229			`.text;`
230			`#define BUILD_HANDLER(exception,verbose) \`
231			`.text; \`
232			`.align 5; \`
233			`NESTED(handle_##exception, FR_SIZE, sp); \`
234			`.set noat; \`
235			`SAVE_ALL; \`
236			`STI; \`
237			`.set at; \`
238			`__BUILD_##verbose(exception); \`
239			`li t0,-1; /* not a sys call */ \`
240			`sw t0,FR_ORIG_REG2(sp); \`
241			`jal do_##exception; \`
242			`move a0,sp; /* delay slot */ \`
243			`j ret_from_sys_call; \`
244			`nop; /* delay slot */ \`
245			`END(handle_##exception)`
246
247			`BUILD_HANDLER(adel,verbose) /* #4 */`
248			`BUILD_HANDLER(ades,verbose) /* #5 */`
249			`BUILD_HANDLER(ibe,verbose) /* #6 */`
250			`BUILD_HANDLER(dbe,verbose) /* #7 */`
251			`BUILD_HANDLER(sys,silent) /* #8 */`
252			`BUILD_HANDLER(bp,verbose) /* #9 */`
253			`BUILD_HANDLER(ri,verbose) /* #10 */`
254			`BUILD_HANDLER(cpu,silent) /* #11 */`
255			`BUILD_HANDLER(ov,verbose) /* #12 */`
256			`BUILD_HANDLER(tr,verbose) /* #13 */`
257			`BUILD_HANDLER(vcei,verbose) /* #14 */`
258			`BUILD_HANDLER(fpe,verbose) /* #15 */`
259			`BUILD_HANDLER(watch,verbose) /* #23 */`
260			`BUILD_HANDLER(vced,verbose) /* #31 */`
261			`BUILD_HANDLER(reserved,verbose) /* others */`
262
263			`/*`
264			`* Exception handler table with 32 entries.`
265			`* This might be extended to handle software exceptions`
266			`*/`
267			`.bss`
268			`.align PTRLOG`
269			`EXPORT(exception_handlers)`
270			`.fill 32,PTRSIZE,0`
271
272			`/*`
273			`* Interrupt handler table with 16 entries.`
274			`*/`
275			`EXPORT(IRQ_vectors)`
276			`.fill 16,PTRSIZE,0`
277
278			`/*`
279			`* Table of syscalls`
280			`*/`
281			`.data`
282			`.align PTRLOG`
283			`EXPORT(sys_call_table)`
284			`/*`
285			`* Reserved space for all the SVR4, SVR, BSD43 and POSIX`
286			`* flavoured syscalls.`
287			`*/`
288			`.space (__NR_Linux)*PTRSIZE`
289
290			`/*`
291			`* Linux flavoured syscalls.`
292			`*/`
293			`#define SYS(call, narg) PTR call`
294			`#include "syscalls.h"`
295
296			`/*`
297			`* Number of arguments of each syscall`
298			`*/`
299			`EXPORT(sys_narg_table)`
300			`/*`
301			`* Reserved space for all the SVR4, SVR, BSD43 and POSIX`
302			`* flavoured syscalls.`
303			`*/`
304			`.space (__NR_Linux)`
305
306			`/*`
307			`* Linux flavoured syscalls.`
308			`*/`
309			`#undef SYS`
310			`#define SYS(call, narg) .byte narg`
311			`#include "syscalls.h"`