/*
* gdb-low.S contains the low-level trap handler for the GDB stub.
*
* Copyright (C) 1995 Andreas Busse
*/
#include <linux/config.h>
#include <linux/sys.h>
#include <asm/asm.h>
#include <asm/errno.h>
#include <asm/mipsregs.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/gdb-stub.h>
#ifdef CONFIG_32BIT
#define DMFC0 mfc0
#define DMTC0 mtc0
#define LDC1 lwc1
#define SDC1 lwc1
#endif
#ifdef CONFIG_64BIT
#define DMFC0 dmfc0
#define DMTC0 dmtc0
#define LDC1 ldc1
#define SDC1 ldc1
#endif
/*
* [jsun] We reserves about 2x GDB_FR_SIZE in stack. The lower (addressed)
* part is used to store registers and passed to exception handler.
* The upper part is reserved for "call func" feature where gdb client
* saves some of the regs, setups call frame and passes args.
*
* A trace shows about 200 bytes are used to store about half of all regs.
* The rest should be big enough for frame setup and passing args.
*/
/*
* The low level trap handler
*/
.align 5
NESTED(trap_low, GDB_FR_SIZE, sp)
.set noat
.set noreorder
mfc0 k0, CP0_STATUS
sll k0, 3 /* extract cu0 bit */
bltz k0, 1f
move k1, sp
/*
* Called from user mode, go somewhere else.
*/
lui k1, %hi(saved_vectors)
mfc0 k0, CP0_CAUSE
andi k0, k0, 0x7c
add k1, k1, k0
lw k0, %lo(saved_vectors)(k1)
jr k0
nop
1:
move k0, sp
subu sp, k1, GDB_FR_SIZE*2 # see comment above
LONG_S k0, GDB_FR_REG29(sp)
LONG_S $2, GDB_FR_REG2(sp)
/*
* First save the CP0 and special registers
*/
mfc0 v0, CP0_STATUS
LONG_S v0, GDB_FR_STATUS(sp)
mfc0 v0, CP0_CAUSE
LONG_S v0, GDB_FR_CAUSE(sp)
DMFC0 v0, CP0_EPC
LONG_S v0, GDB_FR_EPC(sp)
DMFC0 v0, CP0_BADVADDR
LONG_S v0, GDB_FR_BADVADDR(sp)
mfhi v0
LONG_S v0, GDB_FR_HI(sp)
mflo v0
LONG_S v0, GDB_FR_LO(sp)
/*
* Now the integer registers
*/
LONG_S zero, GDB_FR_REG0(sp) /* I know... */
LONG_S $1, GDB_FR_REG1(sp)
/* v0 already saved */
LONG_S $3, GDB_FR_REG3(sp)
LONG_S $4, GDB_FR_REG4(sp)
LONG_S $5, GDB_FR_REG5(sp)
LONG_S $6, GDB_FR_REG6(sp)
LONG_S $7, GDB_FR_REG7(sp)
LONG_S $8, GDB_FR_REG8(sp)
LONG_S $9, GDB_FR_REG9(sp)
LONG_S $10, GDB_FR_REG10(sp)
LONG_S $11, GDB_FR_REG11(sp)
LONG_S $12, GDB_FR_REG12(sp)
LONG_S $13, GDB_FR_REG13(sp)
LONG_S $14, GDB_FR_REG14(sp)
LONG_S $15, GDB_FR_REG15(sp)
LONG_S $16, GDB_FR_REG16(sp)
LONG_S $17, GDB_FR_REG17(sp)
LONG_S $18, GDB_FR_REG18(sp)
LONG_S $19, GDB_FR_REG19(sp)
LONG_S $20, GDB_FR_REG20(sp)
LONG_S $21, GDB_FR_REG21(sp)
LONG_S $22, GDB_FR_REG22(sp)
LONG_S $23, GDB_FR_REG23(sp)
LONG_S $24, GDB_FR_REG24(sp)
LONG_S $25, GDB_FR_REG25(sp)
LONG_S $26, GDB_FR_REG26(sp)
LONG_S $27, GDB_FR_REG27(sp)
LONG_S $28, GDB_FR_REG28(sp)
/* sp already saved */
LONG_S $30, GDB_FR_REG30(sp)
LONG_S $31, GDB_FR_REG31(sp)
CLI /* disable interrupts */
/*
* Followed by the floating point registers
*/
mfc0 v0, CP0_STATUS /* FPU enabled? */
srl v0, v0, 16
andi v0, v0, (ST0_CU1 >> 16)
beqz v0,2f /* disabled, skip */
nop
SDC1 $0, GDB_FR_FPR0(sp)
SDC1 $1, GDB_FR_FPR1(sp)
SDC1 $2, GDB_FR_FPR2(sp)
SDC1 $3, GDB_FR_FPR3(sp)
SDC1 $4, GDB_FR_FPR4(sp)
SDC1 $5, GDB_FR_FPR5(sp)
SDC1 $6, GDB_FR_FPR6(sp)
SDC1 $7, GDB_FR_FPR7(sp)
SDC1 $8, GDB_FR_FPR8(sp)
SDC1 $9, GDB_FR_FPR9(sp)
SDC1 $10, GDB_FR_FPR10(sp)
SDC1 $11, GDB_FR_FPR11(sp)
SDC1 $12, GDB_FR_FPR12(sp)
SDC1 $13, GDB_FR_FPR13(sp)
SDC1 $14, GDB_FR_FPR14(sp)
SDC1 $15, GDB_FR_FPR15(sp)
SDC1 $16, GDB_FR_FPR16(sp)
SDC1 $17, GDB_FR_FPR17(sp)
SDC1 $18, GDB_FR_FPR18(sp)
SDC1 $19, GDB_FR_FPR19(sp)
SDC1 $20, GDB_FR_FPR20(sp)
SDC1 $21, GDB_FR_FPR21(sp)
SDC1 $22, GDB_FR_FPR22(sp)
SDC1 $23, GDB_FR_FPR23(sp)
SDC1 $24, GDB_FR_FPR24(sp)
SDC1 $25, GDB_FR_FPR25(sp)
SDC1 $26, GDB_FR_FPR26(sp)
SDC1 $27, GDB_FR_FPR27(sp)
SDC1 $28, GDB_FR_FPR28(sp)
SDC1 $29, GDB_FR_FPR29(sp)
SDC1 $30, GDB_FR_FPR30(sp)
SDC1 $31, GDB_FR_FPR31(sp)
/*
* FPU control registers
*/
cfc1 v0, CP1_STATUS
LONG_S v0, GDB_FR_FSR(sp)
cfc1 v0, CP1_REVISION
LONG_S v0, GDB_FR_FIR(sp)
/*
* Current stack frame ptr
*/
2:
LONG_S sp, GDB_FR_FRP(sp)
/*
* CP0 registers (R4000/R4400 unused registers skipped)
*/
mfc0 v0, CP0_INDEX
LONG_S v0, GDB_FR_CP0_INDEX(sp)
mfc0 v0, CP0_RANDOM
LONG_S v0, GDB_FR_CP0_RANDOM(sp)
DMFC0 v0, CP0_ENTRYLO0
LONG_S v0, GDB_FR_CP0_ENTRYLO0(sp)
DMFC0 v0, CP0_ENTRYLO1
LONG_S v0, GDB_FR_CP0_ENTRYLO1(sp)
DMFC0 v0, CP0_CONTEXT
LONG_S v0, GDB_FR_CP0_CONTEXT(sp)
mfc0 v0, CP0_PAGEMASK
LONG_S v0, GDB_FR_CP0_PAGEMASK(sp)
mfc0 v0, CP0_WIRED
LONG_S v0, GDB_FR_CP0_WIRED(sp)
DMFC0 v0, CP0_ENTRYHI
LONG_S v0, GDB_FR_CP0_ENTRYHI(sp)
mfc0 v0, CP0_PRID
LONG_S v0, GDB_FR_CP0_PRID(sp)
.set at
/*
* Continue with the higher level handler
*/
move a0,sp
jal handle_exception
nop
/*
* Restore all writable registers, in reverse order
*/
.set noat
LONG_L v0, GDB_FR_CP0_ENTRYHI(sp)
LONG_L v1, GDB_FR_CP0_WIRED(sp)
DMTC0 v0, CP0_ENTRYHI
mtc0 v1, CP0_WIRED
LONG_L v0, GDB_FR_CP0_PAGEMASK(sp)
LONG_L v1, GDB_FR_CP0_ENTRYLO1(sp)
mtc0 v0, CP0_PAGEMASK
DMTC0 v1, CP0_ENTRYLO1
LONG_L v0, GDB_FR_CP0_ENTRYLO0(sp)
LONG_L v1, GDB_FR_CP0_INDEX(sp)
DMTC0 v0, CP0_ENTRYLO0
LONG_L v0, GDB_FR_CP0_CONTEXT(sp)
mtc0 v1, CP0_INDEX
DMTC0 v0, CP0_CONTEXT
/*
* Next, the floating point registers
*/
mfc0 v0, CP0_STATUS /* check if the FPU is enabled */
srl v0, v0, 16
andi v0, v0, (ST0_CU1 >> 16)
beqz v0, 3f /* disabled, skip */
nop
LDC1 $31, GDB_FR_FPR31(sp)
LDC1 $30, GDB_FR_FPR30(sp)
LDC1 $29, GDB_FR_FPR29(sp)
LDC1 $28, GDB_FR_FPR28(sp)
LDC1 $27, GDB_FR_FPR27(sp)
LDC1 $26, GDB_FR_FPR26(sp)
LDC1 $25, GDB_FR_FPR25(sp)
LDC1 $24, GDB_FR_FPR24(sp)
LDC1 $23, GDB_FR_FPR23(sp)
LDC1 $22, GDB_FR_FPR22(sp)
LDC1 $21, GDB_FR_FPR21(sp)
LDC1 $20, GDB_FR_FPR20(sp)
LDC1 $19, GDB_FR_FPR19(sp)
LDC1 $18, GDB_FR_FPR18(sp)
LDC1 $17, GDB_FR_FPR17(sp)
LDC1 $16, GDB_FR_FPR16(sp)
LDC1 $15, GDB_FR_FPR15(sp)
LDC1 $14, GDB_FR_FPR14(sp)
LDC1 $13, GDB_FR_FPR13(sp)
LDC1 $12, GDB_FR_FPR12(sp)
LDC1 $11, GDB_FR_FPR11(sp)
LDC1 $10, GDB_FR_FPR10(sp)
LDC1 $9, GDB_FR_FPR9(sp)
LDC1 $8, GDB_FR_FPR8(sp)
LDC1 $7, GDB_FR_FPR7(sp)
LDC1 $6, GDB_FR_FPR6(sp)
LDC1 $5, GDB_FR_FPR5(sp)
LDC1 $4, GDB_FR_FPR4(sp)
LDC1 $3, GDB_FR_FPR3(sp)
LDC1 $2, GDB_FR_FPR2(sp)
LDC1 $1, GDB_FR_FPR1(sp)
LDC1 $0, GDB_FR_FPR0(sp)
/*
* Now the CP0 and integer registers
*/
3:
mfc0 t0, CP0_STATUS
ori t0, 0x1f
xori t0, 0x1f
mtc0 t0, CP0_STATUS
LONG_L v0, GDB_FR_STATUS(sp)
LONG_L v1, GDB_FR_EPC(sp)
mtc0 v0, CP0_STATUS
DMTC0 v1, CP0_EPC
LONG_L v0, GDB_FR_HI(sp)
LONG_L v1, GDB_FR_LO(sp)
mthi v0
mtlo v1
LONG_L $31, GDB_FR_REG31(sp)
LONG_L $30, GDB_FR_REG30(sp)
LONG_L $28, GDB_FR_REG28(sp)
LONG_L $27, GDB_FR_REG27(sp)
LONG_L $26, GDB_FR_REG26(sp)
LONG_L $25, GDB_FR_REG25(sp)
LONG_L $24, GDB_FR_REG24(sp)
LONG_L $23, GDB_FR_REG23(sp)
LONG_L $22, GDB_FR_REG22(sp)
LONG_L $21, GDB_FR_REG21(sp)
LONG_L $20, GDB_FR_REG20(sp)
LONG_L $19, GDB_FR_REG19(sp)
LONG_L $18, GDB_FR_REG18(sp)
LONG_L $17, GDB_FR_REG17(sp)
LONG_L $16, GDB_FR_REG16(sp)
LONG_L $15, GDB_FR_REG15(sp)
LONG_L $14, GDB_FR_REG14(sp)
LONG_L $13, GDB_FR_REG13(sp)
LONG_L $12, GDB_FR_REG12(sp)
LONG_L $11, GDB_FR_REG11(sp)
LONG_L $10, GDB_FR_REG10(sp)
LONG_L $9, GDB_FR_REG9(sp)
LONG_L $8, GDB_FR_REG8(sp)
LONG_L $7, GDB_FR_REG7(sp)
LONG_L $6, GDB_FR_REG6(sp)
LONG_L $5, GDB_FR_REG5(sp)
LONG_L $4, GDB_FR_REG4(sp)
LONG_L $3, GDB_FR_REG3(sp)
LONG_L $2, GDB_FR_REG2(sp)
LONG_L $1, GDB_FR_REG1(sp)
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
LONG_L k0, GDB_FR_EPC(sp)
LONG_L $29, GDB_FR_REG29(sp) /* Deallocate stack */
jr k0
rfe
#else
LONG_L sp, GDB_FR_REG29(sp) /* Deallocate stack */
.set mips3
eret
.set mips0
#endif
.set at
.set reorder
END(trap_low)
LEAF(kgdb_read_byte)
4: lb t0, (a0)
sb t0, (a1)
li v0, 0
jr ra
.section __ex_table,"a"
PTR 4b, kgdbfault
.previous
END(kgdb_read_byte)
LEAF(kgdb_write_byte)
5: sb a0, (a1)
li v0, 0
jr ra
.section __ex_table,"a"
PTR 5b, kgdbfault
.previous
END(kgdb_write_byte)
.type kgdbfault@function
.ent kgdbfault
kgdbfault: li v0, -EFAULT
jr ra
.end kgdbfault
