From: Paul Mackerras This patch moves the emulate_step function, which is used in xmon's single-stepping code, out of xmon.c and into arch/ppc64/lib/sstep.c, so that kprobes can use it too. Signed-off-by: Paul Mackerras Signed-off-by: Andrew Morton --- 25-akpm/arch/ppc64/lib/Makefile | 1 25-akpm/arch/ppc64/lib/sstep.c | 141 ++++++++++++++++++++++++++++++++++++++ 25-akpm/arch/ppc64/xmon/xmon.c | 116 ++----------------------------- 25-akpm/include/asm-ppc64/sstep.h | 13 +++ 4 files changed, 163 insertions(+), 108 deletions(-) diff -puN arch/ppc64/lib/Makefile~ppc64-move-emulate_step-to-arch-ppc64-lib arch/ppc64/lib/Makefile --- 25/arch/ppc64/lib/Makefile~ppc64-move-emulate_step-to-arch-ppc64-lib 2004-11-17 19:03:07.793675504 -0800 +++ 25-akpm/arch/ppc64/lib/Makefile 2004-11-17 19:03:07.799674592 -0800 @@ -15,3 +15,4 @@ ifdef CONFIG_PPC_ISERIES obj-$(CONFIG_PCI) += e2a.o endif +lib-$(CONFIG_XMON) += sstep.o diff -puN /dev/null arch/ppc64/lib/sstep.c --- /dev/null 2003-09-15 06:40:47.000000000 -0700 +++ 25-akpm/arch/ppc64/lib/sstep.c 2004-11-17 19:03:07.799674592 -0800 @@ -0,0 +1,141 @@ +/* + * Single-step support. + * + * Copyright (C) 2004 Paul Mackerras , IBM + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include +#include +#include +#include + +extern char SystemCall_common[]; + +/* Bits in SRR1 that are copied from MSR */ +#define MSR_MASK 0xffffffff87c0ffff + +/* + * Determine whether a conditional branch instruction would branch. + */ +static int branch_taken(unsigned int instr, struct pt_regs *regs) +{ + unsigned int bo = (instr >> 21) & 0x1f; + unsigned int bi; + + if ((bo & 4) == 0) { + /* decrement counter */ + --regs->ctr; + if (((bo >> 1) & 1) ^ (regs->ctr == 0)) + return 0; + } + if ((bo & 0x10) == 0) { + /* check bit from CR */ + bi = (instr >> 16) & 0x1f; + if (((regs->ccr >> (31 - bi)) & 1) != ((bo >> 3) & 1)) + return 0; + } + return 1; +} + +/* + * Emulate instructions that cause a transfer of control. + * Returns 1 if the step was emulated, 0 if not, + * or -1 if the instruction is one that should not be stepped, + * such as an rfid, or a mtmsrd that would clear MSR_RI. + */ +int emulate_step(struct pt_regs *regs, unsigned int instr) +{ + unsigned int opcode, rd; + unsigned long int imm; + + opcode = instr >> 26; + switch (opcode) { + case 16: /* bc */ + imm = (signed short)(instr & 0xfffc); + if ((instr & 2) == 0) + imm += regs->nip; + regs->nip += 4; + if ((regs->msr & MSR_SF) == 0) + regs->nip &= 0xffffffffUL; + if (instr & 1) + regs->link = regs->nip; + if (branch_taken(instr, regs)) + regs->nip = imm; + return 1; + case 17: /* sc */ + /* + * N.B. this uses knowledge about how the syscall + * entry code works. If that is changed, this will + * need to be changed also. + */ + regs->gpr[9] = regs->gpr[13]; + regs->gpr[11] = regs->nip + 4; + regs->gpr[12] = regs->msr & MSR_MASK; + regs->gpr[13] = (unsigned long) get_paca(); + regs->nip = (unsigned long) &SystemCall_common; + regs->msr = MSR_KERNEL; + return 1; + case 18: /* b */ + imm = instr & 0x03fffffc; + if (imm & 0x02000000) + imm -= 0x04000000; + if ((instr & 2) == 0) + imm += regs->nip; + if (instr & 1) { + regs->link = regs->nip + 4; + if ((regs->msr & MSR_SF) == 0) + regs->link &= 0xffffffffUL; + } + if ((regs->msr & MSR_SF) == 0) + imm &= 0xffffffffUL; + regs->nip = imm; + return 1; + case 19: + switch (instr & 0x7fe) { + case 0x20: /* bclr */ + case 0x420: /* bcctr */ + imm = (instr & 0x400)? regs->ctr: regs->link; + regs->nip += 4; + if ((regs->msr & MSR_SF) == 0) { + regs->nip &= 0xffffffffUL; + imm &= 0xffffffffUL; + } + if (instr & 1) + regs->link = regs->nip; + if (branch_taken(instr, regs)) + regs->nip = imm; + return 1; + case 0x24: /* rfid, scary */ + return -1; + } + case 31: + rd = (instr >> 21) & 0x1f; + switch (instr & 0x7fe) { + case 0xa6: /* mfmsr */ + regs->gpr[rd] = regs->msr & MSR_MASK; + regs->nip += 4; + if ((regs->msr & MSR_SF) == 0) + regs->nip &= 0xffffffffUL; + return 1; + case 0x164: /* mtmsrd */ + /* only MSR_EE and MSR_RI get changed if bit 15 set */ + /* mtmsrd doesn't change MSR_HV and MSR_ME */ + imm = (instr & 0x10000)? 0x8002: 0xefffffffffffefffUL; + imm = (regs->msr & MSR_MASK & ~imm) + | (regs->gpr[rd] & imm); + if ((imm & MSR_RI) == 0) + /* can't step mtmsrd that would clear MSR_RI */ + return -1; + regs->msr = imm; + regs->nip += 4; + if ((imm & MSR_SF) == 0) + regs->nip &= 0xffffffffUL; + return 1; + } + } + return 0; +} diff -puN arch/ppc64/xmon/xmon.c~ppc64-move-emulate_step-to-arch-ppc64-lib arch/ppc64/xmon/xmon.c --- 25/arch/ppc64/xmon/xmon.c~ppc64-move-emulate_step-to-arch-ppc64-lib 2004-11-17 19:03:07.795675200 -0800 +++ 25-akpm/arch/ppc64/xmon/xmon.c 2004-11-17 19:03:07.802674136 -0800 @@ -31,6 +31,7 @@ #include #include #include +#include #include "nonstdio.h" #include "privinst.h" @@ -85,9 +86,6 @@ static unsigned bpinstr = 0x7fe00008; /* #define BP_NUM(bp) ((bp) - bpts + 1) -/* Bits in SRR1 that are copied from MSR */ -#define MSR_MASK 0xffffffff87c0ffff - /* Prototypes */ static int cmds(struct pt_regs *); static int mread(unsigned long, void *, int); @@ -132,7 +130,6 @@ static void csum(void); static void bootcmds(void); void dump_segments(void); static void symbol_lookup(void); -static int emulate_step(struct pt_regs *regs, unsigned int instr); static void xmon_print_symbol(unsigned long address, const char *mid, const char *after); static const char *getvecname(unsigned long vec); @@ -148,7 +145,6 @@ extern int xmon_read_poll(void); extern int setjmp(long *); extern void longjmp(long *, int); extern unsigned long _ASR; -extern char SystemCall_common[]; pte_t *find_linux_pte(pgd_t *pgdir, unsigned long va); /* from htab.c */ @@ -488,6 +484,9 @@ int xmon_core(struct pt_regs *regs, int if (stepped == 0) { regs->nip = (unsigned long) &bp->instr[0]; atomic_inc(&bp->ref_count); + } else if (stepped < 0) { + printf("Couldn't single-step %s instruction\n", + (IS_RFID(bp->instr[0])? "rfid": "mtmsrd")); } } } @@ -755,108 +754,6 @@ static void remove_cpu_bpts(void) set_iabr(0); } -static int branch_taken(unsigned int instr, struct pt_regs *regs) -{ - unsigned int bo = (instr >> 21) & 0x1f; - unsigned int bi; - - if ((bo & 4) == 0) { - /* decrement counter */ - --regs->ctr; - if (((bo >> 1) & 1) ^ (regs->ctr == 0)) - return 0; - } - if ((bo & 0x10) == 0) { - /* check bit from CR */ - bi = (instr >> 16) & 0x1f; - if (((regs->ccr >> (31 - bi)) & 1) != ((bo >> 3) & 1)) - return 0; - } - return 1; -} - -/* - * Emulate instructions that cause a transfer of control. - * Returns 1 if the step was emulated, 0 if not, - * or -1 if the instruction is one that should not be stepped, - * such as an rfid, or a mtmsrd that would clear MSR_RI. - */ -static int emulate_step(struct pt_regs *regs, unsigned int instr) -{ - unsigned int opcode, rd; - unsigned long int imm; - - opcode = instr >> 26; - switch (opcode) { - case 16: /* bc */ - imm = (signed short)(instr & 0xfffc); - if ((instr & 2) == 0) - imm += regs->nip; - regs->nip += 4; /* XXX check 32-bit mode */ - if (instr & 1) - regs->link = regs->nip; - if (branch_taken(instr, regs)) - regs->nip = imm; - return 1; - case 17: /* sc */ - regs->gpr[9] = regs->gpr[13]; - regs->gpr[11] = regs->nip + 4; - regs->gpr[12] = regs->msr & MSR_MASK; - regs->gpr[13] = (unsigned long) get_paca(); - regs->nip = (unsigned long) &SystemCall_common; - regs->msr = MSR_KERNEL; - return 1; - case 18: /* b */ - imm = instr & 0x03fffffc; - if (imm & 0x02000000) - imm -= 0x04000000; - if ((instr & 2) == 0) - imm += regs->nip; - if (instr & 1) - regs->link = regs->nip + 4; - regs->nip = imm; - return 1; - case 19: - switch (instr & 0x7fe) { - case 0x20: /* bclr */ - case 0x420: /* bcctr */ - imm = (instr & 0x400)? regs->ctr: regs->link; - regs->nip += 4; /* XXX check 32-bit mode */ - if (instr & 1) - regs->link = regs->nip; - if (branch_taken(instr, regs)) - regs->nip = imm; - return 1; - case 0x24: /* rfid, scary */ - printf("Can't single-step an rfid instruction\n"); - return -1; - } - case 31: - rd = (instr >> 21) & 0x1f; - switch (instr & 0x7fe) { - case 0xa6: /* mfmsr */ - regs->gpr[rd] = regs->msr & MSR_MASK; - regs->nip += 4; - return 1; - case 0x164: /* mtmsrd */ - /* only MSR_EE and MSR_RI get changed if bit 15 set */ - /* mtmsrd doesn't change MSR_HV and MSR_ME */ - imm = (instr & 0x10000)? 0x8002: 0xefffffffffffefffUL; - imm = (regs->msr & MSR_MASK & ~imm) - | (regs->gpr[rd] & imm); - if ((imm & MSR_RI) == 0) { - printf("Can't step an instruction that would " - "clear MSR.RI\n"); - return -1; - } - regs->msr = imm; - regs->nip += 4; - return 1; - } - } - return 0; -} - /* Command interpreting routine */ static char *last_cmd; @@ -988,8 +885,11 @@ static int do_step(struct pt_regs *regs) if ((regs->msr & (MSR_SF|MSR_PR|MSR_IR)) == (MSR_SF|MSR_IR)) { if (mread(regs->nip, &instr, 4) == 4) { stepped = emulate_step(regs, instr); - if (stepped < 0) + if (stepped < 0) { + printf("Couldn't single-step %s instruction\n", + (IS_RFID(instr)? "rfid": "mtmsrd")); return 0; + } if (stepped > 0) { regs->trap = 0xd00 | (regs->trap & 1); printf("stepped to "); diff -puN /dev/null include/asm-ppc64/sstep.h --- /dev/null 2003-09-15 06:40:47.000000000 -0700 +++ 25-akpm/include/asm-ppc64/sstep.h 2004-11-17 19:03:07.802674136 -0800 @@ -0,0 +1,13 @@ +/* + * Copyright (C) 2004 Paul Mackerras , IBM + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +struct pt_regs; + +/* Emulate instructions that cause a transfer of control. */ +extern int emulate_step(struct pt_regs *regs, unsigned int instr); _