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-rw-r--r--arch/powerpc/kernel/kgdb.c494
1 files changed, 494 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
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+++ b/arch/powerpc/kernel/kgdb.c
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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PowerPC backend to the KGDB stub.
+ *
+ * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
+ * Copyright (C) 2003 Timesys Corporation.
+ * Copyright (C) 2004-2006 MontaVista Software, Inc.
+ * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
+ * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
+ * Sergei Shtylyov <sshtylyov@ru.mvista.com>
+ * Copyright (C) 2007-2008 Wind River Systems, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kgdb.h>
+#include <linux/smp.h>
+#include <linux/signal.h>
+#include <linux/ptrace.h>
+#include <linux/kdebug.h>
+#include <asm/current.h>
+#include <asm/processor.h>
+#include <asm/machdep.h>
+#include <asm/debug.h>
+#include <asm/code-patching.h>
+#include <linux/slab.h>
+#include <asm/inst.h>
+
+/*
+ * This table contains the mapping between PowerPC hardware trap types, and
+ * signals, which are primarily what GDB understands. GDB and the kernel
+ * don't always agree on values, so we use constants taken from gdb-6.2.
+ */
+static struct hard_trap_info
+{
+ unsigned int tt; /* Trap type code for powerpc */
+ unsigned char signo; /* Signal that we map this trap into */
+} hard_trap_info[] = {
+ { 0x0100, 0x02 /* SIGINT */ }, /* system reset */
+ { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */
+ { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */
+ { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */
+ { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */
+ { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */
+ { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */
+ { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */
+ { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */
+ { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */
+#ifdef CONFIG_BOOKE_OR_40x
+ { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */
+#if defined(CONFIG_PPC_85xx)
+ { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */
+ { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */
+ { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */
+ { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */
+ { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */
+ { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */
+ { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */
+ { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */
+ { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */
+#else /* ! CONFIG_PPC_85xx */
+ { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */
+ { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */
+ { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */
+ { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */
+ { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */
+#endif
+#else /* !CONFIG_BOOKE_OR_40x */
+ { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */
+#if defined(CONFIG_PPC_8xx)
+ { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
+#else /* ! CONFIG_PPC_8xx */
+ { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */
+ { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */
+ { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */
+#if defined(CONFIG_PPC64)
+ { 0x1200, 0x05 /* SIGILL */ }, /* system error */
+ { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */
+ { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */
+ { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */
+ { 0x1800, 0x04 /* SIGILL */ }, /* thermal */
+#else /* ! CONFIG_PPC64 */
+ { 0x1400, 0x02 /* SIGINT */ }, /* SMI */
+ { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */
+ { 0x1700, 0x04 /* SIGILL */ }, /* TAU */
+ { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */
+#endif
+#endif
+#endif
+ { 0x0000, 0x00 } /* Must be last */
+};
+
+static int computeSignal(unsigned int tt)
+{
+ struct hard_trap_info *ht;
+
+ for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
+ if (ht->tt == tt)
+ return ht->signo;
+
+ return SIGHUP; /* default for things we don't know about */
+}
+
+/**
+ *
+ * kgdb_skipexception - Bail out of KGDB when we've been triggered.
+ * @exception: Exception vector number
+ * @regs: Current &struct pt_regs.
+ *
+ * On some architectures we need to skip a breakpoint exception when
+ * it occurs after a breakpoint has been removed.
+ *
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+ return kgdb_isremovedbreak(regs->nip);
+}
+
+static int kgdb_debugger_ipi(struct pt_regs *regs)
+{
+ kgdb_nmicallback(raw_smp_processor_id(), regs);
+ return 0;
+}
+
+#ifdef CONFIG_SMP
+void kgdb_roundup_cpus(void)
+{
+ smp_send_debugger_break();
+}
+#endif
+
+/* KGDB functions to use existing PowerPC64 hooks. */
+static int kgdb_debugger(struct pt_regs *regs)
+{
+ return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
+ DIE_OOPS, regs);
+}
+
+static int kgdb_handle_breakpoint(struct pt_regs *regs)
+{
+ if (user_mode(regs))
+ return 0;
+
+ if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
+ return 0;
+
+ if (*(u32 *)regs->nip == BREAK_INSTR)
+ regs_add_return_ip(regs, BREAK_INSTR_SIZE);
+
+ return 1;
+}
+
+static int kgdb_singlestep(struct pt_regs *regs)
+{
+ if (user_mode(regs))
+ return 0;
+
+ kgdb_handle_exception(0, SIGTRAP, 0, regs);
+
+ return 1;
+}
+
+static int kgdb_iabr_match(struct pt_regs *regs)
+{
+ if (user_mode(regs))
+ return 0;
+
+ if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
+ return 0;
+ return 1;
+}
+
+static int kgdb_break_match(struct pt_regs *regs)
+{
+ if (user_mode(regs))
+ return 0;
+
+ if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
+ return 0;
+ return 1;
+}
+
+#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
+
+#define PACK32(ptr, src) do { \
+ u32 *ptr32; \
+ ptr32 = (u32 *)ptr; \
+ *(ptr32++) = (src); \
+ ptr = (unsigned long *)ptr32; \
+ } while (0)
+
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+ struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
+ STACK_INT_FRAME_REGS);
+ unsigned long *ptr = gdb_regs;
+ int reg;
+
+ memset(gdb_regs, 0, NUMREGBYTES);
+
+ /* Regs GPR0-2 */
+ for (reg = 0; reg < 3; reg++)
+ PACK64(ptr, regs->gpr[reg]);
+
+ /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
+ ptr += 11;
+
+ /* Regs GPR14-31 */
+ for (reg = 14; reg < 32; reg++)
+ PACK64(ptr, regs->gpr[reg]);
+
+#ifdef CONFIG_PPC_85xx
+#ifdef CONFIG_SPE
+ for (reg = 0; reg < 32; reg++)
+ PACK64(ptr, p->thread.evr[reg]);
+#else
+ ptr += 32;
+#endif
+#else
+ /* fp registers not used by kernel, leave zero */
+ ptr += 32 * 8 / sizeof(long);
+#endif
+
+ PACK64(ptr, regs->nip);
+ PACK64(ptr, regs->msr);
+ PACK32(ptr, regs->ccr);
+ PACK64(ptr, regs->link);
+ PACK64(ptr, regs->ctr);
+ PACK32(ptr, regs->xer);
+
+ BUG_ON((unsigned long)ptr >
+ (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
+}
+
+#define GDB_SIZEOF_REG sizeof(unsigned long)
+#define GDB_SIZEOF_REG_U32 sizeof(u32)
+
+#ifdef CONFIG_PPC_85xx
+#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
+#else
+#define GDB_SIZEOF_FLOAT_REG sizeof(u64)
+#endif
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+ { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
+ { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
+ { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
+ { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
+ { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
+ { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
+ { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
+ { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
+ { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
+ { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
+ { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
+ { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
+ { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
+ { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
+ { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
+ { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
+ { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
+ { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
+ { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
+ { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
+ { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
+ { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
+ { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
+ { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
+ { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
+ { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
+ { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
+ { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
+ { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
+ { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
+ { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
+ { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
+
+ { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
+ { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
+ { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
+ { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
+ { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
+ { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
+ { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
+ { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
+ { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
+ { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
+ { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
+ { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
+ { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
+ { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
+ { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
+ { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
+ { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
+ { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
+ { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
+ { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
+ { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
+ { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
+ { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
+ { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
+ { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
+ { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
+ { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
+ { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
+ { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
+ { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
+ { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
+ { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
+
+ { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
+ { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
+ { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
+ { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
+ { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
+ { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
+};
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return NULL;
+
+ if (regno < 32 || regno >= 64)
+ /* First 0 -> 31 gpr registers*/
+ /* pc, msr, ls... registers 64 -> 69 */
+ memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
+ dbg_reg_def[regno].size);
+
+ if (regno >= 32 && regno < 64) {
+ /* FP registers 32 -> 63 */
+#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
+ if (current)
+ memcpy(mem, &current->thread.evr[regno-32],
+ dbg_reg_def[regno].size);
+#else
+ /* fp registers not used by kernel, leave zero */
+ memset(mem, 0, dbg_reg_def[regno].size);
+#endif
+ }
+
+ return dbg_reg_def[regno].name;
+}
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return -EINVAL;
+
+ if (regno < 32 || regno >= 64)
+ /* First 0 -> 31 gpr registers*/
+ /* pc, msr, ls... registers 64 -> 69 */
+ memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+ dbg_reg_def[regno].size);
+
+ if (regno >= 32 && regno < 64) {
+ /* FP registers 32 -> 63 */
+#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
+ memcpy(&current->thread.evr[regno-32], mem,
+ dbg_reg_def[regno].size);
+#else
+ /* fp registers not used by kernel, leave zero */
+ return 0;
+#endif
+ }
+
+ return 0;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ regs_set_return_ip(regs, pc);
+}
+
+/*
+ * This function does PowerPC specific processing for interfacing to gdb.
+ */
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+ char *remcom_in_buffer, char *remcom_out_buffer,
+ struct pt_regs *linux_regs)
+{
+ char *ptr = &remcom_in_buffer[1];
+ unsigned long addr;
+
+ switch (remcom_in_buffer[0]) {
+ /*
+ * sAA..AA Step one instruction from AA..AA
+ * This will return an error to gdb ..
+ */
+ case 's':
+ case 'c':
+ /* handle the optional parameter */
+ if (kgdb_hex2long(&ptr, &addr))
+ regs_set_return_ip(linux_regs, addr);
+
+ atomic_set(&kgdb_cpu_doing_single_step, -1);
+ /* set the trace bit if we're stepping */
+ if (remcom_in_buffer[0] == 's') {
+#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+ mtspr(SPRN_DBCR0,
+ mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
+ regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE);
+#else
+ regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE);
+#endif
+ atomic_set(&kgdb_cpu_doing_single_step,
+ raw_smp_processor_id());
+ }
+ return 0;
+ }
+
+ return -1;
+}
+
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ u32 instr, *addr = (u32 *)bpt->bpt_addr;
+ int err;
+
+ err = get_kernel_nofault(instr, addr);
+ if (err)
+ return err;
+
+ err = patch_instruction(addr, ppc_inst(BREAK_INSTR));
+ if (err)
+ return -EFAULT;
+
+ *(u32 *)bpt->saved_instr = instr;
+
+ return 0;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+ unsigned int instr = *(unsigned int *)bpt->saved_instr;
+ u32 *addr = (u32 *)bpt->bpt_addr;
+
+ err = patch_instruction(addr, ppc_inst(instr));
+ if (err)
+ return -EFAULT;
+
+ return 0;
+}
+
+/*
+ * Global data
+ */
+const struct kgdb_arch arch_kgdb_ops;
+
+static int kgdb_not_implemented(struct pt_regs *regs)
+{
+ return 0;
+}
+
+static void *old__debugger_ipi;
+static void *old__debugger;
+static void *old__debugger_bpt;
+static void *old__debugger_sstep;
+static void *old__debugger_iabr_match;
+static void *old__debugger_break_match;
+static void *old__debugger_fault_handler;
+
+int kgdb_arch_init(void)
+{
+ old__debugger_ipi = __debugger_ipi;
+ old__debugger = __debugger;
+ old__debugger_bpt = __debugger_bpt;
+ old__debugger_sstep = __debugger_sstep;
+ old__debugger_iabr_match = __debugger_iabr_match;
+ old__debugger_break_match = __debugger_break_match;
+ old__debugger_fault_handler = __debugger_fault_handler;
+
+ __debugger_ipi = kgdb_debugger_ipi;
+ __debugger = kgdb_debugger;
+ __debugger_bpt = kgdb_handle_breakpoint;
+ __debugger_sstep = kgdb_singlestep;
+ __debugger_iabr_match = kgdb_iabr_match;
+ __debugger_break_match = kgdb_break_match;
+ __debugger_fault_handler = kgdb_not_implemented;
+
+ return 0;
+}
+
+void kgdb_arch_exit(void)
+{
+ __debugger_ipi = old__debugger_ipi;
+ __debugger = old__debugger;
+ __debugger_bpt = old__debugger_bpt;
+ __debugger_sstep = old__debugger_sstep;
+ __debugger_iabr_match = old__debugger_iabr_match;
+ __debugger_break_match = old__debugger_break_match;
+ __debugger_fault_handler = old__debugger_fault_handler;
+}