Introduce PPC64 implementation for the generic hardware breakpoint interfaces
defined in kernel/hw_breakpoint.c. Enable the HAVE_HW_BREAKPOINT flag and the
Makefile.
Signed-off-by: K.Prasad <pra...@linux.vnet.ibm.com>
---
arch/powerpc/Kconfig | 1
arch/powerpc/kernel/Makefile | 2
arch/powerpc/kernel/hw_breakpoint.c | 281 ++++++++++++++++++++++++++++++++++++
3 files changed, 283 insertions(+), 1 deletion(-)
Index: linux-2.6-tip.hbkpt/arch/powerpc/Kconfig
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/Kconfig
+++ linux-2.6-tip.hbkpt/arch/powerpc/Kconfig
@@ -125,6 +125,7 @@ config PPC
select USE_GENERIC_SMP_HELPERS if SMP
select HAVE_OPROFILE
select HAVE_SYSCALL_WRAPPERS if PPC64
+ select HAVE_HW_BREAKPOINT if PPC64
config EARLY_PRINTK
bool
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/Makefile
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/Makefile
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/Makefile
@@ -33,7 +33,7 @@ obj-$(CONFIG_PPC64) += setup_64.o sys_p
signal_64.o ptrace32.o \
paca.o cpu_setup_ppc970.o \
cpu_setup_pa6t.o \
- firmware.o nvram_64.o
+ firmware.o nvram_64.o hw_breakpoint.o
obj64-$(CONFIG_RELOCATABLE) += reloc_64.o
obj-$(CONFIG_PPC64) += vdso64/
obj-$(CONFIG_ALTIVEC) += vecemu.o vector.o
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/hw_breakpoint.c
===================================================================
--- /dev/null
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/hw_breakpoint.c
@@ -0,0 +1,281 @@
+/*
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) 2009 IBM Corporation
+ */
+
+/*
+ * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
+ * using the CPU's debug registers.
+ */
+
+#include <linux/notifier.h>
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/percpu.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#include <asm/hw_breakpoint.h>
+#include <asm/processor.h>
+#include <asm/sstep.h>
+
+/* Store the kernel-space breakpoint address value */
+static unsigned long kdabr;
+
+/*
+ * Temporarily stores address for DABR before it is written by the
+ * single-step handler routine
+ */
+static DEFINE_PER_CPU(unsigned long, dabr_data);
+
+void arch_update_kernel_hw_breakpoint(void *unused)
+{
+ struct hw_breakpoint *bp;
+
+ /* Check if there is nothing to update */
+ if (hbp_kernel_pos == HBP_NUM)
+ return;
+ bp = hbp_kernel[hbp_kernel_pos];
+ if (bp == NULL)
+ kdabr = 0;
+ else
+ kdabr = bp->info.address | bp->info.type | DABR_TRANSLATION;
+ set_dabr(kdabr);
+}
+
+/*
+ * Install the thread breakpoints in their debug registers.
+ */
+void arch_install_thread_hw_breakpoint(struct task_struct *tsk)
+{
+ set_dabr(tsk->thread.dabr);
+}
+
+/*
+ * Install the debug register values for just the kernel, no thread.
+ */
+void arch_uninstall_thread_hw_breakpoint()
+{
+ set_dabr(0);
+}
+
+/*
+ * Check for virtual address in user space.
+ */
+static int arch_check_va_in_userspace(unsigned long va)
+{
+ return (!(is_kernel_addr(va)));
+}
+
+/*
+ * Check for virtual address in kernel space.
+ */
+static int arch_check_va_in_kernelspace(unsigned long va)
+{
+ return is_kernel_addr(va);
+}
+
+/*
+ * Store a breakpoint's encoded address, length, and type.
+ */
+int arch_store_info(struct hw_breakpoint *bp)
+{
+ /*
+ * User-space requests will always have the address field populated
+ * For kernel-addresses, either the address or symbol name can be
+ * specified.
+ */
+ if (bp->info.name)
+ bp->info.address = (unsigned long)
+ kallsyms_lookup_name(bp->info.name);
+ if (bp->info.address)
+ return 0;
+ return -EINVAL;
+}
+
+/*
+ * Validate the arch-specific HW Breakpoint register settings
+ */
+int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
+ struct task_struct *tsk)
+{
+ int ret = -EINVAL;
+
+ if (!bp)
+ return ret;
+
+ switch (bp->info.type) {
+ case DABR_DATA_READ:
+ break;
+ case DABR_DATA_WRITE:
+ break;
+ case DABR_DATA_RW:
+ break;
+ default:
+ return ret;
+ }
+
+ if (bp->triggered)
+ ret = arch_store_info(bp);
+
+ /* Check for double word alignment - 8 bytes */
+ if (bp->info.address & HW_BREAKPOINT_ALIGN)
+ return -EINVAL;
+
+ /* Check that the virtual address is in the proper range */
+ if (tsk) {
+ if (!arch_check_va_in_userspace(bp->info.address))
+ return -EFAULT;
+ } else {
+ if (!arch_check_va_in_kernelspace(bp->info.address))
+ return -EFAULT;
+ }
+
+ return ret;
+}
+
+void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk)
+{
+ struct thread_struct *thread = &(tsk->thread);
+ struct hw_breakpoint *bp = thread->hbp[0];
+
+ if (bp)
+ thread->dabr = bp->info.address | bp->info.type |
+ DABR_TRANSLATION;
+ else
+ thread->dabr = 0;
+}
+
+void arch_flush_thread_hw_breakpoint(struct task_struct *tsk)
+{
+ struct thread_struct *thread = &(tsk->thread);
+
+ thread->dabr = 0;
+}
+
+/*
+ * Handle debug exception notifications.
+ */
+int __kprobes hw_breakpoint_handler(struct die_args *args)
+{
+ int rc = NOTIFY_STOP;
+ struct hw_breakpoint *bp;
+ struct pt_regs *regs = args->regs;
+ unsigned long dar;
+ int cpu, stepped, is_kernel;
+
+ /* Disable breakpoints during exception handling */
+ set_dabr(0);
+
+ dar = regs->dar & (~HW_BREAKPOINT_ALIGN);
+ is_kernel = (dar >= TASK_SIZE) ? 1 : 0;
+
+ if (is_kernel)
+ bp = hbp_kernel[0];
+ else {
+ bp = current->thread.hbp[0];
+ /* Lazy debug register switching */
+ if (!bp)
+ return rc;
+ rc = NOTIFY_DONE;
+ }
+
+ (bp->triggered)(bp, regs);
+
+ cpu = get_cpu();
+ if (is_kernel)
+ per_cpu(dabr_data, cpu) = kdabr;
+ else
+ per_cpu(dabr_data, cpu) = current->thread.dabr;
+
+ stepped = emulate_step(regs, regs->nip);
+ /*
+ * Single-step the causative instruction manually if
+ * emulate_step() could not execute it
+ */
+ if (stepped == 0) {
+ regs->msr |= MSR_SE;
+ goto out;
+ }
+
+ set_dabr(per_cpu(dabr_data, cpu));
+out:
+ /* Enable pre-emption only if single-stepping is finished */
+ if (stepped)
+ put_cpu_no_resched();
+ return rc;
+}
+
+/*
+ * Handle single-step exceptions following a DABR hit.
+ */
+int __kprobes single_step_dabr_instruction(struct die_args *args)
+{
+ struct pt_regs *regs = args->regs;
+ int cpu = get_cpu();
+ int ret = NOTIFY_DONE;
+ siginfo_t info;
+ unsigned long this_dabr_data = per_cpu(dabr_data, cpu);
+
+ /*
+ * Check if we are single-stepping as a result of a
+ * previous HW Breakpoint exception
+ */
+ if (this_dabr_data == 0)
+ goto out;
+
+ regs->msr &= ~MSR_SE;
+ /* Deliver signal to user-space */
+ if (this_dabr_data < TASK_SIZE) {
+ info.si_signo = SIGTRAP;
+ info.si_errno = 0;
+ info.si_code = TRAP_HWBKPT;
+ info.si_addr = (void __user *)(per_cpu(dabr_data, cpu));
+ force_sig_info(SIGTRAP, &info, current);
+ }
+
+ set_dabr(this_dabr_data);
+ per_cpu(dabr_data, cpu) = 0;
+ ret = NOTIFY_STOP;
+ put_cpu_no_resched();
+
+out:
+ put_cpu_no_resched();
+ return ret;
+}
+
+/*
+ * Handle debug exception notifications.
+ */
+int __kprobes hw_breakpoint_exceptions_notify(
+ struct notifier_block *unused, unsigned long val, void *data)
+{
+ int ret = NOTIFY_DONE;
+
+ switch (val) {
+ case DIE_DABR_MATCH:
+ ret = hw_breakpoint_handler(data);
+ break;
+ case DIE_SSTEP:
+ ret = single_step_dabr_instruction(data);
+ break;
+ }
+
+ return ret;
+}
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