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Date: Fri, 9 Aug 2013 15:08:57 -0400
From: Tony Lu <zlu@...era.com>
To: <linux-kernel@...r.kernel.org>,
Ananth N Mavinakayanahalli <ananth@...ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
"David S. Miller" <davem@...emloft.net>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Subject: [PATCH] tile: support kprobes on tilegx
This change includes support for Kprobes, Jprobes and Return Probes.
Signed-off-by: Tony Lu <zlu@...era.com>
Signed-off-by: Chris Metcalf <cmetcalf@...era.com>
---
I assume it makes sense for this to be pushed via the tile tree;
it's currently queued in tile-next.
arch/tile/Kconfig | 2 +
arch/tile/include/asm/Kbuild | 1 -
arch/tile/include/asm/kdebug.h | 28 ++
arch/tile/include/asm/kprobes.h | 79 +++++
arch/tile/include/asm/ptrace.h | 1 +
arch/tile/include/uapi/arch/opcode_tilegx.h | 1 +
arch/tile/include/uapi/arch/opcode_tilepro.h | 1 +
arch/tile/kernel/Makefile | 1 +
arch/tile/kernel/kprobes.c | 476 +++++++++++++++++++++++++++
arch/tile/kernel/smp.c | 14 +-
arch/tile/kernel/traps.c | 42 +++
arch/tile/kernel/vmlinux.lds.S | 1 +
arch/tile/mm/fault.c | 12 +
samples/kprobes/kprobe_example.c | 9 +
14 files changed, 664 insertions(+), 4 deletions(-)
create mode 100644 arch/tile/include/asm/kdebug.h
create mode 100644 arch/tile/include/asm/kprobes.h
create mode 100644 arch/tile/kernel/kprobes.c
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index e1600be..ecff467 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -125,6 +125,8 @@ config TILEGX
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_KPROBES
+ select HAVE_KRETPROBES
config TILEPRO
def_bool !TILEGX
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index b17b9b8..4c0b3c2 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -15,7 +15,6 @@ generic-y += ioctl.h
generic-y += ioctls.h
generic-y += ipcbuf.h
generic-y += irq_regs.h
-generic-y += kdebug.h
generic-y += local.h
generic-y += msgbuf.h
generic-y += mutex.h
diff --git a/arch/tile/include/asm/kdebug.h b/arch/tile/include/asm/kdebug.h
new file mode 100644
index 0000000..5bbbfa9
--- /dev/null
+++ b/arch/tile/include/asm/kdebug.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _ASM_TILE_KDEBUG_H
+#define _ASM_TILE_KDEBUG_H
+
+#include <linux/notifier.h>
+
+enum die_val {
+ DIE_OOPS = 1,
+ DIE_BREAK,
+ DIE_SSTEPBP,
+ DIE_PAGE_FAULT,
+ DIE_COMPILED_BPT
+};
+
+#endif /* _ASM_TILE_KDEBUG_H */
diff --git a/arch/tile/include/asm/kprobes.h b/arch/tile/include/asm/kprobes.h
new file mode 100644
index 0000000..d8f9a83
--- /dev/null
+++ b/arch/tile/include/asm/kprobes.h
@@ -0,0 +1,79 @@
+/*
+ * arch/tile/include/asm/kprobes.h
+ *
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _ASM_TILE_KPROBES_H
+#define _ASM_TILE_KPROBES_H
+
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/percpu.h>
+
+#include <arch/opcode.h>
+
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE 2
+
+#define kretprobe_blacklist_size 0
+
+typedef tile_bundle_bits kprobe_opcode_t;
+
+#define flush_insn_slot(p) \
+ flush_icache_range((unsigned long)p->addr, \
+ (unsigned long)p->addr + \
+ (MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
+
+struct kprobe;
+
+/* Architecture specific copy of original instruction. */
+struct arch_specific_insn {
+ kprobe_opcode_t *insn;
+};
+
+struct prev_kprobe {
+ struct kprobe *kp;
+ unsigned long status;
+ unsigned long saved_pc;
+};
+
+#define MAX_JPROBES_STACK_SIZE 128
+#define MAX_JPROBES_STACK_ADDR \
+ (((unsigned long)current_thread_info()) + THREAD_SIZE - 32 \
+ - sizeof(struct pt_regs))
+
+#define MIN_JPROBES_STACK_SIZE(ADDR) \
+ ((((ADDR) + MAX_JPROBES_STACK_SIZE) > MAX_JPROBES_STACK_ADDR) \
+ ? MAX_JPROBES_STACK_ADDR - (ADDR) \
+ : MAX_JPROBES_STACK_SIZE)
+
+/* per-cpu kprobe control block. */
+struct kprobe_ctlblk {
+ unsigned long kprobe_status;
+ unsigned long kprobe_saved_pc;
+ unsigned long jprobe_saved_sp;
+ struct prev_kprobe prev_kprobe;
+ struct pt_regs jprobe_saved_regs;
+ char jprobes_stack[MAX_JPROBES_STACK_SIZE];
+};
+
+extern tile_bundle_bits breakpoint2_insn;
+extern tile_bundle_bits breakpoint_insn;
+
+void arch_remove_kprobe(struct kprobe *);
+
+extern int kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data);
+
+#endif /* _ASM_TILE_KPROBES_H */
diff --git a/arch/tile/include/asm/ptrace.h b/arch/tile/include/asm/ptrace.h
index 73b681b..0d25c21 100644
--- a/arch/tile/include/asm/ptrace.h
+++ b/arch/tile/include/asm/ptrace.h
@@ -33,6 +33,7 @@ typedef unsigned long pt_reg_t;
#ifndef __ASSEMBLY__
+#define regs_return_value(regs) ((regs)->regs[0])
#define instruction_pointer(regs) ((regs)->pc)
#define profile_pc(regs) instruction_pointer(regs)
#define user_stack_pointer(regs) ((regs)->sp)
diff --git a/arch/tile/include/uapi/arch/opcode_tilegx.h b/arch/tile/include/uapi/arch/opcode_tilegx.h
index c14d02c..d76ff2d 100644
--- a/arch/tile/include/uapi/arch/opcode_tilegx.h
+++ b/arch/tile/include/uapi/arch/opcode_tilegx.h
@@ -61,6 +61,7 @@ typedef tilegx_bundle_bits tile_bundle_bits;
#define TILE_BUNDLE_ALIGNMENT_IN_BYTES TILEGX_BUNDLE_ALIGNMENT_IN_BYTES
#define TILE_LOG2_BUNDLE_ALIGNMENT_IN_BYTES \
TILEGX_LOG2_BUNDLE_ALIGNMENT_IN_BYTES
+#define TILE_BPT_BUNDLE TILEGX_BPT_BUNDLE
/* 64-bit pattern for a { bpt ; nop } bundle. */
#define TILEGX_BPT_BUNDLE 0x286a44ae51485000ULL
diff --git a/arch/tile/include/uapi/arch/opcode_tilepro.h b/arch/tile/include/uapi/arch/opcode_tilepro.h
index 71b763b..4451cff 100644
--- a/arch/tile/include/uapi/arch/opcode_tilepro.h
+++ b/arch/tile/include/uapi/arch/opcode_tilepro.h
@@ -71,6 +71,7 @@ typedef tilepro_bundle_bits tile_bundle_bits;
#define TILE_BUNDLE_ALIGNMENT_IN_BYTES TILEPRO_BUNDLE_ALIGNMENT_IN_BYTES
#define TILE_LOG2_BUNDLE_ALIGNMENT_IN_BYTES \
TILEPRO_LOG2_BUNDLE_ALIGNMENT_IN_BYTES
+#define TILE_BPT_BUNDLE TILEPRO_BPT_BUNDLE
/* 64-bit pattern for a { bpt ; nop } bundle. */
#define TILEPRO_BPT_BUNDLE 0x400b3cae70166000ULL
diff --git a/arch/tile/kernel/Makefile b/arch/tile/kernel/Makefile
index 2e6eaa1..b7c8b5e 100644
--- a/arch/tile/kernel/Makefile
+++ b/arch/tile/kernel/Makefile
@@ -28,5 +28,6 @@ endif
obj-$(CONFIG_TILE_USB) += usb.o
obj-$(CONFIG_TILE_HVGLUE_TRACE) += hvglue_trace.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o mcount_64.o
+obj-$(CONFIG_KPROBES) += kprobes.o
obj-y += vdso/
diff --git a/arch/tile/kernel/kprobes.c b/arch/tile/kernel/kprobes.c
new file mode 100644
index 0000000..926ebad
--- /dev/null
+++ b/arch/tile/kernel/kprobes.c
@@ -0,0 +1,476 @@
+/*
+ * arch/tile/kernel/kprobes.c
+ * Kprobes on TILE-Gx
+ *
+ * Some portions copied from the MIPS version.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ * Copyright 2006 Sony Corp.
+ * Copyright 2010 Cavium Networks
+ *
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+#include <arch/opcode.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+tile_bundle_bits breakpoint_insn = TILEGX_BPT_BUNDLE;
+tile_bundle_bits breakpoint2_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP;
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ unsigned long addr = (unsigned long)p->addr;
+
+ if (addr & (sizeof(kprobe_opcode_t) - 1))
+ return -EINVAL;
+
+ /* insn: must be on special executable page on tile. */
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+
+ /*
+ * In the kprobe->ainsn.insn[] array we store the original
+ * instruction at index zero and a break trap instruction at
+ * index one.
+ */
+ memcpy(&p->ainsn.insn[0], p->addr, sizeof(kprobe_opcode_t));
+ p->ainsn.insn[1] = breakpoint2_insn;
+ p->opcode = *p->addr;
+
+ return 0;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ unsigned long addr_wr;
+
+ /* Operate on writable kernel text mapping. */
+ addr_wr = (unsigned long)p->addr - MEM_SV_START + PAGE_OFFSET;
+
+ if (probe_kernel_write((void *)addr_wr, &breakpoint_insn,
+ sizeof(breakpoint_insn)))
+ pr_err("%s: failed to enable kprobe\n", __func__);
+
+ smp_wmb();
+ flush_insn_slot(p);
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *kp)
+{
+ unsigned long addr_wr;
+
+ /* Operate on writable kernel text mapping. */
+ addr_wr = (unsigned long)kp->addr - MEM_SV_START + PAGE_OFFSET;
+
+ if (probe_kernel_write((void *)addr_wr, &kp->opcode,
+ sizeof(kp->opcode)))
+ pr_err("%s: failed to enable kprobe\n", __func__);
+
+ smp_wmb();
+ flush_insn_slot(kp);
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, 0);
+ p->ainsn.insn = NULL;
+ }
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.saved_pc = kcb->kprobe_saved_pc;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_saved_pc = kcb->prev_kprobe.saved_pc;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ kcb->kprobe_saved_pc = regs->pc;
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ /* Single step inline if the instruction is a break. */
+ if (p->opcode == breakpoint_insn ||
+ p->opcode == breakpoint2_insn)
+ regs->pc = (unsigned long)p->addr;
+ else
+ regs->pc = (unsigned long)&p->ainsn.insn[0];
+}
+
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ int ret = 0;
+ kprobe_opcode_t *addr;
+ struct kprobe_ctlblk *kcb;
+
+ addr = (kprobe_opcode_t *)regs->pc;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing.
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ /* Check we're not actually recursing. */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if (kcb->kprobe_status == KPROBE_HIT_SS &&
+ p->ainsn.insn[0] == breakpoint_insn) {
+ goto no_kprobe;
+ }
+ /*
+ * We have reentered the kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ } else {
+ if (*addr != breakpoint_insn) {
+ /*
+ * The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate.
+ */
+ ret = 1;
+ goto no_kprobe;
+ }
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs))
+ goto ss_probe;
+ }
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p) {
+ if (*addr != breakpoint_insn) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ */
+ ret = 1;
+ }
+ /* Not one of ours: let kernel handle it. */
+ goto no_kprobe;
+ }
+
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ if (p->pre_handler && p->pre_handler(p, regs)) {
+ /* Handler has already set things up, so skip ss setup. */
+ return 1;
+ }
+
+ss_probe:
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+/*
+ * Called after single-stepping. p->addr is the address of the
+ * instruction whose first byte has been replaced by the "break 0"
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction. The address of this
+ * copy is p->ainsn.insn.
+ *
+ * This function prepares to return from the post-single-step
+ * breakpoint trap.
+ */
+static void __kprobes resume_execution(struct kprobe *p,
+ struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ unsigned long orig_pc = kcb->kprobe_saved_pc;
+ regs->pc = orig_pc + 8;
+}
+
+static inline int post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs, kcb);
+
+ /* Restore back the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+
+ return 1;
+}
+
+static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ if (kcb->kprobe_status & KPROBE_HIT_SS) {
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the ip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ resume_execution(cur, regs, kcb);
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ }
+ return 0;
+}
+
+/*
+ * Wrapper routine for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ switch (val) {
+ case DIE_BREAK:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_SSTEPBP:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_PAGE_FAULT:
+ /* kprobe_running() needs smp_processor_id(). */
+ preempt_disable();
+
+ if (kprobe_running()
+ && kprobe_fault_handler(args->regs, args->trapnr))
+ ret = NOTIFY_STOP;
+ preempt_enable();
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ kcb->jprobe_saved_regs = *regs;
+ kcb->jprobe_saved_sp = regs->sp;
+
+ memcpy(kcb->jprobes_stack, (void *)kcb->jprobe_saved_sp,
+ MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp));
+
+ regs->pc = (unsigned long)(jp->entry);
+
+ return 1;
+}
+
+/* Defined in the inline asm below. */
+void jprobe_return_end(void);
+
+void __kprobes jprobe_return(void)
+{
+ asm volatile(
+ "bpt\n\t"
+ ".globl jprobe_return_end\n"
+ "jprobe_return_end:\n");
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (regs->pc >= (unsigned long)jprobe_return &&
+ regs->pc <= (unsigned long)jprobe_return_end) {
+ *regs = kcb->jprobe_saved_regs;
+ memcpy((void *)kcb->jprobe_saved_sp, kcb->jprobes_stack,
+ MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp));
+ preempt_enable_no_resched();
+
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Function return probe trampoline:
+ * - init_kprobes() establishes a probepoint here
+ * - When the probed function returns, this probe causes the
+ * handlers to fire
+ */
+static void __used kretprobe_trampoline_holder(void)
+{
+ asm volatile(
+ "nop\n\t"
+ ".global kretprobe_trampoline\n"
+ "kretprobe_trampoline:\n\t"
+ "nop\n\t"
+ : : : "memory");
+}
+
+void kretprobe_trampoline(void);
+
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *) regs->lr;
+
+ /* Replace the return addr with trampoline addr */
+ regs->lr = (unsigned long)kretprobe_trampoline;
+}
+
+/*
+ * Called when the probe at kretprobe trampoline is hit.
+ */
+static int __kprobes trampoline_probe_handler(struct kprobe *p,
+ struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address = (unsigned long)kretprobe_trampoline;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ kretprobe_hash_lock(current, &head, &flags);
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because multiple functions in the call path have
+ * a return probe installed on them, and/or more than one return
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the first instance's ret_addr will point to the
+ * real return address, and all the rest will point to
+ * kretprobe_trampoline
+ */
+ hlist_for_each_entry_safe(ri, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ if (ri->rp && ri->rp->handler)
+ ri->rp->handler(ri, regs);
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address) {
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+ instruction_pointer(regs) = orig_ret_address;
+
+ reset_current_kprobe();
+ kretprobe_hash_unlock(current, &flags);
+ preempt_enable_no_resched();
+
+ hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we don't want the post_handler
+ * to run (and have re-enabled preemption)
+ */
+ return 1;
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ if (p->addr == (kprobe_opcode_t *)kretprobe_trampoline)
+ return 1;
+
+ return 0;
+}
+
+static struct kprobe trampoline_p = {
+ .addr = (kprobe_opcode_t *)kretprobe_trampoline,
+ .pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init_kprobes(void)
+{
+ register_kprobe(&trampoline_p);
+ return 0;
+}
diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c
index 6cc520d..0ae1c59 100644
--- a/arch/tile/kernel/smp.c
+++ b/arch/tile/kernel/smp.c
@@ -20,6 +20,7 @@
#include <linux/irq.h>
#include <linux/module.h>
#include <asm/cacheflush.h>
+#include <asm/homecache.h>
HV_Topology smp_topology __write_once;
EXPORT_SYMBOL(smp_topology);
@@ -167,9 +168,16 @@ static void ipi_flush_icache_range(void *info)
void flush_icache_range(unsigned long start, unsigned long end)
{
struct ipi_flush flush = { start, end };
- preempt_disable();
- on_each_cpu(ipi_flush_icache_range, &flush, 1);
- preempt_enable();
+
+ /* If invoked with irqs disabled, we can not issue IPIs. */
+ if (irqs_disabled())
+ flush_remote(0, HV_FLUSH_EVICT_L1I, NULL, 0, 0, 0,
+ NULL, NULL, 0);
+ else {
+ preempt_disable();
+ on_each_cpu(ipi_flush_icache_range, &flush, 1);
+ preempt_enable();
+ }
}
diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index a1bbc5de..f110785 100644
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -15,6 +15,7 @@
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/kprobes.h>
+#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/uaccess.h>
@@ -214,6 +215,43 @@ static const char *const int_name[] = {
#endif
};
+static int do_bpt(struct pt_regs *regs)
+{
+ unsigned long bundle, bcode, bpt;
+
+ bundle = *(unsigned long *)instruction_pointer(regs);
+
+ /*
+ * bpt shoule be { bpt; nop }, which is 0x286a44ae51485000ULL.
+ * we encode the unused least significant bits for other purpose.
+ */
+ bpt = bundle & ~((1ULL << 12) - 1);
+ if (bpt != TILE_BPT_BUNDLE)
+ return 0;
+
+ bcode = bundle & ((1ULL << 12) - 1);
+ /*
+ * notify the kprobe handlers, if instruction is likely to
+ * pertain to them.
+ */
+ switch (bcode) {
+ /* breakpoint_insn */
+ case 0:
+ notify_die(DIE_BREAK, "debug", regs, bundle,
+ INT_ILL, SIGTRAP);
+ break;
+ /* breakpoint2_insn */
+ case DIE_SSTEPBP:
+ notify_die(DIE_SSTEPBP, "single_step", regs, bundle,
+ INT_ILL, SIGTRAP);
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
void __kprobes do_trap(struct pt_regs *regs, int fault_num,
unsigned long reason)
{
@@ -233,6 +271,10 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
if (!user_mode(regs)) {
const char *name;
char buf[100];
+ if (fault_num == INT_ILL && do_bpt(regs)) {
+ /* breakpoint */
+ return;
+ }
if (fixup_exception(regs)) /* ILL_TRANS or UNALIGN_DATA */
return;
if (fault_num >= 0 &&
diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S
index 673d00a..aab9955 100644
--- a/arch/tile/kernel/vmlinux.lds.S
+++ b/arch/tile/kernel/vmlinux.lds.S
@@ -43,6 +43,7 @@ SECTIONS
HEAD_TEXT
SCHED_TEXT
LOCK_TEXT
+ KPROBES_TEXT
IRQENTRY_TEXT
__fix_text_end = .; /* tile-cpack won't rearrange before this */
TEXT_TEXT
diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 502664a..64eec3f 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -34,6 +34,7 @@
#include <linux/hugetlb.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
+#include <linux/kdebug.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
@@ -721,6 +722,17 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
{
int is_page_fault;
+#ifdef CONFIG_KPROBES
+ /*
+ * This is to notify the fault handler of the kprobes. The
+ * exception code is redundant as it is also carried in REGS,
+ * but we pass it anyhow.
+ */
+ if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
+ regs->faultnum, SIGSEGV) == NOTIFY_STOP)
+ return;
+#endif
+
#ifdef __tilegx__
/*
* We don't need early do_page_fault_ics() support, since unlike
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
index ebf5e0c..366db1a 100644
--- a/samples/kprobes/kprobe_example.c
+++ b/samples/kprobes/kprobe_example.c
@@ -37,6 +37,11 @@ static int handler_pre(struct kprobe *p, struct pt_regs *regs)
" status = 0x%lx\n",
p->addr, regs->cp0_epc, regs->cp0_status);
#endif
+#ifdef CONFIG_TILEGX
+ printk(KERN_INFO "pre_handler: p->addr = 0x%p, pc = 0x%lx,"
+ " ex1 = 0x%lx\n",
+ p->addr, regs->pc, regs->ex1);
+#endif
/* A dump_stack() here will give a stack backtrace */
return 0;
@@ -58,6 +63,10 @@ static void handler_post(struct kprobe *p, struct pt_regs *regs,
printk(KERN_INFO "post_handler: p->addr = 0x%p, status = 0x%lx\n",
p->addr, regs->cp0_status);
#endif
+#ifdef CONFIG_TILEGX
+ printk(KERN_INFO "post_handler: p->addr = 0x%p, ex1 = 0x%lx\n",
+ p->addr, regs->ex1);
+#endif
}
/*
--
1.8.3.1
--
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