linux/arch/powerpc/include/asm/hw_breakpoint.h
Paul Gortmaker 21f585073d powerpc: Fix smp_processor_id() in preemptible splat in set_breakpoint
Currently, on 8641D, which doesn't set CONFIG_HAVE_HW_BREAKPOINT
we get the following splat:

BUG: using smp_processor_id() in preemptible [00000000] code: login/1382
caller is set_breakpoint+0x1c/0xa0
CPU: 0 PID: 1382 Comm: login Not tainted 3.15.0-rc3-00041-g2aafe1a4d451 #1
Call Trace:
[decd5d80] [c0008dc4] show_stack+0x50/0x158 (unreliable)
[decd5dc0] [c03c6fa0] dump_stack+0x7c/0xdc
[decd5de0] [c01f8818] check_preemption_disabled+0xf4/0x104
[decd5e00] [c00086b8] set_breakpoint+0x1c/0xa0
[decd5e10] [c00d4530] flush_old_exec+0x2bc/0x588
[decd5e40] [c011c468] load_elf_binary+0x2ac/0x1164
[decd5ec0] [c00d35f8] search_binary_handler+0xc4/0x1f8
[decd5ef0] [c00d4ee8] do_execve+0x3d8/0x4b8
[decd5f40] [c001185c] ret_from_syscall+0x0/0x38
 --- Exception: c01 at 0xfeee554
    LR = 0xfeee7d4

The call path in this case is:

	flush_thread
	   --> set_debug_reg_defaults
	     --> set_breakpoint
	       --> __get_cpu_var

Since preemption is enabled in the cleanup of flush thread, and
there is no need to disable it, introduce the distinction between
set_breakpoint and __set_breakpoint, leaving only the flush_thread
instance as the current user of set_breakpoint.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-20 10:54:06 +10:00

93 lines
3.1 KiB
C

/*
* PowerPC BookIII S hardware breakpoint definitions
*
* 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 2010, IBM Corporation.
* Author: K.Prasad <prasad@linux.vnet.ibm.com>
*
*/
#ifndef _PPC_BOOK3S_64_HW_BREAKPOINT_H
#define _PPC_BOOK3S_64_HW_BREAKPOINT_H
#ifdef __KERNEL__
struct arch_hw_breakpoint {
unsigned long address;
u16 type;
u16 len; /* length of the target data symbol */
};
/* Note: Don't change the the first 6 bits below as they are in the same order
* as the dabr and dabrx.
*/
#define HW_BRK_TYPE_READ 0x01
#define HW_BRK_TYPE_WRITE 0x02
#define HW_BRK_TYPE_TRANSLATE 0x04
#define HW_BRK_TYPE_USER 0x08
#define HW_BRK_TYPE_KERNEL 0x10
#define HW_BRK_TYPE_HYP 0x20
#define HW_BRK_TYPE_EXTRANEOUS_IRQ 0x80
/* bits that overlap with the bottom 3 bits of the dabr */
#define HW_BRK_TYPE_RDWR (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE)
#define HW_BRK_TYPE_DABR (HW_BRK_TYPE_RDWR | HW_BRK_TYPE_TRANSLATE)
#define HW_BRK_TYPE_PRIV_ALL (HW_BRK_TYPE_USER | HW_BRK_TYPE_KERNEL | \
HW_BRK_TYPE_HYP)
#ifdef CONFIG_HAVE_HW_BREAKPOINT
#include <linux/kdebug.h>
#include <asm/reg.h>
#include <asm/debug.h>
struct perf_event;
struct pmu;
struct perf_sample_data;
#define HW_BREAKPOINT_ALIGN 0x7
extern int hw_breakpoint_slots(int type);
extern int arch_bp_generic_fields(int type, int *gen_bp_type);
extern int arch_check_bp_in_kernelspace(struct perf_event *bp);
extern int arch_validate_hwbkpt_settings(struct perf_event *bp);
extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
unsigned long val, void *data);
int arch_install_hw_breakpoint(struct perf_event *bp);
void arch_uninstall_hw_breakpoint(struct perf_event *bp);
void hw_breakpoint_pmu_read(struct perf_event *bp);
extern void flush_ptrace_hw_breakpoint(struct task_struct *tsk);
extern struct pmu perf_ops_bp;
extern void ptrace_triggered(struct perf_event *bp,
struct perf_sample_data *data, struct pt_regs *regs);
static inline void hw_breakpoint_disable(void)
{
struct arch_hw_breakpoint brk;
brk.address = 0;
brk.type = 0;
brk.len = 0;
__set_breakpoint(&brk);
}
extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);
#else /* CONFIG_HAVE_HW_BREAKPOINT */
static inline void hw_breakpoint_disable(void) { }
static inline void thread_change_pc(struct task_struct *tsk,
struct pt_regs *regs) { }
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif /* __KERNEL__ */
#endif /* _PPC_BOOK3S_64_HW_BREAKPOINT_H */