diff options
Diffstat (limited to 'arch/arm/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/arm/kernel/hw_breakpoint.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c index ba386bd9410..180dd9f5b19 100644 --- a/arch/arm/kernel/hw_breakpoint.c +++ b/arch/arm/kernel/hw_breakpoint.c @@ -853,6 +853,25 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr, return ret; } +static int hw_breakpoint_undef(struct pt_regs *regs, unsigned int instr) +{ + int reg = (instr >> 12) & 15; + + /* Fake sticky power-down cleared */ + regs->uregs[reg] = 0; + regs->ARM_pc += 4; + + return 0; +} + +static struct undef_hook hw_breakpoint_hook = { + .instr_mask = 0xffff0fff, + .instr_val = 0xee110e95, + .cpsr_mask = MODE_MASK, + .cpsr_val = SVC_MODE, + .fn = hw_breakpoint_undef, +}; + /* * One-time initialisation. */ @@ -899,6 +918,10 @@ static void reset_ctrl_regs(void *unused) /* * Ensure sticky power-down is clear (i.e. debug logic is * powered up). + * + * This could raise an undefined instruction exception. If it + * does, it is fixed up with an undef hook which constructs + * a fake value with the sticky power-down bit cleared. */ asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (dbg_power)); if ((dbg_power & 0x1) == 0) @@ -986,6 +1009,8 @@ static int __init arch_hw_breakpoint_init(void) */ register_undef_hook(&debug_reg_hook); + register_undef_hook(&hw_breakpoint_hook); + /* * Reset the breakpoint resources. We assume that a halting * debugger will leave the world in a nice state for us. |