diff options
| -rw-r--r-- | arch/arm/kernel/hw_breakpoint.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c index 281bf3301241..76a650a1a1d7 100644 --- a/arch/arm/kernel/hw_breakpoint.c +++ b/arch/arm/kernel/hw_breakpoint.c @@ -906,7 +906,7 @@ static struct undef_hook debug_reg_hook = { static void reset_ctrl_regs(void *unused) { int i, raw_num_brps, err = 0, cpu = smp_processor_id(); - u32 dbg_power; + u32 val; /* * v7 debug contains save and restore registers so that debug state @@ -926,16 +926,23 @@ static void reset_ctrl_regs(void *unused) * Ensure sticky power-down is clear (i.e. debug logic is * powered up). */ - asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (dbg_power)); - if ((dbg_power & 0x1) == 0) + asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (val)); + if ((val & 0x1) == 0) err = -EPERM; + + /* + * Check whether we implement OS save and restore. + */ + asm volatile("mrc p14, 0, %0, c1, c1, 4" : "=r" (val)); + if ((val & 0x9) == 0) + goto clear_vcr; break; case ARM_DEBUG_ARCH_V7_1: /* * Ensure the OS double lock is clear. */ - asm volatile("mrc p14, 0, %0, c1, c3, 4" : "=r" (dbg_power)); - if ((dbg_power & 0x1) == 1) + asm volatile("mrc p14, 0, %0, c1, c3, 4" : "=r" (val)); + if ((val & 0x1) == 1) err = -EPERM; break; } @@ -947,7 +954,7 @@ static void reset_ctrl_regs(void *unused) } /* - * Unconditionally clear the lock by writing a value + * Unconditionally clear the OS lock by writing a value * other than 0xC5ACCE55 to the access register. */ asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0)); @@ -957,6 +964,7 @@ static void reset_ctrl_regs(void *unused) * Clear any configured vector-catch events before * enabling monitor mode. */ +clear_vcr: asm volatile("mcr p14, 0, %0, c0, c7, 0" : : "r" (0)); isb(); |