powerpc: Add ppc_breakpoint_available()

Add ppc_breakpoint_available() to determine if a breakpoint is
available currently via the DAWR or DABR.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/debug.h b/arch/powerpc/include/asm/debug.h
index fc97404..ce5da21 100644 (file)
--- a/arch/powerpc/include/asm/debug.h
+++ b/arch/powerpc/include/asm/debug.h
@@ -47,6 +47,7 @@ static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
 
 void set_breakpoint(struct arch_hw_breakpoint *brk);
 void __set_breakpoint(struct arch_hw_breakpoint *brk);
+bool ppc_breakpoint_available(void);
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 extern void do_send_trap(struct pt_regs *regs, unsigned long address,
                         unsigned long error_code, int brkpt);

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1738c41..4466e3d 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -827,6 +827,18 @@ void set_breakpoint(struct arch_hw_breakpoint *brk)
        preempt_enable();
 }
 
+/* Check if we have DAWR or DABR hardware */
+bool ppc_breakpoint_available(void)
+{
+       if (cpu_has_feature(CPU_FTR_DAWR))
+               return true; /* POWER8 DAWR */
+       if (cpu_has_feature(CPU_FTR_ARCH_207S))
+               return false; /* POWER9 with DAWR disabled */
+       /* DABR: Everything but POWER8 and POWER9 */
+       return true;
+}
+EXPORT_SYMBOL_GPL(ppc_breakpoint_available);
+
 #ifdef CONFIG_PPC64
 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 #endif