Hexagon: add support for single-stepping (v4+)

Hardware single-step is only available on v4 and later
architectures.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>

diff --git a/arch/hexagon/include/uapi/asm/ptrace.h b/arch/hexagon/include/uapi/asm/ptrace.h
index 1ffce0c..065e5b3 100644 (file)
--- a/arch/hexagon/include/uapi/asm/ptrace.h
+++ b/arch/hexagon/include/uapi/asm/ptrace.h
@@ -36,4 +36,9 @@ extern const char *regs_query_register_name(unsigned int offset);
        ((struct pt_regs *) \
         ((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
 
+#if CONFIG_HEXAGON_ARCH_VERSION >= 4
+#define arch_has_single_step() (1)
+#endif
+
+
 #endif

diff --git a/arch/hexagon/include/uapi/asm/registers.h b/arch/hexagon/include/uapi/asm/registers.h
index 8050415..fcdb5f9 100644 (file)
--- a/arch/hexagon/include/uapi/asm/registers.h
+++ b/arch/hexagon/include/uapi/asm/registers.h
@@ -211,6 +211,9 @@ struct pt_regs {
 #define pt_psp(regs) ((regs)->hvmer.vmpsp)
 #define pt_badva(regs) ((regs)->hvmer.vmbadva)
 
+#define pt_set_singlestep(regs) ((regs)->hvmer.vmest |= (1<<HVM_VMEST_SS_SFT))
+#define pt_clr_singlestep(regs) ((regs)->hvmer.vmest &= ~(1<<HVM_VMEST_SS_SFT))
+
 #define pt_set_rte_sp(regs, sp) do {\
        pt_psp(regs) = (sp);\
        (regs)->SP = (unsigned long) &((regs)->hvmer);\

diff --git a/arch/hexagon/kernel/ptrace.c b/arch/hexagon/kernel/ptrace.c
index 3982d9c..70df50d 100644 (file)
--- a/arch/hexagon/kernel/ptrace.c
+++ b/arch/hexagon/kernel/ptrace.c
@@ -32,6 +32,21 @@
 
 #include <asm/user.h>
 
+#if arch_has_single_step()
+/*  Both called from ptrace_resume  */
+void user_enable_single_step(struct task_struct *child)
+{
+       pt_set_singlestep(task_pt_regs(child));
+       set_tsk_thread_flag(child, TIF_SINGLESTEP);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+       pt_clr_singlestep(task_pt_regs(child));
+       clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+}
+#endif
+
 static int genregs_get(struct task_struct *target,
                   const struct user_regset *regset,
                   unsigned int pos, unsigned int count,

diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index 12164a3..c2eeeef 100644 (file)
--- a/arch/hexagon/kernel/traps.c
+++ b/arch/hexagon/kernel/traps.c
@@ -451,3 +451,14 @@ void do_machcheck(struct pt_regs *regs)
        /* Halt and catch fire */
        __vmstop();
 }
+
+/*
+ * Treat this like the old 0xdb trap.
+ */
+
+void do_debug_exception(struct pt_regs *regs)
+{
+       regs->hvmer.vmest &= ~HVM_VMEST_CAUSE_MSK;
+       regs->hvmer.vmest |= (TRAP_DEBUG << HVM_VMEST_CAUSE_SFT);
+       do_trap0(regs);
+}

diff --git a/arch/hexagon/kernel/vm_entry.S b/arch/hexagon/kernel/vm_entry.S
index 053551e..9add73a 100644 (file)
--- a/arch/hexagon/kernel/vm_entry.S
+++ b/arch/hexagon/kernel/vm_entry.S
@@ -367,6 +367,9 @@ _K_enter_trap0:
 _K_enter_machcheck:
        vm_event_entry(do_machcheck)
 
+       .globl _K_enter_debug
+_K_enter_debug:
+       vm_event_entry(do_debug_exception)
 
        .globl ret_from_fork
 ret_from_fork:

diff --git a/arch/hexagon/kernel/vm_vectors.S b/arch/hexagon/kernel/vm_vectors.S
index 620f42c..aff4054 100644 (file)
--- a/arch/hexagon/kernel/vm_vectors.S
+++ b/arch/hexagon/kernel/vm_vectors.S
@@ -41,7 +41,7 @@ _K_VM_event_vector:
        jump 1b;  /*  Reset  */
        jump _K_enter_machcheck;
        jump _K_enter_genex;
-       jump 1b;  /*  3 Rsvd  */
+       jump _K_enter_debug;
        jump 1b;  /*  4 Rsvd  */
        jump _K_enter_trap0;
        jump 1b;  /*  6 Rsvd  */