Now that the eh_frame infrastructure is fully in place, make it work by
hooking it up to the unwind_user interface.

Based on Josh Poimboeuf's, Steven Rostedt's, and my unwind user sframe
implementation.

Signed-off-by: Jens Remus <[email protected]>
---
 arch/Kconfig                      |  1 +
 include/linux/unwind_user_types.h |  4 +++-
 kernel/unwind/user.c              | 23 +++++++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 60542d5e5731..ea969811f798 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -488,6 +488,7 @@ config UNWIND_USER
 
 config HAVE_UNWIND_USER_EH_FRAME
        bool
+       select UNWIND_USER
 
 config HAVE_UNWIND_USER_FP
        bool
diff --git a/include/linux/unwind_user_types.h 
b/include/linux/unwind_user_types.h
index 4da058096259..88fc2fee8534 100644
--- a/include/linux/unwind_user_types.h
+++ b/include/linux/unwind_user_types.h
@@ -9,7 +9,8 @@
  * available.
  */
 enum unwind_user_type_bits {
-       UNWIND_USER_TYPE_FP_BIT =               0,
+       UNWIND_USER_TYPE_EH_FRAME_BIT =         0,
+       UNWIND_USER_TYPE_FP_BIT =               1,
 
        NR_UNWIND_USER_TYPE_BITS,
 };
@@ -17,6 +18,7 @@ enum unwind_user_type_bits {
 enum unwind_user_type {
        /* Type "none" for the start of stack walk iteration. */
        UNWIND_USER_TYPE_NONE =                 0,
+       UNWIND_USER_TYPE_EH_FRAME =             
BIT(UNWIND_USER_TYPE_EH_FRAME_BIT),
        UNWIND_USER_TYPE_FP =                   BIT(UNWIND_USER_TYPE_FP_BIT),
 };
 
diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 830c620fe453..85fc82252af1 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -10,6 +10,7 @@
 #include <linux/sched/task_stack.h>
 #include <linux/unwind_user.h>
 #include <linux/uaccess.h>
+#include <linux/eh_frame.h>
 
 #ifdef CONFIG_DYNAMIC_DEBUG
 
@@ -173,6 +174,16 @@ static int unwind_user_next_fp(struct unwind_user_state 
*state)
        return unwind_user_next_common(state, &fp_frame);
 }
 
+static int unwind_user_next_eh_frame(struct unwind_user_state *state)
+{
+       struct unwind_user_frame frame;
+
+       /* eh_frame expects the frame to be local storage */
+       if (eh_frame_find(state->ip, &frame))
+               return -ENOENT;
+       return unwind_user_next_common(state, &frame);
+}
+
 static int unwind_user_next(struct unwind_user_state *state)
 {
        unsigned long iter_mask = state->available_types;
@@ -186,6 +197,16 @@ static int unwind_user_next(struct unwind_user_state 
*state)
 
                state->current_type = type;
                switch (type) {
+               case UNWIND_USER_TYPE_EH_FRAME:
+                       switch (unwind_user_next_eh_frame(state)) {
+                       case 0:
+                               return 0;
+                       case -ENOENT:
+                               continue;       /* Try next method. */
+                       default:
+                               state->done = true;
+                       }
+                       break;
                case UNWIND_USER_TYPE_FP:
                        if (!unwind_user_next_fp(state))
                                return 0;
@@ -214,6 +235,8 @@ static int unwind_user_start(struct unwind_user_state 
*state)
                return -EINVAL;
        }
 
+       if (current_has_eh_frame())
+               state->available_types |= UNWIND_USER_TYPE_EH_FRAME;
        if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP))
                state->available_types |= UNWIND_USER_TYPE_FP;
 
-- 
2.53.0


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