diff --git a/include/sframe.h b/include/sframe.h
index 3b656663ce2..cc439e52154 100644
--- a/include/sframe.h
+++ b/include/sframe.h
@@ -140,6 +140,19 @@ extern "C"
    matching FRE.  */
 #define SFRAME_FDE_TYPE_PCMASK  1
 
+/* SFrame FDE types.  */
+
+/* Default FDE type.  */
+#define SFRAME_FDE_TYPE_DEFAULT	  0
+/* Flexible Frame FDE type.
+   The recovery rule for CFA, RA and FP allow more flexibility.  Examples of
+   patterns supported include:
+     - CFA may be non-SP/FP based.
+     - CFA, FP may encode dereferencing of register after offset adjustment
+     - RA may be in a non-default register.
+   Currently used for SFRAME_ABI_AMD64_ENDIAN_LITTLE.  */
+#define SFRAME_FDE_TYPE_FLEX	  1
+
 typedef struct sframe_preamble
 {
   uint16_t sfp_magic;	/* Magic number (SFRAME_MAGIC).  */
@@ -270,11 +283,13 @@ typedef struct sframe_func_desc_entry_v3
      8        7             6                             5         4              0     */
   uint8_t sfde_func_info;
   /* Additional information for stack tracing from the function:
-     - 8-bits: Unused.
+     - 5-bits: FDE type.
+     - 3-bits: Unused.
      ------------------------------------------------------------
-     |                         Unused                           |
+     |                     Unused                 |  FDE Type   |
+     |                                            |             |
      ------------------------------------------------------------
-     8        7         6                         5             0     */
+     8                7             6             5             0     */
   uint8_t sfde_func_info2;
   /* Size of the block of repeating insns.  Used for SFrame FDEs of type
      SFRAME_FDE_TYPE_PCMASK.  */
@@ -284,17 +299,34 @@ typedef struct sframe_func_desc_entry_v3
 #define SFRAME_V3_FDE_FUNC_INFO(fde_pc_type, fre_type) \
   (SFRAME_V2_FUNC_INFO (fde_pc_type, fre_type))
 
+/* Mask for the ABI/arch specific FDE type (lower 5 bits).  */
+#define SFRAME_V3_FDE_TYPE_MASK		      0x01f
+/* Get the FDE type from the info2 byte.  */
+#define SFRAME_V3_FDE_TYPE(info2) \
+  ((info2) & SFRAME_V3_FDE_TYPE_MASK)
 #define SFRAME_V3_FDE_FRE_TYPE(info)          (SFRAME_V2_FUNC_FRE_TYPE (info))
 #define SFRAME_V3_FDE_PC_TYPE(info)           (SFRAME_V2_FUNC_PC_TYPE (info))
 #define SFRAME_V3_AARCH64_FDE_PAUTH_KEY(info) (SFRAME_V2_FUNC_PAUTH_KEY (info))
 #define SFRAME_V3_FDE_SIGNAL_P(info)           (((info) >> 7) & 0x1)
 
+/* Set the FDE type in the info2 byte, preserving upper bits.  */
+#define SFRAME_V3_SET_FDE_TYPE(info2, fde_type) \
+  (((info2) & ~SFRAME_V3_FDE_TYPE_MASK) \
+   | ((fde_type) & SFRAME_V3_FDE_TYPE_MASK))
+
 #define SFRAME_V3_FDE_UPDATE_PAUTH_KEY(pauth_key, info) \
   SFRAME_V2_FUNC_INFO_UPDATE_PAUTH_KEY (pauth_key, info)
 
 #define SFRAME_V3_FDE_UPDATE_SIGNAL_P(signal_p, info)  \
   ((((signal_p) & 0x1) << 7) | ((info) & 0x7f))
 
+#define SFRAME_V3_FLEX_FDE_REG_ENCODE(reg, deref_p, reg_p)  \
+  ((((reg) << 0x3) | (0 << 0x2) | (((deref_p) & 0x1) << 0x1) | ((reg_p) & 0x1)))
+
+#define SFRAME_V3_FLEX_FDE_OFFSET_REG_NUM(data)       ((data) >> 3)
+#define SFRAME_V3_FLEX_FDE_OFFSET_REG_DEREF_P(data)   (((data) >> 1) & 0x1)
+#define SFRAME_V3_FLEX_FDE_OFFSET_REG_P(data)         ((data) & 0x1)
+
 /* Size of stack frame offsets in an SFrame Frame Row Entry.  A single
    SFrame FRE has all offsets of the same size.  Offset size may vary
    across frame row entries.  */
@@ -359,7 +391,7 @@ typedef struct sframe_fre_info
 
 /* SFrame Frame Row Entry definitions.
 
-   Used for AMD64, AARCH64, and s390x.
+   Used for Default FDEs in AMD64, AARCH64, and s390x.
 
    An SFrame Frame Row Entry is a self-sufficient record which contains
    information on how to generate the stack trace for the specified range of
@@ -367,7 +399,7 @@ typedef struct sframe_fre_info
      S is the size of the stack frame offset for the FRE, and
      N is the number of stack frame offsets in the FRE
 
-   The interpretation of FRE stack offsets is ABI-specific:
+   The interpretation of FRE stack offsets for default FDEs is ABI-specific:
 
    AMD64:
      offset1 (interpreted as CFA = BASE_REG + offset1)