ARC: dw2 unwind: factor CIE specifics for .eh_frame/.debug_frame

This paves way for switching to .eh_frame based unwindiing

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
index 0587bf1..4e5dbe7 100644 (file)
--- a/arch/arc/kernel/unwind.c
+++ b/arch/arc/kernel/unwind.c
@@ -111,6 +111,8 @@ UNW_REGISTER_INFO};
 #define DW_EH_PE_indirect 0x80
 #define DW_EH_PE_omit     0xff
 
+#define CIE_ID 0xffffffffUL
+
 typedef unsigned long uleb128_t;
 typedef signed long sleb128_t;
 
@@ -232,6 +234,7 @@ void __init arc_unwind_init(void)
 
 static const u32 bad_cie, not_fde;
 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
+static const u32 *__cie_for_fde(const u32 *fde);
 static signed fde_pointer_type(const u32 *cie);
 
 struct eh_frame_hdr_table_entry {
@@ -338,10 +341,9 @@ static void init_unwind_hdr(struct unwind_table *table,
        for (fde = table->address, tableSize = table->size, n = 0;
             tableSize;
             tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
-               /* const u32 *cie = fde + 1 - fde[1] / sizeof(*fde); */
-               const u32 *cie = (const u32 *)(fde[1]);
+               const u32 *cie = __cie_for_fde(fde);
 
-               if (fde[1] == 0xffffffff)
+               if (fde[1] == CIE_ID)
                        continue;       /* this is a CIE */
                ptr = (const u8 *)(fde + 2);
                header->table[n].start = read_pointer(&ptr,
@@ -504,6 +506,16 @@ static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
        return value;
 }
 
+static const u32 *__cie_for_fde(const u32 *fde)
+{
+       const u32 *cie;
+
+       /* cie = fde + 1 - fde[1] / sizeof(*fde); */
+       cie = (u32 *) fde[1];
+
+       return cie;
+}
+
 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
 {
        const u32 *cie;
@@ -511,19 +523,18 @@ static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
        if (!*fde || (*fde & (sizeof(*fde) - 1)))
                return &bad_cie;
 
-       if (fde[1] == 0xffffffff)
+       if (fde[1] == CIE_ID)
                return &not_fde;        /* this is a CIE */
 
        if ((fde[1] & (sizeof(*fde) - 1)))
 /* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */
                return NULL;    /* this is not a valid FDE */
 
-       /* cie = fde + 1 - fde[1] / sizeof(*fde); */
-       cie = (u32 *) fde[1];
+       cie = __cie_for_fde(fde);
 
        if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde)
            || (*cie & (sizeof(*cie) - 1))
-           || (cie[1] != 0xffffffff))
+           || (cie[1] != CIE_ID))
                return NULL;    /* this is not a (valid) CIE */
        return cie;
 }