New upstream version 18.08

[deb_dpdk.git] / drivers / net / sfc / base / efx_types.h

diff --git a/drivers/net/sfc/base/efx_types.h b/drivers/net/sfc/base/efx_types.h
index 0581f67..65168ab 100644 (file)
--- a/drivers/net/sfc/base/efx_types.h
+++ b/drivers/net/sfc/base/efx_types.h
@@ -328,6 +328,16 @@ extern int fix_lint;
 #define        FIX_LINT(_x)    (_x)
 #endif
 
+/*
+ * Saturation arithmetic subtract with minimum equal to zero.
+ *
+ * Use saturating arithmetic to ensure a non-negative result. This
+ * avoids undefined behaviour (and compiler warnings) when used as a
+ * shift count.
+ */
+#define        EFX_SSUB(_val, _sub) \
+       ((_val) > (_sub) ? ((_val) - (_sub)) : 0)
+
 /*
  * Extract bit field portion [low,high) from the native-endian element
  * which contains bits [min,max).
@@ -347,8 +357,8 @@ extern int fix_lint;
        ((FIX_LINT(_low > _max) || FIX_LINT(_high < _min)) ?            \
                0U :                                                    \
                ((_low > _min) ?                                        \
-                       ((_element) >> (_low - _min)) :                 \
-                       ((_element) << (_min - _low))))
+                       ((_element) >> EFX_SSUB(_low, _min)) :          \
+                       ((_element) << EFX_SSUB(_min, _low))))
 
 /*
  * Extract bit field portion [low,high) from the 64-bit little-endian
@@ -537,29 +547,29 @@ extern int fix_lint;
        (((_low > _max) || (_high < _min)) ?                            \
                0U :                                                    \
                ((_low > _min) ?                                        \
-                       (((uint64_t)(_value)) << (_low - _min)) :       \
-                       (((uint64_t)(_value)) >> (_min - _low))))
+                       (((uint64_t)(_value)) << EFX_SSUB(_low, _min)) :\
+                       (((uint64_t)(_value)) >> EFX_SSUB(_min, _low))))
 
 #define        EFX_INSERT_NATIVE32(_min, _max, _low, _high, _value)            \
        (((_low > _max) || (_high < _min)) ?                            \
                0U :                                                    \
                ((_low > _min) ?                                        \
-                       (((uint32_t)(_value)) << (_low - _min)) :       \
-                       (((uint32_t)(_value)) >> (_min - _low))))
+                       (((uint32_t)(_value)) << EFX_SSUB(_low, _min)) :\
+                       (((uint32_t)(_value)) >> EFX_SSUB(_min, _low))))
 
 #define        EFX_INSERT_NATIVE16(_min, _max, _low, _high, _value)            \
        (((_low > _max) || (_high < _min)) ?                            \
                0U :                                                    \
                (uint16_t)((_low > _min) ?                              \
-                               ((_value) << (_low - _min)) :           \
-                               ((_value) >> (_min - _low))))
+                               ((_value) << EFX_SSUB(_low, _min)) :    \
+                               ((_value) >> EFX_SSUB(_min, _low))))
 
 #define        EFX_INSERT_NATIVE8(_min, _max, _low, _high, _value)             \
        (((_low > _max) || (_high < _min)) ?                            \
                0U :                                                    \
                (uint8_t)((_low > _min) ?                               \
-                               ((_value) << (_low - _min)) :   \
-                               ((_value) >> (_min - _low))))
+                               ((_value) << EFX_SSUB(_low, _min)) :    \
+                               ((_value) >> EFX_SSUB(_min, _low))))
 
 /*
  * Construct bit field portion
@@ -1288,22 +1298,22 @@ extern int fix_lint;
 
 #define        EFX_SHIFT64(_bit, _base)                                        \
        (((_bit) >= (_base) && (_bit) < (_base) + 64) ?                 \
-               ((uint64_t)1 << ((_bit) - (_base))) :                   \
+               ((uint64_t)1 << EFX_SSUB((_bit), (_base))) :            \
                0U)
 
 #define        EFX_SHIFT32(_bit, _base)                                        \
        (((_bit) >= (_base) && (_bit) < (_base) + 32) ?                 \
-               ((uint32_t)1 << ((_bit) - (_base))) :                   \
+               ((uint32_t)1 << EFX_SSUB((_bit),(_base))) :             \
                0U)
 
 #define        EFX_SHIFT16(_bit, _base)                                        \
        (((_bit) >= (_base) && (_bit) < (_base) + 16) ?                 \
-               (uint16_t)(1 << ((_bit) - (_base))) :                   \
+               (uint16_t)(1 << EFX_SSUB((_bit), (_base))) :            \
                0U)
 
 #define        EFX_SHIFT8(_bit, _base)                                         \
        (((_bit) >= (_base) && (_bit) < (_base) + 8) ?                  \
-               (uint8_t)(1 << ((_bit) - (_base))) :                    \
+               (uint8_t)(1 << EFX_SSUB((_bit), (_base))) :             \
                0U)
 
 #define        EFX_SET_OWORD_BIT64(_oword, _bit)                               \