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authorJohn Högberg <[email protected]>2019-04-24 12:45:36 +0200
committerJohn Högberg <[email protected]>2019-04-24 13:23:27 +0200
commit4fb0813f9004cb75eca065058c4899b0e4183635 (patch)
treef23b83af9c7d8f1d76c2f5bb816a12d6e1eed963 /erts
parent90eb43d0b61b5a51aede0537e394bd02216b6fa0 (diff)
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erts_alloc: Fix incorrect header word packing
Diffstat (limited to 'erts')
-rw-r--r--erts/emulator/beam/erl_alloc_util.c8
-rw-r--r--erts/emulator/beam/erl_alloc_util.h5
2 files changed, 11 insertions, 2 deletions
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c
index 8d4464969a..25ac3bc5af 100644
--- a/erts/emulator/beam/erl_alloc_util.c
+++ b/erts/emulator/beam/erl_alloc_util.c
@@ -6567,6 +6567,14 @@ erts_alcu_start(Allctr_t *allctr, AllctrInit_t *init)
__FILE__, __LINE__);
}
+ /* The various fields packed into the header word must not overlap */
+ ERTS_CT_ASSERT(!(MBC_ABLK_OFFSET_MASK & MBC_ABLK_SZ_MASK));
+ ERTS_CT_ASSERT(!(MBC_ABLK_OFFSET_MASK & BLK_FLG_MASK));
+ ERTS_CT_ASSERT(!(MBC_ABLK_SZ_MASK & BLK_FLG_MASK));
+ ERTS_CT_ASSERT(!(MBC_FBLK_SZ_MASK & BLK_FLG_MASK));
+ ERTS_CT_ASSERT(!(SBC_BLK_SZ_MASK & BLK_FLG_MASK));
+ ERTS_CT_ASSERT(!(CRR_SZ_MASK & CRR_FLG_MASK));
+
if (!initialized)
goto error;
diff --git a/erts/emulator/beam/erl_alloc_util.h b/erts/emulator/beam/erl_alloc_util.h
index ea1afe8f58..b34916271e 100644
--- a/erts/emulator/beam/erl_alloc_util.h
+++ b/erts/emulator/beam/erl_alloc_util.h
@@ -334,8 +334,9 @@ void erts_alcu_sched_spec_data_init(struct ErtsSchedulerData_ *esdp);
#endif
#if MBC_ABLK_OFFSET_BITS
-# define MBC_ABLK_OFFSET_SHIFT (sizeof(UWord)*8 - MBC_ABLK_OFFSET_BITS)
-# define MBC_ABLK_OFFSET_MASK ((~((UWord)0) << MBC_ABLK_OFFSET_SHIFT) & ~BLK_FLG_MASK)
+/* The shift is reduced by 1 since the highest bit is used for a flag. */
+# define MBC_ABLK_OFFSET_SHIFT (sizeof(UWord)*8 - 1 - MBC_ABLK_OFFSET_BITS)
+# define MBC_ABLK_OFFSET_MASK (((1ul << MBC_ABLK_OFFSET_BITS) - 1ul) << MBC_ABLK_OFFSET_SHIFT)
# define MBC_ABLK_SZ_MASK (~MBC_ABLK_OFFSET_MASK & ~BLK_FLG_MASK)
#else
# define MBC_ABLK_SZ_MASK (~BLK_FLG_MASK)