diff options
Diffstat (limited to 'include/exec/exec-all.h')
| -rw-r--r-- | include/exec/exec-all.h | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index 4f07a17..3c2a0ef 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -345,7 +345,7 @@ struct TranslationBlock { #define CF_LAST_IO 0x00008000 /* Last insn may be an IO access. */ #define CF_NOCACHE 0x00010000 /* To be freed after execution */ #define CF_USE_ICOUNT 0x00020000 -#define CF_INVALID 0x00040000 /* TB is stale. Setters need tb_lock */ +#define CF_INVALID 0x00040000 /* TB is stale. Set with @jmp_lock held */ #define CF_PARALLEL 0x00080000 /* Generate code for a parallel context */ /* cflags' mask for hashing/comparison */ #define CF_HASH_MASK \ @@ -364,6 +364,9 @@ struct TranslationBlock { uintptr_t page_next[2]; tb_page_addr_t page_addr[2]; + /* jmp_lock placed here to fill a 4-byte hole. Its documentation is below */ + QemuSpin jmp_lock; + /* The following data are used to directly call another TB from * the code of this one. This can be done either by emitting direct or * indirect native jump instructions. These jumps are reset so that the TB @@ -375,20 +378,26 @@ struct TranslationBlock { #define TB_JMP_RESET_OFFSET_INVALID 0xffff /* indicates no jump generated */ uintptr_t jmp_target_arg[2]; /* target address or offset */ - /* Each TB has an associated circular list of TBs jumping to this one. - * jmp_list_first points to the first TB jumping to this one. - * jmp_list_next is used to point to the next TB in a list. - * Since each TB can have two jumps, it can participate in two lists. - * jmp_list_first and jmp_list_next are 4-byte aligned pointers to a - * TranslationBlock structure, but the two least significant bits of - * them are used to encode which data field of the pointed TB should - * be used to traverse the list further from that TB: - * 0 => jmp_list_next[0], 1 => jmp_list_next[1], 2 => jmp_list_first. - * In other words, 0/1 tells which jump is used in the pointed TB, - * and 2 means that this is a pointer back to the target TB of this list. + /* + * Each TB has a NULL-terminated list (jmp_list_head) of incoming jumps. + * Each TB can have two outgoing jumps, and therefore can participate + * in two lists. The list entries are kept in jmp_list_next[2]. The least + * significant bit (LSB) of the pointers in these lists is used to encode + * which of the two list entries is to be used in the pointed TB. + * + * List traversals are protected by jmp_lock. The destination TB of each + * outgoing jump is kept in jmp_dest[] so that the appropriate jmp_lock + * can be acquired from any origin TB. + * + * jmp_dest[] are tagged pointers as well. The LSB is set when the TB is + * being invalidated, so that no further outgoing jumps from it can be set. + * + * jmp_lock also protects the CF_INVALID cflag; a jump must not be chained + * to a destination TB that has CF_INVALID set. */ + uintptr_t jmp_list_head; uintptr_t jmp_list_next[2]; - uintptr_t jmp_list_first; + uintptr_t jmp_dest[2]; }; extern bool parallel_cpus; |