diff options
Diffstat (limited to 'kernel/printk/printk_ringbuffer.h')
| -rw-r--r-- | kernel/printk/printk_ringbuffer.h | 54 |
1 files changed, 51 insertions, 3 deletions
diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h index 18cd25e489b8..52626d0f1fa3 100644 --- a/kernel/printk/printk_ringbuffer.h +++ b/kernel/printk/printk_ringbuffer.h @@ -75,7 +75,7 @@ struct prb_desc_ring { struct printk_info *infos; atomic_long_t head_id; atomic_long_t tail_id; - atomic_long_t last_finalized_id; + atomic_long_t last_finalized_seq; }; /* @@ -127,8 +127,22 @@ enum desc_state { #define DESC_SV(id, state) (((unsigned long)state << DESC_FLAGS_SHIFT) | id) #define DESC_ID_MASK (~DESC_FLAGS_MASK) #define DESC_ID(sv) ((sv) & DESC_ID_MASK) + +/* + * Special data block logical position values (for fields of + * @prb_desc.text_blk_lpos). + * + * - Bit0 is used to identify if the record has no data block. (Implemented in + * the LPOS_DATALESS() macro.) + * + * - Bit1 specifies the reason for not having a data block. + * + * These special values could never be real lpos values because of the + * meta data and alignment padding of data blocks. (See to_blk_size() for + * details.) + */ #define FAILED_LPOS 0x1 -#define NO_LPOS 0x3 +#define EMPTY_LINE_LPOS 0x3 #define FAILED_BLK_LPOS \ { \ @@ -259,7 +273,7 @@ static struct printk_ringbuffer name = { \ .infos = &_##name##_infos[0], \ .head_id = ATOMIC_INIT(DESC0_ID(descbits)), \ .tail_id = ATOMIC_INIT(DESC0_ID(descbits)), \ - .last_finalized_id = ATOMIC_INIT(DESC0_ID(descbits)), \ + .last_finalized_seq = ATOMIC_INIT(0), \ }, \ .text_data_ring = { \ .size_bits = (avgtextbits) + (descbits), \ @@ -378,7 +392,41 @@ bool prb_read_valid(struct printk_ringbuffer *rb, u64 seq, bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq, struct printk_info *info, unsigned int *line_count); +u64 prb_first_seq(struct printk_ringbuffer *rb); u64 prb_first_valid_seq(struct printk_ringbuffer *rb); u64 prb_next_seq(struct printk_ringbuffer *rb); +u64 prb_next_reserve_seq(struct printk_ringbuffer *rb); + +#ifdef CONFIG_64BIT + +#define __u64seq_to_ulseq(u64seq) (u64seq) +#define __ulseq_to_u64seq(rb, ulseq) (ulseq) + +#else /* CONFIG_64BIT */ + +#define __u64seq_to_ulseq(u64seq) ((u32)u64seq) + +static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq) +{ + u64 rb_first_seq = prb_first_seq(rb); + u64 seq; + + /* + * The provided sequence is only the lower 32 bits of the ringbuffer + * sequence. It needs to be expanded to 64bit. Get the first sequence + * number from the ringbuffer and fold it. + * + * Having a 32bit representation in the console is sufficient. + * If a console ever gets more than 2^31 records behind + * the ringbuffer then this is the least of the problems. + * + * Also the access to the ring buffer is always safe. + */ + seq = rb_first_seq - (s32)((u32)rb_first_seq - ulseq); + + return seq; +} + +#endif /* CONFIG_64BIT */ #endif /* _KERNEL_PRINTK_RINGBUFFER_H */ |