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-rw-r--r--Documentation/admin-guide/kdump/gdbmacros.txt12
-rw-r--r--kernel/printk/printk_ringbuffer.c28
-rw-r--r--kernel/printk/printk_ringbuffer.h31
-rw-r--r--scripts/gdb/linux/dmesg.py11
4 files changed, 41 insertions, 41 deletions
diff --git a/Documentation/admin-guide/kdump/gdbmacros.txt b/Documentation/admin-guide/kdump/gdbmacros.txt
index 7adece30237e..8f533b751c46 100644
--- a/Documentation/admin-guide/kdump/gdbmacros.txt
+++ b/Documentation/admin-guide/kdump/gdbmacros.txt
@@ -295,9 +295,12 @@ document dump_record
end
define dmesg
- set var $desc_committed = 1UL << ((sizeof(long) * 8) - 1)
- set var $flags_mask = 3UL << ((sizeof(long) * 8) - 2)
- set var $id_mask = ~$flags_mask
+ # definitions from kernel/printk/printk_ringbuffer.h
+ set var $desc_committed = 1
+ set var $desc_sv_bits = sizeof(long) * 8
+ set var $desc_flags_shift = $desc_sv_bits - 2
+ set var $desc_flags_mask = 3 << $desc_flags_shift
+ set var $id_mask = ~$desc_flags_mask
set var $desc_count = 1U << prb->desc_ring.count_bits
set var $prev_flags = 0
@@ -309,7 +312,8 @@ define dmesg
set var $desc = &prb->desc_ring.descs[$id % $desc_count]
# skip non-committed record
- if (($desc->state_var.counter & $flags_mask) == $desc_committed)
+ set var $state = 3 & ($desc->state_var.counter >> $desc_flags_shift)
+ if ($state == $desc_committed)
dump_record $desc $prev_flags
set var $prev_flags = $desc->info.flags
end
diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
index 5a9c7c8cff7b..c0d31185ccbf 100644
--- a/kernel/printk/printk_ringbuffer.c
+++ b/kernel/printk/printk_ringbuffer.c
@@ -348,14 +348,6 @@ static bool data_check_size(struct prb_data_ring *data_ring, unsigned int size)
return true;
}
-/* The possible responses of a descriptor state-query. */
-enum desc_state {
- desc_miss, /* ID mismatch */
- desc_reserved, /* reserved, in use by writer */
- desc_committed, /* committed, writer is done */
- desc_reusable, /* free, not yet used by any writer */
-};
-
/* Query the state of a descriptor. */
static enum desc_state get_desc_state(unsigned long id,
unsigned long state_val)
@@ -363,13 +355,7 @@ static enum desc_state get_desc_state(unsigned long id,
if (id != DESC_ID(state_val))
return desc_miss;
- if (state_val & DESC_REUSE_MASK)
- return desc_reusable;
-
- if (state_val & DESC_COMMITTED_MASK)
- return desc_committed;
-
- return desc_reserved;
+ return DESC_STATE(state_val);
}
/*
@@ -484,8 +470,8 @@ out:
static void desc_make_reusable(struct prb_desc_ring *desc_ring,
unsigned long id)
{
- unsigned long val_committed = id | DESC_COMMITTED_MASK;
- unsigned long val_reusable = val_committed | DESC_REUSE_MASK;
+ unsigned long val_committed = DESC_SV(id, desc_committed);
+ unsigned long val_reusable = DESC_SV(id, desc_reusable);
struct prb_desc *desc = to_desc(desc_ring, id);
atomic_long_t *state_var = &desc->state_var;
@@ -921,7 +907,7 @@ static bool desc_reserve(struct printk_ringbuffer *rb, unsigned long *id_out)
*/
prev_state_val = atomic_long_read(&desc->state_var); /* LMM(desc_reserve:E) */
if (prev_state_val &&
- prev_state_val != (id_prev_wrap | DESC_COMMITTED_MASK | DESC_REUSE_MASK)) {
+ get_desc_state(id_prev_wrap, prev_state_val) != desc_reusable) {
WARN_ON_ONCE(1);
return false;
}
@@ -935,7 +921,7 @@ static bool desc_reserve(struct printk_ringbuffer *rb, unsigned long *id_out)
* This pairs with desc_read:D.
*/
if (!atomic_long_try_cmpxchg(&desc->state_var, &prev_state_val,
- id | 0)) { /* LMM(desc_reserve:F) */
+ DESC_SV(id, desc_reserved))) { /* LMM(desc_reserve:F) */
WARN_ON_ONCE(1);
return false;
}
@@ -1254,7 +1240,7 @@ void prb_commit(struct prb_reserved_entry *e)
{
struct prb_desc_ring *desc_ring = &e->rb->desc_ring;
struct prb_desc *d = to_desc(desc_ring, e->id);
- unsigned long prev_state_val = e->id | 0;
+ unsigned long prev_state_val = DESC_SV(e->id, desc_reserved);
/* Now the writer has finished all writing: LMM(prb_commit:A) */
@@ -1267,7 +1253,7 @@ void prb_commit(struct prb_reserved_entry *e)
* this. This pairs with desc_read:B.
*/
if (!atomic_long_try_cmpxchg(&d->state_var, &prev_state_val,
- e->id | DESC_COMMITTED_MASK)) { /* LMM(prb_commit:B) */
+ DESC_SV(e->id, desc_committed))) { /* LMM(prb_commit:B) */
WARN_ON_ONCE(1);
}
diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h
index e6302da041f9..a9d85a6727b1 100644
--- a/kernel/printk/printk_ringbuffer.h
+++ b/kernel/printk/printk_ringbuffer.h
@@ -112,16 +112,25 @@ struct prb_reserved_entry {
unsigned int text_space;
};
-#define _DATA_SIZE(sz_bits) (1UL << (sz_bits))
-#define _DESCS_COUNT(ct_bits) (1U << (ct_bits))
-#define DESC_SV_BITS (sizeof(unsigned long) * 8)
-#define DESC_COMMITTED_MASK (1UL << (DESC_SV_BITS - 1))
-#define DESC_REUSE_MASK (1UL << (DESC_SV_BITS - 2))
-#define DESC_FLAGS_MASK (DESC_COMMITTED_MASK | DESC_REUSE_MASK)
-#define DESC_ID_MASK (~DESC_FLAGS_MASK)
-#define DESC_ID(sv) ((sv) & DESC_ID_MASK)
-#define FAILED_LPOS 0x1
-#define NO_LPOS 0x3
+/* The possible responses of a descriptor state-query. */
+enum desc_state {
+ desc_miss = -1, /* ID mismatch (pseudo state) */
+ desc_reserved = 0x0, /* reserved, in use by writer */
+ desc_committed = 0x1, /* committed by writer */
+ desc_reusable = 0x3, /* free, not yet used by any writer */
+};
+
+#define _DATA_SIZE(sz_bits) (1UL << (sz_bits))
+#define _DESCS_COUNT(ct_bits) (1U << (ct_bits))
+#define DESC_SV_BITS (sizeof(unsigned long) * 8)
+#define DESC_FLAGS_SHIFT (DESC_SV_BITS - 2)
+#define DESC_FLAGS_MASK (3UL << DESC_FLAGS_SHIFT)
+#define DESC_STATE(sv) (3UL & (sv >> DESC_FLAGS_SHIFT))
+#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)
+#define FAILED_LPOS 0x1
+#define NO_LPOS 0x3
#define FAILED_BLK_LPOS \
{ \
@@ -213,7 +222,7 @@ struct prb_reserved_entry {
*/
#define BLK0_LPOS(sz_bits) (-(_DATA_SIZE(sz_bits)))
#define DESC0_ID(ct_bits) DESC_ID(-(_DESCS_COUNT(ct_bits) + 1))
-#define DESC0_SV(ct_bits) (DESC_COMMITTED_MASK | DESC_REUSE_MASK | DESC0_ID(ct_bits))
+#define DESC0_SV(ct_bits) DESC_SV(DESC0_ID(ct_bits), desc_reusable)
/*
* Define a ringbuffer with an external text data buffer. The same as
diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py
index 6c6022012ea8..dd8c0b95063a 100644
--- a/scripts/gdb/linux/dmesg.py
+++ b/scripts/gdb/linux/dmesg.py
@@ -78,10 +78,10 @@ class LxDmesg(gdb.Command):
len_off = off + printk_info_type.get_type()['text_len'].bitpos // 8
# definitions from kernel/printk/printk_ringbuffer.h
+ desc_committed = 1
desc_sv_bits = utils.get_long_type().sizeof * 8
- desc_committed_mask = 1 << (desc_sv_bits - 1)
- desc_reuse_mask = 1 << (desc_sv_bits - 2)
- desc_flags_mask = desc_committed_mask | desc_reuse_mask
+ desc_flags_shift = desc_sv_bits - 2
+ desc_flags_mask = 3 << desc_flags_shift
desc_id_mask = ~desc_flags_mask
# read in tail and head descriptor ids
@@ -96,8 +96,9 @@ class LxDmesg(gdb.Command):
desc_off = desc_sz * ind
# skip non-committed record
- state = utils.read_u64(descs, desc_off + sv_off + counter_off) & desc_flags_mask
- if state != desc_committed_mask:
+ state = 3 & (utils.read_u64(descs, desc_off + sv_off +
+ counter_off) >> desc_flags_shift)
+ if state != desc_committed:
if did == head_id:
break
did = (did + 1) & desc_id_mask
generated by cgit (git 2.34.1) at 2024-05-28 05:21:14 +0000