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Message-Id: <20200902200815.3924-4-maciej.fijalkowski@intel.com>
Date: Wed, 2 Sep 2020 22:08:11 +0200
From: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
To: ast@...nel.org, daniel@...earbox.net
Cc: bpf@...r.kernel.org, netdev@...r.kernel.org, bjorn.topel@...el.com,
magnus.karlsson@...el.com,
Maciej Fijalkowski <maciej.fijalkowski@...el.com>
Subject: [PATCH v7 bpf-next 3/7] bpf: rename poke descriptor's 'ip' member to 'tailcall_target'
Reflect the actual purpose of poke->ip and rename it to
poke->tailcall_target so that it will not the be confused with another
poke target that will be introduced in next commit.
While at it, do the same thing with poke->ip_stable - rename it to
poke->tailcall_target_stable.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
---
arch/x86/net/bpf_jit_comp.c | 20 +++++++++++---------
include/linux/bpf.h | 4 ++--
kernel/bpf/arraymap.c | 17 +++++++++--------
kernel/bpf/core.c | 3 ++-
4 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 6fb8c9435980..7b0ff169c9a0 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -434,7 +434,7 @@ static void emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor *poke,
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
EMIT2_off32(0x89, 0x85, -36 - MAX_BPF_STACK); /* mov dword ptr [rbp -548], eax */
- poke->ip = image + (addr - X86_PATCH_SIZE);
+ poke->tailcall_target = image + (addr - X86_PATCH_SIZE);
poke->adj_off = PROLOGUE_SIZE;
memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE);
@@ -453,7 +453,7 @@ static void bpf_tail_call_direct_fixup(struct bpf_prog *prog)
for (i = 0; i < prog->aux->size_poke_tab; i++) {
poke = &prog->aux->poke_tab[i];
- WARN_ON_ONCE(READ_ONCE(poke->ip_stable));
+ WARN_ON_ONCE(READ_ONCE(poke->tailcall_target_stable));
if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
continue;
@@ -464,18 +464,20 @@ static void bpf_tail_call_direct_fixup(struct bpf_prog *prog)
if (target) {
/* Plain memcpy is used when image is not live yet
* and still not locked as read-only. Once poke
- * location is active (poke->ip_stable), any parallel
- * bpf_arch_text_poke() might occur still on the
- * read-write image until we finally locked it as
- * read-only. Both modifications on the given image
- * are under text_mutex to avoid interference.
+ * location is active (poke->tailcall_target_stable),
+ * any parallel bpf_arch_text_poke() might occur
+ * still on the read-write image until we finally
+ * locked it as read-only. Both modifications on
+ * the given image are under text_mutex to avoid
+ * interference.
*/
- ret = __bpf_arch_text_poke(poke->ip, BPF_MOD_JUMP, NULL,
+ ret = __bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP, NULL,
(u8 *)target->bpf_func +
poke->adj_off, false);
BUG_ON(ret < 0);
}
- WRITE_ONCE(poke->ip_stable, true);
+ WRITE_ONCE(poke->tailcall_target_stable, true);
mutex_unlock(&array->aux->poke_mutex);
}
}
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a3f92500e493..366cef9b67ee 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -697,14 +697,14 @@ enum bpf_jit_poke_reason {
/* Descriptor of pokes pointing /into/ the JITed image. */
struct bpf_jit_poke_descriptor {
- void *ip;
+ void *tailcall_target;
union {
struct {
struct bpf_map *map;
u32 key;
} tail_call;
};
- bool ip_stable;
+ bool tailcall_target_stable;
u8 adj_off;
u16 reason;
u32 insn_idx;
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index e046fb7d17cd..60abf7fe12de 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -918,12 +918,13 @@ static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
* there could be danger of use after free otherwise.
* 2) Initially when we start tracking aux, the program
* is not JITed yet and also does not have a kallsyms
- * entry. We skip these as poke->ip_stable is not
- * active yet. The JIT will do the final fixup before
- * setting it stable. The various poke->ip_stable are
- * successively activated, so tail call updates can
- * arrive from here while JIT is still finishing its
- * final fixup for non-activated poke entries.
+ * entry. We skip these as poke->tailcall_target_stable
+ * is not active yet. The JIT will do the final fixup
+ * before setting it stable. The various
+ * poke->tailcall_target_stable are successively
+ * activated, so tail call updates can arrive from here
+ * while JIT is still finishing its final fixup for
+ * non-activated poke entries.
* 3) On program teardown, the program's kallsym entry gets
* removed out of RCU callback, but we can only untrack
* from sleepable context, therefore bpf_arch_text_poke()
@@ -940,7 +941,7 @@ static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
* 5) Any other error happening below from bpf_arch_text_poke()
* is a unexpected bug.
*/
- if (!READ_ONCE(poke->ip_stable))
+ if (!READ_ONCE(poke->tailcall_target_stable))
continue;
if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
continue;
@@ -948,7 +949,7 @@ static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
poke->tail_call.key != key)
continue;
- ret = bpf_arch_text_poke(poke->ip, BPF_MOD_JUMP,
+ ret = bpf_arch_text_poke(poke->tailcall_target, BPF_MOD_JUMP,
old ? (u8 *)old->bpf_func +
poke->adj_off : NULL,
new ? (u8 *)new->bpf_func +
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ed0b3578867c..a60c342e27e9 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -773,7 +773,8 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
if (size > poke_tab_max)
return -ENOSPC;
- if (poke->ip || poke->ip_stable || poke->adj_off)
+ if (poke->tailcall_target || poke->tailcall_target_stable ||
+ poke->adj_off)
return -EINVAL;
switch (poke->reason) {
--
2.20.1
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