android/android_kernel_samsung_sm8650
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Revert "bpf: Remove bpf trampoline selector"

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This reverts commit 8ea165e1f8 which is
commit 47e79cbeea4b3891ad476047f4c68543eb51c8e0 upstream.

It breaks the Android ABI and can be brought back in an abi-safe way in
the future if it is still needed.

Bug: 161946584
Change-Id: I6b0b4846d8ec26e44c6627b8b4cbb2c46cc01a13
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman 2023-09-05 09:37:47 +00:00
parent 17f0b3c7ee
commit c057db2f88
2 changed files with 8 additions and 4 deletions
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1
include/linux/bpf.h
View File

@ -942,6 +942,7 @@ struct bpf_trampoline {
int progs_cnt[BPF_TRAMP_MAX]; int progs_cnt[BPF_TRAMP_MAX];
/* Executable image of trampoline */ /* Executable image of trampoline */
struct bpf_tramp_image *cur_image; struct bpf_tramp_image *cur_image;
u64 selector;
struct module *mod; struct module *mod;
ANDROID_KABI_RESERVE(1); ANDROID_KABI_RESERVE(1);
}; };

11
kernel/bpf/trampoline.c
View File

@ -377,7 +377,7 @@ static void bpf_tramp_image_put(struct bpf_tramp_image *im)
call_rcu_tasks_trace(&im->rcu, __bpf_tramp_image_put_rcu_tasks); call_rcu_tasks_trace(&im->rcu, __bpf_tramp_image_put_rcu_tasks);
} }
static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key) static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
{ {
struct bpf_tramp_image *im; struct bpf_tramp_image *im;
struct bpf_ksym *ksym; struct bpf_ksym *ksym;
@ -404,7 +404,7 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key)
ksym = &im->ksym; ksym = &im->ksym;
INIT_LIST_HEAD_RCU(&ksym->lnode); INIT_LIST_HEAD_RCU(&ksym->lnode);
snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", key); snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu_%u", key, idx);
bpf_image_ksym_add(image, ksym); bpf_image_ksym_add(image, ksym);
return im; return im;
@ -434,10 +434,11 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut
err = unregister_fentry(tr, tr->cur_image->image); err = unregister_fentry(tr, tr->cur_image->image);
bpf_tramp_image_put(tr->cur_image); bpf_tramp_image_put(tr->cur_image);
tr->cur_image = NULL; tr->cur_image = NULL;
tr->selector = 0;
goto out; goto out;
} }
im = bpf_tramp_image_alloc(tr->key); im = bpf_tramp_image_alloc(tr->key, tr->selector);
if (IS_ERR(im)) { if (IS_ERR(im)) {
err = PTR_ERR(im); err = PTR_ERR(im);
goto out; goto out;
@ -475,7 +476,8 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut
set_memory_ro((long)im->image, 1); set_memory_ro((long)im->image, 1);
set_memory_x((long)im->image, 1); set_memory_x((long)im->image, 1);
WARN_ON(tr->cur_image && total == 0); WARN_ON(tr->cur_image && tr->selector == 0);
WARN_ON(!tr->cur_image && tr->selector);
if (tr->cur_image) if (tr->cur_image)
/* progs already running at this address */ /* progs already running at this address */
err = modify_fentry(tr, tr->cur_image->image, im->image, lock_direct_mutex); err = modify_fentry(tr, tr->cur_image->image, im->image, lock_direct_mutex);
@ -505,6 +507,7 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut
if (tr->cur_image) if (tr->cur_image)
bpf_tramp_image_put(tr->cur_image); bpf_tramp_image_put(tr->cur_image);
tr->cur_image = im; tr->cur_image = im;
tr->selector++;
out: out:
/* If any error happens, restore previous flags */ /* If any error happens, restore previous flags */
if (err) if (err)