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UPSTREAM: fixup! BACKPORT: bpf: Simplify __bpf_arch_text_poke poke type handling

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Change-Id: I86c1a7a5b1f8ab10d3176cc39bca665d913db40a
This commit is contained in:
Daniel Borkmann 2019-11-24 01:39:42 +01:00 • committed by basamaryan
commit 8642e4d3bc
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GPG key ID: 210D5384FB2A5885
1 changed files with 25 additions and 60 deletions
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85
arch/x86/net/bpf_jit_comp.c
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@ -284,76 +284,42 @@ static int __bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *old_addr, void *new_addr,
const bool text_live)
{
int (*emit_patch_fn)(u8 **pprog, void *func, void *ip);
const u8 *nop_insn = ideal_nops[NOP_ATOMIC5];
u8 old_insn[X86_PATCH_SIZE] = {};
u8 new_insn[X86_PATCH_SIZE] = {};
u8 old_insn[X86_PATCH_SIZE];
u8 new_insn[X86_PATCH_SIZE];
u8 *prog;
int ret;
switch (t) {
case BPF_MOD_NOP_TO_CALL ... BPF_MOD_CALL_TO_NOP:
emit_patch_fn = emit_call;
break;
case BPF_MOD_NOP_TO_JUMP ... BPF_MOD_JUMP_TO_NOP:
emit_patch_fn = emit_jump;
break;
default:
return -ENOTSUPP;
memcpy(old_insn, nop_insn, X86_PATCH_SIZE);
if (old_addr) {
prog = old_insn;
ret = t == BPF_MOD_CALL ?
emit_call(&prog, old_addr, ip) :
emit_jump(&prog, old_addr, ip);
if (ret)
return ret;
}
switch (t) {
case BPF_MOD_NOP_TO_CALL:
case BPF_MOD_NOP_TO_JUMP:
if (!old_addr && new_addr) {
memcpy(old_insn, nop_insn, X86_PATCH_SIZE);
prog = new_insn;
ret = emit_patch_fn(&prog, new_addr, ip);
if (ret)
return ret;
break;
}
return -ENXIO;
case BPF_MOD_CALL_TO_CALL:
case BPF_MOD_JUMP_TO_JUMP:
if (old_addr && new_addr) {
prog = old_insn;
ret = emit_patch_fn(&prog, old_addr, ip);
if (ret)
return ret;
prog = new_insn;
ret = emit_patch_fn(&prog, new_addr, ip);
if (ret)
return ret;
break;
}
return -ENXIO;
case BPF_MOD_CALL_TO_NOP:
case BPF_MOD_JUMP_TO_NOP:
if (old_addr && !new_addr) {
memcpy(new_insn, nop_insn, X86_PATCH_SIZE);
prog = old_insn;
ret = emit_patch_fn(&prog, old_addr, ip);
if (ret)
return ret;
break;
}
return -ENXIO;
default:
return -ENOTSUPP;
memcpy(new_insn, nop_insn, X86_PATCH_SIZE);
if (new_addr) {
prog = new_insn;
ret = t == BPF_MOD_CALL ?
emit_call(&prog, new_addr, ip) :
emit_jump(&prog, new_addr, ip);
if (ret)
return ret;
}
ret = -EBUSY;
mutex_lock(&text_mutex);
if (memcmp(ip, old_insn, X86_PATCH_SIZE))
goto out;
if (text_live)
text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL);
else
memcpy(ip, new_insn, X86_PATCH_SIZE);
if (memcmp(ip, new_insn, X86_PATCH_SIZE)) {
if (text_live)
text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL);
else
memcpy(ip, new_insn, X86_PATCH_SIZE);
}
ret = 0;
out:
mutex_unlock(&text_mutex);
@ -480,7 +446,6 @@ static void emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor *poke,
static void bpf_tail_call_direct_fixup(struct bpf_prog *prog)
{
static const enum bpf_text_poke_type type = BPF_MOD_NOP_TO_JUMP;
struct bpf_jit_poke_descriptor *poke;
struct bpf_array *array;
struct bpf_prog *target;
@ -505,7 +470,7 @@ static void bpf_tail_call_direct_fixup(struct bpf_prog *prog)
* read-only. Both modifications on the given image
* are under text_mutex to avoid interference.
*/
ret = __bpf_arch_text_poke(poke->ip, type, NULL,
ret = __bpf_arch_text_poke(poke->ip, BPF_MOD_JUMP, NULL,
(u8 *)target->bpf_func +
poke->adj_off, false);
BUG_ON(ret < 0);