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-rw-r--r--arch/x86/net/bpf_jit_comp.c64
-rw-r--r--include/linux/bpf.h6
2 files changed, 52 insertions, 18 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 2e586f579945..f438bd3b7689 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -203,8 +203,9 @@ struct jit_context {
/* Maximum number of bytes emitted while JITing one eBPF insn */
#define BPF_MAX_INSN_SIZE 128
#define BPF_INSN_SAFETY 64
-/* number of bytes emit_call() needs to generate call instruction */
-#define X86_CALL_SIZE 5
+
+/* Number of bytes emit_patch() needs to generate instructions */
+#define X86_PATCH_SIZE 5
#define PROLOGUE_SIZE 25
@@ -215,7 +216,7 @@ struct jit_context {
static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf)
{
u8 *prog = *pprog;
- int cnt = X86_CALL_SIZE;
+ int cnt = X86_PATCH_SIZE;
/* BPF trampoline can be made to work without these nops,
* but let's waste 5 bytes for now and optimize later
@@ -480,64 +481,91 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
*pprog = prog;
}
-static int emit_call(u8 **pprog, void *func, void *ip)
+static int emit_patch(u8 **pprog, void *func, void *ip, u8 opcode)
{
u8 *prog = *pprog;
int cnt = 0;
s64 offset;
- offset = func - (ip + X86_CALL_SIZE);
+ offset = func - (ip + X86_PATCH_SIZE);
if (!is_simm32(offset)) {
pr_err("Target call %p is out of range\n", func);
return -EINVAL;
}
- EMIT1_off32(0xE8, offset);
+ EMIT1_off32(opcode, offset);
*pprog = prog;
return 0;
}
+static int emit_call(u8 **pprog, void *func, void *ip)
+{
+ return emit_patch(pprog, func, ip, 0xE8);
+}
+
+static int emit_jump(u8 **pprog, void *func, void *ip)
+{
+ return emit_patch(pprog, func, ip, 0xE9);
+}
+
int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *old_addr, void *new_addr)
{
- u8 old_insn[X86_CALL_SIZE] = {};
- u8 new_insn[X86_CALL_SIZE] = {};
+ int (*emit_patch_fn)(u8 **pprog, void *func, void *ip);
+ u8 old_insn[X86_PATCH_SIZE] = {};
+ u8 new_insn[X86_PATCH_SIZE] = {};
u8 *prog;
int ret;
if (!is_kernel_text((long)ip) &&
!is_bpf_text_address((long)ip))
- /* BPF trampoline in modules is not supported */
+ /* BPF poking in modules is not supported */
return -EINVAL;
+ 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;
+ }
+
if (old_addr) {
prog = old_insn;
- ret = emit_call(&prog, old_addr, (void *)ip);
+ ret = emit_patch_fn(&prog, old_addr, (void *)ip);
if (ret)
return ret;
}
if (new_addr) {
prog = new_insn;
- ret = emit_call(&prog, new_addr, (void *)ip);
+ ret = emit_patch_fn(&prog, new_addr, (void *)ip);
if (ret)
return ret;
}
+
ret = -EBUSY;
mutex_lock(&text_mutex);
switch (t) {
case BPF_MOD_NOP_TO_CALL:
- if (memcmp(ip, ideal_nops[NOP_ATOMIC5], X86_CALL_SIZE))
+ case BPF_MOD_NOP_TO_JUMP:
+ if (memcmp(ip, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE))
goto out;
- text_poke_bp(ip, new_insn, X86_CALL_SIZE, NULL);
+ text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL);
break;
case BPF_MOD_CALL_TO_CALL:
- if (memcmp(ip, old_insn, X86_CALL_SIZE))
+ case BPF_MOD_JUMP_TO_JUMP:
+ if (memcmp(ip, old_insn, X86_PATCH_SIZE))
goto out;
- text_poke_bp(ip, new_insn, X86_CALL_SIZE, NULL);
+ text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL);
break;
case BPF_MOD_CALL_TO_NOP:
- if (memcmp(ip, old_insn, X86_CALL_SIZE))
+ case BPF_MOD_JUMP_TO_NOP:
+ if (memcmp(ip, old_insn, X86_PATCH_SIZE))
goto out;
- text_poke_bp(ip, ideal_nops[NOP_ATOMIC5], X86_CALL_SIZE, NULL);
+ text_poke_bp(ip, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE,
+ NULL);
break;
}
ret = 0;
@@ -1394,7 +1422,7 @@ int arch_prepare_bpf_trampoline(void *image, struct btf_func_model *m, u32 flags
/* skip patched call instruction and point orig_call to actual
* body of the kernel function.
*/
- orig_call += X86_CALL_SIZE;
+ orig_call += X86_PATCH_SIZE;
prog = image;
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e89e86122233..7978b617caa8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1284,10 +1284,16 @@ static inline u32 bpf_xdp_sock_convert_ctx_access(enum bpf_access_type type,
#endif /* CONFIG_INET */
enum bpf_text_poke_type {
+ /* All call-related pokes. */
BPF_MOD_NOP_TO_CALL,
BPF_MOD_CALL_TO_CALL,
BPF_MOD_CALL_TO_NOP,
+ /* All jump-related pokes. */
+ BPF_MOD_NOP_TO_JUMP,
+ BPF_MOD_JUMP_TO_JUMP,
+ BPF_MOD_JUMP_TO_NOP,
};
+
int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *addr1, void *addr2);