Merge branch 'bpf-misc'

Daniel Borkmann says:

====================
Misc BPF improvements

This last series for this window adds various misc
improvements to BPF, one is to mark registered map and
prog types as __ro_after_init, another one for removing
cBPF stubs in eBPF JITs and moving the stub to the core
and last also improving JITs is to make generated images
visible to the kernel and kallsyms, so they can be
seen in traces. For details, please have a look at the
individual patches.

Thanks a lot!
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 113 insertions, 3 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 57d60dc5b600..909fc033173a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -8,10 +8,12 @@
 #define _LINUX_BPF_H 1
 
 #include <uapi/linux/bpf.h>
+
 #include <linux/workqueue.h>
 #include <linux/file.h>
 #include <linux/percpu.h>
 #include <linux/err.h>
+#include <linux/rbtree_latch.h>
 
 struct perf_event;
 struct bpf_map;
@@ -177,6 +179,8 @@ struct bpf_prog_aux {
 	atomic_t refcnt;
 	u32 used_map_cnt;
 	u32 max_ctx_offset;
+	struct latch_tree_node ksym_tnode;
+	struct list_head ksym_lnode;
 	const struct bpf_verifier_ops *ops;
 	struct bpf_map **used_maps;
 	struct bpf_prog *prog;
diff --git a/include/linux/filter.h b/include/linux/filter.h
index e4eb2546339a..0c1cc9143cb2 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -54,6 +54,12 @@ struct bpf_prog_aux;
 #define BPF_REG_AX		MAX_BPF_REG
 #define MAX_BPF_JIT_REG		(MAX_BPF_REG + 1)
 
+/* As per nm, we expose JITed images as text (code) section for
+ * kallsyms. That way, tools like perf can find it to match
+ * addresses.
+ */
+#define BPF_SYM_ELF_TYPE	't'
+
 /* BPF program can access up to 512 bytes of stack space. */
 #define MAX_BPF_STACK	512
 
@@ -555,6 +561,11 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 {
 	set_memory_rw((unsigned long)fp, fp->pages);
 }
+
+static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
+{
+	set_memory_rw((unsigned long)hdr, hdr->pages);
+}
 #else
 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 {
@@ -563,8 +574,21 @@ static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 {
 }
+
+static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
+{
+}
 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
 
+static inline struct bpf_binary_header *
+bpf_jit_binary_hdr(const struct bpf_prog *fp)
+{
+	unsigned long real_start = (unsigned long)fp->bpf_func;
+	unsigned long addr = real_start & PAGE_MASK;
+
+	return (void *)addr;
+}
+
 int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
 static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
 {
@@ -607,6 +631,7 @@ void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 
 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
+void bpf_jit_compile(struct bpf_prog *prog);
 bool bpf_helper_changes_pkt_data(void *func);
 
 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
@@ -616,6 +641,7 @@ void bpf_warn_invalid_xdp_action(u32 act);
 #ifdef CONFIG_BPF_JIT
 extern int bpf_jit_enable;
 extern int bpf_jit_harden;
+extern int bpf_jit_kallsyms;
 
 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 
@@ -625,7 +651,6 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 		     bpf_jit_fill_hole_t bpf_fill_ill_insns);
 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 
-void bpf_jit_compile(struct bpf_prog *fp);
 void bpf_jit_free(struct bpf_prog *fp);
 
 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
@@ -651,6 +676,11 @@ static inline bool bpf_jit_is_ebpf(void)
 # endif
 }
 
+static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
+{
+	return fp->jited && bpf_jit_is_ebpf();
+}
+
 static inline bool bpf_jit_blinding_enabled(void)
 {
 	/* These are the prerequisites, should someone ever have the
@@ -668,15 +698,91 @@ static inline bool bpf_jit_blinding_enabled(void)
 
 	return true;
 }
-#else
-static inline void bpf_jit_compile(struct bpf_prog *fp)
+
+static inline bool bpf_jit_kallsyms_enabled(void)
+{
+	/* There are a couple of corner cases where kallsyms should
+	 * not be enabled f.e. on hardening.
+	 */
+	if (bpf_jit_harden)
+		return false;
+	if (!bpf_jit_kallsyms)
+		return false;
+	if (bpf_jit_kallsyms == 1)
+		return true;
+
+	return false;
+}
+
+const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
+				 unsigned long *off, char *sym);
+bool is_bpf_text_address(unsigned long addr);
+int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+		    char *sym);
+
+static inline const char *
+bpf_address_lookup(unsigned long addr, unsigned long *size,
+		   unsigned long *off, char **modname, char *sym)
 {
+	const char *ret = __bpf_address_lookup(addr, size, off, sym);
+
+	if (ret && modname)
+		*modname = NULL;
+	return ret;
+}
+
+void bpf_prog_kallsyms_add(struct bpf_prog *fp);
+void bpf_prog_kallsyms_del(struct bpf_prog *fp);
+
+#else /* CONFIG_BPF_JIT */
+
+static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
+{
+	return false;
 }
 
 static inline void bpf_jit_free(struct bpf_prog *fp)
 {
 	bpf_prog_unlock_free(fp);
 }
+
+static inline bool bpf_jit_kallsyms_enabled(void)
+{
+	return false;
+}
+
+static inline const char *
+__bpf_address_lookup(unsigned long addr, unsigned long *size,
+		     unsigned long *off, char *sym)
+{
+	return NULL;
+}
+
+static inline bool is_bpf_text_address(unsigned long addr)
+{
+	return false;
+}
+
+static inline int bpf_get_kallsym(unsigned int symnum, unsigned long *value,
+				  char *type, char *sym)
+{
+	return -ERANGE;
+}
+
+static inline const char *
+bpf_address_lookup(unsigned long addr, unsigned long *size,
+		   unsigned long *off, char **modname, char *sym)
+{
+	return NULL;
+}
+
+static inline void bpf_prog_kallsyms_add(struct bpf_prog *fp)
+{
+}
+
+static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp)
+{
+}
 #endif /* CONFIG_BPF_JIT */
 
 #define BPF_ANC		BIT(15)