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authorJiri Olsa <jolsa@kernel.org>2020-03-12 20:55:58 +0100
committerAlexei Starovoitov <ast@kernel.org>2020-03-13 12:49:51 -0700
commit535911c80ad4f5801700e9d827a1985bbff41519 (patch)
treebbb6ef548496d99a0d46e3d961748856fe8d285d /kernel/bpf
parent6a64037d4bf252bb8cf13917320c8e001da8997a (diff)
downloadlinux-535911c80ad4f5801700e9d827a1985bbff41519.tar.bz2
bpf: Add struct bpf_ksym
Adding 'struct bpf_ksym' object that will carry the kallsym information for bpf symbol. Adding the start and end address to begin with. It will be used by bpf_prog, bpf_trampoline, bpf_dispatcher objects. The symbol_start/symbol_end values were originally used to sort bpf_prog objects. For the address displayed in /proc/kallsyms we are using prog->bpf_func value. I'm using the bpf_func value for program symbol start instead of the symbol_start, because it makes no difference for sorting bpf_prog objects and we can use it directly as an address to display it in /proc/kallsyms. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200312195610.346362-4-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/core.c28
1 files changed, 12 insertions, 16 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 0f9ca46e1978..e587d6306d7c 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -523,18 +523,16 @@ int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
int bpf_jit_harden __read_mostly;
long bpf_jit_limit __read_mostly;
-static __always_inline void
-bpf_get_prog_addr_region(const struct bpf_prog *prog,
- unsigned long *symbol_start,
- unsigned long *symbol_end)
+static void
+bpf_prog_ksym_set_addr(struct bpf_prog *prog)
{
const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
unsigned long addr = (unsigned long)hdr;
WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
- *symbol_start = addr;
- *symbol_end = addr + hdr->pages * PAGE_SIZE;
+ prog->aux->ksym.start = (unsigned long) prog->bpf_func;
+ prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE;
}
void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
@@ -575,13 +573,10 @@ void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
static __always_inline unsigned long
bpf_get_prog_addr_start(struct latch_tree_node *n)
{
- unsigned long symbol_start, symbol_end;
const struct bpf_prog_aux *aux;
aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
- bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
-
- return symbol_start;
+ return aux->ksym.start;
}
static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
@@ -593,15 +588,13 @@ static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
{
unsigned long val = (unsigned long)key;
- unsigned long symbol_start, symbol_end;
const struct bpf_prog_aux *aux;
aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
- bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
- if (val < symbol_start)
+ if (val < aux->ksym.start)
return -1;
- if (val >= symbol_end)
+ if (val >= aux->ksym.end)
return 1;
return 0;
@@ -649,6 +642,8 @@ void bpf_prog_kallsyms_add(struct bpf_prog *fp)
!capable(CAP_SYS_ADMIN))
return;
+ bpf_prog_ksym_set_addr(fp);
+
spin_lock_bh(&bpf_lock);
bpf_prog_ksym_node_add(fp->aux);
spin_unlock_bh(&bpf_lock);
@@ -677,14 +672,15 @@ static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
unsigned long *off, char *sym)
{
- unsigned long symbol_start, symbol_end;
struct bpf_prog *prog;
char *ret = NULL;
rcu_read_lock();
prog = bpf_prog_kallsyms_find(addr);
if (prog) {
- bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
+ unsigned long symbol_start = prog->aux->ksym.start;
+ unsigned long symbol_end = prog->aux->ksym.end;
+
bpf_get_prog_name(prog, sym);
ret = sym;