AcoSail/kernel_optimize_test
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bpf: Add struct bpf_ksym

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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>
This commit is contained in:
Jiri Olsa 2020-03-12 20:55:58 +01:00 committed by Alexei Starovoitov
parent 6a64037d4b
commit 535911c80a
2 changed files with 18 additions and 16 deletions
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6
include/linux/bpf.h
View File

@ -471,6 +471,11 @@ int arch_prepare_bpf_trampoline(void *image, void *image_end,
u64 notrace __bpf_prog_enter(void);
void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start);
struct bpf_ksym {
unsigned long start;
unsigned long end;
};
enum bpf_tramp_prog_type {
BPF_TRAMP_FENTRY,
BPF_TRAMP_FEXIT,
@ -653,6 +658,7 @@ struct bpf_prog_aux {
u32 size_poke_tab;
struct latch_tree_node ksym_tnode;
struct list_head ksym_lnode;
struct bpf_ksym ksym;
const struct bpf_prog_ops *ops;
struct bpf_map **used_maps;
struct bpf_prog *prog;

28
kernel/bpf/core.c
View File

@ -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;