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bpf: Use size instead of pages in bpf_binary_header

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This is necessary to charge sub page memory for the BPF program.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-4-song@kernel.org
This commit is contained in:
Song Liu 2022-02-04 10:57:36 -08:00 committed by Alexei Starovoitov
parent 3486bedd99
commit ed2d9e1a26
2 changed files with 8 additions and 9 deletions
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6
include/linux/filter.h
View file

@ -548,7 +548,7 @@ struct sock_fprog_kern {
#define BPF_IMAGE_ALIGNMENT 8
struct bpf_binary_header {
u32 pages;
u32 size;
u8 image[] __aligned(BPF_IMAGE_ALIGNMENT);
};
@ -886,8 +886,8 @@ static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
set_vm_flush_reset_perms(hdr);
set_memory_ro((unsigned long)hdr, hdr->pages);
set_memory_x((unsigned long)hdr, hdr->pages);
set_memory_ro((unsigned long)hdr, hdr->size >> PAGE_SHIFT);
set_memory_x((unsigned long)hdr, hdr->size >> PAGE_SHIFT);
}
static inline struct bpf_binary_header *

11
kernel/bpf/core.c
View file

@ -543,7 +543,7 @@ bpf_prog_ksym_set_addr(struct bpf_prog *prog)
WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
prog->aux->ksym.start = (unsigned long) prog->bpf_func;
prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE;
prog->aux->ksym.end = addr + hdr->size;
}
static void
@ -866,7 +866,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
bpf_jit_fill_hole_t bpf_fill_ill_insns)
{
struct bpf_binary_header *hdr;
u32 size, hole, start, pages;
u32 size, hole, start;
WARN_ON_ONCE(!is_power_of_2(alignment) ||
alignment > BPF_IMAGE_ALIGNMENT);
@ -876,7 +876,6 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
* random section of illegal instructions.
*/
size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
pages = size / PAGE_SIZE;
if (bpf_jit_charge_modmem(size))
return NULL;
@ -889,7 +888,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
/* Fill space with illegal/arch-dep instructions. */
bpf_fill_ill_insns(hdr, size);
hdr->pages = pages;
hdr->size = size;
hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
PAGE_SIZE - sizeof(*hdr));
start = (get_random_int() % hole) & ~(alignment - 1);
@ -902,10 +901,10 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
void bpf_jit_binary_free(struct bpf_binary_header *hdr)
{
u32 pages = hdr->pages;
u32 size = hdr->size;
bpf_jit_free_exec(hdr);
bpf_jit_uncharge_modmem(pages << PAGE_SHIFT);
bpf_jit_uncharge_modmem(size);
}
/* This symbol is only overridden by archs that have different