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    Subject[PATCH v5 bpf-next 3/7] bpf: use size instead of pages in bpf_binary_header
    Date
    From: Song Liu <songliubraving@fb.com>

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

    Signed-off-by: Song Liu <songliubraving@fb.com>
    ---
    include/linux/filter.h | 6 +++---
    kernel/bpf/core.c | 11 +++++------
    2 files changed, 8 insertions(+), 9 deletions(-)

    diff --git a/include/linux/filter.h b/include/linux/filter.h
    index d23e999dc032..5855eb474c62 100644
    --- a/include/linux/filter.h
    +++ b/include/linux/filter.h
    @@ -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 *
    diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
    index b9c6a426a7dd..f252d8529b0b 100644
    --- a/kernel/bpf/core.c
    +++ b/kernel/bpf/core.c
    @@ -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
    --
    2.30.2
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