bpf: Use size instead of pages in bpf_binary_header

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

diff --git a/include/linux/filter.h b/include/linux/filter.h
index d23e999..5855eb4 100644 (file)
--- 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 6ca0550..1419922 100644 (file)
--- 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