Commit 0740b642 authored by Andrii Nakryiko's avatar Andrii Nakryiko
Browse files

Merge branch 'bpf-arena-followups' 

Alexei Starovoitov says:

====================
bpf: arena followups.

From: Alexei Starovoitov <ast@kernel.org>

A set of follow ups to clean up bpf_arena and adjust to the latest LLVM.
====================

Link: https://lore.kernel.org/r/20240315021834.62988-1-alexei.starovoitov@gmail.com


Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
parents aae08491 a90c5845

kernel/bpf/arena.c

+18 −7
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ 


/* number of bytes addressable by LDX/STX insn with 16-bit 'off' field */

#define GUARD_SZ (1ull << sizeof(((struct bpf_insn *)0)->off) * 8)

#define KERN_VM_SZ ((1ull << 32) + GUARD_SZ)

#define KERN_VM_SZ (SZ_4G + GUARD_SZ)



struct bpf_arena {

	struct bpf_map map;
@@ -110,7 +110,7 @@ static struct bpf_map *arena_map_alloc(union bpf_attr *attr) 
		return ERR_PTR(-EINVAL);



	vm_range = (u64)attr->max_entries * PAGE_SIZE;

	if (vm_range > (1ull << 32))

	if (vm_range > SZ_4G)

		return ERR_PTR(-E2BIG);



	if ((attr->map_extra >> 32) != ((attr->map_extra + vm_range - 1) >> 32))
@@ -301,7 +301,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad 


	if (pgoff)

		return -EINVAL;

	if (len > (1ull << 32))

	if (len > SZ_4G)

		return -E2BIG;



	/* if user_vm_start was specified at arena creation time */
@@ -322,7 +322,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad 
	if (WARN_ON_ONCE(arena->user_vm_start))

		/* checks at map creation time should prevent this */

		return -EFAULT;

	return round_up(ret, 1ull << 32);

	return round_up(ret, SZ_4G);

}



static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
@@ -346,7 +346,7 @@ static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) 
		return -EBUSY;



	/* Earlier checks should prevent this */

	if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > (1ull << 32) || vma->vm_pgoff))

	if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > SZ_4G || vma->vm_pgoff))

		return -EFAULT;



	if (remember_vma(arena, vma))
@@ -420,7 +420,7 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt 
		if (uaddr & ~PAGE_MASK)

			return 0;

		pgoff = compute_pgoff(arena, uaddr);

		if (pgoff + page_cnt > page_cnt_max)

		if (pgoff > page_cnt_max - page_cnt)

			/* requested address will be outside of user VMA */

			return 0;

	}
@@ -447,7 +447,13 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt 
		goto out;



	uaddr32 = (u32)(arena->user_vm_start + pgoff * PAGE_SIZE);

	/* Earlier checks make sure that uaddr32 + page_cnt * PAGE_SIZE will not overflow 32-bit */

	/* Earlier checks made sure that uaddr32 + page_cnt * PAGE_SIZE - 1

	 * will not overflow 32-bit. Lower 32-bit need to represent

	 * contiguous user address range.

	 * Map these pages at kern_vm_start base.

	 * kern_vm_start + uaddr32 + page_cnt * PAGE_SIZE - 1 can overflow

	 * lower 32-bit and it's ok.

	 */

	ret = vm_area_map_pages(arena->kern_vm, kern_vm_start + uaddr32,

				kern_vm_start + uaddr32 + page_cnt * PAGE_SIZE, pages);

	if (ret) {
@@ -510,6 +516,11 @@ static void arena_free_pages(struct bpf_arena *arena, long uaddr, long page_cnt) 
		if (!page)

			continue;

		if (page_cnt == 1 && page_mapped(page)) /* mapped by some user process */

			/* Optimization for the common case of page_cnt==1:

			 * If page wasn't mapped into some user vma there

			 * is no need to call zap_pages which is slow. When

			 * page_cnt is big it's faster to do the batched zap.

			 */

			zap_pages(arena, full_uaddr, 1);

		vm_area_unmap_pages(arena->kern_vm, kaddr, kaddr + PAGE_SIZE);

		__free_page(page);

tools/bpf/bpftool/gen.c

+1 −1
Original line number Diff line number Diff line
@@ -121,7 +121,7 @@ static bool get_datasec_ident(const char *sec_name, char *buf, size_t buf_sz) 
	int i, n;



	/* recognize hard coded LLVM section name */

	if (strcmp(sec_name, ".arena.1") == 0) {

	if (strcmp(sec_name, ".addr_space.1") == 0) {

		/* this is the name to use in skeleton */

		snprintf(buf, buf_sz, "arena");

		return true;

tools/lib/bpf/libbpf.c

+1 −1
Original line number Diff line number Diff line
@@ -498,7 +498,7 @@ struct bpf_struct_ops { 
#define KSYMS_SEC ".ksyms"

#define STRUCT_OPS_SEC ".struct_ops"

#define STRUCT_OPS_LINK_SEC ".struct_ops.link"

#define ARENA_SEC ".arena.1"

#define ARENA_SEC ".addr_space.1"



enum libbpf_map_type {

	LIBBPF_MAP_UNSPEC,

tools/testing/selftests/bpf/bpf_arena_common.h

+1 −1
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ 
 */

#endif



#if defined(__BPF_FEATURE_ARENA_CAST) && !defined(BPF_ARENA_FORCE_ASM)

#if defined(__BPF_FEATURE_ADDR_SPACE_CAST) && !defined(BPF_ARENA_FORCE_ASM)

#define __arena __attribute__((address_space(1)))

#define cast_kern(ptr) /* nop for bpf prog. emitted by LLVM */

#define cast_user(ptr) /* nop for bpf prog. emitted by LLVM */

tools/testing/selftests/bpf/prog_tests/arena_htab.c

+5 −3
Original line number Diff line number Diff line
@@ -3,12 +3,14 @@ 
#include <test_progs.h>

#include <sys/mman.h>

#include <network_helpers.h>



#include <sys/user.h>

#ifndef PAGE_SIZE /* on some archs it comes in sys/user.h */

#include <unistd.h>

#define PAGE_SIZE getpagesize()

#endif

#include "arena_htab_asm.skel.h"

#include "arena_htab.skel.h"



#define PAGE_SIZE 4096



#include "bpf_arena_htab.h"



static void test_arena_htab_common(struct htab *htab)