Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2021-12-30

The following pull-request contains BPF updates for your *net-next* tree.

We've added 72 non-merge commits during the last 20 day(s) which contain
a total of 223 files changed, 3510 insertions(+), 1591 deletions(-).

The main changes are:

1) Automatic setrlimit in libbpf when bpf is memcg's in the kernel, from Andrii.

2) Beautify and de-verbose verifier logs, from Christy.

3) Composable verifier types, from Hao.

4) bpf_strncmp helper, from Hou.

5) bpf.h header dependency cleanup, from Jakub.

6) get_func_[arg|ret|arg_cnt] helpers, from Jiri.

7) Sleepable local storage, from KP.

8) Extend kfunc with PTR_TO_CTX, PTR_TO_MEM argument support, from Kumar.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 14 deletions

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index c1205414de10..ce1f86f245c9 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1976,7 +1976,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 				void *orig_call)
 {
 	int ret, i, nr_args = m->nr_args;
-	int stack_size = nr_args * 8;
+	int regs_off, ip_off, args_off, stack_size = nr_args * 8;
 	struct bpf_tramp_progs *fentry = &tprogs[BPF_TRAMP_FENTRY];
 	struct bpf_tramp_progs *fexit = &tprogs[BPF_TRAMP_FEXIT];
 	struct bpf_tramp_progs *fmod_ret = &tprogs[BPF_TRAMP_MODIFY_RETURN];
@@ -1991,14 +1991,39 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	if (!is_valid_bpf_tramp_flags(flags))
 		return -EINVAL;
 
+	/* Generated trampoline stack layout:
+	 *
+	 * RBP + 8         [ return address  ]
+	 * RBP + 0         [ RBP             ]
+	 *
+	 * RBP - 8         [ return value    ]  BPF_TRAMP_F_CALL_ORIG or
+	 *                                      BPF_TRAMP_F_RET_FENTRY_RET flags
+	 *
+	 *                 [ reg_argN        ]  always
+	 *                 [ ...             ]
+	 * RBP - regs_off  [ reg_arg1        ]  program's ctx pointer
+	 *
+	 * RBP - args_off  [ args count      ]  always
+	 *
+	 * RBP - ip_off    [ traced function ]  BPF_TRAMP_F_IP_ARG flag
+	 */
+
 	/* room for return value of orig_call or fentry prog */
 	save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
 	if (save_ret)
 		stack_size += 8;
 
+	regs_off = stack_size;
+
+	/* args count  */
+	stack_size += 8;
+	args_off = stack_size;
+
 	if (flags & BPF_TRAMP_F_IP_ARG)
 		stack_size += 8; /* room for IP address argument */
 
+	ip_off = stack_size;
+
 	if (flags & BPF_TRAMP_F_SKIP_FRAME)
 		/* skip patched call instruction and point orig_call to actual
 		 * body of the kernel function.
@@ -2012,23 +2037,25 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	EMIT4(0x48, 0x83, 0xEC, stack_size); /* sub rsp, stack_size */
 	EMIT1(0x53);		 /* push rbx */
 
+	/* Store number of arguments of the traced function:
+	 *   mov rax, nr_args
+	 *   mov QWORD PTR [rbp - args_off], rax
+	 */
+	emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_args);
+	emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -args_off);
+
 	if (flags & BPF_TRAMP_F_IP_ARG) {
 		/* Store IP address of the traced function:
 		 * mov rax, QWORD PTR [rbp + 8]
 		 * sub rax, X86_PATCH_SIZE
-		 * mov QWORD PTR [rbp - stack_size], rax
+		 * mov QWORD PTR [rbp - ip_off], rax
 		 */
 		emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, 8);
 		EMIT4(0x48, 0x83, 0xe8, X86_PATCH_SIZE);
-		emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -stack_size);
-
-		/* Continue with stack_size for regs storage, stack will
-		 * be correctly restored with 'leave' instruction.
-		 */
-		stack_size -= 8;
+		emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -ip_off);
 	}
 
-	save_regs(m, &prog, nr_args, stack_size);
+	save_regs(m, &prog, nr_args, regs_off);
 
 	if (flags & BPF_TRAMP_F_CALL_ORIG) {
 		/* arg1: mov rdi, im */
@@ -2040,7 +2067,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	}
 
 	if (fentry->nr_progs)
-		if (invoke_bpf(m, &prog, fentry, stack_size,
+		if (invoke_bpf(m, &prog, fentry, regs_off,
 			       flags & BPF_TRAMP_F_RET_FENTRY_RET))
 			return -EINVAL;
 
@@ -2050,7 +2077,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 		if (!branches)
 			return -ENOMEM;
 
-		if (invoke_bpf_mod_ret(m, &prog, fmod_ret, stack_size,
+		if (invoke_bpf_mod_ret(m, &prog, fmod_ret, regs_off,
 				       branches)) {
 			ret = -EINVAL;
 			goto cleanup;
@@ -2058,7 +2085,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	}
 
 	if (flags & BPF_TRAMP_F_CALL_ORIG) {
-		restore_regs(m, &prog, nr_args, stack_size);
+		restore_regs(m, &prog, nr_args, regs_off);
 
 		/* call original function */
 		if (emit_call(&prog, orig_call, prog)) {
@@ -2088,13 +2115,13 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	}
 
 	if (fexit->nr_progs)
-		if (invoke_bpf(m, &prog, fexit, stack_size, false)) {
+		if (invoke_bpf(m, &prog, fexit, regs_off, false)) {
 			ret = -EINVAL;
 			goto cleanup;
 		}
 
 	if (flags & BPF_TRAMP_F_RESTORE_REGS)
-		restore_regs(m, &prog, nr_args, stack_size);
+		restore_regs(m, &prog, nr_args, regs_off);
 
 	/* This needs to be done regardless. If there were fmod_ret programs,
 	 * the return value is only updated on the stack and still needs to be