[PATCH 5.4 040/191] net: make socket read/write_iter() honor IOCB_NOWAIT

[PATCH 5.4 040/191] net: make socket read/write_iter() honor IOCB_NOWAIT

[Greg Kroah-Hartman]

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit ebfcd8955c0b52eb793bcbc9e71140e3d0cdb228 ]

The socket read/write helpers only look at the file O_NONBLOCK. not
the iocb IOCB_NOWAIT flag. This breaks users like preadv2/pwritev2
and io_uring that rely on not having the file itself marked nonblocking,
but rather the iocb itself.

Cc: netdev@vger.kernel.org
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index d7a106028f0e..ca8de9e1582d 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -955,7 +955,7 @@ static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
 			     .msg_iocb = iocb};
 	ssize_t res;
 
-	if (file->f_flags & O_NONBLOCK)
+	if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT))
 		msg.msg_flags = MSG_DONTWAIT;
 
 	if (iocb->ki_pos != 0)
@@ -980,7 +980,7 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (iocb->ki_pos != 0)
 		return -ESPIPE;
 
-	if (file->f_flags & O_NONBLOCK)
+	if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT))
 		msg.msg_flags = MSG_DONTWAIT;
 
 	if (sock->type == SOCK_SEQPACKET)
-- 
2.20.1

[PATCH 5.4 076/191] MIPS: BPF: Disable MIPS32 eBPF JIT

[Greg Kroah-Hartman]

From: Paul Burton <paulburton@kernel.org>

commit f8fffebdea752a25757b906f3dffecf1a59a6194 upstream.

Commit 716850ab104d ("MIPS: eBPF: Initial eBPF support for MIPS32
architecture.") enabled our eBPF JIT for MIPS32 kernels, whereas it has
previously only been availailable for MIPS64. It was my understanding at
the time that the BPF test suite was passing & JITing a comparable
number of tests to our cBPF JIT [1], but it turns out that was not the
case.

The eBPF JIT has a number of problems on MIPS32:

- Most notably various code paths still result in emission of MIPS64
  instructions which will cause reserved instruction exceptions & kernel
  panics when run on MIPS32 CPUs.

- The eBPF JIT doesn't account for differences between the O32 ABI used
  by MIPS32 kernels versus the N64 ABI used by MIPS64 kernels. Notably
  arguments beyond the first 4 are passed on the stack in O32, and this
  is entirely unhandled when JITing a BPF_CALL instruction. Stack space
  must be reserved for arguments even if they all fit in registers, and
  the callee is free to assume that stack space has been reserved for
  its use - with the eBPF JIT this is not the case, so calling any
  function can result in clobbering values on the stack & unpredictable
  behaviour. Function arguments in eBPF are always 64-bit values which
  is also entirely unhandled - the JIT still uses a single (32-bit)
  register per argument. As a result all function arguments are always
  passed incorrectly when JITing a BPF_CALL instruction, leading to
  kernel crashes or strange behavior.

- The JIT attempts to bail our on use of ALU64 instructions or 64-bit
  memory access instructions. The code doing this at the start of
  build_one_insn() incorrectly checks whether BPF_OP() equals BPF_DW,
  when it should really be checking BPF_SIZE() & only doing so when
  BPF_CLASS() is one of BPF_{LD,LDX,ST,STX}. This results in false
  positives that cause more bailouts than intended, and that in turns
  hides some of the problems described above.

- The kernel's cBPF->eBPF translation makes heavy use of 64-bit eBPF
  instructions that the MIPS32 eBPF JIT bails out on, leading to most
  cBPF programs not being JITed at all.

Until these problems are resolved, revert the enabling of the eBPF JIT
on MIPS32 done by commit 716850ab104d ("MIPS: eBPF: Initial eBPF support
for MIPS32 architecture.").

Note that this does not undo the changes made to the eBPF JIT by that
commit, since they are a useful starting point to providing MIPS32
support - they're just not nearly complete.

[1] https://lore.kernel.org/linux-mips/MWHPR2201MB13583388481F01A422CE7D66D4410@MWHPR2201MB1358.namprd22.prod.outlook.com/

Signed-off-by: Paul Burton <paulburton@kernel.org>
Fixes: 716850ab104d ("MIPS: eBPF: Initial eBPF support for MIPS32 architecture.")
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Hassan Naveed <hnaveed@wavecomp.com>
Cc: Tony Ambardar <itugrok@yahoo.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: <stable@vger.kernel.org> # v5.2+
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -46,7 +46,7 @@ config MIPS
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES
 	select HAVE_ASM_MODVERSIONS
-	select HAVE_EBPF_JIT if (!CPU_MICROMIPS)
+	select HAVE_EBPF_JIT if (64BIT && !CPU_MICROMIPS)
 	select HAVE_CONTEXT_TRACKING
 	select HAVE_COPY_THREAD_TLS
 	select HAVE_C_RECORDMCOUNT

[PATCH 5.4 077/191] MIPS: BPF: eBPF JIT: check for MIPS ISA compliance in Kconfig

[Greg Kroah-Hartman]

From: Alexander Lobakin <alobakin@dlink.ru>

commit f596cf0d8062cb5d0a4513a8b3afca318c13be10 upstream.

It is completely wrong to check for compile-time MIPS ISA revision in
the body of bpf_int_jit_compile() as it may lead to get MIPS JIT fully
omitted by the CC while the rest system will think that the JIT is
actually present and works [1].
We can check if the selected CPU really supports MIPS eBPF JIT at
configure time and avoid such situations when kernel can be built
without both JIT and interpreter, but with CONFIG_BPF_SYSCALL=y.

[1] https://lore.kernel.org/linux-mips/09d713a59665d745e21d021deeaebe0a@dlink.ru/

Fixes: 716850ab104d ("MIPS: eBPF: Initial eBPF support for MIPS32 architecture.")
Cc: <stable@vger.kernel.org> # v5.2+
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Hassan Naveed <hnaveed@wavecomp.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: bpf@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/Kconfig        |    2 +-
 arch/mips/net/ebpf_jit.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -46,7 +46,7 @@ config MIPS
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES
 	select HAVE_ASM_MODVERSIONS
-	select HAVE_EBPF_JIT if (64BIT && !CPU_MICROMIPS)
+	select HAVE_EBPF_JIT if 64BIT && !CPU_MICROMIPS && TARGET_ISA_REV >= 2
 	select HAVE_CONTEXT_TRACKING
 	select HAVE_COPY_THREAD_TLS
 	select HAVE_C_RECORDMCOUNT
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c
@@ -1803,7 +1803,7 @@ struct bpf_prog *bpf_int_jit_compile(str
 	unsigned int image_size;
 	u8 *image_ptr;
 
-	if (!prog->jit_requested || MIPS_ISA_REV < 2)
+	if (!prog->jit_requested)
 		return prog;
 
 	tmp = bpf_jit_blind_constants(prog);