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Support mips #107

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ojeda opened this issue Mar 14, 2021 · 2 comments
Open

Support mips #107

ojeda opened this issue Mar 14, 2021 · 2 comments
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• arch Related to a particular arch, `arch/` support in general...

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@ojeda
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ojeda commented Mar 14, 2021 •
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MIPS little-endian, both 32-bit and 64-bit, is supported by Debian, which means we should eventually support the mipsel and mips64el architectures.

Linux mips targets with official Ubuntu binutils etc. support:

Linux arch  QEMU target       LLVM target  Ubuntu binutils                   Example Rust triple
----------  ----------------  -----------  --------------------------------  -------------------------------

mips        mips-softmmu      Mips         binutils-mips-linux-gnu           mips-unknown-linux-gnu
mips        mipsel-softmmu    Mips         binutils-mipsel-linux-gnu         mipsel-unknown-linux-gnu
mips        mips64-softmmu    Mips         binutils-mips64-linux-gnuabi64    mips64-unknown-linux-gnuabi64
mips        mips64el-softmmu  Mips         binutils-mips64el-linux-gnuabi64  mips64el-unknown-linux-gnuabi64
@ojeda ojeda added upstream - optional • misc Related to other topics (e.g. CI). • arch Related to a particular arch, `arch/` support in general... and removed • misc Related to other topics (e.g. CI). prio: low labels Mar 14, 2021
ojeda pushed a commit that referenced this issue Feb 6, 2022
@davem330
net/smc: Forward wakeup to smc socket waitqueue after fallback
341adee 
When we replace TCP with SMC and a fallback occurs, there may be
some socket waitqueue entries remaining in smc socket->wq, such
as eppoll_entries inserted by userspace applications.

After the fallback, data flows over TCP/IP and only clcsocket->wq
will be woken up. Applications can't be notified by the entries
which were inserted in smc socket->wq before fallback. So we need
a mechanism to wake up smc socket->wq at the same time if some
entries remaining in it.

The current workaround is to transfer the entries from smc socket->wq
to clcsock->wq during the fallback. But this may cause a crash
like this:

 general protection fault, probably for non-canonical address 0xdead000000000100: 0000 [#1] PREEMPT SMP PTI
 CPU: 3 PID: 0 Comm: swapper/3 Kdump: loaded Tainted: G E     5.16.0+ #107
 RIP: 0010:__wake_up_common+0x65/0x170
 Call Trace:
  <IRQ>
  __wake_up_common_lock+0x7a/0xc0
  sock_def_readable+0x3c/0x70
  tcp_data_queue+0x4a7/0xc40
  tcp_rcv_established+0x32f/0x660
  ? sk_filter_trim_cap+0xcb/0x2e0
  tcp_v4_do_rcv+0x10b/0x260
  tcp_v4_rcv+0xd2a/0xde0
  ip_protocol_deliver_rcu+0x3b/0x1d0
  ip_local_deliver_finish+0x54/0x60
  ip_local_deliver+0x6a/0x110
  ? tcp_v4_early_demux+0xa2/0x140
  ? tcp_v4_early_demux+0x10d/0x140
  ip_sublist_rcv_finish+0x49/0x60
  ip_sublist_rcv+0x19d/0x230
  ip_list_rcv+0x13e/0x170
  __netif_receive_skb_list_core+0x1c2/0x240
  netif_receive_skb_list_internal+0x1e6/0x320
  napi_complete_done+0x11d/0x190
  mlx5e_napi_poll+0x163/0x6b0 [mlx5_core]
  __napi_poll+0x3c/0x1b0
  net_rx_action+0x27c/0x300
  __do_softirq+0x114/0x2d2
  irq_exit_rcu+0xb4/0xe0
  common_interrupt+0xba/0xe0
  </IRQ>
  <TASK>

The crash is caused by privately transferring waitqueue entries from
smc socket->wq to clcsock->wq. The owners of these entries, such as
epoll, have no idea that the entries have been transferred to a
different socket wait queue and still use original waitqueue spinlock
(smc socket->wq.wait.lock) to make the entries operation exclusive,
but it doesn't work. The operations to the entries, such as removing
from the waitqueue (now is clcsock->wq after fallback), may cause a
crash when clcsock waitqueue is being iterated over at the moment.

This patch tries to fix this by no longer transferring wait queue
entries privately, but introducing own implementations of clcsock's
callback functions in fallback situation. The callback functions will
forward the wakeup to smc socket->wq if clcsock->wq is actually woken
up and smc socket->wq has remaining entries.

Fixes: 2153bd1 ("net/smc: Transfer remaining wait queue entries during fallback")
Suggested-by: Karsten Graul <[email protected]>
Signed-off-by: Wen Gu <[email protected]>
Acked-by: Karsten Graul <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Sep 3, 2024
@FlyGoat @intel-lab-lkp
rust: Enable for MIPS
1597cb6 
Enable rust for linux by implement generate_rust_target.rs
and select relevant Kconfig options.

We don't use builtin target as there is no sutiable baremetal
target for us that can cover all ISA variants supported by kernel.

Link: Rust-for-Linux#107
Signed-off-by: Jiaxun Yang <[email protected]>
@FlyGoat
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FlyGoat commented Sep 4, 2024

Related discussion: rust-embedded/wg#792 (comment)

@FlyGoat
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FlyGoat commented Sep 4, 2024

Initial Patch: https://lore.kernel.org/linux-mips/[email protected]/

intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Sep 5, 2024
@FlyGoat @intel-lab-lkp
rust: Enable for MIPS
e8ff034 
Enable rust for linux by implement generate_rust_target.rs
and select relevant Kconfig options.

We don't use builtin target as there is no sutiable baremetal
target for us that can cover all ISA variants supported by kernel.

Link: Rust-for-Linux#107
Signed-off-by: Jiaxun Yang <[email protected]>
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