From: Tushar Dave Date: Wed, 26 Oct 2016 17:49:27 +0000 (-0700) Subject: i40e: fix panic on SPARC while changing num of desc X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=2f7679ee2ec1bfc5042ff334bade395ef208d4fe;p=openwrt%2Fstaging%2Fblogic.git i40e: fix panic on SPARC while changing num of desc On SPARC, writel() should not be used to write directly to memory address but only to memory mapped I/O address otherwise it causes data access exception. Commit 147e81ec75689 ("i40e: Test memory before ethtool alloc succeeds") introduced a code that uses memory address to fake the HW tail address and attempt to write to that address using writel() causes kernel panic on SPARC. The issue is reproduced while changing number of descriptors using ethtool. This change resolves the panic by using HW read-only memory mapped I/O register to fake HW tail address instead memory address. e.g. > ethtool -G eth2 tx 2048 rx 2048 i40e 0000:03:00.2 eth2: Changing Tx descriptor count from 512 to 2048. i40e 0000:03:00.2 eth2: Changing Rx descriptor count from 512 to 2048 sun4v_data_access_exception: ADDR[fff8001f9734a000] CTX[0000] TYPE[0004], going. \|/ ____ \|/ "@'/ .. \`@" /_| \__/ |_\ \__U_/ ethtool(3273): Dax [#1] CPU: 9 PID: 3273 Comm: ethtool Tainted: G E 4.8.0-linux-net_temp+ #7 task: fff8001f96d7a660 task.stack: fff8001f97348000 TSTATE: 0000009911001601 TPC: 00000000103189e4 TNPC: 00000000103189e8 Y: 00000000 Tainted: G E TPC: g0: fff8001f4eb64000 g1: 00000000000007ff g2: fff8001f9734b92c g3: 00203e0000000000 g4: fff8001f96d7a660 g5: fff8001fa6704000 g6: fff8001f97348000 g7: 0000000000000001 o0: 0006000046706928 o1: 00000000db3e2000 o2: fff8001f00000000 o3: 0000000000002000 o4: 0000000000002000 o5: 0000000000000001 sp: fff8001f9734afc1 ret_pc: 0000000010318a64 RPC: l0: fff8001f4e8bffe0 l1: fff8001f4e8cffe0 l2: 00000000000007ff l3: 00000000ff000000 l4: 0000000000ff0000 l5: 000000000000ff00 l6: 0000000000cda6a8 l7: 0000000000e822f0 i0: fff8001f96380000 i1: 0000000000000000 i2: 00203edb00000000 i3: 0006000046706928 i4: 0000000002086320 i5: 0000000000e82370 i6: fff8001f9734b071 i7: 00000000103062d4 I7: Call Trace: [00000000103062d4] i40e_set_ringparam+0x3b4/0x540 [i40e] [000000000094e2f8] dev_ethtool+0x898/0xbe0 [0000000000965570] dev_ioctl+0x250/0x300 [0000000000923800] sock_do_ioctl+0x40/0x60 [000000000092427c] sock_ioctl+0x7c/0x280 [00000000005ef040] vfs_ioctl+0x20/0x60 [00000000005ef5d4] do_vfs_ioctl+0x194/0x4c0 [00000000005ef974] SyS_ioctl+0x74/0xa0 [0000000000406214] linux_sparc_syscall+0x34/0x44 Disabling lock debugging due to kernel taint Caller[00000000103062d4]: i40e_set_ringparam+0x3b4/0x540 [i40e] Caller[000000000094e2f8]: dev_ethtool+0x898/0xbe0 Caller[0000000000965570]: dev_ioctl+0x250/0x300 Caller[0000000000923800]: sock_do_ioctl+0x40/0x60 Caller[000000000092427c]: sock_ioctl+0x7c/0x280 Caller[00000000005ef040]: vfs_ioctl+0x20/0x60 Caller[00000000005ef5d4]: do_vfs_ioctl+0x194/0x4c0 Caller[00000000005ef974]: SyS_ioctl+0x74/0xa0 Caller[0000000000406214]: linux_sparc_syscall+0x34/0x44 Caller[0000000000107154]: 0x107154 Instruction DUMP: e43620c8 e436204a c45e2038 82102000 81cfe008 90086001 82102000 81cfe008 Kernel panic - not syncing: Fatal exception Signed-off-by: Tushar Dave Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c index f99c135718dd..92a2f03a06c8 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c +++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c @@ -1217,6 +1217,7 @@ static int i40e_set_ringparam(struct net_device *netdev, { struct i40e_ring *tx_rings = NULL, *rx_rings = NULL; struct i40e_netdev_priv *np = netdev_priv(netdev); + struct i40e_hw *hw = &np->vsi->back->hw; struct i40e_vsi *vsi = np->vsi; struct i40e_pf *pf = vsi->back; u32 new_rx_count, new_tx_count; @@ -1309,10 +1310,6 @@ static int i40e_set_ringparam(struct net_device *netdev, } for (i = 0; i < vsi->num_queue_pairs; i++) { - /* this is to allow wr32 to have something to write to - * during early allocation of Rx buffers - */ - u32 __iomem faketail = 0; struct i40e_ring *ring; u16 unused; @@ -1324,7 +1321,10 @@ static int i40e_set_ringparam(struct net_device *netdev, */ rx_rings[i].desc = NULL; rx_rings[i].rx_bi = NULL; - rx_rings[i].tail = (u8 __iomem *)&faketail; + /* this is to allow wr32 to have something to write to + * during early allocation of Rx buffers + */ + rx_rings[i].tail = hw->hw_addr + I40E_PRTGEN_STATUS; err = i40e_setup_rx_descriptors(&rx_rings[i]); if (err) goto rx_unwind;