[PATCH 4.11 38/84] MIPS: pm-cps: Drop manual cache-line alignment of ready_count

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.11 38/84] MIPS: pm-cps: Drop manual cache-line alignment of ready_count
Date	2017-07-03 16:00 +0200
Message-ID	<tZa3r-2gz-87@gated-at.bofh.it> (permalink)
References	<tZ9TH-2c1-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Burton <paul.burton@imgtec.com>

commit 161c51ccb7a6faf45ffe09aa5cf1ad85ccdad503 upstream.

We allocate memory for a ready_count variable per-CPU, which is accessed
via a cached non-coherent TLB mapping to perform synchronisation between
threads within the core using LL/SC instructions. In order to ensure
that the variable is contained within its own data cache line we
allocate 2 lines worth of memory & align the resulting pointer to a line
boundary. This is however unnecessary, since kmalloc is guaranteed to
return memory which is at least cache-line aligned (see
ARCH_DMA_MINALIGN). Stop the redundant manual alignment.

Besides cleaning up the code & avoiding needless work, this has the side
effect of avoiding an arithmetic error found by Bryan on 64 bit systems
due to the 32 bit size of the former dlinesz. This led the ready_count
variable to have its upper 32b cleared erroneously for MIPS64 kernels,
causing problems when ready_count was later used on MIPS64 via cpuidle.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 3179d37ee1ed ("MIPS: pm-cps: add PM state entry code for CPS systems")
Reported-by: Bryan O'Donoghue <bryan.odonoghue@imgtec.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@imgtec.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15383/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/pm-cps.c |    9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

--- a/arch/mips/kernel/pm-cps.c
+++ b/arch/mips/kernel/pm-cps.c
@@ -56,7 +56,6 @@ DECLARE_BITMAP(state_support, CPS_PM_STA
  * state. Actually per-core rather than per-CPU.
  */
 static DEFINE_PER_CPU_ALIGNED(u32*, ready_count);
-static DEFINE_PER_CPU_ALIGNED(void*, ready_count_alloc);
 
 /* Indicates online CPUs coupled with the current CPU */
 static DEFINE_PER_CPU_ALIGNED(cpumask_t, online_coupled);
@@ -642,7 +641,6 @@ static int cps_pm_online_cpu(unsigned in
 {
 	enum cps_pm_state state;
 	unsigned core = cpu_data[cpu].core;
-	unsigned dlinesz = cpu_data[cpu].dcache.linesz;
 	void *entry_fn, *core_rc;
 
 	for (state = CPS_PM_NC_WAIT; state < CPS_PM_STATE_COUNT; state++) {
@@ -662,16 +660,11 @@ static int cps_pm_online_cpu(unsigned in
 	}
 
 	if (!per_cpu(ready_count, core)) {
-		core_rc = kmalloc(dlinesz * 2, GFP_KERNEL);
+		core_rc = kmalloc(sizeof(u32), GFP_KERNEL);
 		if (!core_rc) {
 			pr_err("Failed allocate core %u ready_count\n", core);
 			return -ENOMEM;
 		}
-		per_cpu(ready_count_alloc, core) = core_rc;
-
-		/* Ensure ready_count is aligned to a cacheline boundary */
-		core_rc += dlinesz - 1;
-		core_rc = (void *)((unsigned long)core_rc & ~(dlinesz - 1));
 		per_cpu(ready_count, core) = core_rc;
 	}

Thread

[PATCH 4.11 00/84] 4.11.9-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 15:50 +0200
  [PATCH 4.11 39/84] MIPS: Fix IRQ tracing & lockdep when rescheduling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 15:50 +0200
  [PATCH 4.11 13/84] net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 15:50 +0200
  [PATCH 4.11 61/84] ARM64: PCI: Fix struct acpi_pci_root_ops allocation failure path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 23/84] ipv6: fix calling in6_ifa_hold incorrectly for dad work Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 64/84] ARM: davinci: PM: Free resources in error handling path in davinci_pm_init Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 80/84] mtd: nand: fsmc: fix NAND width handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 50/84] dm thin: do not queue freed thin mapping for next stage processing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 47/84] x86/intel_rdt: Fix memory leak on mount failure Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 76/84] iommu/amd: Fix incorrect error handling in amd_iommu_bind_pasid() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 60/84] watchdog: bcm281xx: Fix use of uninitialized spinlock. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 67/84] Revert "x86/entry: Fix the end of the stack for newly forked tasks" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 78/84] infiniband: hns: avoid gcc-7.0.1 warning for uninitialized data Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 36/84] MIPS: head: Reorder instructions missing a delay slot Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 81/84] KVM: x86: fix emulation of RSM and IRET instructions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 58/84] xfrm: NULL dereference on allocation failure Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 69/84] x86/boot/KASLR: Fix kexec crash due to virt_addr calculation bug Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 75/84] iommu/dma: Dont reserve PCI I/O windows Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 74/84] ocfs2: fix deadlock caused by recursive locking in xattr Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 33/84] netfilter: synproxy: fix conntrackd interaction Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 72/84] x86/mm: Fix flush_tlb_page() on Xen Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 55/84] xfrm6: Fix IPv6 payload_len in xfrm6_transport_finish Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 46/84] gpiolib: fix filtering out unwanted events Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 73/84] ocfs2: o2hb: revert hb threshold to keep compatible Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 66/84] tools arch: Sync arch/x86/lib/memcpy_64.S with the kernel Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 79/84] mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 38/84] MIPS: pm-cps: Drop manual cache-line alignment of ready_count Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 65/84] ARM: davinci: PM: Do not free useful resources in normal path in davinci_pm_init Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 34/84] NFSv4.x/callback: Create the callback service through svc_create_pooled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 62/84] ARM64/ACPI: Fix BAD_MADT_GICC_ENTRY() macro implementation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 70/84] perf/x86: Fix spurious NMI with PEBS Load Latency event Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 31/84] ipv6: Do not leak throw route references Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 56/84] xfrm: move xfrm_garbage_collect out of xfrm_policy_flush Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 68/84] x86/mshyperv: Remove excess #includes from mshyperv.h Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 53/84] mm/vmalloc.c: huge-vmap: fail gracefully on unexpected huge vmap mappings Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 37/84] MIPS: Avoid accidental raw backtrace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 40/84] ALSA: hda - Fix endless loop of codec configure Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 71/84] x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 77/84] iommu/amd: Fix interrupt remapping when disable guest_mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 51/84] x86/mm: Fix boot crash caused by incorrect loop count calculation in sync_global_pgds() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:00 +0200
  [PATCH 4.11 25/84] net/mlx5e: Fix min inline value for VF rep SQs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 16/84] net/mlx5e: Fix wrong indications in DIM due to counter wraparound Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 45/84] ovl: copy-up: dont unlock between lookup and link Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 20/84] igmp: add a missing spin_lock_init() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 01/84] net: dont call strlen on non-terminated string in dev_set_alias() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 22/84] net: dont global ICMP rate limit packets originating from loopback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 06/84] net: Zero ifla_vf_info in rtnl_fill_vfinfo() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 05/84] decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skb Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 27/84] net/mlx5: Wait for FW readiness before initializing command interface Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 43/84] NFSv4.1: Fix a race in nfs4_proc_layoutget Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 17/84] net/mlx5: Enable 4K UAR only when page size is bigger than 4K Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 32/84] rtnetlink: add IFLA_GROUP to ifla_policy Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 41/84] ALSA: hda - set input_path bitmap to zero after moving it to new place Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 08/84] net: vrf: Make add_fib_rules per network namespace flag Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 04/84] mac80211: free netdev on dev_alloc_name() error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 19/84] igmp: acquire pmc lock for ip_mc_clear_src() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 02/84] net: Fix inconsistent teardown and release of private netdev state. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 29/84] decnet: always not take dst->__refcnt when inserting dst into hash table Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 44/84] Revert "NFS: nfs_rename() handle -ERESTARTSYS dentry left behind" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 14/84] net/mlx5: Remove several module events out of ethtool stats Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 09/84] af_unix: Add sockaddr length checks before accessing sa_family in bind and connect handlers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 18/84] proc: snmp6: Use correct type in memset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 42/84] NFSv4.2: Dont send mode again in post-EXCLUSIVE4_1 SETATTR with umask Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  [PATCH 4.11 07/84] net: ipv6: Release route when device is unregistering Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-03 16:10 +0200
  Re: [PATCH 4.11 00/84] 4.11.9-stable review Guenter Roeck <linux@roeck-us.net> - 2017-07-03 22:00 +0200
    Re: [PATCH 4.11 00/84] 4.11.9-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-04 10:00 +0200

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