fix sign in sdhci_bcm2708_raw_writel wait calculation #549

whitslack · 2014-03-25T07:54:07Z

The ns_wait variable is intended to hold a lower bound on the number of nanoseconds that have elapsed since the last sdhci register write. However, the actual calculation of it was incorrect, as the subtraction was inverted. This commit fixes the calculation.

Note that this correction has no bearing when running with the default cycle_delay of 2 and the default clock rate of 50 MHz, under which conditions ns_2clk is 40 nanoseconds and ns_wait, regardless of whether the subtraction is done correctly or incorrectly, cannot possibly be less than 40 except for during the one-microsecond period just before the tick counter wraps around to meet last_write_hpt (i.e., approximately 4295 seconds after the preceding sdhci register write). The correction in this commit only comes into play if ns_2clk > 1000, which requires a cycle_delay of 51 or greater when using the default clock rate. Under those conditions, sdhci_bcm2708_raw_writel will not wait for the full cycle_delay count if at least 1000 nanoseconds have elapsed since the last register write.

The ns_wait variable is intended to hold a lower bound on the number of nanoseconds that have elapsed since the last sdhci register write. However, the actual calculation of it was incorrect, as the subtraction was inverted. This commit fixes the calculation. Note that this correction has no bearing when running with the default cycle_delay of 2 and the default clock rate of 50 MHz, under which conditions ns_2clk is 40 nanoseconds and ns_wait, regardless of whether the subtraction is done correctly or incorrectly, cannot possibly be less than 40 except for during the one-microsecond period just before the tick counter wraps around to meet last_write_hpt (i.e., approximately 4295 seconds after the preceding sdhci register write). The correction in this commit only comes into play if ns_2clk > 1000, which requires a cycle_delay of 51 or greater when using the default clock rate. Under those conditions, sdhci_bcm2708_raw_writel will not wait for the full cycle_delay count if at least 1000 nanoseconds have elapsed since the last register write.

fix sign in sdhci_bcm2708_raw_writel wait calculation

kernel: fix sign in sdhci_bcm2708_raw_writel wait calculation see: raspberrypi/linux#549 firmware: audio_mixer: Support 8-bit input and float input and output. Support non-power of 2 channels

Currently, resource tree allocates memory blocks while iterating on the list. It leads to following kernel warning because memblock allocation also invokes memory block reservation API. [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/resource.c:795 __insert_resource+0x8e/0xd0 [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.0-00022-ge20097fb37e2-dirty #549 [ 0.000000] epc: c00125c2 ra : c001262c sp : c1c01f50 [ 0.000000] gp : c1d456e0 tp : c1c0a980 t0 : ffffcf20 [ 0.000000] t1 : 00000000 t2 : 00000000 s0 : c1c01f60 [ 0.000000] s1 : ffffcf00 a0 : ffffff00 a1 : c1c0c0c4 [ 0.000000] a2 : 80c12b15 a3 : 80402000 a4 : 80402000 [ 0.000000] a5 : c1c0c0c4 a6 : 80c12b15 a7 : f5faf600 [ 0.000000] s2 : c1c0c0c4 s3 : c1c0e000 s4 : c1009a80 [ 0.000000] s5 : c1c0c000 s6 : c1d48000 s7 : c1613b4c [ 0.000000] s8 : 00000fff s9 : 80000200 s10: c1613b40 [ 0.000000] s11: 00000000 t3 : c1d4a000 t4 : ffffffff This is also unnecessary as we can pre-compute the total memblocks required for each memory region and allocate it before the loop. It save precious boot time not going through memblock allocation code every time. Fixes: 00ab027 ("RISC-V: Add kernel image sections to the resource tree") Reviewed-by: Anup Patel <anup@brainfault.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

[ Upstream commit 6ef0505 ] pasid_mutex and dev->iommu->param->lock are held while unbinding mm is flushing IO page fault workqueue and waiting for all page fault works to finish. But an in-flight page fault work also need to hold the two locks while unbinding mm are holding them and waiting for the work to finish. This may cause an ABBA deadlock issue as shown below: idxd 0000:00:0a.0: unbind PASID 2 ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc7+ #549 Not tainted [ 186.615245] ---------- dsa_test/898 is trying to acquire lock: ffff888100d854e8 (&param->lock){+.+.}-{3:3}, at: iopf_queue_flush_dev+0x29/0x60 but task is already holding lock: ffffffff82b2f7c8 (pasid_mutex){+.+.}-{3:3}, at: intel_svm_unbind+0x34/0x1e0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (pasid_mutex){+.+.}-{3:3}: __mutex_lock+0x75/0x730 mutex_lock_nested+0x1b/0x20 intel_svm_page_response+0x8e/0x260 iommu_page_response+0x122/0x200 iopf_handle_group+0x1c2/0x240 process_one_work+0x2a5/0x5a0 worker_thread+0x55/0x400 kthread+0x13b/0x160 ret_from_fork+0x22/0x30 -> #1 (&param->fault_param->lock){+.+.}-{3:3}: __mutex_lock+0x75/0x730 mutex_lock_nested+0x1b/0x20 iommu_report_device_fault+0xc2/0x170 prq_event_thread+0x28a/0x580 irq_thread_fn+0x28/0x60 irq_thread+0xcf/0x180 kthread+0x13b/0x160 ret_from_fork+0x22/0x30 -> #0 (&param->lock){+.+.}-{3:3}: __lock_acquire+0x1134/0x1d60 lock_acquire+0xc6/0x2e0 __mutex_lock+0x75/0x730 mutex_lock_nested+0x1b/0x20 iopf_queue_flush_dev+0x29/0x60 intel_svm_drain_prq+0x127/0x210 intel_svm_unbind+0xc5/0x1e0 iommu_sva_unbind_device+0x62/0x80 idxd_cdev_release+0x15a/0x200 [idxd] __fput+0x9c/0x250 ____fput+0xe/0x10 task_work_run+0x64/0xa0 exit_to_user_mode_prepare+0x227/0x230 syscall_exit_to_user_mode+0x2c/0x60 do_syscall_64+0x48/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: &param->lock --> &param->fault_param->lock --> pasid_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(pasid_mutex); lock(&param->fault_param->lock); lock(pasid_mutex); lock(&param->lock); *** DEADLOCK *** 2 locks held by dsa_test/898: #0: ffff888100cc1cc0 (&group->mutex){+.+.}-{3:3}, at: iommu_sva_unbind_device+0x53/0x80 #1: ffffffff82b2f7c8 (pasid_mutex){+.+.}-{3:3}, at: intel_svm_unbind+0x34/0x1e0 stack backtrace: CPU: 2 PID: 898 Comm: dsa_test Not tainted 5.14.0-rc7+ #549 Hardware name: Intel Corporation Kabylake Client platform/KBL S DDR4 UD IMM CRB, BIOS KBLSE2R1.R00.X050.P01.1608011715 08/01/2016 Call Trace: dump_stack_lvl+0x5b/0x74 dump_stack+0x10/0x12 print_circular_bug.cold+0x13d/0x142 check_noncircular+0xf1/0x110 __lock_acquire+0x1134/0x1d60 lock_acquire+0xc6/0x2e0 ? iopf_queue_flush_dev+0x29/0x60 ? pci_mmcfg_read+0xde/0x240 __mutex_lock+0x75/0x730 ? iopf_queue_flush_dev+0x29/0x60 ? pci_mmcfg_read+0xfd/0x240 ? iopf_queue_flush_dev+0x29/0x60 mutex_lock_nested+0x1b/0x20 iopf_queue_flush_dev+0x29/0x60 intel_svm_drain_prq+0x127/0x210 ? intel_pasid_tear_down_entry+0x22e/0x240 intel_svm_unbind+0xc5/0x1e0 iommu_sva_unbind_device+0x62/0x80 idxd_cdev_release+0x15a/0x200 pasid_mutex protects pasid and svm data mapping data. It's unnecessary to hold pasid_mutex while flushing the workqueue. To fix the deadlock issue, unlock pasid_pasid during flushing the workqueue to allow the works to be handled. Fixes: d5b9e4b ("iommu/vt-d: Report prq to io-pgfault framework") Reported-and-tested-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Link: https://lore.kernel.org/r/20210826215918.4073446-1-fenghua.yu@intel.com Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20210828070622.2437559-3-baolu.lu@linux.intel.com [joro: Removed timing information from kernel log messages] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org>

ghollingworth added a commit that referenced this pull request Mar 25, 2014

Merge pull request #549 from whitslack/rpi-3.10.y

dea8280

fix sign in sdhci_bcm2708_raw_writel wait calculation

ghollingworth merged commit dea8280 into raspberrypi:rpi-3.10.y Mar 25, 2014

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fix sign in sdhci_bcm2708_raw_writel wait calculation #549

fix sign in sdhci_bcm2708_raw_writel wait calculation #549

whitslack commented Mar 25, 2014

fix sign in sdhci_bcm2708_raw_writel wait calculation #549

fix sign in sdhci_bcm2708_raw_writel wait calculation #549

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whitslack commented Mar 25, 2014