From bd2767ec3df2775bc336f441f9068a989ccb919d Mon Sep 17 00:00:00 2001 From: Linu Cherian Date: Wed, 23 Aug 2023 09:59:48 +0530 Subject: [PATCH 1/2] coresight: Fix run time warnings while reusing ETR buffer Fix the below warning by avoding calls to tmc_etr_enable_hw, if we are reusing the ETR buffer for multiple sources in sysfs mode. echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink echo 1 > /sys/bus/coresight/devices/ete1/enable_source echo 1 > /sys/bus/coresight/devices/ete2/enable_source [ 166.918290] ------------[ cut here ]------------ [ 166.922905] WARNING: CPU: 4 PID: 2288 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1037 tmc_etr_enable_hw+0xb0/0xc8 [ 166.933862] Modules linked in: [ 166.936911] CPU: 4 PID: 2288 Comm: bash Not tainted 6.5.0-rc7 #132 [ 166.943084] Hardware name: Marvell CN106XX board (DT) [ 166.948127] pstate: 834000c9 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--) [ 166.955083] pc : tmc_etr_enable_hw+0xb0/0xc8 [ 166.959345] lr : tmc_enable_etr_sink+0x134/0x210 snip.. 167.038545] Call trace: [ 167.040982] tmc_etr_enable_hw+0xb0/0xc8 [ 167.044897] tmc_enable_etr_sink+0x134/0x210 [ 167.049160] coresight_enable_path+0x160/0x278 [ 167.053596] coresight_enable+0xd4/0x298 [ 167.057510] enable_source_store+0x54/0xa0 [ 167.061598] dev_attr_store+0x20/0x40 [ 167.065254] sysfs_kf_write+0x4c/0x68 [ 167.068909] kernfs_fop_write_iter+0x128/0x200 [ 167.073345] vfs_write+0x1ac/0x2f8 [ 167.076739] ksys_write+0x74/0x110 [ 167.080132] __arm64_sys_write+0x24/0x38 [ 167.084045] invoke_syscall.constprop.0+0x58/0xf8 [ 167.088744] do_el0_svc+0x60/0x160 [ 167.092137] el0_svc+0x40/0x170 [ 167.095273] el0t_64_sync_handler+0x100/0x130 [ 167.099621] el0t_64_sync+0x190/0x198 [ 167.103277] ---[ end trace 0000000000000000 ]--- -bash: echo: write error: Device or resource busy Fixes: 296b01fd106e ("coresight: Refactor out buffer allocation function for ETR") Signed-off-by: Linu Cherian Reviewed-by: James Clark Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20230823042948.12879-1-lcherian@marvell.com --- .../hwtracing/coresight/coresight-tmc-etr.c | 24 ++++++++++--------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 66dc5f97a009..6132c5b3db9c 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1173,16 +1173,6 @@ static struct etr_buf *tmc_etr_get_sysfs_buffer(struct coresight_device *csdev) goto out; } - /* - * In sysFS mode we can have multiple writers per sink. Since this - * sink is already enabled no memory is needed and the HW need not be - * touched, even if the buffer size has changed. - */ - if (drvdata->mode == CS_MODE_SYSFS) { - atomic_inc(&csdev->refcnt); - goto out; - } - /* * If we don't have a buffer or it doesn't match the requested size, * use the buffer allocated above. Otherwise reuse the existing buffer. @@ -1204,7 +1194,7 @@ out: static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev) { - int ret; + int ret = 0; unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); struct etr_buf *sysfs_buf = tmc_etr_get_sysfs_buffer(csdev); @@ -1213,12 +1203,24 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev) return PTR_ERR(sysfs_buf); spin_lock_irqsave(&drvdata->spinlock, flags); + + /* + * In sysFS mode we can have multiple writers per sink. Since this + * sink is already enabled no memory is needed and the HW need not be + * touched, even if the buffer size has changed. + */ + if (drvdata->mode == CS_MODE_SYSFS) { + atomic_inc(&csdev->refcnt); + goto out; + } + ret = tmc_etr_enable_hw(drvdata, sysfs_buf); if (!ret) { drvdata->mode = CS_MODE_SYSFS; atomic_inc(&csdev->refcnt); } +out: spin_unlock_irqrestore(&drvdata->spinlock, flags); if (!ret) From e5028011885a85032aa3c1b7e3e493bcdacb4a0a Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Thu, 17 Aug 2023 17:19:51 +0100 Subject: [PATCH 2/2] coresight: tmc-etr: Disable warnings for allocation failures Running the following command on Juno triggers the warning: $ perf record -e cs_etm// -m ,128M ... ------------[ cut here ]------------ WARNING: CPU: 1 PID: 412 at mm/page_alloc.c:4453 __alloc_pages+0x334/0x1420 CPU: 1 PID: 412 Comm: perf Not tainted 6.5.0-rc3+ #181 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019 pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __alloc_pages+0x334/0x1420 lr : dma_common_alloc_pages+0x108/0x138 sp : ffffffc087fb7440 x29: ffffffc087fb7440 x28: 0000000000000000 x27: ffffffc07e48fba0 x26: 0000000000000001 x25: 000000000000000f x24: ffffffc081f24880 x23: 0000000000000cc0 x22: ffffff88012b6f08 x21: 0000000008000000 x20: ffffff8801433000 x19: 0000000000000000 x18: 0000000000000000 x17: ffffffc080316e5c x16: ffffffc07e46406c x15: ffffffc0803af580 x14: ffffffc08036b460 x13: ffffffc080025cbc x12: ffffffb8108c3fc4 x11: 1ffffff8108c3fc3 x10: 1ffffff810ff6eac x9 : 00000000f204f204 x8 : 000000000000f204 x7 : 00000000f2f2f2f2 x6 : 00000000f3f3f3f3 x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000cc0 x1 : 0000000000000000 x0 : ffffffc085333000 Call trace: __alloc_pages+0x334/0x1420 dma_common_alloc_pages+0x108/0x138 __dma_alloc_pages+0xf4/0x108 dma_alloc_pages+0x18/0x30 tmc_etr_alloc_flat_buf+0xa0/0x190 [coresight_tmc] tmc_alloc_etr_buf.constprop.0+0x124/0x298 [coresight_tmc] alloc_etr_buf.constprop.0.isra.0+0x88/0xc8 [coresight_tmc] tmc_alloc_etr_buffer+0x164/0x2f0 [coresight_tmc] etm_setup_aux+0x32c/0x520 [coresight] rb_alloc_aux+0x29c/0x3f8 perf_mmap+0x59c/0xce0 mmap_region+0x340/0x10e0 do_mmap+0x48c/0x580 vm_mmap_pgoff+0x160/0x248 ksys_mmap_pgoff+0x1e8/0x278 __arm64_sys_mmap+0x8c/0xb8 With the flat mode, we only attempt to allocate large memory if there is an IOMMU connected to the ETR. If the allocation fails, we always have a fallback path and return an error if nothing else worked. So, suppress the warning for flat mode allocations. Cc: Mike Leach Cc: James Clark Cc: Anshuman Khandual Signed-off-by: Suzuki K Poulose Reviewed-by: James Clark Link: https://lore.kernel.org/r/20230817161951.658534-1-suzuki.poulose@arm.com --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 6132c5b3db9c..8311e1028ddb 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -610,7 +610,8 @@ static int tmc_etr_alloc_flat_buf(struct tmc_drvdata *drvdata, flat_buf->vaddr = dma_alloc_noncoherent(real_dev, etr_buf->size, &flat_buf->daddr, - DMA_FROM_DEVICE, GFP_KERNEL); + DMA_FROM_DEVICE, + GFP_KERNEL | __GFP_NOWARN); if (!flat_buf->vaddr) { kfree(flat_buf); return -ENOMEM;