[PATCH AUTOSEL 6.1 03/19] coresight: tmc-etr: Disable warnings for allocation failures

Sasha Levin
2023-10-18T14:15:27Z

From: Suzuki K Poulose <suzuki.poulose@arm.com>

[ Upstream commit e5028011885a85032aa3c1b7e3e493bcdacb4a0a ]

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 <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20230817161951.658534-1-suzuki.poulose@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 1be0e5e0e80b2..c88a6afb29512 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;
--
2.40.1