Dear Alexander,
Am 10.04.21 um 23:11 schrieb Alexander Monakov:
print_iommu_info prints the EFR register and then the decoded list of
features on a separate line:
pci 0000:00:00.2: AMD-Vi: Extended features (0x206d73ef22254ade):
PPR X2APIC NX GT IA GA PC GA_vAPIC
The second line is emitted via 'pr_cont', which causes it to have a
different ('warn') loglevel compared to the previous line ('info').
Commit 9a295ff0ffc9 attempted to rectify this by removing the newline
from the pci_info format string, but this doesn't work, as pci_info
calls implicitly append a newline anyway.
Hmm, did I really screw that up during my testing? I am sorry about that.
I tried to wrap my head around, where the newline is implicitly
appended, and only found the definitions below.
include/linux/pci.h:#define pci_info(pdev, fmt, arg...)
dev_info(&(pdev)->dev, fmt, ##arg)
include/linux/dev_printk.h:#define dev_info(dev, fmt, ...)
\
include/linux/dev_printk.h: _dev_info(dev, dev_fmt(fmt),
##__VA_ARGS__)
include/linux/dev_printk.h:__printf(2, 3) __cold
include/linux/dev_printk.h:void _dev_info(const struct device *dev,
const char *fmt, ...);
include/linux/compiler_attributes.h:#define __printf(a, b)
__attribute__((__format__(printf, a, b)))
Restore the newline, and call pr_info with empty format string to set
the loglevel for subsequent pr_cont calls. The same solution is used in
EFI and uvesafb drivers.
Thank you for fixing this.
Fixes: 9a295ff0ffc9 ("iommu/amd: Print extended features in one line to fix
divergent log levels")
Signed-off-by: Alexander Monakov <amona...@ispras.ru>
Cc: Paul Menzel <pmen...@molgen.mpg.de>
Cc: Joerg Roedel <jroe...@suse.de>
Cc: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
Cc: io...@lists.linux-foundation.org
---
drivers/iommu/amd/init.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 596d0c413473..a25e241eff1c 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -1929,8 +1929,11 @@ static void print_iommu_info(void)
pci_info(pdev, "Found IOMMU cap 0x%hx\n", iommu->cap_ptr);
if (iommu->cap & (1 << IOMMU_CAP_EFR)) {
- pci_info(pdev, "Extended features (%#llx):",
+ pci_info(pdev, "Extended features (%#llx):\n",
iommu->features);
+
+ pr_info("");
+
for (i = 0; i < ARRAY_SIZE(feat_str); ++i) {
if (iommu_feature(iommu, (1ULL << i)))
pr_cont(" %s", feat_str[i]);
In the discussion *smpboot: CPU numbers printed as warning* [1] John wrote:
It is supported to provide loglevels for CONT messages. The loglevel is
then only used if the append fails:
pr_cont(KERN_INFO "message part");
I don't know if we want to go down that path. But it is supported.
Kind regards,
Paul
[1]: https://lkml.org/lkml/2021/2/16/191
