From: Vasant Hegde <vasant.hegde@amd.com>
To: kernel test robot <lkp@intel.com>
Cc: oe-kbuild-all@lists.linux.dev, iommu@lists.linux.dev,
Joerg Roedel <jroedel@suse.de>, Jason Gunthorpe <jgg@nvidia.com>,
Jerry Snitselaar <jsnitsel@redhat.com>
Subject: Re: [joro-iommu:x86/amd 16/19] drivers/iommu/amd/iommu.c:829:21: warning: variable 'entry' set but not used
Date: Thu, 12 Oct 2023 10:56:27 +0530 [thread overview]
Message-ID: <f8163afc-858e-7830-d6dc-79c6b60d7c2d@amd.com> (raw)
In-Reply-To: <202310071103.BYatoc0b-lkp@intel.com>
Hi,
On 10/7/2023 8:50 AM, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git x86/amd
> head: 189116d5ad54eee2bab82c5f12e837912fc0b4c4
> commit: d55b0d2e075ad32d560cdd35a2016973fda52ed6 [16/19] iommu/amd: Remove PPR support
> config: x86_64-randconfig-003-20231007 (https://download.01.org/0day-ci/archive/20231007/202310071103.BYatoc0b-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231007/202310071103.BYatoc0b-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202310071103.BYatoc0b-lkp@intel.com/
>
> All warnings (new ones prefixed by >>):
>
> drivers/iommu/amd/iommu.c: In function 'iommu_poll_ppr_log':
>>> drivers/iommu/amd/iommu.c:829:21: warning: variable 'entry' set but not used [-Wunused-but-set-variable]
> 829 | u64 entry[2];
> | ^~~~~
Commit d55b0d2e075 (iommu/next branch), removed PPR support. Hence this become
unused variable. But soon we will be adding PPR support for SVA [1]. Hence I
just added comment and left it as is (instead of removing and adding it back again).
[1]
https://lore.kernel.org/linux-iommu/20230911121046.1025732-1-vasant.hegde@amd.com/T/#u
-Vasant
>
>
> vim +/entry +829 drivers/iommu/amd/iommu.c
>
> 90008ee4b811c9 arch/x86/kernel/amd_iommu.c Joerg Roedel 2008-09-09 816
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 817 static void iommu_poll_ppr_log(struct amd_iommu *iommu)
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 818 {
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 819 u32 head, tail;
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 820
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 821 if (iommu->ppr_log == NULL)
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 822 return;
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 823
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 824 head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 825 tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 826
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 827 while (head != tail) {
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 828 volatile u64 *raw;
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 @829 u64 entry[2];
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 830 int i;
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 831
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 832 raw = (u64 *)(iommu->ppr_log + head);
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 833
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 834 /*
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 835 * Hardware bug: Interrupt may arrive before the entry is
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 836 * written to memory. If this happens we need to wait for the
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 837 * entry to arrive.
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 838 */
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 839 for (i = 0; i < LOOP_TIMEOUT; ++i) {
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 840 if (PPR_REQ_TYPE(raw[0]) != 0)
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 841 break;
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 842 udelay(1);
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 843 }
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 844
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 845 /* Avoid memcpy function-call overhead */
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 846 entry[0] = raw[0];
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 847 entry[1] = raw[1];
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 848
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 849 /*
> 05d227efbd8d3c drivers/iommu/amd/iommu.c Tom Lendacky 2023-01-17 850 * To detect the hardware errata 733 we need to clear the
> 05d227efbd8d3c drivers/iommu/amd/iommu.c Tom Lendacky 2023-01-17 851 * entry back to zero. This issue does not exist on SNP
> 05d227efbd8d3c drivers/iommu/amd/iommu.c Tom Lendacky 2023-01-17 852 * enabled system. Also this buffer is not writeable on
> 05d227efbd8d3c drivers/iommu/amd/iommu.c Tom Lendacky 2023-01-17 853 * SNP enabled system.
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 854 */
> 05d227efbd8d3c drivers/iommu/amd/iommu.c Tom Lendacky 2023-01-17 855 if (!amd_iommu_snp_en)
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 856 raw[0] = raw[1] = 0UL;
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 857
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 858 /* Update head pointer of hardware ring-buffer */
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 859 head = (head + PPR_ENTRY_SIZE) % PPR_LOG_SIZE;
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 860 writel(head, iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 861
> d55b0d2e075ad3 drivers/iommu/amd/iommu.c Vasant Hegde 2023-10-06 862 /* TODO: PPR Handler will be added when we add IOPF support */
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 863
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 864 /* Refresh ring-buffer information */
> eee53537c476c9 drivers/iommu/amd_iommu.c Joerg Roedel 2012-06-01 865 head = readl(iommu->mmio_base + MMIO_PPR_HEAD_OFFSET);
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 866 tail = readl(iommu->mmio_base + MMIO_PPR_TAIL_OFFSET);
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 867 }
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 868 }
> 72e1dcc4192288 drivers/iommu/amd_iommu.c Joerg Roedel 2011-11-10 869
>
> :::::: The code at line 829 was first introduced by commit
> :::::: eee53537c476c947bf7faa1c916d2f5a0ae8ec93 iommu/amd: Fix deadlock in ppr-handling error path
>
> :::::: TO: Joerg Roedel <joerg.roedel@amd.com>
> :::::: CC: Joerg Roedel <joerg.roedel@amd.com>
>
next prev parent reply other threads:[~2023-10-12 5:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-07 3:20 [joro-iommu:x86/amd 16/19] drivers/iommu/amd/iommu.c:829:21: warning: variable 'entry' set but not used kernel test robot
2023-10-12 5:26 ` Vasant Hegde [this message]
2023-10-12 13:21 ` Jason Gunthorpe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f8163afc-858e-7830-d6dc-79c6b60d7c2d@amd.com \
--to=vasant.hegde@amd.com \
--cc=iommu@lists.linux.dev \
--cc=jgg@nvidia.com \
--cc=jroedel@suse.de \
--cc=jsnitsel@redhat.com \
--cc=lkp@intel.com \
--cc=oe-kbuild-all@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox