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f968dc119a
linux/arch/x86
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Reinette Chatre f968dc119a x86/intel_rdt: Fix size reporting of MBA resource 
Chen Yu reported a divide-by-zero error when accessing the 'size'
resctrl file when a MBA resource is enabled.

divide error: 0000 [#1] SMP PTI
CPU: 93 PID: 1929 Comm: cat Not tainted 4.19.0-rc2-debug-rdt+ #25
RIP: 0010:rdtgroup_cbm_to_size+0x7e/0xa0
Call Trace:
rdtgroup_size_show+0x11a/0x1d0
seq_read+0xd8/0x3b0

Quoting Chen Yu's report: This is because for MB resource, the
r->cache.cbm_len is zero, thus calculating size in rdtgroup_cbm_to_size()
will trigger the exception.

Fix this issue in the 'size' file by getting correct memory bandwidth value
which is in MBps when MBA software controller is enabled or in percentage
when MBA software controller is disabled.

Fixes: d9b48c86eb ("x86/intel_rdt: Display resource groups' allocations in bytes")
Reported-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Xiaochen Shen" <xiaochen.shen@intel.com>
Link: https://lkml.kernel.org/r/20180904174614.26682-1-yu.c.chen@intel.com
Link: https://lkml.kernel.org/r/1537048707-76280-3-git-send-email-fenghua.yu@intel.com
2018-09-18 23:38:05 +02:00
..
boot Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
configs
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-08-29 13:38:39 -07:00
entry x86/vdso: Fix vDSO build if a retpoline is emitted 2018-08-20 18:04:41 +02:00
events perf/x86/intel: Add support/quirk for the MISPREDICT bit on Knights Landing CPUs 2018-09-10 10:03:01 +02:00
hyperv x86/mm: Only use tlb_remove_table() for paravirt 2018-08-23 11:56:31 -07:00
ia32
include x86/mm: Add .bss..decrypted section to hold shared variables 2018-09-15 20:48:45 +02:00
kernel x86/intel_rdt: Fix size reporting of MBA resource 2018-09-18 23:38:05 +02:00
kvm KVM: LAPIC: Fix pv ipis out-of-bounds access 2018-09-07 18:38:43 +02:00
lib x86/nmi: Fix NMI uaccess race against CR3 switching 2018-08-31 17:08:22 +02:00
math-emu
mm x86/mm: Add .bss..decrypted section to hold shared variables 2018-09-15 20:48:45 +02:00
net bpf, x32: Fix regression caused by commit 24dea04767 2018-07-26 02:51:12 +02:00
oprofile
pci PCI: Make early dump functionality generic 2018-06-29 20:06:07 -05:00
platform x86/efi: Load fixmap GDT in efi_call_phys_epilog() before setting %cr3 2018-09-12 21:53:34 +02:00
power Power management updates for 4.19-rc1 2018-08-14 13:12:24 -07:00
purgatory kbuild: move bin2c back to scripts/ from scripts/basic/ 2018-07-18 01:18:05 +09:00
ras
realmode
tools x86/relocs: Add __end_rodata_aligned to S_REL 2018-08-09 20:42:07 +02:00
um Consolidation of Kconfig files by Christoph Hellwig. 2018-08-15 13:05:12 -07:00
video
xen xen: fixes for 4.19-rc2 2018-08-31 08:45:16 -07:00
.gitignore
Kbuild
Kconfig x86/Kconfig: Fix trivial typo 2018-08-27 10:29:14 +02:00
Kconfig.cpu
Kconfig.debug Kconfig: consolidate the "Kernel hacking" menu 2018-08-02 08:06:48 +09:00
Makefile x86: Allow generating user-space headers without a compiler 2018-08-31 17:08:22 +02:00
Makefile_32.cpu
Makefile.um kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00