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kernel_a52xq/arch
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Filename Latest commit message Latest commit date
Gustavo L. F. Walbon ebd3980c8d powerpc/security: Fix wrong message when RFI Flush is disable
[ Upstream commit 4e706af3cd8e1d0503c25332b30cad33c97ed442 ]

The issue was showing "Mitigation" message via sysfs whatever the
state of "RFI Flush", but it should show "Vulnerable" when it is
disabled.

If you have "L1D private" feature enabled and not "RFI Flush" you are
vulnerable to meltdown attacks.

"RFI Flush" is the key feature to mitigate the meltdown whatever the
"L1D private" state.

SEC_FTR_L1D_THREAD_PRIV is a feature for Power9 only.

So the message should be as the truth table shows:

  CPU | L1D private | RFI Flush |                sysfs
  ----|-------------|-----------|-------------------------------------
   P9 |    False    |   False   | Vulnerable
   P9 |    False    |   True    | Mitigation: RFI Flush
   P9 |    True     |   False   | Vulnerable: L1D private per thread
   P9 |    True     |   True    | Mitigation: RFI Flush, L1D private per thread
   P8 |    False    |   False   | Vulnerable
   P8 |    False    |   True    | Mitigation: RFI Flush

Output before this fix:
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Mitigation: RFI Flush, L1D private per thread
  # echo 0 > /sys/kernel/debug/powerpc/rfi_flush
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Mitigation: L1D private per thread

Output after fix:
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Mitigation: RFI Flush, L1D private per thread
  # echo 0 > /sys/kernel/debug/powerpc/rfi_flush
  # cat /sys/devices/system/cpu/vulnerabilities/meltdown
  Vulnerable: L1D private per thread

Signed-off-by: Gustavo L. F. Walbon <gwalbon@linux.ibm.com>
Signed-off-by: Mauro S. M. Rodrigues <maurosr@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190502210907.42375-1-gwalbon@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-04 19:12:56 +01:00
..
alpha alpha: Fix Eiger NR_IRQS to 128 2019-02-20 10:25:47 +01:00
arc ARC: IOC: panic if kernel was started with previously enabled IOC 2019-12-13 08:51:12 +01:00
arm ARM: tegra: Fix FLOW_CTLR_HALT register clobbering by tegra_resume() 2019-12-21 10:57:36 +01:00
arm64 KVM: arm64: Ensure 'params' is initialised when looking up sys register 2019-12-31 16:36:28 +01:00
c6x kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
h8300 h8300: use cc-cross-prefix instead of hardcoding h8300-unknown-linux- 2019-04-05 22:32:55 +02:00
hexagon hexagon: modify ffs() and fls() to return int 2018-09-10 19:42:15 -05:00
ia64 ia64:unwind: fix double free for mod->arch.init_unw_table 2019-10-05 13:09:38 +02:00
m68k m68k: fix command-line parsing when passed from u-boot 2019-12-01 09:16:22 +01:00
microblaze microblaze: fix multiple bugs in arch/microblaze/boot/Makefile 2019-12-05 09:20:13 +01:00
mips mips: fix build when "48 bits virtual memory" is enabled 2019-12-31 16:36:14 +01:00
nds32 nds32: Fix the items of hwcap_str ordering issue. 2019-12-13 08:51:35 +01:00
nios2 nios2: kconfig: remove duplicate DEBUG_STACK_USAGE symbol defintions 2018-08-27 09:47:20 +08:00
openrisc openrisc: Fix broken paths to arch/or32 2019-12-05 09:20:40 +01:00
parisc parisc: Fix vmap memory leak in ioremap()/iounmap() 2019-10-29 09:20:00 +01:00
powerpc powerpc/security: Fix wrong message when RFI Flush is disable 2020-01-04 19:12:56 +01:00
riscv RISC-V: Avoid corrupting the upper 32-bit of phys_addr_t in ioremap 2019-12-01 09:16:53 +01:00
s390 s390/ftrace: fix endless recursion in function_graph tracer 2019-12-31 16:36:20 +01:00
sh pinctrl: sh-pfc: sh7734: Fix duplicate TCLK1_B 2019-12-31 16:35:32 +01:00
sparc sparc: Correct ctx->saw_frame_pointer logic. 2019-12-13 08:51:52 +01:00
um um: Make GCOV depend on !KCOV 2019-12-05 09:20:52 +01:00
unicore32 mm: convert return type of handle_mm_fault() caller to vm_fault_t 2018-08-17 16:20:28 -07:00
x86 x86/MCE/AMD: Allow Reserved types to be overwritten in smca_banks[] 2019-12-31 16:36:30 +01:00
xtensa xtensa: fix TLB sanity checker 2019-12-21 10:57:25 +01:00
.gitignore
Kconfig jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00