4.4-stable review patch. If anyone has any objections, please let me know.
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From: Michael Ellerman mpe@ellerman.id.au
commit fd6e440f20b1a4304553775fc55938848ff617c9 upstream.
The recent commit 87590ce6e373 ("sysfs/cpu: Add vulnerability folder") added a generic folder and set of files for reporting information on CPU vulnerabilities. One of those was for meltdown:
/sys/devices/system/cpu/vulnerabilities/meltdown
This commit wires up that file for 64-bit Book3S powerpc.
For now we default to "Vulnerable" unless the RFI flush is enabled. That may not actually be true on all hardware, further patches will refine the reporting based on the CPU/platform etc. But for now we default to being pessimists.
Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/setup_64.c | 8 ++++++++ 2 files changed, 9 insertions(+)
--- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -136,6 +136,7 @@ config PPC select GENERIC_SMP_IDLE_THREAD select GENERIC_CMOS_UPDATE select GENERIC_TIME_VSYSCALL_OLD + select GENERIC_CPU_VULNERABILITIES if PPC_BOOK3S_64 select GENERIC_CLOCKEVENTS select GENERIC_CLOCKEVENTS_BROADCAST if SMP select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -934,5 +934,13 @@ void __init setup_rfi_flush(enum l1d_flu if (!no_rfi_flush) rfi_flush_enable(enable); } + +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) +{ + if (rfi_flush) + return sprintf(buf, "Mitigation: RFI Flush\n"); + + return sprintf(buf, "Vulnerable\n"); +} #endif /* CONFIG_PPC_BOOK3S_64 */ #endif