Borislav Petkov 548a0973fe x86/mce: Defer processing of early errors ... [ Upstream commit 3bff147b187d5dfccfca1ee231b0761a89f1eff5 ] When a fatal machine check results in a system reset, Linux does not clear the error(s) from machine check bank(s) - hardware preserves the machine check banks across a warm reset. During initialization of the kernel after the reboot, Linux reads, logs, and clears all machine check banks. But there is a problem. In: 5de97c9f6d ("x86/mce: Factor out and deprecate the /dev/mcelog driver") the call to mce_register_decode_chain() moved later in the boot sequence. This means that /dev/mcelog doesn't see those early error logs. This was partially fixed by: cd9c57cad3 ("x86/MCE: Dump MCE to dmesg if no consumers") which made sure that the logs were not lost completely by printing to the console. But parsing console logs is error prone. Users of /dev/mcelog should expect to find any early errors logged to standard places. Add a new flag MCP_QUEUE_LOG to machine_check_poll() to be used in early machine check initialization to indicate that any errors found should just be queued to genpool. When mcheck_late_init() is called it will call mce_schedule_work() to actually log and flush any errors queued in the genpool. [ Based on an original patch, commit message by and completely productized by Tony Luck. ] Fixes: 5de97c9f6d ("x86/mce: Factor out and deprecate the /dev/mcelog driver") Reported-by: Sumanth Kamatala <skamatala@juniper.net> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210824003129.GA1642753@agluck-desk2.amr.corp.intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-07-05 19:10:21 +02:00
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asm	x86/mce: Defer processing of early errors	2024-07-05 19:10:21 +02:00
uapi/asm	init: add dsm gpl source	2024-07-05 18:00:04 +02:00