Messages in this thread | | | Date | Wed, 8 Oct 2014 16:52:06 -0500 | From | Aravind Gopalakrishnan <> | Subject | Re: Fwd: [PATCH] x86, MCE, AMD: save IA32_MCi_STATUS before machine_check_poll() resets it |
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> > Ok, this return is still bugging me - we're logging the error which > caused the counter overflow but we go and explicitly clear _STATUS so > that machine_check_poll doesn't pick up the same error again. > > Even though, machine_check_poll is intended to log the thresholding > error. > > Which actually makes me think that that machine_check_poll is actually > completely useless there. IOW, how about that instead: > > --- > From: Chen Yucong <slaoub@gmail.com <mailto:slaoub@gmail.com>> > Date: Thu, 2 Oct 2014 14:48:19 +0200 > Subject: [PATCH] x86, MCE, AMD: Correct thresholding error logging > > mce_setup() does not gather the content of IA32_MCG_STATUS, so it > should be read explicitly. Moreover, we need to clear IA32_MCx_STATUS > to avoid that mce_log() logs the processed threshold event again > at next time. > > But we do the logging ourselves and machine_check_poll() is completely > useless there. So kill it. > > Signed-off-by: Chen Yucong <slaoub@gmail.com <mailto:slaoub@gmail.com>> > Signed-off-by: Borislav Petkov <bp@suse.de <mailto:bp@suse.de>> > --- > arch/x86/kernel/cpu/mcheck/mce_amd.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c > b/arch/x86/kernel/cpu/mcheck/mce_amd.c > index 1c54d3d61a4d..9ce64955559d 100644 > --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c > +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c > @@ -270,14 +270,13 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c) > static void amd_threshold_interrupt(void) > { > u32 low = 0, high = 0, address = 0; > + int cpu = smp_processor_id(); > unsigned int bank, block; > struct mce m; > > - mce_setup(&m); > - > /* assume first bank caused it */ > for (bank = 0; bank < mca_cfg.banks; ++bank) { > - if (!(per_cpu(bank_map, m.cpu) & (1 << bank))) > + if (!(per_cpu(bank_map, cpu) & (1 << bank))) > continue; > for (block = 0; block < NR_BLOCKS; ++block) { > if (block == 0) { > @@ -309,20 +308,21 @@ static void amd_threshold_interrupt(void) > * Log the machine check that caused the threshold > * event. > */ > - machine_check_poll(MCP_TIMESTAMP, > - &__get_cpu_var(mce_poll_banks)); > - > - if (high & MASK_OVERFLOW_HI) { > - rdmsrl(address, m.misc); > - rdmsrl(MSR_IA32_MCx_STATUS(bank), m.status); > - m.bank = K8_MCE_THRESHOLD_BASE > - + bank * NR_BLOCKS > - + block; > - mce_log(&m); > - return; > - } > + if (high & MASK_OVERFLOW_HI) > + goto log; > } > } > + return; > + > +log: > + mce_setup(&m); > + rdmsrl(MSR_IA32_MCG_STATUS, m.mcgstatus); > + rdmsrl(address, m.misc); > + rdmsrl(MSR_IA32_MCx_STATUS(bank), m.status); > + m.bank = K8_MCE_THRESHOLD_BASE + bank * NR_BLOCKS + block;
I am not understanding why m.bank is assigned this value..
It only causes incorrect decoding- [ 608.832916] DEBUG: raise_amd_threshold_event [ 608.832926] [Hardware Error]: Corrected error, no action required. [ 608.833143] [Hardware Error]: CPU:26 (15:2:0) MC165_STATUS[-|CE|MiscV|-|AddrV|-|-]: 0x8c00000000000000 [ 608.833551] [Hardware Error]: MC165_ADDR: 0x0000000000000000 [ 608.833777] [Hardware Error]: cache level: RESV, tx: INSN [ 608.834034] amd_inject module loaded ...
(Obviously, as in amd_decode_mce() we switch (m->bank) for decoding the status and there is no bank 165)
OTOH, if m.bank = bank; Then we get correct decoding info- [ 58.021978] DEBUG: raise_amd_threshold_event [ 58.021992] [Hardware Error]: Corrected error, no action required. [ 58.022155] [Hardware Error]: CPU:0 (15:60:0) MC4_STATUS[-|CE|MiscV|-|AddrV|-|-]: 0x8c00000000000000 [ 58.022393] [Hardware Error]: MC4_ADDR: 0x0000000000000000 [ 58.022531] [Hardware Error]: MC4 Error (node 0): DRAM ECC error detected on the NB. <snip..it's throws WARN as "Something is rotten in the state of Denmark".> <.. but that's fine. we are just fake-injecting errors here.. :) > [ 58.022933] [Hardware Error]: cache level: RESV, tx: INSN [ 58.023084] amd_inject module loaded ...
Thanks, -Aravind.
> + mce_log(&m); > + > + wrmsrl(MSR_IA32_MCx_STATUS(bank), 0); > } > > /* > -- > 2.0.0 > > -- > Regards/Gruss, > Boris.
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