Messages in this thread | | | Date | Tue, 10 Nov 2015 12:21:42 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 2/3] x86, ras: Extend machine check recovery code to annotated ring0 areas |
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On Fri, Nov 06, 2015 at 01:01:55PM -0800, Tony Luck wrote: > Extend the severity checking code to add a new context IN_KERN_RECOV > which is used to indicate that the machine check was triggered by code > in the kernel with a fixup entry. > > Add code to check for this situation and respond by altering the return > IP to the fixup address and changing the regs->ax so that the recovery > code knows the physical address of the error. Note that we also set bit > 63 because 0x0 is a legal physical address. > > Signed-off-by: Tony Luck <tony.luck@intel.com> > --- > arch/x86/kernel/cpu/mcheck/mce-severity.c | 19 +++++++++++++++++-- > arch/x86/kernel/cpu/mcheck/mce.c | 13 ++++++++++--- > 2 files changed, 27 insertions(+), 5 deletions(-)
...
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c > index 9d014b82a124..472d11150b7a 100644 > --- a/arch/x86/kernel/cpu/mcheck/mce.c > +++ b/arch/x86/kernel/cpu/mcheck/mce.c > @@ -31,6 +31,7 @@ > #include <linux/types.h> > #include <linux/slab.h> > #include <linux/init.h> > +#include <linux/module.h> > #include <linux/kmod.h> > #include <linux/poll.h> > #include <linux/nmi.h> > @@ -1132,9 +1133,15 @@ void do_machine_check(struct pt_regs *regs, long error_code)
You could save a precious indentation level here:
if (cfg->tolerant == 3) goto clear;
and add the "clear" label below.
clear: if (worst > 0) mce_report_event(regs); mce_wrmsrl(MSR_IA32_MCG_STATUS, 0)
> if (no_way_out) > mce_panic("Fatal machine check on current CPU", &m, msg); > if (worst == MCE_AR_SEVERITY) { > - recover_paddr = m.addr; > - if (!(m.mcgstatus & MCG_STATUS_RIPV)) > - flags |= MF_MUST_KILL; > + if ((m.cs & 3) == 3) { > + recover_paddr = m.addr; > + if (!(m.mcgstatus & MCG_STATUS_RIPV)) > + flags |= MF_MUST_KILL; > + } else if (fixup_mcexception(regs)) { > + regs->ax = BIT(63) | m.addr; > + } else > + mce_panic("Failed kernel mode recovery", > + &m, NULL); > } else if (kill_it) { > force_sig(SIGBUS, current); > } > -- > 2.1.4 > >
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply.
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