| Message ID | 20090119.225228.194299431.davem@davemloft.net |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
On Tuesday 20 January 2009 12:52:28 am David Miller wrote: > From: David Miller <davem@davemloft.net> > Date: Mon, 19 Jan 2009 22:35:17 -0800 (PST) > > > The code in sun4v_data_access_exception() needs some logic to properly > > handle the case of the kernel doing a userspace access. Currently it > > does an OOPS unconditionally when triggered from kernel space, which > > is wrong. > > > > I'll fix this up and post a patch. Dave, The patch does fix the issue. Dennis > Dennis, here is a 2.6.27 based patch that should fix this bug. > > sparc64: Fix DAX handling via userspace access from kernel. > > If we do a userspace access from kernel mode, and get a > data access exception, we need to check the exception > table just like a normal fault does. > > The spitfire DAX handler was doing this, but such logic > was missing from the sun4v DAX code. > > Reported-by: Dennis Gilmore <dgilmore@redhat.com> > Signed-off-by: David S. Miller <davem@davemloft.net> > > diff --git a/arch/sparc64/kernel/traps.c b/arch/sparc64/kernel/traps.c > index c824df1..eb19724 100644 > --- a/arch/sparc64/kernel/traps.c > +++ b/arch/sparc64/kernel/traps.c > @@ -1,6 +1,6 @@ > /* arch/sparc64/kernel/traps.c > * > - * Copyright (C) 1995,1997,2008 David S. Miller (davem@davemloft.net) > + * Copyright (C) 1995,1997,2008,2009 David S. Miller (davem@davemloft.net) > * Copyright (C) 1997,1999,2000 Jakub Jelinek (jakub@redhat.com) > */ > > @@ -262,6 +262,21 @@ void sun4v_data_access_exception(struct pt_regs *regs, > unsigned long addr, unsig return; > > if (regs->tstate & TSTATE_PRIV) { > + /* Test if this comes from uaccess places. */ > + const struct exception_table_entry *entry; > + > + entry = search_exception_tables(regs->tpc); > + if (entry) { > + /* Ouch, somebody is trying VM hole tricks on us... */ > +#ifdef DEBUG_EXCEPTIONS > + printk("Exception: PC<%016lx> faddr<UNKNOWN>\n", regs->tpc); > + printk("EX_TABLE: insn<%016lx> fixup<%016lx>\n", > + regs->tpc, entry->fixup); > +#endif > + regs->tpc = entry->fixup; > + regs->tnpc = regs->tpc + 4; > + return; > + } > printk("sun4v_data_access_exception: ADDR[%016lx] " > "CTX[%04x] TYPE[%04x], going.\n", > addr, ctx, type); > -- > To unsubscribe from this list: send the line "unsubscribe sparclinux" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Dennis Gilmore <dennis@ausil.us> Date: Fri, 23 Jan 2009 11:31:48 -0600 > On Tuesday 20 January 2009 12:52:28 am David Miller wrote: > > From: David Miller <davem@davemloft.net> > > Date: Mon, 19 Jan 2009 22:35:17 -0800 (PST) > > > > > The code in sun4v_data_access_exception() needs some logic to properly > > > handle the case of the kernel doing a userspace access. Currently it > > > does an OOPS unconditionally when triggered from kernel space, which > > > is wrong. > > > > > > I'll fix this up and post a patch. > Dave, > > The patch does fix the issue. Thanks a lot for testing. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/sparc64/kernel/traps.c b/arch/sparc64/kernel/traps.c index c824df1..eb19724 100644 --- a/arch/sparc64/kernel/traps.c +++ b/arch/sparc64/kernel/traps.c @@ -1,6 +1,6 @@ /* arch/sparc64/kernel/traps.c * - * Copyright (C) 1995,1997,2008 David S. Miller (davem@davemloft.net) + * Copyright (C) 1995,1997,2008,2009 David S. Miller (davem@davemloft.net) * Copyright (C) 1997,1999,2000 Jakub Jelinek (jakub@redhat.com) */ @@ -262,6 +262,21 @@ void sun4v_data_access_exception(struct pt_regs *regs, unsigned long addr, unsig return; if (regs->tstate & TSTATE_PRIV) { + /* Test if this comes from uaccess places. */ + const struct exception_table_entry *entry; + + entry = search_exception_tables(regs->tpc); + if (entry) { + /* Ouch, somebody is trying VM hole tricks on us... */ +#ifdef DEBUG_EXCEPTIONS + printk("Exception: PC<%016lx> faddr<UNKNOWN>\n", regs->tpc); + printk("EX_TABLE: insn<%016lx> fixup<%016lx>\n", + regs->tpc, entry->fixup); +#endif + regs->tpc = entry->fixup; + regs->tnpc = regs->tpc + 4; + return; + } printk("sun4v_data_access_exception: ADDR[%016lx] " "CTX[%04x] TYPE[%04x], going.\n", addr, ctx, type);