On Fri, May 09, 2014 at 09:28:58AM +1000, Michael Neuling wrote:
> On Thu, 2014-05-08 at 06:52 -0700, Guenter Roeck wrote:
> > On 05/07/2014 10:52 PM, Michael Neuling wrote:
> > > On Wed, 2014-05-07 at 22:00 -0700, Guenter Roeck wrote:
> > >> Both 3.10 and 3.14 are affected.
> > >>
> > >> powerpc:defconfig, powerpc:allmodconfig:
> > >>
> > >> arch/powerpc/kernel/signal_32.c: In function 'restore_tm_user_regs':
> > >> arch/powerpc/kernel/signal_32.c:867:31: error: 'TEXASR_FS' undeclared
> > >> (first use in this function)
> > >> arch/powerpc/kernel/signal_32.c:867:31: note: each undeclared identifier
> > >> is reported only once for each function it appears in
> > >> make[1]: *** [arch/powerpc/kernel/signal_32.o] Error 1
> > >>
> > >> Due to 'powerpc/tm: Disable IRQ in tm_recheckpoint' which uses the above
> > >> define
> > >> without defining it. TEXASR_FS is defined with commit e4e381215 (KVM:
> > >> PPC: Book3S
> > >> HV: Add transactional memory support) upstream.
> > >
> > > Argh, bugger.
> > >
> > > The below should fix both trees. It's just the #define from upstream
> > > e4e38121507a27d2ccc4b28d9e7fc4818a12c44c (we don't want the rest of that
> > > patch
> > > in stable as it's not a fix).
> > >
> >
> > It would probably be better to merge it into the other patch, as it is
> > really
> > part of the back-port (and bisect would be broken otherwise for the affected
> > images).
>
>
> In case it's useful, here's merged patch which should replace the existing
> one.
>
> Mikey
>
Thanks, I am using this merged patch for the 3.11 kernel as well.
Cheers,
--
Luís
>
> From: Michael Neuling <mi...@neuling.org>
>
> powerpc/tm: Disable IRQ in tm_recheckpoint
>
> We can't take an IRQ when we're about to do a trechkpt as our GPR state is set
> to user GPR values.
>
> We've hit this when running some IBM Java stress tests in the lab resulting in
> the following dump:
>
> cpu 0x3f: Vector: 700 (Program Check) at [c000000007eb3d40]
> pc: c000000000050074: restore_gprs+0xc0/0x148
> lr: 00000000b52a8184
> sp: ac57d360
> msr: 8000000100201030
> current = 0xc00000002c500000
> paca = 0xc000000007dbfc00 softe: 0 irq_happened: 0x00
> pid = 34535, comm = Pooled Thread #
> R00 = 00000000b52a8184 R16 = 00000000b3e48fda
> R01 = 00000000ac57d360 R17 = 00000000ade79bd8
> R02 = 00000000ac586930 R18 = 000000000fac9bcc
> R03 = 00000000ade60000 R19 = 00000000ac57f930
> R04 = 00000000f6624918 R20 = 00000000ade79be8
> R05 = 00000000f663f238 R21 = 00000000ac218a54
> R06 = 0000000000000002 R22 = 000000000f956280
> R07 = 0000000000000008 R23 = 000000000000007e
> R08 = 000000000000000a R24 = 000000000000000c
> R09 = 00000000b6e69160 R25 = 00000000b424cf00
> R10 = 0000000000000181 R26 = 00000000f66256d4
> R11 = 000000000f365ec0 R27 = 00000000b6fdcdd0
> R12 = 00000000f66400f0 R28 = 0000000000000001
> R13 = 00000000ada71900 R29 = 00000000ade5a300
> R14 = 00000000ac2185a8 R30 = 00000000f663f238
> R15 = 0000000000000004 R31 = 00000000f6624918
> pc = c000000000050074 restore_gprs+0xc0/0x148
> cfar= c00000000004fe28 dont_restore_vec+0x1c/0x1a4
> lr = 00000000b52a8184
> msr = 8000000100201030 cr = 24804888
> ctr = 0000000000000000 xer = 0000000000000000 trap = 700
>
> This moves tm_recheckpoint to a C function and moves the tm_restore_sprs into
> that function. It then adds IRQ disabling over the trechkpt critical section.
> It also sets the TEXASR FS in the signals code to ensure this is never set now
> that we explictly write the TM sprs in tm_recheckpoint.
>
> Cherry picked from commit e6b8fd028b584ffca7a7255b8971f254932c9fce with added
> #define from e4e38121507a27d2ccc4b28d9e7fc4818a12c44c upstream.
>
> Signed-off-by: Michael Neuling <mi...@neuling.org>
> cc: stable@vger.kernel.org
> Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
>
> diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
> index e1fb161..795f677 100644
> --- a/arch/powerpc/include/asm/reg.h
> +++ b/arch/powerpc/include/asm/reg.h
> @@ -208,6 +208,7 @@
> #define SPRN_ACOP 0x1F /* Available Coprocessor Register */
> #define SPRN_TFIAR 0x81 /* Transaction Failure Inst Addr */
> #define SPRN_TEXASR 0x82 /* Transaction EXception & Summary */
> +#define TEXASR_FS __MASK(63-36) /* Transaction Failure Summary */
> #define SPRN_TEXASRU 0x83 /* '' '' '' Upper 32 */
> #define SPRN_TFHAR 0x80 /* Transaction Failure Handler Addr */
> #define SPRN_CTRLF 0x088
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 7baa27b..1e1c995 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -523,6 +523,31 @@ out_and_saveregs:
> tm_save_sprs(thr);
> }
>
> +extern void __tm_recheckpoint(struct thread_struct *thread,
> + unsigned long orig_msr);
> +
> +void tm_recheckpoint(struct thread_struct *thread,
> + unsigned long orig_msr)
> +{
> + unsigned long flags;
> +
> + /* We really can't be interrupted here as the TEXASR registers can't
> + * change and later in the trecheckpoint code, we have a userspace R1.
> + * So let's hard disable over this region.
> + */
> + local_irq_save(flags);
> + hard_irq_disable();
> +
> + /* The TM SPRs are restored here, so that TEXASR.FS can be set
> + * before the trecheckpoint and no explosion occurs.
> + */
> + tm_restore_sprs(thread);
> +
> + __tm_recheckpoint(thread, orig_msr);
> +
> + local_irq_restore(flags);
> +}
> +
> static inline void tm_recheckpoint_new_task(struct task_struct *new)
> {
> unsigned long msr;
> @@ -541,13 +566,10 @@ static inline void tm_recheckpoint_new_task(struct
> task_struct *new)
> if (!new->thread.regs)
> return;
>
> - /* The TM SPRs are restored here, so that TEXASR.FS can be set
> - * before the trecheckpoint and no explosion occurs.
> - */
> - tm_restore_sprs(&new->thread);
> -
> - if (!MSR_TM_ACTIVE(new->thread.regs->msr))
> + if (!MSR_TM_ACTIVE(new->thread.regs->msr)){
> + tm_restore_sprs(&new->thread);
> return;
> + }
> msr = new->thread.tm_orig_msr;
> /* Recheckpoint to restore original checkpointed register state. */
> TM_DEBUG("*** tm_recheckpoint of pid %d "
> diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
> index 7e9dff8..81f929f 100644
> --- a/arch/powerpc/kernel/signal_32.c
> +++ b/arch/powerpc/kernel/signal_32.c
> @@ -863,6 +863,8 @@ static long restore_tm_user_regs(struct pt_regs *regs,
> * transactional versions should be loaded.
> */
> tm_enable();
> + /* Make sure the transaction is marked as failed */
> + current->thread.tm_texasr |= TEXASR_FS;
> /* This loads the checkpointed FP/VEC state, if used */
> tm_recheckpoint(¤t->thread, msr);
> /* Get the top half of the MSR */
> diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
> index 35c20a1..74d9615 100644
> --- a/arch/powerpc/kernel/signal_64.c
> +++ b/arch/powerpc/kernel/signal_64.c
> @@ -513,6 +513,8 @@ static long restore_tm_sigcontexts(struct pt_regs *regs,
> }
> #endif
> tm_enable();
> + /* Make sure the transaction is marked as failed */
> + current->thread.tm_texasr |= TEXASR_FS;
> /* This loads the checkpointed FP/VEC state, if used */
> tm_recheckpoint(¤t->thread, msr);
>
> diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
> index f2abb21..1e43ed4 100644
> --- a/arch/powerpc/kernel/tm.S
> +++ b/arch/powerpc/kernel/tm.S
> @@ -296,7 +296,7 @@ dont_backup_fp:
> * Call with IRQs off, stacks get all out of sync for
> * some periods in here!
> */
> -_GLOBAL(tm_recheckpoint)
> +_GLOBAL(__tm_recheckpoint)
> mfcr r5
> mflr r0
> std r5, 8(r1)
>
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