On Tue, Aug 27, 2013 at 01:02:12AM +0530, Mahesh J Salgaonkar wrote:
> From: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com>
>
> If we get a machine check exception due to SLB or TLB errors, then flush
> SLBs/TLBs and reload SLBs to recover. We do this in real mode before turning
> on MMU. Otherwise we would run into nested machine checks.
>
> If we get a machine check when we are in guest, then just flush the
> SLBs and continue. This patch handles errors for power7. The next
> patch will handle errors for power8
Some comments...
> +/* PPC bit number conversion */
> +#define PPC_BIT(bit) (0x8000000000000000UL >> (bit))
> +#define PPC_BITLSHIFT(be) (63 - (be))
> +#define PPC_BITMASK(bs, be) ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))
This will break if anyone is so incautious as to use this in a 32-bit
kernel. It would be kinder to do:
#define PPC_BITLSHIFT(be) (BITS_PER_LONG - 1 - (be))
#define PPC_BIT(bit) (1ul << PPC_BITLSHIFT(bit))
> +/* SRR1 bits for machine check (On Power7 and Power8) */
> +#define P7_SRR1_MC_IFETCH(srr1) ((srr1) & PPC_BITMASK(43, 45)) /* P8
> too */
> +
> +#define P7_SRR1_MC_IFETCH_UE (0x1 << PPC_BITLSHIFT(45)) /* P8 too */
> +#define P7_SRR1_MC_IFETCH_SLB_PARITY (0x2 << PPC_BITLSHIFT(45)) /* P8 too */
> +#define P7_SRR1_MC_IFETCH_SLB_MULTIHIT (0x3 << PPC_BITLSHIFT(45)) /*
> P8 too */
> +#define P7_SRR1_MC_IFETCH_SLB_BOTH (0x4 << PPC_BITLSHIFT(45)) /* P8 too */
> +#define P7_SRR1_MC_IFETCH_TLB_MULTIHIT (0x5 << PPC_BITLSHIFT(45)) /*
> P8 too */
> +#define P7_SRR1_MC_IFETCH_UE_TLB_RELOAD (0x6 << PPC_BITLSHIFT(45)) /*
> P8 too */
> +#define P7_SRR1_MC_IFETCH_UE_IFU_INTERNAL (0x7 << PPC_BITLSHIFT(45))
> +
> +/* SRR1 bits for machine check (On Power8) */
> +#define P8_SRR1_MC_IFETCH_ERAT_MULTIHIT (0x4 << PPC_BITLSHIFT(45))
How do we tell the difference between that and P7_SRR1_MC_IFETCH_SLB_BOTH?
> +/* flush SLBs and reload */
> +static void flush_and_reload_slb(void)
> +{
> + struct slb_shadow *slb;
> + unsigned long i, n;
> +
> + if (!mmu_has_feature(MMU_FTR_SLB))
> + return;
This seems unnecessary when we can only call this on POWER7.
Paul.
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