powerpc/e6500: TLB miss handler with hardware tablewalk support

There are a few things that make the existing hw tablewalk handlers
unsuitable for e6500:

 - Indirect entries go in TLB1 (though the resulting direct entries go in
   TLB0).

 - It has threads, but no "tlbsrx." -- so we need a spinlock and
   a normal "tlbsx".  Because we need this lock, hardware tablewalk
   is mandatory on e6500 unless we want to add spinlock+tlbsx to
   the normal bolted TLB miss handler.

 - TLB1 has no HES (nor next-victim hint) so we need software round robin
   (TODO: integrate this round robin data with hugetlb/KVM)

 - The existing tablewalk handlers map half of a page table at a time,
   because IBM hardware has a fixed 1MiB indirect page size.  e6500
   has variable size indirect entries, with a minimum of 2MiB.
   So we can't do the half-page indirect mapping, and even if we
   could it would be less efficient than mapping the full page.

 - Like on e5500, the linear mapping is bolted, so we don't need the
   overhead of supporting nested tlb misses.

Note that hardware tablewalk does not work in rev1 of e6500.
We do not expect to support e6500 rev1 in mainline Linux.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index c3523d1dda58..e81731c62a7f 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -113,6 +113,10 @@ struct paca_struct {
 	/* Keep pgd in the same cacheline as the start of extlb */
 	pgd_t *pgd __attribute__((aligned(0x80))); /* Current PGD */
 	pgd_t *kernel_pgd;		/* Kernel PGD */
+
+	/* Shared by all threads of a core -- points to tcd of first thread */
+	struct tlb_core_data *tcd_ptr;
+
 	/* We can have up to 3 levels of reentrancy in the TLB miss handler */
 	u64 extlb[3][EX_TLB_SIZE / sizeof(u64)];
 	u64 exmc[8];		/* used for machine checks */
@@ -123,6 +127,8 @@ struct paca_struct {
 	void *mc_kstack;
 	void *crit_kstack;
 	void *dbg_kstack;
+
+	struct tlb_core_data tcd;
 #endif /* CONFIG_PPC_BOOK3E */
 
 	mm_context_t context;