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authorDavid S. Miller <davem@davemloft.net>2014-05-07 14:07:32 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-08-14 09:24:16 +0800
commit720910a60cc2509160ec043459081f274c12ccce (patch)
parente5bd62b99772098f5123bff888247dbc8e68f602 (diff)
sparc64: Fix huge TSB mapping on pre-UltraSPARC-III cpus.
[ Upstream commit b18eb2d779240631a098626cb6841ee2dd34fda0 ] Access to the TSB hash tables during TLB misses requires that there be an atomic 128-bit quad load available so that we fetch a matching TAG and DATA field at the same time. On cpus prior to UltraSPARC-III only virtual address based quad loads are available. UltraSPARC-III and later provide physical address based variants which are easier to use. When we only have virtual address based quad loads available this means that we have to lock the TSB into the TLB at a fixed virtual address on each cpu when it runs that process. We can't just access the PAGE_OFFSET based aliased mapping of these TSBs because we cannot take a recursive TLB miss inside of the TLB miss handler without risking running out of hardware trap levels (some trap combinations can be deep, such as those generated by register window spill and fill traps). Without huge pages it's working perfectly fine, but when the huge TSB got added another chunk of fixed virtual address space was not allocated for this second TSB mapping. So we were mapping both the 8K and 4MB TSBs to the same exact virtual address, causing multiple TLB matches which gives undefined behavior. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 17 insertions, 3 deletions
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index dfb0019bf05b..6663604a902a 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -24,7 +24,8 @@
/* The kernel image occupies 0x4000000 to 0x6000000 (4MB --> 96MB).
* The page copy blockops can use 0x6000000 to 0x8000000.
- * The TSB is mapped in the 0x8000000 to 0xa000000 range.
+ * The 8K TSB is mapped in the 0x8000000 to 0x8400000 range.
+ * The 4M TSB is mapped in the 0x8400000 to 0x8800000 range.
* The PROM resides in an area spanning 0xf0000000 to 0x100000000.
* The vmalloc area spans 0x100000000 to 0x200000000.
* Since modules need to be in the lowest 32-bits of the address space,
@@ -33,7 +34,8 @@
* 0x400000000.
#define TLBTEMP_BASE _AC(0x0000000006000000,UL)
-#define TSBMAP_BASE _AC(0x0000000008000000,UL)
+#define TSBMAP_8K_BASE _AC(0x0000000008000000,UL)
+#define TSBMAP_4M_BASE _AC(0x0000000008400000,UL)
#define MODULES_VADDR _AC(0x0000000010000000,UL)
#define MODULES_LEN _AC(0x00000000e0000000,UL)
#define MODULES_END _AC(0x00000000f0000000,UL)
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
index 2cc3bce5ee91..71d99a6c75a7 100644
--- a/arch/sparc/mm/tsb.c
+++ b/arch/sparc/mm/tsb.c
@@ -133,7 +133,19 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsign
mm->context.tsb_block[tsb_idx].tsb_nentries =
tsb_bytes / sizeof(struct tsb);
- base = TSBMAP_BASE;
+ switch (tsb_idx) {
+ case MM_TSB_BASE:
+ base = TSBMAP_8K_BASE;
+ break;
+ case MM_TSB_HUGE:
+ base = TSBMAP_4M_BASE;
+ break;
+ default:
+ BUG();
+ }
tte = pgprot_val(PAGE_KERNEL_LOCKED);
tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
BUG_ON(tsb_paddr & (tsb_bytes - 1UL));