[PATCH 3.16 117/127] sparc64: Define VA hole at run time, rather than at compile time.

From: Greg Kroah-Hartman
Date: Tue Oct 28 2014 - 03:02:24 EST


3.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <davem@xxxxxxxxxxxxx>

[ Upstream commit 4397bed080598001e88f612deb8b080bb1cc2322 ]

Now that we use 4-level page tables, we can provide up to 53-bits of
virtual address space to the user.

Adjust the VA hole based upon the capabilities of the cpu type probed.

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Acked-by: Bob Picco <bob.picco@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/include/asm/page_64.h | 15 ++++-----------
arch/sparc/mm/init_64.c | 21 +++++++++++++++++++++
2 files changed, 25 insertions(+), 11 deletions(-)

--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -102,21 +102,14 @@ typedef unsigned long pgprot_t;

typedef pte_t *pgtable_t;

-/* These two values define the virtual address space range in which we
- * must forbid 64-bit user processes from making mappings. It used to
- * represent precisely the virtual address space hole present in most
- * early sparc64 chips including UltraSPARC-I. But now it also is
- * further constrained by the limits of our page tables, which is
- * 43-bits of virtual address.
- */
-#define SPARC64_VA_HOLE_TOP _AC(0xfffffc0000000000,UL)
-#define SPARC64_VA_HOLE_BOTTOM _AC(0x0000040000000000,UL)
+extern unsigned long sparc64_va_hole_top;
+extern unsigned long sparc64_va_hole_bottom;

/* The next two defines specify the actual exclusion region we
* enforce, wherein we use a 4GB red zone on each side of the VA hole.
*/
-#define VA_EXCLUDE_START (SPARC64_VA_HOLE_BOTTOM - (1UL << 32UL))
-#define VA_EXCLUDE_END (SPARC64_VA_HOLE_TOP + (1UL << 32UL))
+#define VA_EXCLUDE_START (sparc64_va_hole_bottom - (1UL << 32UL))
+#define VA_EXCLUDE_END (sparc64_va_hole_top + (1UL << 32UL))

#define TASK_UNMAPPED_BASE (test_thread_flag(TIF_32BIT) ? \
_AC(0x0000000070000000,UL) : \
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -1629,25 +1629,46 @@ static void __init page_offset_shift_pat
}
}

+unsigned long sparc64_va_hole_top = 0xfffff80000000000UL;
+unsigned long sparc64_va_hole_bottom = 0x0000080000000000UL;
+
static void __init setup_page_offset(void)
{
unsigned long max_phys_bits = 40;

if (tlb_type == cheetah || tlb_type == cheetah_plus) {
+ /* Cheetah/Panther support a full 64-bit virtual
+ * address, so we can use all that our page tables
+ * support.
+ */
+ sparc64_va_hole_top = 0xfff0000000000000UL;
+ sparc64_va_hole_bottom = 0x0010000000000000UL;
+
max_phys_bits = 42;
} else if (tlb_type == hypervisor) {
switch (sun4v_chip_type) {
case SUN4V_CHIP_NIAGARA1:
case SUN4V_CHIP_NIAGARA2:
+ /* T1 and T2 support 48-bit virtual addresses. */
+ sparc64_va_hole_top = 0xffff800000000000UL;
+ sparc64_va_hole_bottom = 0x0000800000000000UL;
+
max_phys_bits = 39;
break;
case SUN4V_CHIP_NIAGARA3:
+ /* T3 supports 48-bit virtual addresses. */
+ sparc64_va_hole_top = 0xffff800000000000UL;
+ sparc64_va_hole_bottom = 0x0000800000000000UL;
+
max_phys_bits = 43;
break;
case SUN4V_CHIP_NIAGARA4:
case SUN4V_CHIP_NIAGARA5:
case SUN4V_CHIP_SPARC64X:
default:
+ /* T4 and later support 52-bit virtual addresses. */
+ sparc64_va_hole_top = 0xfff8000000000000UL;
+ sparc64_va_hole_bottom = 0x0008000000000000UL;
max_phys_bits = 47;
break;
}


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