runtime: make the test addresses for pageAlloc smaller on 32-bit

This change makes the test addresses start at 1 GiB instead of 2 GiB to
support mips and mipsle, which only have 31-bit address spaces.

It also changes some tests to use smaller offsets for the chunk index to
avoid jumping too far ahead in the address space to support 31-bit
address spaces. The tests don't require such large jumps for what
they're testing anyway.

Updates #35112.
Fixes #35440.

Change-Id: Ic68ff2b0a1f10ef37ac00d4bb5b910ddcdc76f2e
Reviewed-on: https://go-review.googlesource.com/c/go/+/205938
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index ef977b302e..1db465673c 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -830,7 +830,10 @@ func FreePageAlloc(pp *PageAlloc) {
 // BaseChunkIdx is a convenient chunkIdx value which works on both
 // 64 bit and 32 bit platforms, allowing the tests to share code
 // between the two.
-var BaseChunkIdx = ChunkIdx(chunkIndex((0xc000*pageAlloc64Bit + 0x200*pageAlloc32Bit) * pallocChunkBytes))
+//
+// This should not be higher than 0x100*pallocChunkBytes to support
+// mips and mipsle, which only have 31-bit address spaces.
+var BaseChunkIdx = ChunkIdx(chunkIndex((0xc000*pageAlloc64Bit + 0x100*pageAlloc32Bit) * pallocChunkBytes))
 
 // PageBase returns an address given a chunk index and a page index
 // relative to that chunk.