RISC-V: mm: Add tests for RISC-V mm

Add tests that enforce mmap hint address behavior. mmap should default
to sv48. mmap will provide an address at the highest address space that
can fit into the hint address, unless the hint address is less than sv39
and not 0, then it will return a sv39 address.

These tests are split into two files: mmap_default.c and mmap_bottomup.c
because a new process must be exec'd in order to change the mmap layout.
The run_mmap.sh script sets the stack to be unlimited for the
mmap_bottomup.c test which triggers a bottomup layout.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20230809232218.849726-3-charlie@rivosinc.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

tools/testing/selftests/riscv/Makefile

@@ -5,7 +5,7 @@
 ARCH ?= $(shell uname -m 2>/dev/null || echo not)
 
 ifneq (,$(filter $(ARCH),riscv))
-RISCV_SUBTARGETS ?= hwprobe vector
+RISCV_SUBTARGETS ?= hwprobe vector mm
 else
 RISCV_SUBTARGETS :=
 endif

tools/testing/selftests/riscv/mm/.gitignore

+mmap_bottomup
+mmap_default

tools/testing/selftests/riscv/mm/Makefile

+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 ARM Limited
+# Originally tools/testing/arm64/abi/Makefile
+
+# Additional include paths needed by kselftest.h and local headers
+CFLAGS += -D_GNU_SOURCE -std=gnu99 -I.
+
+TEST_GEN_FILES := testcases/mmap_default testcases/mmap_bottomup
+
+TEST_PROGS := testcases/run_mmap.sh
+
+include ../../lib.mk
+
+$(OUTPUT)/mm: testcases/mmap_default.c testcases/mmap_bottomup.c testcases/mmap_tests.h
+	$(CC) -o$@ $(CFLAGS) $(LDFLAGS) $^

tools/testing/selftests/riscv/mm/testcases/mmap_bottomup.c

+// SPDX-License-Identifier: GPL-2.0-only
+#include <sys/mman.h>
+#include <testcases/mmap_test.h>
+
+#include "../../kselftest_harness.h"
+
+TEST(infinite_rlimit)
+{
+// Only works on 64 bit
+#if __riscv_xlen == 64
+	struct addresses mmap_addresses;
+
+	EXPECT_EQ(BOTTOM_UP, memory_layout());
+
+	do_mmaps(&mmap_addresses);
+
+	EXPECT_NE(MAP_FAILED, mmap_addresses.no_hint);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_37_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_38_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_46_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_47_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_55_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_56_addr);
+
+	EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.no_hint);
+	EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_37_addr);
+	EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_38_addr);
+	EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_46_addr);
+	EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_47_addr);
+	EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_55_addr);
+	EXPECT_GT(1UL << 56, (unsigned long)mmap_addresses.on_56_addr);
+#endif
+}
+
+TEST_HARNESS_MAIN

tools/testing/selftests/riscv/mm/testcases/mmap_default.c

+// SPDX-License-Identifier: GPL-2.0-only
+#include <sys/mman.h>
+#include <testcases/mmap_test.h>
+
+#include "../../kselftest_harness.h"
+
+TEST(default_rlimit)
+{
+// Only works on 64 bit
+#if __riscv_xlen == 64
+	struct addresses mmap_addresses;
+
+	EXPECT_EQ(TOP_DOWN, memory_layout());
+
+	do_mmaps(&mmap_addresses);
+
+	EXPECT_NE(MAP_FAILED, mmap_addresses.no_hint);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_37_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_38_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_46_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_47_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_55_addr);
+	EXPECT_NE(MAP_FAILED, mmap_addresses.on_56_addr);
+
+	EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.no_hint);
+	EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_37_addr);
+	EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_38_addr);
+	EXPECT_GT(1UL << 38, (unsigned long)mmap_addresses.on_46_addr);
+	EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_47_addr);
+	EXPECT_GT(1UL << 47, (unsigned long)mmap_addresses.on_55_addr);
+	EXPECT_GT(1UL << 56, (unsigned long)mmap_addresses.on_56_addr);
+#endif
+}
+
+TEST_HARNESS_MAIN

tools/testing/selftests/riscv/mm/testcases/mmap_test.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _TESTCASES_MMAP_TEST_H
+#define _TESTCASES_MMAP_TEST_H
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <stddef.h>
+
+#define TOP_DOWN 0
+#define BOTTOM_UP 1
+
+struct addresses {
+	int *no_hint;
+	int *on_37_addr;
+	int *on_38_addr;
+	int *on_46_addr;
+	int *on_47_addr;
+	int *on_55_addr;
+	int *on_56_addr;
+};
+
+static inline void do_mmaps(struct addresses *mmap_addresses)
+{
+	/*
+	 * Place all of the hint addresses on the boundaries of mmap
+	 * sv39, sv48, sv57
+	 * User addresses end at 1<<38, 1<<47, 1<<56 respectively
+	 */
+	void *on_37_bits = (void *)(1UL << 37);
+	void *on_38_bits = (void *)(1UL << 38);
+	void *on_46_bits = (void *)(1UL << 46);
+	void *on_47_bits = (void *)(1UL << 47);
+	void *on_55_bits = (void *)(1UL << 55);
+	void *on_56_bits = (void *)(1UL << 56);
+
+	int prot = PROT_READ | PROT_WRITE;
+	int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+
+	mmap_addresses->no_hint =
+		mmap(NULL, 5 * sizeof(int), prot, flags, 0, 0);
+	mmap_addresses->on_37_addr =
+		mmap(on_37_bits, 5 * sizeof(int), prot, flags, 0, 0);
+	mmap_addresses->on_38_addr =
+		mmap(on_38_bits, 5 * sizeof(int), prot, flags, 0, 0);
+	mmap_addresses->on_46_addr =
+		mmap(on_46_bits, 5 * sizeof(int), prot, flags, 0, 0);
+	mmap_addresses->on_47_addr =
+		mmap(on_47_bits, 5 * sizeof(int), prot, flags, 0, 0);
+	mmap_addresses->on_55_addr =
+		mmap(on_55_bits, 5 * sizeof(int), prot, flags, 0, 0);
+	mmap_addresses->on_56_addr =
+		mmap(on_56_bits, 5 * sizeof(int), prot, flags, 0, 0);
+}
+
+static inline int memory_layout(void)
+{
+	int prot = PROT_READ | PROT_WRITE;
+	int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+
+	void *value1 = mmap(NULL, sizeof(int), prot, flags, 0, 0);
+	void *value2 = mmap(NULL, sizeof(int), prot, flags, 0, 0);
+
+	return value2 > value1;
+}
+#endif /* _TESTCASES_MMAP_TEST_H */

tools/testing/selftests/riscv/mm/testcases/run_mmap.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+original_stack_limit=$(ulimit -s)
+
+./mmap_default
+
+# Force mmap_bottomup to be ran with bottomup memory due to
+# the unlimited stack
+ulimit -s unlimited
+./mmap_bottomup
+ulimit -s $original_stack_limit