[PATCH V7 11/18] x86/pks: Add PKS Test code
From: ira . weiny
Date: Wed Aug 04 2021 - 00:33:24 EST
From: Ira Weiny <ira.weiny@xxxxxxxxx>
The core PKS functionality provides an interface for kernel users to
reserve a key and set up page tables with that key.
Define test code under CONFIG_PKS_TEST which exercises the core
functionality of PKS via a debugfs entry. Basic checks can be triggered
on boot with a kernel command line option while both basic and
preemption checks can be triggered with separate debugfs values. [See
the comment at the top of pks_test.c for details on the values which can
be used and what tests they run.]
CONFIG_PKS_TEST enables ARCH_ENABLE_SUPERVISOR_PKEYS but can not
co-exist with any GENERAL_PKS_USER. This is because the test code
iterates through all the keys and is pretty much not useful in general
kernel configs. General PKS users should select GENERAL_PKS_USER which
will disable PKS_TEST as well as enable ARCH_ENABLE_SUPERVISOR_PKEYS.
A PKey is not reserved for this test and the test code defines its own
PKS_KEY_PKS_TEST.
To test pks_abandon_protections() each test requires the thread to be
re-run after resetting the abandoned mask value. Do this by allowing
the test code access to the abandoned mask value.
Co-developed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
Changes for V7
Add testing for pks_abandon_protections()
Adjust pkrs_init_value
Adjust for new defines
Clean up comments
Adjust test for static allocation of pkeys
Use lookup_address() instead of follow_pte()
follow_pte only works on IO and raw PFN mappings, use
lookup_address() instead. lookup_address() is
constrained to architectures which support it.
---
Documentation/core-api/protection-keys.rst | 6 +-
arch/x86/include/asm/pks.h | 18 +
arch/x86/mm/fault.c | 8 +
arch/x86/mm/pkeys.c | 18 +-
lib/Kconfig.debug | 13 +
lib/Makefile | 3 +
lib/pks/Makefile | 3 +
lib/pks/pks_test.c | 864 +++++++++++++++++++++
mm/Kconfig | 5 +-
tools/testing/selftests/x86/Makefile | 2 +-
tools/testing/selftests/x86/test_pks.c | 157 ++++
11 files changed, 1092 insertions(+), 5 deletions(-)
create mode 100644 lib/pks/Makefile
create mode 100644 lib/pks/pks_test.c
create mode 100644 tools/testing/selftests/x86/test_pks.c
diff --git a/Documentation/core-api/protection-keys.rst b/Documentation/core-api/protection-keys.rst
index 202088634fa3..8cf7eaaed3e5 100644
--- a/Documentation/core-api/protection-keys.rst
+++ b/Documentation/core-api/protection-keys.rst
@@ -122,8 +122,8 @@ available in future non-server Intel parts.
Also qemu has some support as well: https://www.qemu.org/2021/04/30/qemu-6-0-0/
Kernel users intending to use PKS support should depend on
-ARCH_HAS_SUPERVISOR_PKEYS, and add their config to ARCH_ENABLE_SUPERVISOR_PKEYS
-to turn on this support within the core.
+ARCH_HAS_SUPERVISOR_PKEYS, and add their config to GENERAL_PKS_USER to turn on
+this support within the core.
Users reserve a key value by adding an entry to the enum pks_pkey_consumers and
defining the initial protections in the consumer_defaults[] array.
@@ -188,3 +188,5 @@ text:
affected by PKRU register will not execute (even transiently)
until all prior executions of WRPKRU have completed execution
and updated the PKRU register.
+
+Example code can be found in lib/pks/pks_test.c
diff --git a/arch/x86/include/asm/pks.h b/arch/x86/include/asm/pks.h
index ed293ef4509e..e28413cc410d 100644
--- a/arch/x86/include/asm/pks.h
+++ b/arch/x86/include/asm/pks.h
@@ -39,4 +39,22 @@ static inline int handle_abandoned_pks_value(struct pt_regs *regs)
#endif /* CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS */
+
+#ifdef CONFIG_PKS_TEST
+
+#define __static_or_pks_test
+
+bool pks_test_callback(struct pt_regs *regs);
+
+#else /* !CONFIG_PKS_TEST */
+
+#define __static_or_pks_test static
+
+static inline bool pks_test_callback(struct pt_regs *regs)
+{
+ return false;
+}
+
+#endif /* CONFIG_PKS_TEST */
+
#endif /* _ASM_X86_PKS_H */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index bf3353d8e011..3780ed0f9597 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1154,6 +1154,14 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
*/
WARN_ON_ONCE(!cpu_feature_enabled(X86_FEATURE_PKS));
+ /*
+ * If a protection key exception occurs it could be because a PKS test
+ * is running. If so, pks_test_callback() will clear the protection
+ * mechanism and return true to indicate the fault was handled.
+ */
+ if (pks_test_callback(regs))
+ return;
+
if (handle_abandoned_pks_value(regs))
return;
}
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 56d37840186b..c7358662ec07 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -218,7 +218,7 @@ u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
#ifdef CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS
-static DEFINE_PER_CPU(u32, pkrs_cache);
+__static_or_pks_test DEFINE_PER_CPU(u32, pkrs_cache);
u32 __read_mostly pkrs_init_value;
/*
@@ -289,6 +289,22 @@ static int __init create_initial_pkrs_value(void)
pkrs_init_value = 0;
pkrs_pkey_allowed_mask = PKRS_ALLOWED_MASK_DEFAULT;
+ /*
+ * PKS_TEST is mutually exclusive to any real users of PKS so define a PKS_TEST
+ * appropriate value.
+ *
+ * NOTE: PKey 0 must still be fully permissive for normal kernel mappings to
+ * work correctly.
+ */
+ if (IS_ENABLED(CONFIG_PKS_TEST)) {
+ pkrs_init_value = (PKR_AD_KEY(1) | PKR_AD_KEY(2) | PKR_AD_KEY(3) | \
+ PKR_AD_KEY(4) | PKR_AD_KEY(5) | PKR_AD_KEY(6) | \
+ PKR_AD_KEY(7) | PKR_AD_KEY(8) | PKR_AD_KEY(9) | \
+ PKR_AD_KEY(10) | PKR_AD_KEY(11) | PKR_AD_KEY(12) | \
+ PKR_AD_KEY(13) | PKR_AD_KEY(14) | PKR_AD_KEY(15));
+ return 0;
+ }
+
/* Fill the defaults for the consumers */
for (i = 0; i < PKS_NUM_PKEYS; i++)
pkrs_init_value |= PKR_VALUE(i, consumer_defaults[i]);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 831212722924..28579084649d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2650,6 +2650,19 @@ config HYPERV_TESTING
help
Select this option to enable Hyper-V vmbus testing.
+config PKS_TEST
+ bool "PKey (S)upervisor testing"
+ depends on ARCH_HAS_SUPERVISOR_PKEYS
+ depends on !GENERAL_PKS_USER
+ help
+ Select this option to enable testing of PKS core software and
+ hardware. The PKS core provides a mechanism to allocate keys as well
+ as maintain the protection settings across context switches.
+
+ Answer N if you don't know what supervisor keys are.
+
+ If unsure, say N.
+
endmenu # "Kernel Testing and Coverage"
source "Documentation/Kconfig"
diff --git a/lib/Makefile b/lib/Makefile
index 5efd1b435a37..fc31f2d6d8e4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -360,3 +360,6 @@ obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o
obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
+
+# PKS test
+obj-y += pks/
diff --git a/lib/pks/Makefile b/lib/pks/Makefile
new file mode 100644
index 000000000000..9daccba4f7c4
--- /dev/null
+++ b/lib/pks/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_PKS_TEST) += pks_test.o
diff --git a/lib/pks/pks_test.c b/lib/pks/pks_test.c
new file mode 100644
index 000000000000..679edd487360
--- /dev/null
+++ b/lib/pks/pks_test.c
@@ -0,0 +1,864 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright(c) 2020 Intel Corporation. All rights reserved.
+ *
+ * Implement PKS testing
+ * Access to run this test can be with a command line parameter
+ * ("pks-test-on-boot") or more detailed tests can be triggered through:
+ *
+ * /sys/kernel/debug/x86/run_pks
+ *
+ * debugfs controls are:
+ *
+ * '0' -- Run access tests with a single pkey
+ * '1' -- Set up the pkey register with no access for the pkey allocated to
+ * this fd
+ * '2' -- Check that the pkey register updated in '1' is still the same.
+ * (To be used after a forced context switch.)
+ * '3' -- Allocate all pkeys possible and run tests on each pkey allocated.
+ * DEFAULT when run at boot.
+ * '4' -- The same as '0' with additional kernel debugging
+ * '5' -- The same as '3' with additional kernel debugging
+ * '6' -- Test abandoning a pkey
+ * '9' -- Set up and fault on a PKS protected page. This will crash the
+ * kernel and requires the option to be specified 2 times in a row.
+ *
+ * Closing the fd will cleanup and release the pkey, to exercise context
+ * switch testing a user space program is provided in:
+ *
+ * .../tools/testing/selftests/x86/test_pks.c
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/entry-common.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/percpu-defs.h>
+#include <linux/pgtable.h>
+#include <linux/pkeys.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include <asm/ptrace.h> /* for struct pt_regs */
+#include <asm/pkeys_common.h>
+#include <asm/processor.h>
+#include <asm/pks.h>
+
+/*
+ * PKS testing uses all pkeys but define 1 key to use for some tests. Any
+ * value from [1-PKS_NUM_PKEYS) will work.
+ */
+#define PKS_KEY_PKS_TEST 1
+#define PKS_TEST_MEM_SIZE (PAGE_SIZE)
+
+#define RUN_ALLOCATE "0"
+#define ARM_CTX_SWITCH "1"
+#define CHECK_CTX_SWITCH "2"
+#define RUN_ALLOCATE_ALL "3"
+#define RUN_ALLOCATE_DEBUG "4"
+#define RUN_ALLOCATE_ALL_DEBUG "5"
+#define RUN_DISABLE_TEST "6"
+#define RUN_CRASH_TEST "9"
+
+/* The testing needs some knowledge of the internals */
+DECLARE_PER_CPU(u32, pkrs_cache);
+extern u32 pkrs_pkey_allowed_mask;
+
+/*
+ * run_on_boot default '= false' which checkpatch complains about initializing;
+ * so don't
+ */
+static bool run_on_boot;
+static struct dentry *pks_test_dentry;
+static bool run_9;
+
+/*
+ * The following globals must be protected for brief periods while the fault
+ * handler checks/updates them.
+ */
+static DEFINE_SPINLOCK(test_lock);
+static int test_armed_key;
+static unsigned long prev_cnt;
+static unsigned long fault_cnt;
+
+struct pks_test_ctx {
+ bool pass;
+ bool pks_cpu_enabled;
+ bool debug;
+ int pkey;
+ char data[64];
+};
+static struct pks_test_ctx *test_exception_ctx;
+
+static bool check_pkey_val(u32 pk_reg, int pkey, u32 expected)
+{
+ pk_reg = (pk_reg & PKR_PKEY_MASK(pkey)) >> PKR_PKEY_SHIFT(pkey);
+ return (pk_reg == expected);
+}
+
+/*
+ * Check if the register @pkey value matches @expected value
+ *
+ * Both the cached and actual MSR must match.
+ */
+static bool check_pkrs(int pkey, u32 expected)
+{
+ bool ret = true;
+ u64 pkrs;
+ u32 *tmp_cache;
+
+ tmp_cache = get_cpu_ptr(&pkrs_cache);
+ if (!check_pkey_val(*tmp_cache, pkey, expected))
+ ret = false;
+ put_cpu_ptr(tmp_cache);
+
+ rdmsrl(MSR_IA32_PKRS, pkrs);
+ if (!check_pkey_val(pkrs, pkey, expected))
+ ret = false;
+
+ return ret;
+}
+
+static void check_exception(u32 thread_pkrs)
+{
+ /* Check the thread saved state */
+ if (!check_pkey_val(thread_pkrs, test_armed_key, PKEY_DISABLE_WRITE)) {
+ pr_err(" FAIL: checking ept_regs->thread_pkrs\n");
+ test_exception_ctx->pass = false;
+ }
+
+ /* Check the exception state */
+ if (!check_pkrs(test_armed_key, PKEY_DISABLE_ACCESS)) {
+ pr_err(" FAIL: PKRS cache and MSR\n");
+ test_exception_ctx->pass = false;
+ }
+
+ /*
+ * Ensure an update can occur during exception without affecting the
+ * interrupted thread. The interrupted thread is checked after
+ * exception...
+ */
+ pks_mk_readwrite(test_armed_key);
+ if (!check_pkrs(test_armed_key, 0)) {
+ pr_err(" FAIL: exception did not change register to 0\n");
+ test_exception_ctx->pass = false;
+ }
+ pks_mk_noaccess(test_armed_key);
+ if (!check_pkrs(test_armed_key, PKEY_DISABLE_ACCESS)) {
+ pr_err(" FAIL: exception did not change register to 0x%x\n",
+ PKEY_DISABLE_ACCESS);
+ test_exception_ctx->pass = false;
+ }
+}
+
+/**
+ * pks_test_callback() is exported so that the fault handler can detect
+ * and report back status of intentional faults.
+ *
+ * NOTE: It clears the protection key from the page such that the fault handler
+ * will not re-trigger.
+ */
+bool pks_test_callback(struct pt_regs *regs)
+{
+ struct extended_pt_regs *ept_regs = extended_pt_regs(regs);
+ bool armed = (test_armed_key != 0);
+
+ if (test_exception_ctx) {
+ check_exception(ept_regs->thread_pkrs);
+ /*
+ * Stop this check directly within the exception because the
+ * fault handler clean up code will call again while checking
+ * the PMD entry and there is no need to check this again.
+ */
+ test_exception_ctx = NULL;
+ }
+
+ if (armed) {
+ /* Enable read and write to stop faults */
+ ept_regs->thread_pkrs = update_pkey_val(ept_regs->thread_pkrs,
+ test_armed_key, 0);
+ fault_cnt++;
+ }
+
+ return armed;
+}
+
+static bool exception_caught(void)
+{
+ bool ret = (fault_cnt != prev_cnt);
+
+ prev_cnt = fault_cnt;
+ return ret;
+}
+
+static void report_pkey_settings(void *info)
+{
+ u8 pkey;
+ unsigned long long msr = 0;
+ unsigned int cpu = smp_processor_id();
+ struct pks_test_ctx *ctx = info;
+
+ rdmsrl(MSR_IA32_PKRS, msr);
+
+ pr_info("for CPU %d : 0x%llx\n", cpu, msr);
+
+ if (ctx->debug) {
+ for (pkey = 0; pkey < PKS_NUM_PKEYS; pkey++) {
+ int ad, wd;
+
+ ad = (msr >> PKR_PKEY_SHIFT(pkey)) & PKEY_DISABLE_ACCESS;
+ wd = (msr >> PKR_PKEY_SHIFT(pkey)) & PKEY_DISABLE_WRITE;
+ pr_info(" %u: A:%d W:%d\n", pkey, ad, wd);
+ }
+ }
+}
+
+enum pks_access_mode {
+ PKS_TEST_NO_ACCESS,
+ PKS_TEST_RDWR,
+ PKS_TEST_RDONLY
+};
+
+static char *get_mode_str(enum pks_access_mode mode)
+{
+ switch (mode) {
+ case PKS_TEST_NO_ACCESS:
+ return "No Access";
+ case PKS_TEST_RDWR:
+ return "Read Write";
+ case PKS_TEST_RDONLY:
+ return "Read Only";
+ default:
+ pr_err("BUG in test invalid mode\n");
+ break;
+ }
+
+ return "";
+}
+
+struct pks_access_test {
+ enum pks_access_mode mode;
+ bool write;
+ bool exception;
+};
+
+static struct pks_access_test pkey_test_ary[] = {
+ /* disable both */
+ { PKS_TEST_NO_ACCESS, true, true },
+ { PKS_TEST_NO_ACCESS, false, true },
+
+ /* enable both */
+ { PKS_TEST_RDWR, true, false },
+ { PKS_TEST_RDWR, false, false },
+
+ /* enable read only */
+ { PKS_TEST_RDONLY, true, true },
+ { PKS_TEST_RDONLY, false, false },
+};
+
+static int test_it(struct pks_test_ctx *ctx, struct pks_access_test *test,
+ void *ptr, bool forced_sched)
+{
+ bool exception;
+ int ret = 0;
+
+ spin_lock(&test_lock);
+ WRITE_ONCE(test_armed_key, ctx->pkey);
+
+ if (test->write)
+ memcpy(ptr, ctx->data, 8);
+ else
+ memcpy(ctx->data, ptr, 8);
+
+ exception = exception_caught();
+
+ WRITE_ONCE(test_armed_key, 0);
+ spin_unlock(&test_lock);
+
+ /*
+ * After a forced schedule the allowed mask should be applied on
+ * sched_in and therefore no exception should ever be seen.
+ */
+ if (forced_sched && exception) {
+ pr_err("pkey test FAILED: mode %s; write %s; exception %s != %s; sched TRUE\n",
+ get_mode_str(test->mode),
+ test->write ? "TRUE" : "FALSE",
+ test->exception ? "TRUE" : "FALSE",
+ exception ? "TRUE" : "FALSE");
+ ret = -EFAULT;
+ } else if (test->exception != exception) {
+ pr_err("pkey test FAILED: mode %s; write %s; exception %s != %s\n",
+ get_mode_str(test->mode),
+ test->write ? "TRUE" : "FALSE",
+ test->exception ? "TRUE" : "FALSE",
+ exception ? "TRUE" : "FALSE");
+ ret = -EFAULT;
+ }
+
+ return ret;
+}
+
+static int run_access_test(struct pks_test_ctx *ctx,
+ struct pks_access_test *test,
+ void *ptr,
+ bool forced_sched)
+{
+ switch (test->mode) {
+ case PKS_TEST_NO_ACCESS:
+ pks_mk_noaccess(ctx->pkey);
+ break;
+ case PKS_TEST_RDWR:
+ pks_mk_readwrite(ctx->pkey);
+ break;
+ case PKS_TEST_RDONLY:
+ pks_mk_readonly(ctx->pkey);
+ break;
+ default:
+ pr_err("BUG in test invalid mode\n");
+ break;
+ }
+
+ return test_it(ctx, test, ptr, forced_sched);
+}
+
+static void *alloc_test_page(int pkey)
+{
+ return __vmalloc_node_range(PKS_TEST_MEM_SIZE, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL, PAGE_KERNEL_PKEY(pkey), 0,
+ NUMA_NO_NODE, __builtin_return_address(0));
+}
+
+static void test_mem_access(struct pks_test_ctx *ctx)
+{
+ int i, rc;
+ u8 pkey;
+ void *ptr = NULL;
+ pte_t *ptep = NULL;
+ unsigned int level;
+
+ ptr = alloc_test_page(ctx->pkey);
+ if (!ptr) {
+ pr_err("Failed to vmalloc page???\n");
+ ctx->pass = false;
+ return;
+ }
+
+ ptep = lookup_address((unsigned long)ptr, &level);
+ if (!ptep) {
+ pr_err("Failed to lookup address???\n");
+ ctx->pass = false;
+ goto done;
+ }
+
+ pr_info("lookup address ptr %p ptep %p\n",
+ ptr, ptep);
+
+ pkey = pte_flags_pkey(ptep->pte);
+ pr_info("ptep flags 0x%lx pkey %u\n",
+ (unsigned long)ptep->pte, pkey);
+
+ if (pkey != ctx->pkey) {
+ pr_err("invalid pkey found: %u, test_pkey: %u\n",
+ pkey, ctx->pkey);
+ ctx->pass = false;
+ goto done;
+ }
+
+ if (!ctx->pks_cpu_enabled) {
+ pr_err("not CPU enabled; skipping access tests...\n");
+ ctx->pass = true;
+ goto done;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(pkey_test_ary); i++) {
+ rc = run_access_test(ctx, &pkey_test_ary[i], ptr, false);
+
+ /* only save last error is fine */
+ if (rc)
+ ctx->pass = false;
+ }
+
+done:
+ vfree(ptr);
+}
+
+static void pks_run_test(struct pks_test_ctx *ctx)
+{
+ ctx->pass = true;
+
+ pr_info("\n");
+ pr_info("\n");
+ pr_info(" ***** BEGIN: Testing (CPU enabled : %s) *****\n",
+ ctx->pks_cpu_enabled ? "TRUE" : "FALSE");
+
+ if (ctx->pks_cpu_enabled)
+ on_each_cpu(report_pkey_settings, ctx, 1);
+
+ pr_info(" BEGIN: pkey %d Testing\n", ctx->pkey);
+ test_mem_access(ctx);
+ pr_info(" END: PAGE_KERNEL_PKEY Testing : %s\n",
+ ctx->pass ? "PASS" : "FAIL");
+
+ pr_info(" ***** END: Testing *****\n");
+ pr_info("\n");
+ pr_info("\n");
+}
+
+static ssize_t pks_read_file(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct pks_test_ctx *ctx = file->private_data;
+ char buf[32];
+ unsigned int len;
+
+ if (!ctx)
+ len = sprintf(buf, "not run\n");
+ else
+ len = sprintf(buf, "%s\n", ctx->pass ? "PASS" : "FAIL");
+
+ return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static struct pks_test_ctx *alloc_ctx(u8 pkey)
+{
+ struct pks_test_ctx *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+
+ if (!ctx) {
+ pr_err("Failed to allocate memory for test context\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ ctx->pkey = pkey;
+ ctx->pks_cpu_enabled = cpu_feature_enabled(X86_FEATURE_PKS);
+ sprintf(ctx->data, "%s", "DEADBEEF");
+ return ctx;
+}
+
+static void free_ctx(struct pks_test_ctx *ctx)
+{
+ kfree(ctx);
+}
+
+static void run_exception_test(void)
+{
+ void *ptr = NULL;
+ bool pass = true;
+ struct pks_test_ctx *ctx;
+
+ pr_info(" ***** BEGIN: exception checking\n");
+
+ ctx = alloc_ctx(PKS_KEY_PKS_TEST);
+ if (IS_ERR(ctx)) {
+ pr_err(" FAIL: no context\n");
+ pass = false;
+ goto result;
+ }
+ ctx->pass = true;
+
+ ptr = alloc_test_page(ctx->pkey);
+ if (!ptr) {
+ pr_err(" FAIL: no vmalloc page\n");
+ pass = false;
+ goto free_context;
+ }
+
+ pks_mk_readonly(ctx->pkey);
+
+ spin_lock(&test_lock);
+ WRITE_ONCE(test_exception_ctx, ctx);
+ WRITE_ONCE(test_armed_key, ctx->pkey);
+
+ memcpy(ptr, ctx->data, 8);
+
+ if (!exception_caught()) {
+ pr_err(" FAIL: did not get an exception\n");
+ pass = false;
+ }
+
+ /*
+ * NOTE The exception code has to enable access (b00) to keep the fault
+ * from looping forever. Therefore full access is seen here rather
+ * than write disabled.
+ *
+ * Furthermore, check_exception() disabled access during the exception
+ * so this is testing that the thread value was restored back to the
+ * thread value.
+ */
+ if (!check_pkrs(test_armed_key, 0)) {
+ pr_err(" FAIL: PKRS not restored\n");
+ pass = false;
+ }
+
+ if (!ctx->pass)
+ pass = false;
+
+ WRITE_ONCE(test_armed_key, 0);
+ spin_unlock(&test_lock);
+
+ vfree(ptr);
+free_context:
+ free_ctx(ctx);
+result:
+ pr_info(" ***** END: exception checking : %s\n",
+ pass ? "PASS" : "FAIL");
+}
+
+static struct pks_access_test abandon_test_ary[] = {
+ /* disable both */
+ { PKS_TEST_NO_ACCESS, true, false },
+ { PKS_TEST_NO_ACCESS, false, false },
+
+ /* enable both */
+ { PKS_TEST_RDWR, true, false },
+ { PKS_TEST_RDWR, false, false },
+
+ /* enable read only */
+ { PKS_TEST_RDONLY, true, false },
+ { PKS_TEST_RDONLY, false, false },
+};
+
+static DEFINE_SPINLOCK(abandoned_test_lock);
+struct shared_data {
+ struct pks_test_ctx *ctx;
+ void *kmap_addr;
+ struct pks_access_test *test;
+ bool thread_running;
+ bool sched_thread;
+};
+
+static int abandoned_test_main(void *d)
+{
+ struct shared_data *data = d;
+ struct pks_test_ctx *ctx = data->ctx;
+
+ spin_lock(&abandoned_test_lock);
+ data->thread_running = true;
+ spin_unlock(&abandoned_test_lock);
+
+ while (!kthread_should_stop()) {
+ spin_lock(&abandoned_test_lock);
+ if (data->kmap_addr) {
+ pr_info(" Thread ->saved_pkrs Before 0x%x (%d)\n",
+ current->thread.saved_pkrs, ctx->pkey);
+ if (data->sched_thread)
+ msleep(20);
+ if (run_access_test(ctx, data->test, data->kmap_addr,
+ data->sched_thread))
+ ctx->pass = false;
+ pr_info(" Thread Remote ->saved_pkrs After 0x%x (%d)\n",
+ current->thread.saved_pkrs, ctx->pkey);
+ data->kmap_addr = NULL;
+ }
+ spin_unlock(&abandoned_test_lock);
+ }
+
+ return 0;
+}
+
+static void run_abandon_pkey_test(struct pks_test_ctx *ctx,
+ struct pks_access_test *test,
+ void *ptr,
+ bool sched_thread)
+{
+ struct task_struct *other_task;
+ struct shared_data data;
+ bool running = false;
+
+ pr_info("checking... mode %s; write %s\n",
+ get_mode_str(test->mode), test->write ? "TRUE" : "FALSE");
+
+ pkrs_pkey_allowed_mask = 0xffffffff;
+
+ memset(&data, 0, sizeof(data));
+ data.ctx = ctx;
+ data.thread_running = false;
+ data.sched_thread = sched_thread;
+ other_task = kthread_run(abandoned_test_main, &data, "PKRS abandoned test");
+ if (IS_ERR(other_task)) {
+ pr_err(" FAIL: Failed to start thread\n");
+ ctx->pass = false;
+ return;
+ }
+
+ while (!running) {
+ spin_lock(&abandoned_test_lock);
+ running = data.thread_running;
+ spin_unlock(&abandoned_test_lock);
+ }
+
+ spin_lock(&abandoned_test_lock);
+ pr_info("Local ->saved_pkrs Before 0x%x (%d)\n",
+ current->thread.saved_pkrs, ctx->pkey);
+ pks_abandon_protections(ctx->pkey);
+ data.test = test;
+ data.kmap_addr = ptr;
+ spin_unlock(&abandoned_test_lock);
+
+ while (data.kmap_addr)
+ msleep(20);
+
+ pr_info("Local ->saved_pkrs After 0x%x (%d)\n",
+ current->thread.saved_pkrs, ctx->pkey);
+
+ kthread_stop(other_task);
+}
+
+static void run_abandoned_test(void)
+{
+ struct pks_test_ctx *ctx;
+ bool pass = true;
+ void *ptr;
+ int i;
+
+ pr_info(" ***** BEGIN: abandoned pkey checking\n");
+
+ ctx = alloc_ctx(PKS_KEY_PKS_TEST);
+ if (IS_ERR(ctx)) {
+ pr_err(" FAIL: no context\n");
+ pass = false;
+ goto result;
+ }
+
+ ptr = alloc_test_page(ctx->pkey);
+ if (!ptr) {
+ pr_err(" FAIL: no vmalloc page\n");
+ pass = false;
+ goto free_context;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(abandon_test_ary); i++) {
+ ctx->pass = true;
+ run_abandon_pkey_test(ctx, &abandon_test_ary[i], ptr, false);
+ /* sticky fail */
+ if (!ctx->pass)
+ pass = ctx->pass;
+
+ ctx->pass = true;
+ run_abandon_pkey_test(ctx, &abandon_test_ary[i], ptr, true);
+ /* sticky fail */
+ if (!ctx->pass)
+ pass = ctx->pass;
+ }
+
+ /* Force re-enable all keys */
+ pkrs_pkey_allowed_mask = 0xffffffff;
+
+ vfree(ptr);
+free_context:
+ free_ctx(ctx);
+result:
+ pr_info(" ***** END: abandoned pkey checking : %s\n",
+ pass ? "PASS" : "FAIL");
+}
+
+static void run_all(bool debug)
+{
+ struct pks_test_ctx *ctx[PKS_NUM_PKEYS];
+ static char name[PKS_NUM_PKEYS][64];
+ int i;
+
+ for (i = 1; i < PKS_NUM_PKEYS; i++) {
+ sprintf(name[i], "pks ctx %d", i);
+ ctx[i] = alloc_ctx(i);
+ if (!IS_ERR(ctx[i]))
+ ctx[i]->debug = debug;
+ }
+
+ for (i = 1; i < PKS_NUM_PKEYS; i++) {
+ if (!IS_ERR(ctx[i]))
+ pks_run_test(ctx[i]);
+ }
+
+ for (i = 1; i < PKS_NUM_PKEYS; i++) {
+ if (!IS_ERR(ctx[i]))
+ free_ctx(ctx[i]);
+ }
+
+ run_exception_test();
+
+ run_abandoned_test();
+}
+
+static void crash_it(void)
+{
+ struct pks_test_ctx *ctx;
+ void *ptr;
+
+ pr_warn(" ***** BEGIN: Unhandled fault test *****\n");
+
+ ctx = alloc_ctx(PKS_KEY_PKS_TEST);
+ if (IS_ERR(ctx)) {
+ pr_err("Failed to allocate context???\n");
+ return;
+ }
+
+ ptr = alloc_test_page(ctx->pkey);
+ if (!ptr) {
+ pr_err("Failed to vmalloc page???\n");
+ ctx->pass = false;
+ return;
+ }
+
+ pks_mk_noaccess(ctx->pkey);
+
+ spin_lock(&test_lock);
+ WRITE_ONCE(test_armed_key, 0);
+ /* This purposely faults */
+ memcpy(ptr, ctx->data, 8);
+ spin_unlock(&test_lock);
+
+ vfree(ptr);
+ free_ctx(ctx);
+}
+
+static ssize_t pks_write_file(struct file *file, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char buf[2];
+ struct pks_test_ctx *ctx = file->private_data;
+
+ if (copy_from_user(buf, user_buf, 1))
+ return -EFAULT;
+ buf[1] = '\0';
+
+ /*
+ * WARNING: Test "9" will crash the kernel.
+ *
+ * Arm the test and print a warning. A second "9" will run the test.
+ */
+ if (!strcmp(buf, RUN_CRASH_TEST)) {
+ if (run_9) {
+ crash_it();
+ run_9 = false;
+ } else {
+ pr_warn("CAUTION: Test 9 will crash in the kernel.\n");
+ pr_warn(" Specify 9 a second time to run\n");
+ pr_warn(" run any other test to clear\n");
+ run_9 = true;
+ }
+ } else {
+ run_9 = false;
+ }
+
+ /*
+ * Test "3" will test allocating all keys. Do it first without
+ * using "ctx".
+ */
+ if (!strcmp(buf, RUN_ALLOCATE_ALL))
+ run_all(false);
+ if (!strcmp(buf, RUN_ALLOCATE_ALL_DEBUG))
+ run_all(true);
+
+ if (!strcmp(buf, RUN_DISABLE_TEST))
+ run_abandoned_test();
+
+ /*
+ * This context is only required if the file is held open for the below
+ * tests. Otherwise the context just get's freed in pks_release_file.
+ */
+ if (!ctx) {
+ ctx = alloc_ctx(PKS_KEY_PKS_TEST);
+ if (IS_ERR(ctx))
+ return -ENOMEM;
+ file->private_data = ctx;
+ }
+
+ if (!strcmp(buf, RUN_ALLOCATE)) {
+ ctx->debug = false;
+ pks_run_test(ctx);
+ }
+ if (!strcmp(buf, RUN_ALLOCATE_DEBUG)) {
+ ctx->debug = true;
+ pks_run_test(ctx);
+ }
+
+ /* start of context switch test */
+ if (!strcmp(buf, ARM_CTX_SWITCH)) {
+ unsigned long reg_pkrs;
+ int access;
+
+ /* Ensure a known state to test context switch */
+ pks_mk_readwrite(ctx->pkey);
+
+ rdmsrl(MSR_IA32_PKRS, reg_pkrs);
+
+ access = (reg_pkrs >> PKR_PKEY_SHIFT(ctx->pkey)) &
+ PKEY_ACCESS_MASK;
+ pr_info("Context switch armed : pkey %d: 0x%x reg: 0x%lx\n",
+ ctx->pkey, access, reg_pkrs);
+ }
+
+ /* After context switch msr should be restored */
+ if (!strcmp(buf, CHECK_CTX_SWITCH) && ctx->pks_cpu_enabled) {
+ unsigned long reg_pkrs;
+ int access;
+
+ rdmsrl(MSR_IA32_PKRS, reg_pkrs);
+
+ access = (reg_pkrs >> PKR_PKEY_SHIFT(ctx->pkey)) &
+ PKEY_ACCESS_MASK;
+ if (access != 0) {
+ ctx->pass = false;
+ pr_err("Context switch check failed: pkey %d: 0x%x reg: 0x%lx\n",
+ ctx->pkey, access, reg_pkrs);
+ } else {
+ pr_err("Context switch check passed: pkey %d: 0x%x reg: 0x%lx\n",
+ ctx->pkey, access, reg_pkrs);
+ }
+ }
+
+ return count;
+}
+
+static int pks_release_file(struct inode *inode, struct file *file)
+{
+ struct pks_test_ctx *ctx = file->private_data;
+
+ if (!ctx)
+ return 0;
+
+ free_ctx(ctx);
+ return 0;
+}
+
+static const struct file_operations fops_init_pks = {
+ .read = pks_read_file,
+ .write = pks_write_file,
+ .llseek = default_llseek,
+ .release = pks_release_file,
+};
+
+static int __init parse_pks_test_options(char *str)
+{
+ run_on_boot = true;
+
+ return 0;
+}
+early_param("pks-test-on-boot", parse_pks_test_options);
+
+static int __init pks_test_init(void)
+{
+ if (cpu_feature_enabled(X86_FEATURE_PKS)) {
+ if (run_on_boot)
+ run_all(true);
+
+ pks_test_dentry = debugfs_create_file("run_pks", 0600, arch_debugfs_dir,
+ NULL, &fops_init_pks);
+ }
+
+ return 0;
+}
+late_initcall(pks_test_init);
+
+static void __exit pks_test_exit(void)
+{
+ debugfs_remove(pks_test_dentry);
+ pr_info("test exit\n");
+}
diff --git a/mm/Kconfig b/mm/Kconfig
index e0d29c655ade..ea6ffee69f55 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -820,8 +820,11 @@ config ARCH_HAS_PKEYS
bool
config ARCH_HAS_SUPERVISOR_PKEYS
bool
+config GENERAL_PKS_USER
+ def_bool n
config ARCH_ENABLE_SUPERVISOR_PKEYS
- bool
+ def_bool y
+ depends on PKS_TEST || GENERAL_PKS_USER
config PERCPU_STATS
bool "Collect percpu memory statistics"
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index b4142cd1c5c2..b2f852f0e7e1 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -13,7 +13,7 @@ CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh $(CC) trivial_program.c -no-pie)
TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
check_initial_reg_state sigreturn iopl ioperm \
test_vsyscall mov_ss_trap \
- syscall_arg_fault fsgsbase_restore sigaltstack
+ syscall_arg_fault fsgsbase_restore sigaltstack test_pks
TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
diff --git a/tools/testing/selftests/x86/test_pks.c b/tools/testing/selftests/x86/test_pks.c
new file mode 100644
index 000000000000..c12b38760c9c
--- /dev/null
+++ b/tools/testing/selftests/x86/test_pks.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright(c) 2020 Intel Corporation. All rights reserved.
+ *
+ * User space tool to test PKS operations. Accesses test code through
+ * <debugfs>/x86/run_pks when CONFIG_PKS_TEST is enabled.
+ *
+ */
+
+#define _GNU_SOURCE
+#include <sched.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <unistd.h>
+#include <assert.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdbool.h>
+
+#define PKS_TEST_FILE "/sys/kernel/debug/x86/run_pks"
+
+#define RUN_ALLOCATE "0"
+#define SETUP_CTX_SWITCH "1"
+#define CHECK_CTX_SWITCH "2"
+#define RUN_ALLOCATE_ALL "3"
+#define RUN_ALLOCATE_DEBUG "4"
+#define RUN_ALLOCATE_ALL_DEBUG "5"
+#define RUN_DISABLE_TEST "6"
+#define RUN_CRASH_TEST "9"
+
+int main(int argc, char *argv[])
+{
+ cpu_set_t cpuset;
+ char result[32];
+ pid_t pid;
+ int fd;
+ int setup_done[2];
+ int switch_done[2];
+ int cpu = 0;
+ int rc = 0;
+ int c;
+ bool debug = false;
+
+ while (1) {
+ int option_index = 0;
+ static struct option long_options[] = {
+ {"debug", no_argument, 0, 0 },
+ {0, 0, 0, 0 }
+ };
+
+ c = getopt_long(argc, argv, "", long_options, &option_index);
+ if (c == -1)
+ break;
+
+ switch (c) {
+ case 0:
+ debug = true;
+ break;
+ }
+ }
+
+ if (optind < argc)
+ cpu = strtoul(argv[optind], NULL, 0);
+
+ if (cpu >= sysconf(_SC_NPROCESSORS_ONLN)) {
+ printf("CPU %d is invalid\n", cpu);
+ cpu = sysconf(_SC_NPROCESSORS_ONLN) - 1;
+ printf(" running on max CPU: %d\n", cpu);
+ }
+
+ CPU_ZERO(&cpuset);
+ CPU_SET(cpu, &cpuset);
+ /* Two processes run on CPU 0 so that they go through context switch. */
+ sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset);
+
+ if (pipe(setup_done))
+ printf("Failed to create pipe\n");
+ if (pipe(switch_done))
+ printf("Failed to create pipe\n");
+
+ pid = fork();
+ if (pid == 0) {
+ char done = 'y';
+
+ fd = open(PKS_TEST_FILE, O_RDWR);
+ if (fd < 0) {
+ printf("cannot open %s\n", PKS_TEST_FILE);
+ return -1;
+ }
+
+ cpu = sched_getcpu();
+ printf("Child running on cpu %d...\n", cpu);
+
+ /* Allocate test_pkey1 and run test. */
+ if (debug)
+ write(fd, RUN_ALLOCATE_DEBUG, 1);
+ else
+ write(fd, RUN_ALLOCATE, 1);
+
+ /* Arm for context switch test */
+ write(fd, SETUP_CTX_SWITCH, 1);
+
+ printf(" tell parent to go\n");
+ write(setup_done[1], &done, sizeof(done));
+
+ /* Context switch out... */
+ printf(" Waiting for parent...\n");
+ read(switch_done[0], &done, sizeof(done));
+
+ /* Check msr restored */
+ printf("Checking result\n");
+ write(fd, CHECK_CTX_SWITCH, 1);
+
+ read(fd, result, 10);
+ printf(" #PF, context switch, pkey allocation and free tests: %s\n", result);
+ if (!strncmp(result, "PASS", 10)) {
+ rc = -1;
+ done = 'F';
+ }
+
+ /* Signal result */
+ write(setup_done[1], &done, sizeof(done));
+ } else {
+ char done = 'y';
+
+ read(setup_done[0], &done, sizeof(done));
+ cpu = sched_getcpu();
+ printf("Parent running on cpu %d\n", cpu);
+
+ fd = open(PKS_TEST_FILE, O_RDWR);
+ if (fd < 0) {
+ printf("cannot open %s\n", PKS_TEST_FILE);
+ return -1;
+ }
+
+ /* run test with alternate pkey */
+ if (debug)
+ write(fd, RUN_ALLOCATE_DEBUG, 1);
+ else
+ write(fd, RUN_ALLOCATE, 1);
+
+ printf(" Signaling child.\n");
+ write(switch_done[1], &done, sizeof(done));
+
+ /* Wait for result */
+ read(setup_done[0], &done, sizeof(done));
+ if (done == 'F')
+ rc = -1;
+ }
+
+ close(fd);
+
+ return rc;
+}
--
2.28.0.rc0.12.gb6a658bd00c9