This series introduces the selftests/arm directory, which tests 32 and 64-bit
kernel compatibility with 32-bit ELFs running on the Aarch platform.
The need for this bucket of tests is that 32 bit applications built on legacy
ARM architecture must not break on the new Aarch64 platforms and the 64-bit
kernel. The kernel must emulate the data structures, system calls and the
registers according to Aarch32, when running a 32-bit process; this directory
fills that testing requirement.
One may find similarity between this directory and selftests/arm64; it is
advisable to refer to that since a lot has been copied from there itself.
The mm directory includes a test for checking 4GB limit of the virtual
address space of a process.
The signal directory contains two tests, following a common theme: mangle
with arm_cpsr, dumped by the kernel to user space while invoking the signal
handler; kernel must spot this illegal attempt and terminate the program by
SEGV.
The elf directory includes a test for checking the 32-bit status of the ELF.
The series has been tested on 6.9-rc5, on Aarch64 platform. Testing remains
to be done on Aaarch32.
Changes in v2:
- Formatting changes
- Add .gitignore files and config file
Dev Jain (4):
selftests/arm: Add mm test
selftests/arm: Add signal tests
selftests/arm: Add elf test
selftests: Add build infrastructure along with README
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/arm/Makefile | 57 ++++
tools/testing/selftests/arm/README | 31 +++
tools/testing/selftests/arm/config | 1 +
tools/testing/selftests/arm/elf/.gitignore | 2 +
tools/testing/selftests/arm/elf/Makefile | 6 +
tools/testing/selftests/arm/elf/parse_elf.c | 74 +++++
tools/testing/selftests/arm/mm/.gitignore | 2 +
tools/testing/selftests/arm/mm/Makefile | 6 +
tools/testing/selftests/arm/mm/compat_va.c | 92 +++++++
tools/testing/selftests/arm/signal/.gitignore | 3 +
tools/testing/selftests/arm/signal/Makefile | 30 ++
.../selftests/arm/signal/test_signals.c | 27 ++
.../selftests/arm/signal/test_signals.h | 74 +++++
.../selftests/arm/signal/test_signals_utils.c | 257 ++++++++++++++++++
.../selftests/arm/signal/test_signals_utils.h | 128 +++++++++
.../signal/testcases/mangle_cpsr_aif_bits.c | 33 +++
.../mangle_cpsr_invalid_compat_toggle.c | 29 ++
18 files changed, 853 insertions(+)
create mode 100644 tools/testing/selftests/arm/Makefile
create mode 100644 tools/testing/selftests/arm/README
create mode 100644 tools/testing/selftests/arm/config
create mode 100644 tools/testing/selftests/arm/elf/.gitignore
create mode 100644 tools/testing/selftests/arm/elf/Makefile
create mode 100644 tools/testing/selftests/arm/elf/parse_elf.c
create mode 100644 tools/testing/selftests/arm/mm/.gitignore
create mode 100644 tools/testing/selftests/arm/mm/Makefile
create mode 100644 tools/testing/selftests/arm/mm/compat_va.c
create mode 100644 tools/testing/selftests/arm/signal/.gitignore
create mode 100644 tools/testing/selftests/arm/signal/Makefile
create mode 100644 tools/testing/selftests/arm/signal/test_signals.c
create mode 100644 tools/testing/selftests/arm/signal/test_signals.h
create mode 100644 tools/testing/selftests/arm/signal/test_signals_utils.c
create mode 100644 tools/testing/selftests/arm/signal/test_signals_utils.h
create mode 100644 tools/testing/selftests/arm/signal/testcases/mangle_cpsr_aif_bits.c
create mode 100644 tools/testing/selftests/arm/signal/testcases/mangle_cpsr_invalid_compat_toggle.c
--
2.39.2
This patch tests the 4GB VA restriction for 32-bit processes; it is required
to test the compat layer, whether the kernel knows that it is running a 32-bit
process or not. Chunks are allocated until the VA gets exhausted; mmap must
fail beyond 4GB. This is asserted against the VA mappings found
in /proc/self/maps.
Signed-off-by: Dev Jain <[email protected]>
---
tools/testing/selftests/arm/mm/compat_va.c | 92 ++++++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 tools/testing/selftests/arm/mm/compat_va.c
diff --git a/tools/testing/selftests/arm/mm/compat_va.c b/tools/testing/selftests/arm/mm/compat_va.c
new file mode 100644
index 000000000000..03f662fad79f
--- /dev/null
+++ b/tools/testing/selftests/arm/mm/compat_va.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Author : Dev Jain <[email protected]>
+ *
+ * Tests 4GB VA restriction for 32 bit process
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include <linux/sizes.h>
+#include <kselftest.h>
+
+#define MAP_CHUNK_SIZE SZ_1M
+#define NR_CHUNKS_4G (SZ_1G / MAP_CHUNK_SIZE) * 4 /* prevent overflow */
+
+static int validate_address_hint(void)
+{
+ char *ptr;
+
+ ptr = mmap((void *) (1UL << 29), MAP_CHUNK_SIZE, PROT_READ |
+ PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+ if (ptr == MAP_FAILED)
+ return 0;
+
+ return -1;
+}
+
+int main(int argc, char *argv[])
+{
+ char *ptr[NR_CHUNKS_4G + 3];
+ char line[1000];
+ int chunks;
+ FILE *file;
+ int i;
+
+ ksft_print_header();
+ ksft_set_plan(1);
+
+ /* try allocation beyond 4 GB */
+ for (i = 0; i < NR_CHUNKS_4G + 3; ++i) {
+ ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+ if (ptr[i] == MAP_FAILED) {
+ if (validate_address_hint())
+ ksft_exit_fail_msg("VA exhaustion failed\n");
+ break;
+ }
+ }
+
+ chunks = i;
+ if (chunks >= NR_CHUNKS_4G) {
+ ksft_test_result_fail("mmapped chunks beyond 4GB\n");
+ ksft_finished();
+ }
+
+ /* parse /proc/self/maps, confirm 32 bit VA mappings */
+ file = fopen("/proc/self/maps", "r");
+ if (file == NULL)
+ ksft_exit_fail_msg("/proc/self/maps cannot be opened\n");
+
+ while (fgets(line, sizeof(line), file)) {
+ const char *whitespace_loc, *hyphen_loc;
+
+ hyphen_loc = strchr(line, '-');
+ whitespace_loc = strchr(line, ' ');
+
+ if (!(hyphen_loc && whitespace_loc)) {
+ ksft_test_result_skip("Unexpected format");
+ ksft_finished();
+ }
+
+ if ((hyphen_loc - line > 8) ||
+ (whitespace_loc - hyphen_loc) > 9) {
+ ksft_test_result_fail("Memory map more than 32 bits\n");
+ ksft_finished();
+ }
+ }
+
+ for (int i = 0; i < chunks; ++i)
+ munmap(ptr[i], MAP_CHUNK_SIZE);
+
+ ksft_test_result_pass("Test\n");
+ ksft_finished();
+}
--
2.39.2
This patch introduces two signal tests, and generic test wrappers similar to
selftests/arm64/signal directory, along with the mangling testcases found
therein. arm_cpsr, dumped by the kernel to user space in the ucontext structure
to the signal handler, is mangled with. The kernel must spot this illegal
attempt and the testcases are expected to terminate via SEGV.
Signed-off-by: Dev Jain <[email protected]>
---
.../selftests/arm/signal/test_signals.c | 27 ++
.../selftests/arm/signal/test_signals.h | 74 +++++
.../selftests/arm/signal/test_signals_utils.c | 257 ++++++++++++++++++
.../selftests/arm/signal/test_signals_utils.h | 128 +++++++++
.../signal/testcases/mangle_cpsr_aif_bits.c | 33 +++
.../mangle_cpsr_invalid_compat_toggle.c | 29 ++
6 files changed, 548 insertions(+)
create mode 100644 tools/testing/selftests/arm/signal/test_signals.c
create mode 100644 tools/testing/selftests/arm/signal/test_signals.h
create mode 100644 tools/testing/selftests/arm/signal/test_signals_utils.c
create mode 100644 tools/testing/selftests/arm/signal/test_signals_utils.h
create mode 100644 tools/testing/selftests/arm/signal/testcases/mangle_cpsr_aif_bits.c
create mode 100644 tools/testing/selftests/arm/signal/testcases/mangle_cpsr_invalid_compat_toggle.c
diff --git a/tools/testing/selftests/arm/signal/test_signals.c b/tools/testing/selftests/arm/signal/test_signals.c
new file mode 100644
index 000000000000..1ecf1e9f041c
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/test_signals.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Generic test wrapper for arm signal tests.
+ *
+ * Each test provides its own tde struct tdescr descriptor to link with
+ * this wrapper. Framework provides common helpers.
+ */
+#include <kselftest.h>
+
+#include "test_signals.h"
+#include "test_signals_utils.h"
+
+struct tdescr *current = &tde;
+
+int main(int argc, char *argv[])
+{
+ ksft_print_msg("%s :: %s\n", current->name, current->descr);
+ if (test_setup(current) && test_init(current)) {
+ test_run(current);
+ test_cleanup(current);
+ }
+ test_result(current);
+
+ return current->result;
+}
diff --git a/tools/testing/selftests/arm/signal/test_signals.h b/tools/testing/selftests/arm/signal/test_signals.h
new file mode 100644
index 000000000000..bbd147127d66
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/test_signals.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2024 ARM Limited */
+
+#ifndef __TEST_SIGNALS_H__
+#define __TEST_SIGNALS_H__
+
+#include <signal.h>
+#include <stdbool.h>
+#include <ucontext.h>
+
+/*
+ * Using ARCH specific and sanitized Kernel headers from the tree.
+ */
+#include <asm/ptrace.h>
+#include <asm/hwcap.h>
+
+/*
+ * A descriptor used to describe and configure a test case.
+ * Fields with a non-trivial meaning are described inline in the following.
+ */
+struct tdescr {
+ /* KEEP THIS FIELD FIRST for easier lookup from assembly */
+ void *token;
+ /* when disabled token based sanity checking is skipped in handler */
+ bool sanity_disabled;
+ /* just a name for the test-case; manadatory field */
+ char *name;
+ char *descr;
+
+ bool initialized;
+ unsigned int minsigstksz;
+ /* signum used as a test trigger. Zero if no trigger-signal is used */
+ int sig_trig;
+ /*
+ * signum considered as a successful test completion.
+ * Zero when no signal is expected on success
+ */
+ int sig_ok;
+ /* signum expected on unsupported CPU features. */
+ int sig_unsupp;
+ /* a timeout in second for test completion */
+ unsigned int timeout;
+ bool triggered;
+ bool pass;
+ unsigned int result;
+ /* optional sa_flags for the installed handler */
+ int sa_flags;
+ ucontext_t saved_uc;
+ /* used by get_current_ctx() */
+ size_t live_sz;
+ ucontext_t *live_uc;
+ volatile sig_atomic_t live_uc_valid;
+ /* optional test private data */
+ void *priv;
+
+ /* a custom setup: called alternatively to default_setup */
+ int (*setup)(struct tdescr *td);
+ /* a custom init: called by default test init after test_setup */
+ bool (*init)(struct tdescr *td);
+ /* a custom cleanup function called before test exits */
+ void (*cleanup)(struct tdescr *td);
+ /* an optional function to be used as a trigger for starting test */
+ int (*trigger)(struct tdescr *td);
+ /*
+ * the actual test-core: invoked differently depending on the
+ * presence of the trigger function above; this is mandatory
+ */
+ int (*run)(struct tdescr *td, siginfo_t *si, ucontext_t *uc);
+ /* an optional function for custom results' processing */
+ void (*check_result)(struct tdescr *td);
+};
+
+extern struct tdescr tde;
+#endif
diff --git a/tools/testing/selftests/arm/signal/test_signals_utils.c b/tools/testing/selftests/arm/signal/test_signals_utils.c
new file mode 100644
index 000000000000..96aeb11de151
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/test_signals_utils.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2024 ARM Limited */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <sys/auxv.h>
+#include <linux/auxvec.h>
+#include <ucontext.h>
+
+#include <asm/unistd.h>
+
+#include <kselftest.h>
+
+#include "test_signals.h"
+#include "test_signals_utils.h"
+
+
+extern struct tdescr *current;
+
+static int sig_copyctx = SIGTRAP;
+
+static void unblock_signal(int signum)
+{
+ sigset_t sset;
+
+ sigemptyset(&sset);
+ sigaddset(&sset, signum);
+ sigprocmask(SIG_UNBLOCK, &sset, NULL);
+}
+
+static void default_result(struct tdescr *td, bool force_exit)
+{
+ if (td->result == KSFT_SKIP) {
+ fprintf(stderr, "==>> completed. SKIP.\n");
+ } else if (td->pass) {
+ fprintf(stderr, "==>> completed. PASS(1)\n");
+ td->result = KSFT_PASS;
+ } else {
+ fprintf(stdout, "==>> completed. FAIL(0)\n");
+ td->result = KSFT_FAIL;
+ }
+
+ if (force_exit)
+ exit(td->result);
+}
+
+/*
+ * The following handle_signal_* helpers are used by main default_handler
+ * and are meant to return true when signal is handled successfully:
+ * when false is returned instead, it means that the signal was somehow
+ * unexpected in that context and it was NOT handled; default_handler will
+ * take care of such unexpected situations.
+ */
+
+static bool handle_signal_unsupported(struct tdescr *td,
+ siginfo_t *si, void *uc)
+{
+
+ /* Mangling PC to avoid loops on original SIGILL */
+ ((ucontext_t *)uc)->uc_mcontext.arm_pc += 4;
+
+ if (!td->initialized) {
+ fprintf(stderr,
+ "Got SIG_UNSUPP @test_init. Ignore.\n");
+ } else {
+ fprintf(stderr,
+ "-- RX SIG_UNSUPP on unsupported feat...OK\n");
+ td->pass = 1;
+ default_result(current, 1);
+ }
+
+ return true;
+}
+
+static bool handle_signal_trigger(struct tdescr *td,
+ siginfo_t *si, void *uc)
+{
+ td->triggered = 1;
+
+ /* ->run was asserted NON-NULL in test_setup() already */
+ td->run(td, si, uc);
+
+ return true;
+}
+
+static bool handle_signal_ok(struct tdescr *td,
+ siginfo_t *si, void *uc)
+{
+
+ /*
+ * it's a bug in the test code when this assert fail:
+ * if sig_trig was defined, it must have been used before getting here.
+ */
+ assert(!td->sig_trig || td->triggered);
+ fprintf(stderr,
+ "SIG_OK -- SP:0x%lX si_addr@:%p si_code:%d token@:%p offset:%d\n",
+ ((ucontext_t *)uc)->uc_mcontext.arm_sp,
+ si->si_addr, si->si_code, td->token, td->token - si->si_addr);
+
+ /*
+ * Trying to narrow down the SEGV to the ones generated by Kernel itself
+ * via arm64_notify_segfault(). This is a best-effort check anyway, and
+ * the si_code check may need to change if this aspect of the kernel
+ * ABI changes.
+ */
+ if (td->sig_ok == SIGSEGV && si->si_code != SEGV_ACCERR) {
+ fprintf(stdout,
+ "si_code != SEGV_ACCERR...test is probably broken!\n");
+ abort();
+ }
+ td->pass = 1;
+ /*
+ * Some tests can lead to SEGV loops: in such a case we want to
+ * terminate immediately exiting straight away; some others are not
+ * supposed to outlive the signal handler code, due to the content of
+ * the fake sigframe which caused the signal itself.
+ */
+ default_result(current, 1);
+
+ return true;
+}
+
+static void default_handler(int signum, siginfo_t *si, void *uc)
+{
+ if (current->sig_unsupp && signum == current->sig_unsupp &&
+ handle_signal_unsupported(current, si, uc)) {
+ fprintf(stderr, "Handled SIG_UNSUPP\n");
+ } else if (current->sig_trig && signum == current->sig_trig &&
+ handle_signal_trigger(current, si, uc)) {
+ fprintf(stderr, "Handled SIG_TRIG\n");
+ } else if (current->sig_ok && signum == current->sig_ok &&
+ handle_signal_ok(current, si, uc)) {
+ fprintf(stderr, "Handled SIG_OK\n");
+ } else if (signum == sig_copyctx && current->live_uc) {
+ fprintf(stderr, "Handled SIG_COPYCTX\n");
+ } else {
+ if (signum == SIGALRM && current->timeout) {
+ fprintf(stderr, "-- Timeout !\n");
+ } else {
+ fprintf(stderr,
+ "-- RX UNEXPECTED SIGNAL: %d code %d address %p\n",
+ signum, si->si_code, si->si_addr);
+ }
+ default_result(current, 1);
+ }
+}
+
+static int default_setup(struct tdescr *td)
+{
+ struct sigaction sa;
+
+ sa.sa_sigaction = default_handler;
+ sa.sa_flags = SA_SIGINFO | SA_RESTART;
+ sa.sa_flags |= td->sa_flags;
+ sigemptyset(&sa.sa_mask);
+ /* uncatchable signals naturally skipped ... */
+ for (int sig = 1; sig < 32; sig++)
+ sigaction(sig, &sa, NULL);
+ /*
+ * RT Signals default disposition is Term but they cannot be
+ * generated by the Kernel in response to our tests; so just catch
+ * them all and report them as UNEXPECTED signals.
+ */
+ for (int sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
+ sigaction(sig, &sa, NULL);
+
+ /* just in case...unblock explicitly all we need */
+ if (td->sig_trig)
+ unblock_signal(td->sig_trig);
+ if (td->sig_ok)
+ unblock_signal(td->sig_ok);
+ if (td->sig_unsupp)
+ unblock_signal(td->sig_unsupp);
+
+ if (td->timeout) {
+ unblock_signal(SIGALRM);
+ alarm(td->timeout);
+ }
+ fprintf(stderr, "Registered handlers for all signals.\n");
+
+ return 1;
+}
+
+static inline int default_trigger(struct tdescr *td)
+{
+ return !raise(td->sig_trig);
+}
+
+int test_init(struct tdescr *td)
+{
+ if (td->sig_trig == sig_copyctx) {
+ fprintf(stdout,
+ "Signal %d is RESERVED, cannot be used as a trigger. Aborting\n",
+ sig_copyctx);
+ return 0;
+ }
+ /* just in case */
+ unblock_signal(sig_copyctx);
+
+ td->minsigstksz = getauxval(AT_MINSIGSTKSZ);
+ if (!td->minsigstksz)
+ td->minsigstksz = MINSIGSTKSZ;
+ fprintf(stderr, "Detected MINSTKSIGSZ:%d\n", td->minsigstksz);
+
+ /* Perform test specific additional initialization */
+ if (td->init && !td->init(td)) {
+ fprintf(stderr, "FAILED Testcase initialization.\n");
+ return 0;
+ }
+ td->initialized = 1;
+ fprintf(stderr, "Testcase initialized.\n");
+
+ return 1;
+}
+
+int test_setup(struct tdescr *td)
+{
+ /* assert core invariants symptom of a rotten testcase */
+ assert(current);
+ assert(td);
+ assert(td->name);
+ assert(td->run);
+
+ /* Default result is FAIL if test setup fails */
+ td->result = KSFT_FAIL;
+ if (td->setup)
+ return td->setup(td);
+ else
+ return default_setup(td);
+}
+
+int test_run(struct tdescr *td)
+{
+ if (td->trigger)
+ return td->trigger(td);
+ else if (td->sig_trig)
+ return default_trigger(td);
+ else
+ return td->run(td, NULL, NULL);
+}
+
+void test_result(struct tdescr *td)
+{
+ if (td->initialized && td->result != KSFT_SKIP && td->check_result)
+ td->check_result(td);
+ default_result(td, 0);
+}
+
+void test_cleanup(struct tdescr *td)
+{
+ if (td->cleanup)
+ td->cleanup(td);
+}
diff --git a/tools/testing/selftests/arm/signal/test_signals_utils.h b/tools/testing/selftests/arm/signal/test_signals_utils.h
new file mode 100644
index 000000000000..386dcc6c268d
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/test_signals_utils.h
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2024 ARM Limited */
+
+#ifndef __TEST_SIGNALS_UTILS_H__
+#define __TEST_SIGNALS_UTILS_H__
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <linux/compiler.h>
+#include "test_signals.h"
+
+int test_init(struct tdescr *td);
+int test_setup(struct tdescr *td);
+void test_cleanup(struct tdescr *td);
+int test_run(struct tdescr *td);
+void test_result(struct tdescr *td);
+
+/*
+ * Obtaining a valid and full-blown ucontext_t from userspace is tricky:
+ * libc getcontext does() not save all the regs and messes with some of
+ * them (pstate value in particular is not reliable).
+ *
+ * Here we use a service signal to grab the ucontext_t from inside a
+ * dedicated signal handler, since there, it is populated by Kernel
+ * itself in setup_sigframe(). The grabbed context is then stored and
+ * made available in td->live_uc.
+ *
+ * As service-signal is used a SIGTRAP induced by a 'brk' instruction,
+ * because here we have to avoid syscalls to trigger the signal since
+ * they would cause any SVE sigframe content (if any) to be removed.
+ *
+ * Anyway this function really serves a dual purpose:
+ *
+ * 1. grab a valid sigcontext into td->live_uc for result analysis: in
+ * such case it returns 1.
+ *
+ * 2. detect if, somehow, a previously grabbed live_uc context has been
+ * used actively with a sigreturn: in such a case the execution would have
+ * magically resumed in the middle of this function itself (seen_already==1):
+ * in such a case return 0, since in fact we have not just simply grabbed
+ * the context.
+ *
+ * This latter case is useful to detect when a fake_sigreturn test-case has
+ * unexpectedly survived without hitting a SEGV.
+ *
+ * Note that the case of runtime dynamically sized sigframes (like in SVE
+ * context) is still NOT addressed: sigframe size is supposed to be fixed
+ * at sizeof(ucontext_t).
+ */
+static __always_inline bool get_current_context(struct tdescr *td,
+ ucontext_t *dest_uc,
+ size_t dest_sz)
+{
+ static volatile bool seen_already;
+ int i;
+ char *uc = (char *)dest_uc;
+
+ assert(td && dest_uc);
+ /* it's a genuine invocation..reinit */
+ seen_already = 0;
+ td->live_uc_valid = 0;
+ td->live_sz = dest_sz;
+
+ /*
+ * This is a memset() but we don't want the compiler to
+ * optimise it into either instructions or a library call
+ * which might be incompatible with streaming mode.
+ */
+ for (i = 0; i < td->live_sz; i++) {
+ uc[i] = 0;
+ OPTIMIZER_HIDE_VAR(uc[0]);
+ }
+
+ td->live_uc = dest_uc;
+ /*
+ * Grab ucontext_t triggering a SIGTRAP.
+ *
+ * Note that:
+ * - live_uc_valid is declared volatile sig_atomic_t in
+ * struct tdescr since it will be changed inside the
+ * sig_copyctx handler
+ * - the additional 'memory' clobber is there to avoid possible
+ * compiler's assumption on live_uc_valid and the content
+ * pointed by dest_uc, which are all changed inside the signal
+ * handler
+ * - BRK causes a debug exception which is handled by the Kernel
+ * and finally causes the SIGTRAP signal to be delivered to this
+ * test thread. Since such delivery happens on the ret_to_user()
+ * /do_notify_resume() debug exception return-path, we are sure
+ * that the registered SIGTRAP handler has been run to completion
+ * before the execution path is restored here: as a consequence
+ * we can be sure that the volatile sig_atomic_t live_uc_valid
+ * carries a meaningful result. Being in a single thread context
+ * we'll also be sure that any access to memory modified by the
+ * handler (namely ucontext_t) will be visible once returned.
+ * - note that since we are using a breakpoint instruction here
+ * to cause a SIGTRAP, the ucontext_t grabbed from the signal
+ * handler would naturally contain a PC pointing exactly to this
+ * BRK line, which means that, on return from the signal handler,
+ * or if we place the ucontext_t on the stack to fake a sigreturn,
+ * we'll end up in an infinite loop of BRK-SIGTRAP-handler.
+ * For this reason we take care to artificially move forward the
+ * PC to the next instruction while inside the signal handler.
+ */
+ asm volatile ("brk #666"
+ : "+m" (*dest_uc)
+ :
+ : "memory");
+
+ /*
+ * If we get here with seen_already==1 it implies the td->live_uc
+ * context has been used to get back here....this probably means
+ * a test has failed to cause a SEGV...anyway live_uc does not
+ * point to a just acquired copy of ucontext_t...so return 0
+ */
+ if (seen_already) {
+ fprintf(stdout,
+ "Unexpected successful sigreturn detected: live_uc is stale !\n");
+ return 0;
+ }
+ seen_already = 1;
+
+ return td->live_uc_valid;
+}
+
+#endif
diff --git a/tools/testing/selftests/arm/signal/testcases/mangle_cpsr_aif_bits.c b/tools/testing/selftests/arm/signal/testcases/mangle_cpsr_aif_bits.c
new file mode 100644
index 000000000000..f422cd11ccf2
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/testcases/mangle_cpsr_aif_bits.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, mangling the
+ * AIF bits in an illegal manner: this attempt must be spotted by Kernel
+ * and the test case is expected to be terminated via SEGV.
+ *
+ */
+
+#include "test_signals_utils.h"
+
+static int mangle_invalid_cpsr_run(struct tdescr *td, siginfo_t *si,
+ ucontext_t *uc)
+{
+
+ /*
+ * This config should trigger a SIGSEGV by Kernel when it checks
+ * the sigframe consistency in valid_user_regs() routine.
+ */
+ uc->uc_mcontext.arm_cpsr |= PSR_A_BIT | PSR_I_BIT | PSR_F_BIT;
+
+ return 1;
+}
+
+struct tdescr tde = {
+ .sanity_disabled = true,
+ .name = "MANGLE_CPSR_INVALID_AIF_BITS",
+ .descr = "Mangling uc_mcontext with INVALID AIF_BITS",
+ .sig_trig = SIGUSR1,
+ .sig_ok = SIGSEGV,
+ .run = mangle_invalid_cpsr_run,
+};
diff --git a/tools/testing/selftests/arm/signal/testcases/mangle_cpsr_invalid_compat_toggle.c b/tools/testing/selftests/arm/signal/testcases/mangle_cpsr_invalid_compat_toggle.c
new file mode 100644
index 000000000000..cb7eb8aec7f2
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/testcases/mangle_cpsr_invalid_compat_toggle.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the execution state bit: this attempt must be spotted by Kernel and
+ * the test case is expected to be terminated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+
+static int mangle_invalid_cpsr_run(struct tdescr *td, siginfo_t *si,
+ ucontext_t *uc)
+{
+
+ /* This config should trigger a SIGSEGV by Kernel */
+ uc->uc_mcontext.arm_cpsr ^= MODE32_BIT;
+
+ return 1;
+}
+
+struct tdescr tde = {
+ .sanity_disabled = true,
+ .name = "MANGLE_CPSR_INVALID_STATE_TOGGLE",
+ .descr = "Mangling uc_mcontext with INVALID STATE_TOGGLE",
+ .sig_trig = SIGUSR1,
+ .sig_ok = SIGSEGV,
+ .run = mangle_invalid_cpsr_run,
+};
--
2.39.2
This patch introduces an ELF parsing test; the 5th byte of the ELF header
must be 0x01 for a 32-bit process. A basic sanity check is required to ensure
that we are actually testing a 32-bit build.
Signed-off-by: Dev Jain <[email protected]>
---
tools/testing/selftests/arm/elf/parse_elf.c | 74 +++++++++++++++++++++
1 file changed, 74 insertions(+)
create mode 100644 tools/testing/selftests/arm/elf/parse_elf.c
diff --git a/tools/testing/selftests/arm/elf/parse_elf.c b/tools/testing/selftests/arm/elf/parse_elf.c
new file mode 100644
index 000000000000..86a2ec88b47d
--- /dev/null
+++ b/tools/testing/selftests/arm/elf/parse_elf.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 ARM Limited
+ *
+ * Author : Dev Jain <[email protected]>
+ *
+ * Parse elf header to confirm 32-bit process
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <elf.h>
+#include <stdint.h>
+
+#include <kselftest.h>
+
+/* The ELF file header. This appears at the start of every ELF file. */
+
+struct elf_header {
+ unsigned char e_ident[16]; /* Magic number and other info */
+ uint16_t e_type; /* Object file type */
+ uint16_t e_machine; /* Architecture */
+ uint32_t e_version; /* Object file version */
+ uint64_t e_entry; /* Entry point virtual address */
+ uint64_t e_phoff; /* Program header table file offset */
+ uint64_t e_shoff; /* Section header table file offset */
+ uint32_t e_flags; /* Processor-specific flags */
+ uint16_t e_ehsize; /* ELF header size in bytes */
+ uint16_t e_phentsize; /* Program header table entry size */
+ uint16_t e_phnum; /* Program header table entry count */
+ uint16_t e_shentsize; /* Section header table entry size */
+ uint16_t e_shnum; /* Section header table entry count */
+ uint16_t e_shstrndx; /* Section header string table index */
+};
+
+static int read_elf_header(const char *elfFile)
+{
+ struct elf_header header;
+ FILE *file;
+ int ret = -1;
+
+ file = fopen(elfFile, "r");
+ if (file) {
+
+ /* store header in struct */
+ fread(&header, 1, sizeof(header), file);
+ fclose(file);
+
+ /* sanity check: does it really follow ELF format */
+ if (header.e_ident[0] == 0x7f &&
+ header.e_ident[1] == 'E' &&
+ header.e_ident[2] == 'L' &&
+ header.e_ident[3] == 'F') {
+ if (header.e_ident[4] == 0x01)
+ ret = 0;
+ } else {
+ ksft_print_msg("Cannot parse /proc/self/exe\n");
+ }
+ } else {
+ ksft_print_msg("Cannot open /proc/self/exe\n");
+ }
+ return ret;
+}
+
+int main(int argc, char *argv[])
+{
+ ksft_print_header();
+ ksft_set_plan(1);
+
+ ksft_test_result(read_elf_header("/proc/self/exe") == 0, "ELF is 32 bit\n");
+ ksft_finished();
+}
--
2.39.2
Add arm target, individual Makefile targets, and instructions to build the
tests, along with .gitignore files and a config file.
Signed-off-by: Dev Jain <[email protected]>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/arm/Makefile | 57 +++++++++++++++++++
tools/testing/selftests/arm/README | 31 ++++++++++
tools/testing/selftests/arm/config | 1 +
tools/testing/selftests/arm/elf/.gitignore | 2 +
tools/testing/selftests/arm/elf/Makefile | 6 ++
tools/testing/selftests/arm/mm/.gitignore | 2 +
tools/testing/selftests/arm/mm/Makefile | 6 ++
tools/testing/selftests/arm/signal/.gitignore | 3 +
tools/testing/selftests/arm/signal/Makefile | 30 ++++++++++
10 files changed, 139 insertions(+)
create mode 100644 tools/testing/selftests/arm/Makefile
create mode 100644 tools/testing/selftests/arm/README
create mode 100644 tools/testing/selftests/arm/config
create mode 100644 tools/testing/selftests/arm/elf/.gitignore
create mode 100644 tools/testing/selftests/arm/elf/Makefile
create mode 100644 tools/testing/selftests/arm/mm/.gitignore
create mode 100644 tools/testing/selftests/arm/mm/Makefile
create mode 100644 tools/testing/selftests/arm/signal/.gitignore
create mode 100644 tools/testing/selftests/arm/signal/Makefile
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index e1504833654d..3966d2541ef7 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
TARGETS += alsa
TARGETS += amd-pstate
+TARGETS += arm
TARGETS += arm64
TARGETS += bpf
TARGETS += breakpoints
diff --git a/tools/testing/selftests/arm/Makefile b/tools/testing/selftests/arm/Makefile
new file mode 100644
index 000000000000..039224bc006e
--- /dev/null
+++ b/tools/testing/selftests/arm/Makefile
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# When ARCH not overridden for crosscompiling, lookup machine
+ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+
+ifneq (,$(filter $(ARCH),aarch64 arm64 arm armv7l armv8l))
+ARM_SUBTARGETS ?= mm signal elf
+else
+ARM_SUBTARGETS :=
+endif
+
+CFLAGS := -Wall -O2 -g -static
+
+# A proper top_srcdir is needed by KSFT(lib.mk)
+top_srcdir = $(realpath ../../../../)
+
+# Additional include paths needed by kselftest.h and local headers
+CFLAGS += -I$(top_srcdir)/tools/testing/selftests/
+
+CFLAGS += -I$(top_srcdir)/tools/include
+
+export CFLAGS
+export top_srcdir
+
+all:
+ @for DIR in $(ARM_SUBTARGETS); do \
+ BUILD_TARGET=$(OUTPUT)/$$DIR; \
+ mkdir -p $$BUILD_TARGET; \
+ make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
+ done
+
+install: all
+ @for DIR in $(ARM_SUBTARGETS); do \
+ BUILD_TARGET=$(OUTPUT)/$$DIR; \
+ make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
+ done
+
+run_tests: all
+ @for DIR in $(ARM_SUBTARGETS); do \
+ BUILD_TARGET=$(OUTPUT)/$$DIR; \
+ make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
+ done
+
+# Avoid any output on non arm on emit_tests
+emit_tests:
+ @for DIR in $(ARM_SUBTARGETS); do \
+ BUILD_TARGET=$(OUTPUT)/$$DIR; \
+ make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
+ done
+
+clean:
+ @for DIR in $(ARM_SUBTARGETS); do \
+ BUILD_TARGET=$(OUTPUT)/$$DIR; \
+ make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
+ done
+
+.PHONY: all clean install run_tests emit_tests
diff --git a/tools/testing/selftests/arm/README b/tools/testing/selftests/arm/README
new file mode 100644
index 000000000000..1a05c043d7ee
--- /dev/null
+++ b/tools/testing/selftests/arm/README
@@ -0,0 +1,31 @@
+KSelfTest ARM
+===============
+
+- This is a series of compatibility tests, wherein the source files are
+ built statically into a 32 bit ELF; they should pass on both 32 and 64
+ bit kernels. They are not built or run but just skipped completely when
+ env-variable ARCH is found to be different than 'arm64' or 'arm' and
+ `uname -m` reports other than 'aarch64', 'armv7l' or 'armv8l'.
+
+- Please ensure that the test kernel is built with CONFIG_COMPAT enabled.
+
+- Holding true the above, ARM KSFT tests can be run within the KSelfTest
+ framework using standard Linux top-level-makefile targets. Please set
+ $(CROSS_COMPILE) to 'arm-linux-gnueabi-' or 'arm-linux-gnueabihf-'.
+
+ $ make TARGETS=arm kselftest-clean
+ $ make $(CROSS_COMPILE) TARGETS=arm kselftest
+
+ or
+
+ $ make $(CROSS_COMPILE) -C tools/testing/selftests TARGETS=arm \
+ INSTALL_PATH=<your-installation-path> install
+
+ or, alternatively, only specific arm/ subtargets can be picked:
+
+ $ make $(CROSS_COMPILE) -C tools/testing/selftests TARGETS=arm \
+ ARM_SUBTARGETS="signal" INSTALL_PATH=<your-installation-path> \
+ install
+
+ Further details on building and running KFST can be found in:
+ Documentation/dev-tools/kselftest.rst
diff --git a/tools/testing/selftests/arm/config b/tools/testing/selftests/arm/config
new file mode 100644
index 000000000000..9b072bae787e
--- /dev/null
+++ b/tools/testing/selftests/arm/config
@@ -0,0 +1 @@
+CONFIG_COMPAT=y
diff --git a/tools/testing/selftests/arm/elf/.gitignore b/tools/testing/selftests/arm/elf/.gitignore
new file mode 100644
index 000000000000..41458ecbcd72
--- /dev/null
+++ b/tools/testing/selftests/arm/elf/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+parse_elf
diff --git a/tools/testing/selftests/arm/elf/Makefile b/tools/testing/selftests/arm/elf/Makefile
new file mode 100644
index 000000000000..86636fe02994
--- /dev/null
+++ b/tools/testing/selftests/arm/elf/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2024 ARM Limited
+
+TEST_GEN_PROGS := parse_elf
+
+include ../../lib.mk
diff --git a/tools/testing/selftests/arm/mm/.gitignore b/tools/testing/selftests/arm/mm/.gitignore
new file mode 100644
index 000000000000..eb28169bb1b5
--- /dev/null
+++ b/tools/testing/selftests/arm/mm/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+compat_va
diff --git a/tools/testing/selftests/arm/mm/Makefile b/tools/testing/selftests/arm/mm/Makefile
new file mode 100644
index 000000000000..d8bfa45df98c
--- /dev/null
+++ b/tools/testing/selftests/arm/mm/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2024 ARM Limited
+
+TEST_GEN_PROGS := compat_va
+
+include ../../lib.mk
diff --git a/tools/testing/selftests/arm/signal/.gitignore b/tools/testing/selftests/arm/signal/.gitignore
new file mode 100644
index 000000000000..26929e3c20ea
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+mangle_cpsr_aif_bits
+mangle_cpsr_invalid_compat_toggle
diff --git a/tools/testing/selftests/arm/signal/Makefile b/tools/testing/selftests/arm/signal/Makefile
new file mode 100644
index 000000000000..3540a25de75a
--- /dev/null
+++ b/tools/testing/selftests/arm/signal/Makefile
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2024 ARM Limited
+
+# Additional include paths needed by kselftest.h and local headers
+CFLAGS += -D_GNU_SOURCE -std=gnu99 -I.
+
+SRCS := $(filter-out testcases/testcases.c,$(wildcard testcases/*.c))
+PROGS := $(patsubst %.c,%,$(SRCS))
+
+# Generated binaries to be installed by top KSFT script
+TEST_GEN_PROGS := $(notdir $(PROGS))
+
+# Get Kernel headers installed and use them.
+
+# Including KSFT lib.mk here will also mangle the TEST_GEN_PROGS list
+# to account for any OUTPUT target-dirs optionally provided by
+# the toplevel makefile
+include ../../lib.mk
+
+$(TEST_GEN_PROGS): $(PROGS)
+ cp $(PROGS) $(OUTPUT)/
+
+# Common test-unit targets to build common-layout test-cases executables
+# Needs secondary expansion to properly include the testcase c-file in pre-reqs
+COMMON_SOURCES := test_signals.c test_signals_utils.c
+COMMON_HEADERS := test_signals.h test_signals_utils.h
+
+.SECONDEXPANSION:
+$(PROGS): [email protected] ${COMMON_SOURCES} ${COMMON_HEADERS}
+ $(CC) $(CFLAGS) ${@}.c ${COMMON_SOURCES} -o $@
--
2.39.2
On Mon, Apr 22, 2024 at 12:37:13PM +0530, Dev Jain wrote:
> This series introduces the selftests/arm directory, which tests 32 and 64-bit
> kernel compatibility with 32-bit ELFs running on the Aarch platform.
> The need for this bucket of tests is that 32 bit applications built on legacy
> ARM architecture must not break on the new Aarch64 platforms and the 64-bit
> kernel. The kernel must emulate the data structures, system calls and the
> registers according to Aarch32, when running a 32-bit process; this directory
> fills that testing requirement.
>
> One may find similarity between this directory and selftests/arm64; it is
> advisable to refer to that since a lot has been copied from there itself.
Isn't this going to be difficult to maintain if we have two divergent copies
of the same stuff? From a very quick skim, a bunch of the signals stuff is
idential to what we have on arm64...
Will
On 4/22/24 10:21 PM, Will Deacon wrote:
> On Mon, Apr 22, 2024 at 12:37:13PM +0530, Dev Jain wrote:
>> This series introduces the selftests/arm directory, which tests 32 and 64-bit
>> kernel compatibility with 32-bit ELFs running on the Aarch platform.
>> The need for this bucket of tests is that 32 bit applications built on legacy
>> ARM architecture must not break on the new Aarch64 platforms and the 64-bit
>> kernel. The kernel must emulate the data structures, system calls and the
>> registers according to Aarch32, when running a 32-bit process; this directory
>> fills that testing requirement.
>>
>> One may find similarity between this directory and selftests/arm64; it is
>> advisable to refer to that since a lot has been copied from there itself.
>
> Isn't this going to be difficult to maintain if we have two divergent copies
> of the same stuff? From a very quick skim, a bunch of the signals stuff is
> idential to what we have on arm64...
Agreed.
Why don't we follow what x86 suite has been doing? Compile tests for both
arm and arm64, and add conditionals in the tests based on architecture.
If someone has objection that the suite name is arm64, just rename it to
arm which would be a generic name.
>
> Will
>
--
BR,
Muhammad Usama Anjum
On Tue, Apr 23, 2024 at 01:55:07PM +0500, Muhammad Usama Anjum wrote:
> On 4/22/24 10:21 PM, Will Deacon wrote:
> > Isn't this going to be difficult to maintain if we have two divergent copies
> > of the same stuff? From a very quick skim, a bunch of the signals stuff is
> > idential to what we have on arm64...
> Agreed.
> Why don't we follow what x86 suite has been doing? Compile tests for both
> arm and arm64, and add conditionals in the tests based on architecture.
> If someone has objection that the suite name is arm64, just rename it to
> arm which would be a generic name.
Given that we haven't done that for any other arm/arm64 stuff I suspect
that specific approach would lead to some combination of confusion and
people just plain missing the fact that the 32 bit tests are there.
It's just not the idiom that's been used for handling things elsewhere
so it feels like asking for people to make mistakes. With the signal
tests (which seem like the only bit that's really shared here) it's
mostly just some of the library code that we want to duplicate, the
actual test set for 32 bit will be different.
What some of the other testsuites do to pull in other tests as libraries
is to just reference the source files (KVM does this with rseq IIRC).
We could do that here and try to refactor the framework code for the
signal tests so that it can be built for both 64 and 32 bit, then have
the 32 bit Makefile pull in the shared code from the 64 bit directory.
I'm not sure if it's worth the effort or not - there is some obvious
duplication but a good chunk of the arm64 code is feature detection and
handling of the extensible signal context neither of which apply for 32
bit.
If we are pulling stuff out it might even make sense to have something
that other non-arm architectures can use since I'm not sure how much of
the framework code that can be shared is even arm specific.