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Subject[PATCH AUTOSEL 4.14 37/46] selftests/powerpc: Add ptrace hw breakpoint test
Date
From: Michael Neuling <mikey@neuling.org>

[ Upstream commit 9c2ddfe55c42bf4b9bc336a0650ab78f9222a159 ]

This test the ptrace hw breakpoints via PTRACE_SET_DEBUGREG and
PPC_PTRACE_SETHWDEBUG. This test was use to find the bugs fixed by
these recent commits:

4f7c06e26e powerpc/ptrace: Fix setting 512B aligned breakpoints with PTRACE_SET_DEBUGREG
cd6ef7eebf powerpc/ptrace: Fix enforcement of DAWR constraints

Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Add SPDX tag, clang format it]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../selftests/powerpc/ptrace/.gitignore | 1 +
.../testing/selftests/powerpc/ptrace/Makefile | 2 +-
.../selftests/powerpc/ptrace/ptrace-hwbreak.c | 342 ++++++++++++++++++
3 files changed, 344 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c

diff --git a/tools/testing/selftests/powerpc/ptrace/.gitignore b/tools/testing/selftests/powerpc/ptrace/.gitignore
index 349acfafc95b..9dcc16ea8179 100644
--- a/tools/testing/selftests/powerpc/ptrace/.gitignore
+++ b/tools/testing/selftests/powerpc/ptrace/.gitignore
@@ -8,3 +8,4 @@ ptrace-vsx
ptrace-tm-vsx
ptrace-tm-spd-vsx
ptrace-tm-spr
+ptrace-hwbreak
diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile
index 480305266504..0e2f4601d1a8 100644
--- a/tools/testing/selftests/powerpc/ptrace/Makefile
+++ b/tools/testing/selftests/powerpc/ptrace/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
TEST_PROGS := ptrace-gpr ptrace-tm-gpr ptrace-tm-spd-gpr \
ptrace-tar ptrace-tm-tar ptrace-tm-spd-tar ptrace-vsx ptrace-tm-vsx \
- ptrace-tm-spd-vsx ptrace-tm-spr
+ ptrace-tm-spd-vsx ptrace-tm-spr ptrace-hwbreak

include ../../lib.mk

diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c b/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c
new file mode 100644
index 000000000000..3066d310f32b
--- /dev/null
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Ptrace test for hw breakpoints
+ *
+ * Based on tools/testing/selftests/breakpoints/breakpoint_test.c
+ *
+ * This test forks and the parent then traces the child doing various
+ * types of ptrace enabled breakpoints
+ *
+ * Copyright (C) 2018 Michael Neuling, IBM Corporation.
+ */
+
+#include <sys/ptrace.h>
+#include <unistd.h>
+#include <stddef.h>
+#include <sys/user.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include "ptrace.h"
+
+/* Breakpoint access modes */
+enum {
+ BP_X = 1,
+ BP_RW = 2,
+ BP_W = 4,
+};
+
+static pid_t child_pid;
+static struct ppc_debug_info dbginfo;
+
+static void get_dbginfo(void)
+{
+ int ret;
+
+ ret = ptrace(PPC_PTRACE_GETHWDBGINFO, child_pid, NULL, &dbginfo);
+ if (ret) {
+ perror("Can't get breakpoint info\n");
+ exit(-1);
+ }
+}
+
+static bool hwbreak_present(void)
+{
+ return (dbginfo.num_data_bps != 0);
+}
+
+static bool dawr_present(void)
+{
+ return !!(dbginfo.features & PPC_DEBUG_FEATURE_DATA_BP_DAWR);
+}
+
+static void set_breakpoint_addr(void *addr)
+{
+ int ret;
+
+ ret = ptrace(PTRACE_SET_DEBUGREG, child_pid, 0, addr);
+ if (ret) {
+ perror("Can't set breakpoint addr\n");
+ exit(-1);
+ }
+}
+
+static int set_hwbreakpoint_addr(void *addr, int range)
+{
+ int ret;
+
+ struct ppc_hw_breakpoint info;
+
+ info.version = 1;
+ info.trigger_type = PPC_BREAKPOINT_TRIGGER_RW;
+ info.addr_mode = PPC_BREAKPOINT_MODE_EXACT;
+ if (range > 0)
+ info.addr_mode = PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE;
+ info.condition_mode = PPC_BREAKPOINT_CONDITION_NONE;
+ info.addr = (__u64)addr;
+ info.addr2 = (__u64)addr + range;
+ info.condition_value = 0;
+
+ ret = ptrace(PPC_PTRACE_SETHWDEBUG, child_pid, 0, &info);
+ if (ret < 0) {
+ perror("Can't set breakpoint\n");
+ exit(-1);
+ }
+ return ret;
+}
+
+static int del_hwbreakpoint_addr(int watchpoint_handle)
+{
+ int ret;
+
+ ret = ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, watchpoint_handle);
+ if (ret < 0) {
+ perror("Can't delete hw breakpoint\n");
+ exit(-1);
+ }
+ return ret;
+}
+
+#define DAWR_LENGTH_MAX 512
+
+/* Dummy variables to test read/write accesses */
+static unsigned long long
+ dummy_array[DAWR_LENGTH_MAX / sizeof(unsigned long long)]
+ __attribute__((aligned(512)));
+static unsigned long long *dummy_var = dummy_array;
+
+static void write_var(int len)
+{
+ long long *plval;
+ char *pcval;
+ short *psval;
+ int *pival;
+
+ switch (len) {
+ case 1:
+ pcval = (char *)dummy_var;
+ *pcval = 0xff;
+ break;
+ case 2:
+ psval = (short *)dummy_var;
+ *psval = 0xffff;
+ break;
+ case 4:
+ pival = (int *)dummy_var;
+ *pival = 0xffffffff;
+ break;
+ case 8:
+ plval = (long long *)dummy_var;
+ *plval = 0xffffffffffffffffLL;
+ break;
+ }
+}
+
+static void read_var(int len)
+{
+ char cval __attribute__((unused));
+ short sval __attribute__((unused));
+ int ival __attribute__((unused));
+ long long lval __attribute__((unused));
+
+ switch (len) {
+ case 1:
+ cval = *(char *)dummy_var;
+ break;
+ case 2:
+ sval = *(short *)dummy_var;
+ break;
+ case 4:
+ ival = *(int *)dummy_var;
+ break;
+ case 8:
+ lval = *(long long *)dummy_var;
+ break;
+ }
+}
+
+/*
+ * Do the r/w accesses to trigger the breakpoints. And run
+ * the usual traps.
+ */
+static void trigger_tests(void)
+{
+ int len, ret;
+
+ ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);
+ if (ret) {
+ perror("Can't be traced?\n");
+ return;
+ }
+
+ /* Wake up father so that it sets up the first test */
+ kill(getpid(), SIGUSR1);
+
+ /* Test write watchpoints */
+ for (len = 1; len <= sizeof(long); len <<= 1)
+ write_var(len);
+
+ /* Test read/write watchpoints (on read accesses) */
+ for (len = 1; len <= sizeof(long); len <<= 1)
+ read_var(len);
+
+ /* Test when breakpoint is unset */
+
+ /* Test write watchpoints */
+ for (len = 1; len <= sizeof(long); len <<= 1)
+ write_var(len);
+
+ /* Test read/write watchpoints (on read accesses) */
+ for (len = 1; len <= sizeof(long); len <<= 1)
+ read_var(len);
+}
+
+static void check_success(const char *msg)
+{
+ const char *msg2;
+ int status;
+
+ /* Wait for the child to SIGTRAP */
+ wait(&status);
+
+ msg2 = "Failed";
+
+ if (WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP) {
+ msg2 = "Child process hit the breakpoint";
+ }
+
+ printf("%s Result: [%s]\n", msg, msg2);
+}
+
+static void launch_watchpoints(char *buf, int mode, int len,
+ struct ppc_debug_info *dbginfo, bool dawr)
+{
+ const char *mode_str;
+ unsigned long data = (unsigned long)(dummy_var);
+ int wh, range;
+
+ data &= ~0x7UL;
+
+ if (mode == BP_W) {
+ data |= (1UL << 1);
+ mode_str = "write";
+ } else {
+ data |= (1UL << 0);
+ data |= (1UL << 1);
+ mode_str = "read";
+ }
+
+ /* Set DABR_TRANSLATION bit */
+ data |= (1UL << 2);
+
+ /* use PTRACE_SET_DEBUGREG breakpoints */
+ set_breakpoint_addr((void *)data);
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ sprintf(buf, "Test %s watchpoint with len: %d ", mode_str, len);
+ check_success(buf);
+ /* Unregister hw brkpoint */
+ set_breakpoint_addr(NULL);
+
+ data = (data & ~7); /* remove dabr control bits */
+
+ /* use PPC_PTRACE_SETHWDEBUG breakpoint */
+ if (!(dbginfo->features & PPC_DEBUG_FEATURE_DATA_BP_RANGE))
+ return; /* not supported */
+ wh = set_hwbreakpoint_addr((void *)data, 0);
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ sprintf(buf, "Test %s watchpoint with len: %d ", mode_str, len);
+ check_success(buf);
+ /* Unregister hw brkpoint */
+ del_hwbreakpoint_addr(wh);
+
+ /* try a wider range */
+ range = 8;
+ if (dawr)
+ range = 512 - ((int)data & (DAWR_LENGTH_MAX - 1));
+ wh = set_hwbreakpoint_addr((void *)data, range);
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ sprintf(buf, "Test %s watchpoint with len: %d ", mode_str, len);
+ check_success(buf);
+ /* Unregister hw brkpoint */
+ del_hwbreakpoint_addr(wh);
+}
+
+/* Set the breakpoints and check the child successfully trigger them */
+static int launch_tests(bool dawr)
+{
+ char buf[1024];
+ int len, i, status;
+
+ struct ppc_debug_info dbginfo;
+
+ i = ptrace(PPC_PTRACE_GETHWDBGINFO, child_pid, NULL, &dbginfo);
+ if (i) {
+ perror("Can't set breakpoint info\n");
+ exit(-1);
+ }
+ if (!(dbginfo.features & PPC_DEBUG_FEATURE_DATA_BP_RANGE))
+ printf("WARNING: Kernel doesn't support PPC_PTRACE_SETHWDEBUG\n");
+
+ /* Write watchpoint */
+ for (len = 1; len <= sizeof(long); len <<= 1)
+ launch_watchpoints(buf, BP_W, len, &dbginfo, dawr);
+
+ /* Read-Write watchpoint */
+ for (len = 1; len <= sizeof(long); len <<= 1)
+ launch_watchpoints(buf, BP_RW, len, &dbginfo, dawr);
+
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+
+ /*
+ * Now we have unregistered the breakpoint, access by child
+ * should not cause SIGTRAP.
+ */
+
+ wait(&status);
+
+ if (WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP) {
+ printf("FAIL: Child process hit the breakpoint, which is not expected\n");
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ return TEST_FAIL;
+ }
+
+ if (WIFEXITED(status))
+ printf("Child exited normally\n");
+
+ return TEST_PASS;
+}
+
+static int ptrace_hwbreak(void)
+{
+ pid_t pid;
+ int ret;
+ bool dawr;
+
+ pid = fork();
+ if (!pid) {
+ trigger_tests();
+ return 0;
+ }
+
+ wait(NULL);
+
+ child_pid = pid;
+
+ get_dbginfo();
+ SKIP_IF(!hwbreak_present());
+ dawr = dawr_present();
+
+ ret = launch_tests(dawr);
+
+ wait(NULL);
+
+ return ret;
+}
+
+int main(int argc, char **argv, char **envp)
+{
+ return test_harness(ptrace_hwbreak, "ptrace-hwbreak");
+}
--
2.17.1
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