Re: [PATCH v6 8/8] powerpc/watchpoint/selftests: Tests for kernel accessing user memory
From: Rogerio Alves <hidden>
Date: 2020-09-17 13:55:13
Also in:
lkml
On 9/2/20 1:29 AM, Ravi Bangoria wrote:
Introduce tests to cover simple scenarios where user is watching memory which can be accessed by kernel as well. We also support _MODE_EXACT with _SETHWDEBUG interface. Move those testcases out- side of _BP_RANGE condition. This will help to test _MODE_EXACT scenarios when CONFIG_HAVE_HW_BREAKPOINT is not set, eg: $ ./ptrace-hwbreak ... PTRACE_SET_DEBUGREG, Kernel Access Userspace, len: 8: Ok PPC_PTRACE_SETHWDEBUG, MODE_EXACT, WO, len: 1: Ok PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RO, len: 1: Ok PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RW, len: 1: Ok PPC_PTRACE_SETHWDEBUG, MODE_EXACT, Kernel Access Userspace, len: 1: Ok success: ptrace-hwbreak Suggested-by: Pedro Miraglia Franco de Carvalho <redacted> Signed-off-by: Ravi Bangoria <redacted>
Tested-by: Rogerio Alves <redacted>
quoted hunk ↗ jump to hunk
--- .../selftests/powerpc/ptrace/ptrace-hwbreak.c | 48 ++++++++++++++++++- 1 file changed, 46 insertions(+), 2 deletions(-)diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c b/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c index fc477dfe86a2..2e0d86e0687e 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-hwbreak.c@@ -20,6 +20,8 @@ #include <signal.h> #include <sys/types.h> #include <sys/wait.h> +#include <sys/syscall.h> +#include <linux/limits.h> #include "ptrace.h" #define SPRN_PVR 0x11F@@ -44,6 +46,7 @@ struct gstruct { }; static volatile struct gstruct gstruct __attribute__((aligned(512))); +static volatile char cwd[PATH_MAX] __attribute__((aligned(8))); static void get_dbginfo(pid_t child_pid, struct ppc_debug_info *dbginfo) {@@ -138,6 +141,9 @@ static void test_workload(void) write_var(len); } + /* PTRACE_SET_DEBUGREG, Kernel Access Userspace test */ + syscall(__NR_getcwd, &cwd, PATH_MAX); + /* PPC_PTRACE_SETHWDEBUG, MODE_EXACT, WO test */ write_var(1);@@ -150,6 +156,9 @@ static void test_workload(void) else read_var(1); + /* PPC_PTRACE_SETHWDEBUG, MODE_EXACT, Kernel Access Userspace test */ + syscall(__NR_getcwd, &cwd, PATH_MAX); + /* PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, WO test */ gstruct.a[rand() % A_LEN] = 'a';@@ -293,6 +302,24 @@ static int test_set_debugreg(pid_t child_pid) return 0; } +static int test_set_debugreg_kernel_userspace(pid_t child_pid) +{ + unsigned long wp_addr = (unsigned long)cwd; + char *name = "PTRACE_SET_DEBUGREG"; + + /* PTRACE_SET_DEBUGREG, Kernel Access Userspace test */ + wp_addr &= ~0x7UL; + wp_addr |= (1Ul << DABR_READ_SHIFT); + wp_addr |= (1UL << DABR_WRITE_SHIFT); + wp_addr |= (1UL << DABR_TRANSLATION_SHIFT); + ptrace_set_debugreg(child_pid, wp_addr); + ptrace(PTRACE_CONT, child_pid, NULL, 0); + check_success(child_pid, name, "Kernel Access Userspace", wp_addr, 8); + + ptrace_set_debugreg(child_pid, 0); + return 0; +} + static void get_ppc_hw_breakpoint(struct ppc_hw_breakpoint *info, int type, unsigned long addr, int len) {@@ -338,6 +365,22 @@ static void test_sethwdebug_exact(pid_t child_pid) ptrace_delhwdebug(child_pid, wh); } +static void test_sethwdebug_exact_kernel_userspace(pid_t child_pid) +{ + struct ppc_hw_breakpoint info; + unsigned long wp_addr = (unsigned long)&cwd; + char *name = "PPC_PTRACE_SETHWDEBUG, MODE_EXACT"; + int len = 1; /* hardcoded in kernel */ + int wh; + + /* PPC_PTRACE_SETHWDEBUG, MODE_EXACT, Kernel Access Userspace test */ + get_ppc_hw_breakpoint(&info, PPC_BREAKPOINT_TRIGGER_WRITE, wp_addr, 0); + wh = ptrace_sethwdebug(child_pid, &info); + ptrace(PTRACE_CONT, child_pid, NULL, 0); + check_success(child_pid, name, "Kernel Access Userspace", wp_addr, len); + ptrace_delhwdebug(child_pid, wh); +} + static void test_sethwdebug_range_aligned(pid_t child_pid) { struct ppc_hw_breakpoint info;@@ -452,9 +495,10 @@ static void run_tests(pid_t child_pid, struct ppc_debug_info *dbginfo, bool dawr) { test_set_debugreg(child_pid); + test_set_debugreg_kernel_userspace(child_pid); + test_sethwdebug_exact(child_pid); + test_sethwdebug_exact_kernel_userspace(child_pid); if (dbginfo->features & PPC_DEBUG_FEATURE_DATA_BP_RANGE) { - test_sethwdebug_exact(child_pid); - test_sethwdebug_range_aligned(child_pid); if (dawr || is_8xx) { test_sethwdebug_range_unaligned(child_pid);