Commit ac234524 authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Michael Ellerman

selftests/powerpc: Tests for kernel accessing user memory

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 outside
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: default avatarPedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902042945.129369-9-ravi.bangoria@linux.ibm.com
parent fa725cc5
......@@ -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);
......
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