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[kernel][syscalls] Add mx_debug_write_memory.
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Change-Id: I920209244cfd7fa8e089a2b9107d5f21f074022a
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@xdje42
xdje42 committed Sep 20, 2016
1 parent 1f8c39e commit 399dfa6
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Showing 3 changed files with 134 additions and 15 deletions.
41 changes: 41 additions & 0 deletions kernel/lib/syscalls/syscalls_debug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@

constexpr uint32_t kMaxDebugWriteSize = 256u;
constexpr mx_size_t kMaxDebugReadBlock = 64 * 1024u * 1024u;
constexpr mx_size_t kMaxDebugWriteBlock = 64 * 1024u * 1024u;

constexpr uint32_t kMaxThreadStateSize = MX_MAX_THREAD_STATE_SIZE;

Expand Down Expand Up @@ -232,6 +233,46 @@ mx_ssize_t sys_debug_read_memory(mx_handle_t proc, uintptr_t vaddr, mx_size_t le
return static_cast<mx_ssize_t>(read);
}

mx_ssize_t sys_debug_write_memory(mx_handle_t proc, uintptr_t vaddr, mx_size_t len, user_ptr<const void> buffer) {
if (!buffer)
return ERR_INVALID_ARGS;
if (len == 0 || len > kMaxDebugWriteBlock)
return ERR_INVALID_ARGS;

auto up = ProcessDispatcher::GetCurrent();

mxtl::RefPtr<ProcessDispatcher> process;
mx_status_t status = up->GetDispatcher(proc, &process, MX_RIGHT_WRITE);
if (status != NO_ERROR)
return status;

// Disallow this call on self.
if (process.get() == up)
return ERR_INVALID_ARGS;

auto aspace = process->aspace();
if (!aspace)
return ERR_BAD_STATE;

auto region = aspace->FindRegion(vaddr);
if (!region)
return ERR_NO_MEMORY;

auto vmo = region->vmo();
if (!vmo)
return ERR_NO_MEMORY;

uint64_t offset = vaddr - region->base() + region->object_offset();
size_t written = 0;

status_t st = vmo->WriteUser(buffer, offset, len, &written);

if (st < 0)
return st;

return static_cast<mx_ssize_t>(written);
}

mx_ssize_t sys_ktrace_read(mx_handle_t handle, void* ptr, uint32_t off, uint32_t len) {
// TODO: finer grained validation
mx_status_t status;
Expand Down
6 changes: 4 additions & 2 deletions system/public/magenta/syscalls.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -63,9 +63,11 @@ MAGENTA_SYSCALL_DEF(2, 3, 7, mx_handle_t, debug_task_get_child, mx_handle_t hand
MAGENTA_SYSCALL_DEF(2, 2, 8, mx_handle_t, debug_transfer_handle, mx_handle_t proc, mx_handle_t handle)
MAGENTA_SYSCALL_DEF(4, 4, 9, mx_ssize_t, debug_read_memory, mx_handle_t proc, uintptr_t vaddr,
mx_size_t len, USER_PTR(void) buffer)
MAGENTA_SYSCALL_DEF(4, 4, 10, mx_ssize_t, debug_write_memory, mx_handle_t proc, uintptr_t vaddr,
mx_size_t len, USER_PTR(const void) buffer)

MAGENTA_SYSCALL_DEF(4, 4, 10, mx_ssize_t, ktrace_read, mx_handle_t handle, void* ptr, uint32_t off, uint32_t len)
MAGENTA_SYSCALL_DEF(3, 3, 11, mx_status_t, ktrace_control, mx_handle_t handle, uint32_t action, uint32_t options)
MAGENTA_SYSCALL_DEF(4, 4, 11, mx_ssize_t, ktrace_read, mx_handle_t handle, void* ptr, uint32_t off, uint32_t len)
MAGENTA_SYSCALL_DEF(3, 3, 12, mx_status_t, ktrace_control, mx_handle_t handle, uint32_t action, uint32_t options)

// Logging
MAGENTA_SYSCALL_DEF(1, 1, 30, mx_handle_t, log_create, uint32_t flags)
Expand Down
102 changes: 89 additions & 13 deletions system/utest/debugger/debugger.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,12 +15,15 @@
#include <test-utils/test-utils.h>
#include <unittest/unittest.h>

#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))

// 0.5 seconds
#define WATCHDOG_DURATION_TICK ((int64_t) 500 * 1000 * 1000)
// 5 seconds
#define WATCHDOG_DURATION_TICKS 10

#define TEST_MEMORY_SIZE 8
#define TEST_DATA_ADJUST 0x10

// Do the segv recovery test a number of times to stress test the API.
#define NUM_SEGV_TRIES 4
Expand Down Expand Up @@ -121,7 +124,7 @@ static const regspec_t general_regs[] =
static void dump_gregs(mx_handle_t thread_handle, void* buf)
{
#if defined(__x86_64__) || defined(__aarch64__)
printf("Registers for thread %d\n", thread_handle);
unittest_printf("Registers for thread %d\n", thread_handle);
for (unsigned i = 0; i < sizeof(general_regs) / sizeof(general_regs[0]); ++i) {
const regspec_t* r = &general_regs[i];
uint64_t val;
Expand All @@ -138,9 +141,9 @@ static void dump_gregs(mx_handle_t thread_handle, void* buf)
val = get_uint64(value_ptr);
}
if (r->count == 1)
printf(" %8s %24ld 0x%lx\n", r->name, (long) val, (long) val);
unittest_printf(" %8s %24ld 0x%lx\n", r->name, (long) val, (long) val);
else
printf(" %8s[%2u] %24ld 0x%lx\n", r->name, j, (long) val, (long) val);
unittest_printf(" %8s[%2u] %24ld 0x%lx\n", r->name, j, (long) val, (long) val);
}
}
#endif
Expand Down Expand Up @@ -168,7 +171,7 @@ static bool dump_inferior_regs(mx_handle_t thread)
uint32_t regset_size = 0;
status = mx_thread_read_state(thread, MX_THREAD_STATE_REGSET0 + i, NULL, &regset_size);
ASSERT_EQ(status, ERR_BUFFER_TOO_SMALL, "getting regset size failed");
void *buf = tu_malloc(regset_size);
void* buf = tu_malloc(regset_size);
status = mx_thread_read_state(thread, MX_THREAD_STATE_REGSET0 + i, buf, &regset_size);
ASSERT_EQ(status, NO_ERROR, "getting regset failed");
dump_arch_regs(thread, i, buf);
Expand Down Expand Up @@ -231,6 +234,51 @@ static void set_uint64_register(mx_handle_t thread, size_t offset, uint64_t valu
free(buf);
}

static mx_ssize_t read_inferior_memory(mx_handle_t proc, uintptr_t vaddr, void* buf, mx_size_t buf_size)
{
mx_ssize_t bytes_read = mx_debug_read_memory(proc, vaddr, buf_size, buf);
if (bytes_read < 0)
tu_fatal("read_inferior_memory", bytes_read);
return bytes_read;
}

static mx_ssize_t write_inferior_memory(mx_handle_t proc, uintptr_t vaddr, const void* buf, mx_size_t buf_size)
{
mx_ssize_t bytes_written = mx_debug_write_memory(proc, vaddr, buf_size, buf);
if (bytes_written < 0)
tu_fatal("write_inferior_memory", bytes_written);
return bytes_written;
}

static void test_memory_ops(mx_handle_t inferior, mx_handle_t thread)
{
uint64_t test_data_addr = 0;
mx_ssize_t ssize;
uint8_t test_data[TEST_MEMORY_SIZE];

#ifdef __x86_64__
test_data_addr = get_uint64_register(thread, offsetof(mx_x86_64_general_regs_t, r9));
#endif
#ifdef __aarch64__
test_data_addr = get_uint64_register(thread, offsetof(mx_aarch64_general_regs_t, r9));
#endif

ssize = read_inferior_memory(inferior, test_data_addr, test_data, sizeof(test_data));
EXPECT_EQ(ssize, (mx_ssize_t) sizeof(test_data), "read_inferior_memory: short read");

for (unsigned i = 0; i < sizeof(test_data); ++i) {
EXPECT_EQ(test_data[i], i, "test_memory_ops");
}

for (unsigned i = 0; i < sizeof(test_data); ++i)
test_data[i] += TEST_DATA_ADJUST;

ssize = write_inferior_memory(inferior, test_data_addr, test_data, sizeof(test_data));
EXPECT_EQ(ssize, (mx_ssize_t) sizeof(test_data), "write_inferior_memory: short write");

// Note: Verification of the write is done in the inferior.
}

static void fix_inferior_segv(mx_handle_t thread)
{
unittest_printf("Fixing inferior segv\n");
Expand Down Expand Up @@ -278,8 +326,10 @@ static bool wait_inferior_thread_worker(void* arg)
mx_handle_t thread = mx_debug_task_get_child(inferior, tid);
ASSERT_GT(thread, 0, "mx_debug_task_get_child failed");

if (i == 0)
dump_inferior_regs(thread);
dump_inferior_regs(thread);

// Do some tests that require a suspended inferior.
test_memory_ops(inferior, thread);

// Now correct the issue and resume the inferior.

Expand Down Expand Up @@ -364,14 +414,15 @@ static bool debugger_test(void)
mx_handle_t pipe1, pipe2;
tu_message_pipe_create(&pipe1, &pipe2);

const char* const argv[] = { test_child_path, test_inferior_child_name };
const char verbosity_string[] = { 'v', '=', utest_verbosity_level + '0', '\0' };
const char* const argv[] = { test_child_path, test_inferior_child_name, verbosity_string };
mx_handle_t handles[1] = { pipe2 };
uint32_t handle_ids[1] = { MX_HND_TYPE_USER0 };

launchpad_t* lp;
unittest_printf("Starting process \"%s\"\n", test_inferior_child_name);
status = create_inferior(test_inferior_child_name, 2, argv, NULL,
1, handles, handle_ids, &lp);
status = create_inferior(test_inferior_child_name, ARRAY_SIZE(argv), argv, NULL,
ARRAY_SIZE(handles), handles, handle_ids, &lp);
ASSERT_EQ(status, NO_ERROR, "failed to create inferior");

mx_handle_t inferior = launchpad_get_process_handle(lp);
Expand Down Expand Up @@ -457,7 +508,8 @@ __NO_INLINE static bool test_prep_and_segv(void)
__asm__ ("movq .Lsegv_here@GOTPCREL(%%rip),%0" : "=r" (segv_pc));
unittest_printf("About to segv, pc 0x%lx\n", (long) segv_pc);

// r9 is set for debugging purposes
// Set r9 to point to test_data so we can easily access it
// from the parent process.
__asm__ ("\
movq %0,%%r9\n\
movq $0,%%r8\n\
Expand All @@ -473,7 +525,8 @@ __NO_INLINE static bool test_prep_and_segv(void)
__asm__ ("mov %0,.Lsegv_here" : "=r" (segv_pc));
unittest_printf("About to segv, pc 0x%lx\n", (long) segv_pc);

// r9 is set for debugging purposes
// Set r9 to point to test_data so we can easily access it
// from the parent process.
__asm__ ("\
mov x9,%0\n\
mov x8,0\n\
Expand All @@ -483,6 +536,16 @@ __NO_INLINE static bool test_prep_and_segv(void)
: : "r" (&test_data[0]) : "x0", "x8", "x9");
#endif

// On resumption test_data should have had TEST_DATA_ADJUST added to each element.
// Note: This is the inferior process, it's not running under the test harness.
for (unsigned i = 0; i < sizeof(test_data); ++i) {
if (test_data[i] != i + TEST_DATA_ADJUST) {
unittest_printf("test_prep_and_segv: bad data on resumption, test_data[%u] = 0x%x\n",
i, test_data[i]);
return false;
}
}

unittest_printf("Inferior successfully resumed!\n");

return true;
Expand Down Expand Up @@ -530,13 +593,26 @@ BEGIN_TEST_CASE(debugger_tests)
RUN_TEST(debugger_test);
END_TEST_CASE(debugger_tests)

static void check_verbosity(int argc, char** argv)
{
for (int i = 1; i < argc; ++i) {
if (strncmp(argv[i], "v=", 2) == 0) {
int verbosity = atoi(argv[i] + 2);
unittest_set_verbosity_level(verbosity);
break;
}
}
}

int main(int argc, char **argv)
{
if (argc == 2 && strcmp(argv[1], test_inferior_child_name) == 0) {
if (argc >= 2 && strcmp(argv[1], test_inferior_child_name) == 0) {
check_verbosity(argc, argv);
test_inferior();
return 0;
}
if (argc == 2 && strcmp(argv[1], test_segfault_child_name) == 0) {
if (argc >= 2 && strcmp(argv[1], test_segfault_child_name) == 0) {
check_verbosity(argc, argv);
test_segfault();
return 0;
}
Expand Down

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