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Enable merged os_mmap for aot data sections and aot text (bytecodeall…
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…iance#3743)

Enable merged os_mmap for aot data sections first, and try enabling merged
os_mmap for them and aot text except on platform nuttx and esp-idf.

This fixes the issue that aarch64 AOT module fails to load on android:
bytecodealliance#2274

And also refine os_mmap related code.
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@wenyongh
wenyongh authored Aug 21, 2024
1 parent 1329e1d commit 67dce48
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Showing 2 changed files with 178 additions and 72 deletions.
243 changes: 171 additions & 72 deletions core/iwasm/aot/aot_loader.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -294,6 +294,39 @@ loader_malloc(uint64 size, char *error_buf, uint32 error_buf_size)
return mem;
}

static void *
loader_mmap(uint32 size, bool prot_exec, char *error_buf, uint32 error_buf_size)
{
int map_prot =
MMAP_PROT_READ | MMAP_PROT_WRITE | (prot_exec ? MMAP_PROT_EXEC : 0);
int map_flags;
void *mem;

#if UINTPTR_MAX == UINT64_MAX
/* The mmapped AOT data and code in 64-bit targets had better be in
range 0 to 2G, or aot loader may fail to apply some relocations,
e.g., R_X86_64_32/R_X86_64_32S/R_X86_64_PC32/R_RISCV_32.
We try to mmap with MMAP_MAP_32BIT flag first, and if fails, mmap
again without the flag. */
map_flags = MMAP_MAP_32BIT;
if ((mem = os_mmap(NULL, size, map_prot, map_flags,
os_get_invalid_handle()))) {
/* The mmapped memory must be in the first 2 Gigabytes of the
process address space */
bh_assert((uintptr_t)mem < INT32_MAX);
return mem;
}
#endif

map_flags = MMAP_MAP_NONE;
if (!(mem = os_mmap(NULL, size, map_prot, map_flags,
os_get_invalid_handle()))) {
set_error_buf(error_buf, error_buf_size, "allocate memory failed");
return NULL;
}
return mem;
}

static char *
load_string(uint8 **p_buf, const uint8 *buf_end, AOTModule *module,
bool is_load_from_file_buf,
Expand Down Expand Up @@ -2378,7 +2411,6 @@ destroy_object_data_sections(AOTObjectDataSection *data_sections,
}
}
#endif
os_munmap(data_section->data, data_section->size);
}
wasm_runtime_free(data_sections);
}
Expand All @@ -2392,6 +2424,9 @@ load_object_data_sections(const uint8 **p_buf, const uint8 *buf_end,
AOTObjectDataSection *data_sections;
uint64 size;
uint32 i;
uint64 total_size = 0;
uint32 page_size = os_getpagesize();
uint8 *merged_sections = NULL;

/* Allocate memory */
size = sizeof(AOTObjectDataSection) * (uint64)module->data_section_count;
Expand All @@ -2400,41 +2435,40 @@ load_object_data_sections(const uint8 **p_buf, const uint8 *buf_end,
return false;
}

/* Create each data section */
/* First iteration: read data from buf, and calculate total memory needed */
for (i = 0; i < module->data_section_count; i++) {
int map_prot = MMAP_PROT_READ | MMAP_PROT_WRITE;
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64) \
|| defined(BUILD_TARGET_RISCV64_LP64D) \
|| defined(BUILD_TARGET_RISCV64_LP64)
/* aot code and data in x86_64 must be in range 0 to 2G due to
relocation for R_X86_64_32/32S/PC32 */
int map_flags = MMAP_MAP_32BIT;
#else
int map_flags = MMAP_MAP_NONE;
#endif

read_string(buf, buf_end, data_sections[i].name);
read_uint32(buf, buf_end, data_sections[i].size);

CHECK_BUF(buf, buf_end, data_sections[i].size);
/* Temporary record data ptr for merge, will be replaced after the
merged_data_sections is mmapped */
if (data_sections[i].size > 0)
data_sections[i].data = (uint8 *)buf;
buf += data_sections[i].size;
total_size += align_uint64((uint64)data_sections[i].size, page_size);
}
if (total_size > UINT32_MAX) {
set_error_buf(error_buf, error_buf_size, "data sections too large");
return false;
}
if (total_size > 0) {
/* Allocate memory for data */
if (data_sections[i].size > 0
&& !(data_sections[i].data =
os_mmap(NULL, data_sections[i].size, map_prot, map_flags,
os_get_invalid_handle()))) {
set_error_buf(error_buf, error_buf_size, "allocate memory failed");
merged_sections = module->merged_data_sections =
loader_mmap((uint32)total_size, false, error_buf, error_buf_size);
if (!merged_sections) {
return false;
}
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64)
#if !defined(BH_PLATFORM_LINUX_SGX) && !defined(BH_PLATFORM_WINDOWS) \
&& !defined(BH_PLATFORM_DARWIN)
/* address must be in the first 2 Gigabytes of
the process address space */
bh_assert((uintptr_t)data_sections[i].data < INT32_MAX);
#endif
#endif
module->merged_data_sections_size = (uint32)total_size;
}

read_byte_array(buf, buf_end, data_sections[i].data,
data_sections[i].size);
/* Second iteration: Create each data section */
for (i = 0; i < module->data_section_count; i++) {
if (data_sections[i].size > 0) {
bh_memcpy_s(merged_sections, data_sections[i].size,
data_sections[i].data, data_sections[i].size);
data_sections[i].data = merged_sections;
merged_sections += align_uint(data_sections[i].size, page_size);
}
}

*p_buf = buf;
Expand Down Expand Up @@ -2532,6 +2566,82 @@ load_init_data_section(const uint8 *buf, const uint8 *buf_end,
return false;
}

#if !defined(BH_PLATFORM_NUTTX) && !defined(BH_PLATFORM_ESP_IDF)
static bool
try_merge_data_and_text(const uint8 **buf, const uint8 **buf_end,
AOTModule *module, char *error_buf,
uint32 error_buf_size)
{
uint8 *old_buf = (uint8 *)*buf;
uint8 *old_end = (uint8 *)*buf_end;
size_t code_size = (size_t)(old_end - old_buf);
uint32 page_size = os_getpagesize();
uint64 total_size = 0;
uint32 i;
uint8 *sections;

if (code_size == 0) {
return true;
}

/* calculate the total memory needed */
total_size += align_uint64((uint64)code_size, page_size);
for (i = 0; i < module->data_section_count; ++i) {
total_size +=
align_uint64((uint64)module->data_sections[i].size, page_size);
}
/* distance between .data and .text should not be greater than 4GB
for some targets (e.g. arm64 reloc need < 4G distance) */
if (total_size > UINT32_MAX) {
return false;
}
/* code_size was checked and must be larger than 0 here */
bh_assert(total_size > 0);

sections = loader_mmap((uint32)total_size, false, NULL, 0);
if (!sections) {
/* merge failed but may be not critical for some targets */
return false;
}
/* change the code part to be executable */
if (os_mprotect(sections, code_size,
MMAP_PROT_READ | MMAP_PROT_WRITE | MMAP_PROT_EXEC)
!= 0) {
os_munmap(sections, (uint32)total_size);
return false;
}

module->merged_data_text_sections = sections;
module->merged_data_text_sections_size = (uint32)total_size;

/* order not essential just as compiler does: .text section first */
*buf = sections;
*buf_end = sections + code_size;
bh_memcpy_s(sections, code_size, old_buf, code_size);
os_munmap(old_buf, code_size);
sections += align_uint((uint32)code_size, page_size);

/* then migrate .data sections */
for (i = 0; i < module->data_section_count; ++i) {
AOTObjectDataSection *data_section = module->data_sections + i;
uint8 *old_data = data_section->data;
data_section->data = sections;
bh_memcpy_s(data_section->data, data_section->size, old_data,
data_section->size);
sections += align_uint(data_section->size, page_size);
}
/* free the original data sections */
if (module->merged_data_sections) {
os_munmap(module->merged_data_sections,
module->merged_data_sections_size);
module->merged_data_sections = NULL;
module->merged_data_sections_size = 0;
}

return true;
}
#endif /* ! defined(BH_PLATFORM_NUTTX) && !defined(BH_PLATFORM_ESP_IDF) */

static bool
load_text_section(const uint8 *buf, const uint8 *buf_end, AOTModule *module,
char *error_buf, uint32 error_buf_size)
Expand Down Expand Up @@ -3391,16 +3501,9 @@ load_relocation_section(const uint8 *buf, const uint8 *buf_end,
+ sizeof(uint64) * module->real_plt_count
+ sizeof(uint32) * module->float_plt_count;
if (size > 0) {
map_prot = MMAP_PROT_READ | MMAP_PROT_WRITE | MMAP_PROT_EXEC;
/* aot code and data in x86_64 must be in range 0 to 2G due to
relocation for R_X86_64_32/32S/PC32 */
map_flags = MMAP_MAP_32BIT;

if (size > UINT32_MAX
|| !(module->extra_plt_data =
os_mmap(NULL, (uint32)size, map_prot, map_flags,
os_get_invalid_handle()))) {
set_error_buf(error_buf, error_buf_size, "mmap memory failed");
|| !(module->extra_plt_data = loader_mmap(
(uint32)size, true, error_buf, error_buf_size))) {
goto fail;
}
module->extra_plt_data_size = (uint32)size;
Expand Down Expand Up @@ -3512,19 +3615,12 @@ load_relocation_section(const uint8 *buf, const uint8 *buf_end,
GOTItem *got_item = module->got_item_list;
uint32 got_item_idx = 0;

map_prot = MMAP_PROT_READ | MMAP_PROT_WRITE;
/* aot code and data in x86_64 must be in range 0 to 2G due to
relocation for R_X86_64_32/32S/PC32 */
map_flags = MMAP_MAP_32BIT;

/* Create the GOT for func_ptrs, note that it is different from
the .got section of a dynamic object file */
size = (uint64)sizeof(void *) * got_item_count;
if (size > UINT32_MAX
|| !(module->got_func_ptrs =
os_mmap(NULL, (uint32)size, map_prot, map_flags,
os_get_invalid_handle()))) {
set_error_buf(error_buf, error_buf_size, "mmap memory failed");
|| !(module->got_func_ptrs = loader_mmap(
(uint32)size, false, error_buf, error_buf_size))) {
goto fail;
}

Expand Down Expand Up @@ -3749,6 +3845,17 @@ load_from_sections(AOTModule *module, AOTSection *sections,
return false;
break;
case AOT_SECTION_TYPE_TEXT:
#if !defined(BH_PLATFORM_NUTTX) && !defined(BH_PLATFORM_ESP_IDF)
/* try to merge .data and .text, with exceptions:
* 1. XIP mode
* 2. pre-mmapped module load from aot_load_from_sections()
* 3. nuttx & esp-idf: have separate region for MMAP_PROT_EXEC
*/
if (!module->is_indirect_mode && is_load_from_file_buf)
if (!try_merge_data_and_text(&buf, &buf_end, module,
error_buf, error_buf_size))
LOG_WARNING("merge .data and .text sections failed");
#endif /* ! defined(BH_PLATFORM_NUTTX) && !defined(BH_PLATFORM_ESP_IDF) */
if (!load_text_section(buf, buf_end, module, error_buf,
error_buf_size))
return false;
Expand Down Expand Up @@ -4065,37 +4172,16 @@ create_sections(AOTModule *module, const uint8 *buf, uint32 size,

if (section_type == AOT_SECTION_TYPE_TEXT) {
if ((section_size > 0) && !module->is_indirect_mode) {
int map_prot =
MMAP_PROT_READ | MMAP_PROT_WRITE | MMAP_PROT_EXEC;
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64) \
|| defined(BUILD_TARGET_RISCV64_LP64D) \
|| defined(BUILD_TARGET_RISCV64_LP64)
/* aot code and data in x86_64 must be in range 0 to 2G due
to relocation for R_X86_64_32/32S/PC32 */
int map_flags = MMAP_MAP_32BIT;
#else
int map_flags = MMAP_MAP_NONE;
#endif
total_size =
(uint64)section_size + aot_get_plt_table_size();
total_size = (total_size + 3) & ~((uint64)3);
if (total_size >= UINT32_MAX
|| !(aot_text =
os_mmap(NULL, (uint32)total_size, map_prot,
map_flags, os_get_invalid_handle()))) {
loader_mmap((uint32)total_size, true,
error_buf, error_buf_size))) {
wasm_runtime_free(section);
set_error_buf(error_buf, error_buf_size,
"mmap memory failed");
goto fail;
}
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64)
#if !defined(BH_PLATFORM_LINUX_SGX) && !defined(BH_PLATFORM_WINDOWS) \
&& !defined(BH_PLATFORM_DARWIN)
/* address must be in the first 2 Gigabytes of
the process address space */
bh_assert((uintptr_t)aot_text < INT32_MAX);
#endif
#endif

#if (WASM_MEM_DUAL_BUS_MIRROR != 0)
mirrored_text = os_get_dbus_mirror(aot_text);
Expand Down Expand Up @@ -4179,7 +4265,11 @@ load(const uint8 *buf, uint32 size, AOTModule *module,
if (!ret) {
/* If load_from_sections() fails, then aot text is destroyed
in destroy_sections() */
destroy_sections(section_list, module->is_indirect_mode ? false : true);
destroy_sections(section_list,
module->is_indirect_mode
|| module->merged_data_text_sections
? false
: true);
/* aot_unload() won't destroy aot text again */
module->code = NULL;
}
Expand Down Expand Up @@ -4329,7 +4419,8 @@ aot_unload(AOTModule *module)
}
#endif

if (module->code && !module->is_indirect_mode) {
if (module->code && !module->is_indirect_mode
&& !module->merged_data_text_sections) {
/* The layout is: literal size + literal + code (with plt table) */
uint8 *mmap_addr = module->literal - sizeof(uint32);
uint32 total_size =
Expand Down Expand Up @@ -4364,6 +4455,14 @@ aot_unload(AOTModule *module)
destroy_object_data_sections(module->data_sections,
module->data_section_count);

if (module->merged_data_sections)
os_munmap(module->merged_data_sections,
module->merged_data_sections_size);

if (module->merged_data_text_sections)
os_munmap(module->merged_data_text_sections,
module->merged_data_text_sections_size);

#if WASM_ENABLE_DEBUG_AOT != 0
jit_code_entry_destroy(module->elf_hdr);
#endif
Expand Down
7 changes: 7 additions & 0 deletions core/iwasm/aot/aot_runtime.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -315,6 +315,13 @@ typedef struct AOTModule {

/* Whether the underlying wasm binary buffer can be freed */
bool is_binary_freeable;

/* `.data` sections merged into one mmaped to reduce the tlb cache miss */
uint8 *merged_data_sections;
uint32 merged_data_sections_size;
/* `.data` and `.text` sections merged into one large mmaped section */
uint8 *merged_data_text_sections;
uint32 merged_data_text_sections_size;
} AOTModule;

#define AOTMemoryInstance WASMMemoryInstance
Expand Down

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