Files
rt-thread/components/lwp/arch/common/vdso_kernel.c

314 lines
8.5 KiB
C

/*
* Copyright (c) 2006-2025 RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2024-07-04 rcitach init ver.
* 2025-04-22 ScuDays Add VDSO functionality under the riscv64 architecture.
* 2026-04-21 rcitach Refactor vDSO runtime around the clock data page.
*/
#include <rtthread.h>
#include <mmu.h>
#include <elf.h>
#include <time.h>
#include <lwp_user_mm.h>
#include <drivers/clock_time.h>
#ifdef RT_USING_RTC
#include <rtdevice.h>
#endif
#include <vdso_kernel.h>
#include <vdso_kernel_internal.h>
#define DBG_TAG "vdso"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
enum rt_vdso_binary_id
{
RT_VDSO_BINARY_COMMON,
};
struct rt_vdso_binary_info
{
const char *name;
const char *image_start;
const char *image_end;
unsigned long page_count;
};
static struct rt_vdso_binary_info rt_vdso_binaries[] = {
[RT_VDSO_BINARY_COMMON] = {
.name = "rt_vdso_common",
.image_start = __rt_vdso_image_start,
.image_end = __rt_vdso_image_end,
},
};
static union {
struct rt_vdso_data_page data_page;
uint8_t raw[RT_VDSO_DATA_PAGE_COUNT * ARCH_PAGE_SIZE];
} rt_vdso_data_page_store RT_VDSO_DATA_PAGE_ALIGNED;
struct rt_vdso_data_page *rt_vdso_kernel_data_page = &rt_vdso_data_page_store.data_page;
static int rt_vdso_runtime_status = RT_EOK;
static struct timespec rt_vdso_realtime_offset;
static rt_bool_t rt_vdso_realtime_offset_ready;
#ifndef MMU_MAP_U_ROCB
#define MMU_MAP_U_ROCB MMU_MAP_U_RWCB
#endif
#ifndef MMU_MAP_U_RWCB_XN
#define MMU_MAP_U_RWCB_XN MMU_MAP_U_RWCB
#endif
#ifdef MMU_MAP_U_ROCB_XN
#define RT_VDSO_DATA_PAGE_ATTR MMU_MAP_U_ROCB_XN
#elif defined(MMU_MAP_U_RWCB_XN)
#define RT_VDSO_DATA_PAGE_ATTR MMU_MAP_U_RWCB_XN
#else
#define RT_VDSO_DATA_PAGE_ATTR MMU_MAP_U_ROCB
#endif
#define RT_VDSO_IMAGE_PAGE_ATTR MMU_MAP_U_ROCB
static void rt_vdso_normalize_timespec(struct timespec *ts)
{
while (ts->tv_nsec >= RT_VDSO_NSEC_PER_SEC)
{
ts->tv_sec += 1;
ts->tv_nsec -= RT_VDSO_NSEC_PER_SEC;
}
while (ts->tv_nsec < 0)
{
ts->tv_sec -= 1;
ts->tv_nsec += RT_VDSO_NSEC_PER_SEC;
}
}
static void rt_vdso_counter_to_timespec(rt_uint64_t counter_value,
struct timespec *ts)
{
rt_uint64_t monotonic_ns;
monotonic_ns = rt_clock_time_counter_to_ns(counter_value);
ts->tv_sec = monotonic_ns / RT_VDSO_NSEC_PER_SEC;
ts->tv_nsec = monotonic_ns % RT_VDSO_NSEC_PER_SEC;
}
static struct timespec rt_vdso_add_timespec(const struct timespec *lhs,
const struct timespec *rhs)
{
struct timespec ret;
ret.tv_sec = lhs->tv_sec + rhs->tv_sec;
ret.tv_nsec = lhs->tv_nsec + rhs->tv_nsec;
rt_vdso_normalize_timespec(&ret);
return ret;
}
static int rt_vdso_read_monotonic_snapshot(struct timespec *monotonic_time,
rt_uint64_t *counter_value,
rt_uint64_t *counter_freq)
{
*counter_value = rt_clock_time_get_counter();
*counter_freq = rt_clock_time_get_freq();
if (*counter_freq == 0)
{
return -RT_ERROR;
}
rt_vdso_counter_to_timespec(*counter_value, monotonic_time);
return RT_EOK;
}
static void rt_vdso_store_clock_snapshot(const struct timespec *monotonic_time,
rt_uint64_t counter_value,
rt_uint64_t counter_freq)
{
rt_vdso_kernel_data_page->counter_last = counter_value;
rt_vdso_kernel_data_page->counter_freq = counter_freq;
rt_vdso_kernel_data_page->base_time[RT_VDSO_CLOCK_MONOTONIC_INDEX] = *monotonic_time;
rt_vdso_kernel_data_page->base_time[RT_VDSO_CLOCK_REALTIME_INDEX] =
rt_vdso_add_timespec(monotonic_time, &rt_vdso_realtime_offset);
}
static void *rt_vdso_map_physical_pages(struct rt_lwp *lwp, void *user_va,
void *kernel_pa, size_t map_size,
rt_size_t attr)
{
int err;
char *va;
size_t offset = 0;
if (!map_size)
{
return RT_NULL;
}
if (user_va)
{
if (((size_t)user_va & ARCH_PAGE_MASK) !=
((size_t)kernel_pa & ARCH_PAGE_MASK))
{
return RT_NULL;
}
}
offset = (size_t)kernel_pa & ARCH_PAGE_MASK;
map_size += offset + ARCH_PAGE_SIZE - 1;
map_size &= ~ARCH_PAGE_MASK;
kernel_pa = (void *)((size_t)kernel_pa & ~ARCH_PAGE_MASK);
struct rt_mm_va_hint hint = {
.flags = 0,
.limit_range_size = lwp->aspace->size,
.limit_start = lwp->aspace->start,
.prefer = user_va,
.map_size = map_size,
};
if (user_va != RT_NULL)
{
hint.flags |= MMF_MAP_FIXED;
}
err = rt_aspace_map_phy(lwp->aspace, &hint, attr, MM_PA_TO_OFF(kernel_pa),
(void **)&va);
if (err != RT_EOK)
{
return RT_NULL;
}
return va + offset;
}
static int rt_vdso_map_binary_pages(enum rt_vdso_binary_id binary_id,
struct rt_lwp *lwp)
{
void *data_page_base = RT_NULL;
void *image_base = RT_NULL;
unsigned long data_page_len;
unsigned long image_len;
RT_ASSERT(lwp != RT_NULL);
data_page_len = RT_VDSO_DATA_PAGE_COUNT * ARCH_PAGE_SIZE;
image_len = rt_vdso_binaries[binary_id].page_count << ARCH_PAGE_SHIFT;
data_page_base = rt_vdso_map_physical_pages(
lwp, RT_NULL, rt_kmem_v2p((void *)rt_vdso_get_kernel_data_page()),
data_page_len, RT_VDSO_DATA_PAGE_ATTR);
if (data_page_base == RT_NULL)
{
lwp->vdso_vbase = RT_NULL;
return RT_ERROR;
}
image_base = (uint8_t *)data_page_base + data_page_len;
image_base = rt_vdso_map_physical_pages(
lwp, image_base,
rt_kmem_v2p((void *)rt_vdso_binaries[binary_id].image_start),
image_len, RT_VDSO_IMAGE_PAGE_ATTR);
if (image_base == RT_NULL)
{
lwp_unmap_user_phy(lwp, data_page_base);
lwp->vdso_vbase = RT_NULL;
return RT_ERROR;
}
lwp->vdso_vbase = image_base;
return RT_EOK;
}
int rt_vdso_map_process_image(struct rt_lwp *lwp)
{
if (rt_vdso_runtime_status != RT_EOK)
{
return -RT_ERROR;
}
return rt_vdso_map_binary_pages(RT_VDSO_BINARY_COMMON, lwp);
}
void rt_vdso_sync_clock_data(void)
{
struct timespec monotonic;
rt_uint64_t counter;
rt_uint64_t freq;
if (rt_vdso_runtime_status != RT_EOK)
{
return;
}
if (rt_vdso_read_monotonic_snapshot(&monotonic, &counter, &freq) != RT_EOK)
{
return;
}
rt_vdso_data_page_write_begin(rt_vdso_kernel_data_page);
rt_vdso_store_clock_snapshot(&monotonic, counter, freq);
rt_vdso_data_page_write_end(rt_vdso_kernel_data_page);
}
static int rt_vdso_validate_image(void)
{
const Elf64_Ehdr *ehdr =
(const Elf64_Ehdr *)rt_vdso_binaries[RT_VDSO_BINARY_COMMON].image_start;
rt_memset(rt_vdso_data_page_store.raw, 0, sizeof(rt_vdso_data_page_store.raw));
rt_vdso_realtime_offset_ready = RT_FALSE;
if (rt_memcmp(rt_vdso_binaries[RT_VDSO_BINARY_COMMON].image_start,
RT_VDSO_IMAGE_ELF_MAGIC, RT_VDSO_IMAGE_ELF_MAGIC_LEN))
{
LOG_E("vDSO is not a valid ELF object!");
rt_vdso_runtime_status = -RT_ERROR;
return -RT_ERROR;
}
if (ehdr->e_ident[EI_CLASS] != ELFCLASS64 || ehdr->e_type != ET_DYN)
{
LOG_E("vDSO ELF class/type mismatch!");
rt_vdso_runtime_status = -RT_ERROR;
return -RT_ERROR;
}
#if defined(__aarch64__)
if (ehdr->e_machine != EM_AARCH64)
{
LOG_E("vDSO machine mismatch: expect AArch64");
rt_vdso_runtime_status = -RT_ERROR;
return -RT_ERROR;
}
#elif defined(__riscv)
if (ehdr->e_machine != EM_RISCV)
{
LOG_E("vDSO machine mismatch: expect RISC-V");
rt_vdso_runtime_status = -RT_ERROR;
return -RT_ERROR;
}
#endif
rt_vdso_binaries[RT_VDSO_BINARY_COMMON].page_count =
(rt_vdso_binaries[RT_VDSO_BINARY_COMMON].image_end -
rt_vdso_binaries[RT_VDSO_BINARY_COMMON].image_start) >>
ARCH_PAGE_SHIFT;
if (rt_vdso_binaries[RT_VDSO_BINARY_COMMON].page_count == 0)
{
LOG_E("vDSO image is empty!");
rt_vdso_runtime_status = -RT_ERROR;
return -RT_ERROR;
}
return RT_EOK;
}
INIT_COMPONENT_EXPORT(rt_vdso_validate_image);