From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/mfd/macsmc.c | 504 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 504 insertions(+) create mode 100644 drivers/mfd/macsmc.c (limited to 'drivers/mfd/macsmc.c') diff --git a/drivers/mfd/macsmc.c b/drivers/mfd/macsmc.c new file mode 100644 index 000000000..358feec2d --- /dev/null +++ b/drivers/mfd/macsmc.c @@ -0,0 +1,504 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple SMC (System Management Controller) MFD driver + * + * Copyright The Asahi Linux Contributors + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define SMC_ENDPOINT 0x20 + +/* We don't actually know the true size here but this seem reasonable */ +#define SMC_SHMEM_SIZE 0x1000 +#define SMC_MAX_SIZE 255 + +#define SMC_MSG_READ_KEY 0x10 +#define SMC_MSG_WRITE_KEY 0x11 +#define SMC_MSG_GET_KEY_BY_INDEX 0x12 +#define SMC_MSG_GET_KEY_INFO 0x13 +#define SMC_MSG_INITIALIZE 0x17 +#define SMC_MSG_NOTIFICATION 0x18 +#define SMC_MSG_RW_KEY 0x20 + +#define SMC_DATA GENMASK_ULL(63, 32) +#define SMC_WSIZE GENMASK_ULL(31, 24) +#define SMC_SIZE GENMASK_ULL(23, 16) +#define SMC_ID GENMASK_ULL(15, 12) +#define SMC_MSG GENMASK_ULL(7, 0) +#define SMC_RESULT SMC_MSG + +#define SMC_TIMEOUT_MS 500 + +static const struct mfd_cell apple_smc_devs[] = { + MFD_CELL_NAME("macsmc-input"), + MFD_CELL_NAME("macsmc-power"), + MFD_CELL_OF("macsmc-gpio", NULL, NULL, 0, 0, "apple,smc-gpio"), + MFD_CELL_OF("macsmc-hwmon", NULL, NULL, 0, 0, "apple,smc-hwmon"), + MFD_CELL_OF("macsmc-reboot", NULL, NULL, 0, 0, "apple,smc-reboot"), + MFD_CELL_OF("macsmc-rtc", NULL, NULL, 0, 0, "apple,smc-rtc"), +}; + +static int apple_smc_cmd_locked(struct apple_smc *smc, u64 cmd, u64 arg, + u64 size, u64 wsize, u32 *ret_data) +{ + u8 result; + int ret; + u64 msg; + + lockdep_assert_held(&smc->mutex); + + if (smc->boot_stage != APPLE_SMC_INITIALIZED) + return -EIO; + if (smc->atomic_mode) + return -EIO; + + reinit_completion(&smc->cmd_done); + + smc->msg_id = (smc->msg_id + 1) & 0xf; + msg = (FIELD_PREP(SMC_MSG, cmd) | + FIELD_PREP(SMC_SIZE, size) | + FIELD_PREP(SMC_WSIZE, wsize) | + FIELD_PREP(SMC_ID, smc->msg_id) | + FIELD_PREP(SMC_DATA, arg)); + + ret = apple_rtkit_send_message(smc->rtk, SMC_ENDPOINT, msg, NULL, false); + if (ret) { + dev_err(smc->dev, "Failed to send command\n"); + return ret; + } + + if (wait_for_completion_timeout(&smc->cmd_done, msecs_to_jiffies(SMC_TIMEOUT_MS)) <= 0) { + dev_err(smc->dev, "Command timed out (%llx)", msg); + return -ETIMEDOUT; + } + + if (FIELD_GET(SMC_ID, smc->cmd_ret) != smc->msg_id) { + dev_err(smc->dev, "Command sequence mismatch (expected %d, got %d)\n", + smc->msg_id, (unsigned int)FIELD_GET(SMC_ID, smc->cmd_ret)); + return -EIO; + } + + result = FIELD_GET(SMC_RESULT, smc->cmd_ret); + if (result) + return -EIO; + + if (ret_data) + *ret_data = FIELD_GET(SMC_DATA, smc->cmd_ret); + + return FIELD_GET(SMC_SIZE, smc->cmd_ret); +} + +static int apple_smc_cmd(struct apple_smc *smc, u64 cmd, u64 arg, + u64 size, u64 wsize, u32 *ret_data) +{ + guard(mutex)(&smc->mutex); + + return apple_smc_cmd_locked(smc, cmd, arg, size, wsize, ret_data); +} + +static int apple_smc_rw_locked(struct apple_smc *smc, smc_key key, + const void *wbuf, size_t wsize, + void *rbuf, size_t rsize) +{ + u64 smc_size, smc_wsize; + u32 rdata; + int ret; + u64 cmd; + + lockdep_assert_held(&smc->mutex); + + if (rsize > SMC_MAX_SIZE) + return -EINVAL; + if (wsize > SMC_MAX_SIZE) + return -EINVAL; + + if (rsize && wsize) { + cmd = SMC_MSG_RW_KEY; + memcpy_toio(smc->shmem.iomem, wbuf, wsize); + smc_size = rsize; + smc_wsize = wsize; + } else if (wsize && !rsize) { + cmd = SMC_MSG_WRITE_KEY; + memcpy_toio(smc->shmem.iomem, wbuf, wsize); + /* + * Setting size to the length we want to write and wsize to 0 + * looks silly but that's how the SMC protocol works ¯\_(ツ)_/¯ + */ + smc_size = wsize; + smc_wsize = 0; + } else if (!wsize && rsize) { + cmd = SMC_MSG_READ_KEY; + smc_size = rsize; + smc_wsize = 0; + } else { + return -EINVAL; + } + + ret = apple_smc_cmd_locked(smc, cmd, key, smc_size, smc_wsize, &rdata); + if (ret < 0) + return ret; + + if (rsize) { + /* + * Small data <= 4 bytes is returned as part of the reply + * message which is sent over the mailbox FIFO. Everything + * bigger has to be copied from SRAM which is mapped as + * Device memory. + */ + if (rsize <= 4) + memcpy(rbuf, &rdata, rsize); + else + memcpy_fromio(rbuf, smc->shmem.iomem, rsize); + } + + return ret; +} + +int apple_smc_read(struct apple_smc *smc, smc_key key, void *buf, size_t size) +{ + guard(mutex)(&smc->mutex); + + return apple_smc_rw_locked(smc, key, NULL, 0, buf, size); +} +EXPORT_SYMBOL(apple_smc_read); + +int apple_smc_write(struct apple_smc *smc, smc_key key, const void *buf, size_t size) +{ + guard(mutex)(&smc->mutex); + + return apple_smc_rw_locked(smc, key, buf, size, NULL, 0); +} +EXPORT_SYMBOL(apple_smc_write); + +int apple_smc_rw(struct apple_smc *smc, smc_key key, const void *wbuf, size_t wsize, + void *rbuf, size_t rsize) +{ + guard(mutex)(&smc->mutex); + + return apple_smc_rw_locked(smc, key, wbuf, wsize, rbuf, rsize); +} +EXPORT_SYMBOL(apple_smc_rw); + +int apple_smc_get_key_by_index(struct apple_smc *smc, int index, smc_key *key) +{ + int ret; + + ret = apple_smc_cmd(smc, SMC_MSG_GET_KEY_BY_INDEX, index, 0, 0, key); + + *key = swab32(*key); + return ret; +} +EXPORT_SYMBOL(apple_smc_get_key_by_index); + +int apple_smc_get_key_info(struct apple_smc *smc, smc_key key, struct apple_smc_key_info *info) +{ + u8 key_info[6]; + int ret; + + ret = apple_smc_cmd(smc, SMC_MSG_GET_KEY_INFO, key, 0, 0, NULL); + if (ret >= 0 && info) { + memcpy_fromio(key_info, smc->shmem.iomem, sizeof(key_info)); + info->size = key_info[0]; + info->type_code = get_unaligned_be32(&key_info[1]); + info->flags = key_info[5]; + } + return ret; +} +EXPORT_SYMBOL(apple_smc_get_key_info); + +int apple_smc_enter_atomic(struct apple_smc *smc) +{ + guard(mutex)(&smc->mutex); + + /* + * Disable notifications since this is called before shutdown and no + * notification handler will be able to handle the notification + * using atomic operations only. Also ignore any failure here + * because we're about to shut down or reboot anyway. + * We can't use apple_smc_write_flag here since that would try to lock + * smc->mutex again. + */ + const u8 flag = 0; + + apple_smc_rw_locked(smc, SMC_KEY(NTAP), &flag, sizeof(flag), NULL, 0); + + smc->atomic_mode = true; + + return 0; +} +EXPORT_SYMBOL(apple_smc_enter_atomic); + +int apple_smc_write_atomic(struct apple_smc *smc, smc_key key, const void *buf, size_t size) +{ + guard(spinlock_irqsave)(&smc->lock); + u8 result; + int ret; + u64 msg; + + if (size > SMC_MAX_SIZE || size == 0) + return -EINVAL; + + if (smc->boot_stage != APPLE_SMC_INITIALIZED) + return -EIO; + if (!smc->atomic_mode) + return -EIO; + + memcpy_toio(smc->shmem.iomem, buf, size); + smc->msg_id = (smc->msg_id + 1) & 0xf; + msg = (FIELD_PREP(SMC_MSG, SMC_MSG_WRITE_KEY) | + FIELD_PREP(SMC_SIZE, size) | + FIELD_PREP(SMC_ID, smc->msg_id) | + FIELD_PREP(SMC_DATA, key)); + smc->atomic_pending = true; + + ret = apple_rtkit_send_message(smc->rtk, SMC_ENDPOINT, msg, NULL, true); + if (ret < 0) { + dev_err(smc->dev, "Failed to send command (%d)\n", ret); + return ret; + } + + while (smc->atomic_pending) { + ret = apple_rtkit_poll(smc->rtk); + if (ret < 0) { + dev_err(smc->dev, "RTKit poll failed (%llx)", msg); + return ret; + } + udelay(100); + } + + if (FIELD_GET(SMC_ID, smc->cmd_ret) != smc->msg_id) { + dev_err(smc->dev, "Command sequence mismatch (expected %d, got %d)\n", + smc->msg_id, (unsigned int)FIELD_GET(SMC_ID, smc->cmd_ret)); + return -EIO; + } + + result = FIELD_GET(SMC_RESULT, smc->cmd_ret); + if (result) + return -EIO; + + return FIELD_GET(SMC_SIZE, smc->cmd_ret); +} +EXPORT_SYMBOL(apple_smc_write_atomic); + +static void apple_smc_rtkit_crashed(void *cookie, const void *bfr, size_t bfr_len) +{ + struct apple_smc *smc = cookie; + + smc->boot_stage = APPLE_SMC_ERROR_CRASHED; + dev_err(smc->dev, "SMC crashed! Your system will reboot in a few seconds...\n"); +} + +static int apple_smc_rtkit_shmem_setup(void *cookie, struct apple_rtkit_shmem *bfr) +{ + struct apple_smc *smc = cookie; + size_t bfr_end; + + if (!bfr->iova) { + dev_err(smc->dev, "RTKit wants a RAM buffer\n"); + return -EIO; + } + + if (check_add_overflow(bfr->iova, bfr->size - 1, &bfr_end)) + return -EFAULT; + + if (bfr->iova < smc->sram->start || bfr->iova > smc->sram->end || + bfr_end > smc->sram->end) { + dev_err(smc->dev, "RTKit buffer request outside SRAM region: [0x%llx, 0x%llx]\n", + (unsigned long long)bfr->iova, + (unsigned long long)bfr_end); + return -EFAULT; + } + + bfr->iomem = smc->sram_base + (bfr->iova - smc->sram->start); + bfr->is_mapped = true; + + return 0; +} + +static bool apple_smc_rtkit_recv_early(void *cookie, u8 endpoint, u64 message) +{ + struct apple_smc *smc = cookie; + + if (endpoint != SMC_ENDPOINT) { + dev_warn(smc->dev, "Received message for unknown endpoint 0x%x\n", endpoint); + return false; + } + + if (smc->boot_stage == APPLE_SMC_BOOTING) { + int ret; + + smc->shmem.iova = message; + smc->shmem.size = SMC_SHMEM_SIZE; + ret = apple_smc_rtkit_shmem_setup(smc, &smc->shmem); + if (ret < 0) { + smc->boot_stage = APPLE_SMC_ERROR_NO_SHMEM; + dev_err(smc->dev, "Failed to initialize shared memory (%d)\n", ret); + } else { + smc->boot_stage = APPLE_SMC_INITIALIZED; + } + complete(&smc->init_done); + } else if (FIELD_GET(SMC_MSG, message) == SMC_MSG_NOTIFICATION) { + /* Handle these in the RTKit worker thread */ + return false; + } else { + smc->cmd_ret = message; + if (smc->atomic_pending) + smc->atomic_pending = false; + else + complete(&smc->cmd_done); + } + + return true; +} + +static void apple_smc_rtkit_recv(void *cookie, u8 endpoint, u64 message) +{ + struct apple_smc *smc = cookie; + + if (endpoint != SMC_ENDPOINT) { + dev_warn(smc->dev, "Received message for unknown endpoint 0x%x\n", endpoint); + return; + } + + if (FIELD_GET(SMC_MSG, message) != SMC_MSG_NOTIFICATION) { + dev_warn(smc->dev, "Received unknown message from worker: 0x%llx\n", message); + return; + } + + blocking_notifier_call_chain(&smc->event_handlers, FIELD_GET(SMC_DATA, message), NULL); +} + +static const struct apple_rtkit_ops apple_smc_rtkit_ops = { + .crashed = apple_smc_rtkit_crashed, + .recv_message = apple_smc_rtkit_recv, + .recv_message_early = apple_smc_rtkit_recv_early, + .shmem_setup = apple_smc_rtkit_shmem_setup, +}; + +static void apple_smc_rtkit_shutdown(void *data) +{ + struct apple_smc *smc = data; + + /* Shut down SMC firmware, if it's not completely wedged */ + if (apple_rtkit_is_running(smc->rtk)) + apple_rtkit_quiesce(smc->rtk); +} + +static void apple_smc_disable_notifications(void *data) +{ + struct apple_smc *smc = data; + + apple_smc_write_flag(smc, SMC_KEY(NTAP), false); +} + +static int apple_smc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct apple_smc *smc; + u32 count; + int ret; + + smc = devm_kzalloc(dev, sizeof(*smc), GFP_KERNEL); + if (!smc) + return -ENOMEM; + + mutex_init(&smc->mutex); + smc->dev = &pdev->dev; + smc->sram_base = devm_platform_get_and_ioremap_resource(pdev, 1, &smc->sram); + if (IS_ERR(smc->sram_base)) + return dev_err_probe(dev, PTR_ERR(smc->sram_base), "Failed to map SRAM region"); + + smc->rtk = devm_apple_rtkit_init(dev, smc, NULL, 0, &apple_smc_rtkit_ops); + if (IS_ERR(smc->rtk)) + return dev_err_probe(dev, PTR_ERR(smc->rtk), "Failed to initialize RTKit"); + + smc->boot_stage = APPLE_SMC_BOOTING; + ret = apple_rtkit_wake(smc->rtk); + if (ret) + return dev_err_probe(dev, ret, "Failed to wake up SMC"); + + ret = devm_add_action_or_reset(dev, apple_smc_rtkit_shutdown, smc); + if (ret) + return ret; + + ret = apple_rtkit_start_ep(smc->rtk, SMC_ENDPOINT); + if (ret) + return dev_err_probe(dev, ret, "Failed to start SMC endpoint"); + + init_completion(&smc->init_done); + init_completion(&smc->cmd_done); + + ret = apple_rtkit_send_message(smc->rtk, SMC_ENDPOINT, + FIELD_PREP(SMC_MSG, SMC_MSG_INITIALIZE), NULL, false); + if (ret) + return dev_err_probe(dev, ret, "Failed to send init message"); + + if (wait_for_completion_timeout(&smc->init_done, msecs_to_jiffies(SMC_TIMEOUT_MS)) == 0) { + dev_err(dev, "Timed out initializing SMC"); + return -ETIMEDOUT; + } + + if (smc->boot_stage != APPLE_SMC_INITIALIZED) { + dev_err(dev, "SMC failed to boot successfully, boot stage=%d\n", smc->boot_stage); + return -EIO; + } + + dev_set_drvdata(&pdev->dev, smc); + BLOCKING_INIT_NOTIFIER_HEAD(&smc->event_handlers); + + ret = apple_smc_read_u32(smc, SMC_KEY(#KEY), &count); + if (ret) + return dev_err_probe(smc->dev, ret, "Failed to get key count"); + smc->key_count = be32_to_cpu(count); + + /* Enable notifications */ + apple_smc_write_flag(smc, SMC_KEY(NTAP), true); + ret = devm_add_action_or_reset(dev, apple_smc_disable_notifications, smc); + if (ret) + return ret; + + ret = devm_mfd_add_devices(smc->dev, PLATFORM_DEVID_NONE, + apple_smc_devs, ARRAY_SIZE(apple_smc_devs), + NULL, 0, NULL); + if (ret) + return dev_err_probe(smc->dev, ret, "Failed to register sub-devices"); + + + return 0; +} + +static const struct of_device_id apple_smc_of_match[] = { + { .compatible = "apple,t8103-smc" }, + { .compatible = "apple,smc" }, + {}, +}; +MODULE_DEVICE_TABLE(of, apple_smc_of_match); + +static struct platform_driver apple_smc_driver = { + .driver = { + .name = "macsmc", + .of_match_table = apple_smc_of_match, + }, + .probe = apple_smc_probe, +}; +module_platform_driver(apple_smc_driver); + +MODULE_AUTHOR("Hector Martin "); +MODULE_AUTHOR("Sven Peter "); +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_DESCRIPTION("Apple SMC driver"); -- cgit v1.3.1