From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/soundwire/amd_init.c | 229 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 229 insertions(+) create mode 100644 drivers/soundwire/amd_init.c (limited to 'drivers/soundwire/amd_init.c') diff --git a/drivers/soundwire/amd_init.c b/drivers/soundwire/amd_init.c new file mode 100644 index 000000000..8e419ddfa --- /dev/null +++ b/drivers/soundwire/amd_init.c @@ -0,0 +1,229 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +/* + * SoundWire AMD Manager Initialize routines + * + * Initializes and creates SDW devices based on ACPI and Hardware values + * + * Copyright 2024 Advanced Micro Devices, Inc. + */ + +#include +#include +#include +#include +#include +#include + +#include "amd_init.h" + +#define ACP_PAD_PULLDOWN_CTRL 0x0001448 +#define ACP_SW_PAD_KEEPER_EN 0x0001454 +#define AMD_SDW0_PAD_CTRL_MASK 0x60 +#define AMD_SDW1_PAD_CTRL_MASK 5 +#define AMD_SDW_PAD_CTRL_MASK (AMD_SDW0_PAD_CTRL_MASK | AMD_SDW1_PAD_CTRL_MASK) +#define AMD_SDW0_PAD_EN 1 +#define AMD_SDW1_PAD_EN 0x10 +#define AMD_SDW_PAD_EN (AMD_SDW0_PAD_EN | AMD_SDW1_PAD_EN) + +static int amd_enable_sdw_pads(void __iomem *mmio, u32 link_mask, struct device *dev) +{ + u32 pad_keeper_en, pad_pulldown_ctrl_mask; + + switch (link_mask) { + case 1: + pad_keeper_en = AMD_SDW0_PAD_EN; + pad_pulldown_ctrl_mask = AMD_SDW0_PAD_CTRL_MASK; + break; + case 2: + pad_keeper_en = AMD_SDW1_PAD_EN; + pad_pulldown_ctrl_mask = AMD_SDW1_PAD_CTRL_MASK; + break; + case 3: + pad_keeper_en = AMD_SDW_PAD_EN; + pad_pulldown_ctrl_mask = AMD_SDW_PAD_CTRL_MASK; + break; + default: + dev_err(dev, "No SDW Links are enabled\n"); + return -ENODEV; + } + + amd_updatel(mmio, ACP_SW_PAD_KEEPER_EN, pad_keeper_en, pad_keeper_en); + amd_updatel(mmio, ACP_PAD_PULLDOWN_CTRL, pad_pulldown_ctrl_mask, 0); + + return 0; +} + +static int sdw_amd_cleanup(struct sdw_amd_ctx *ctx) +{ + int i; + + for (i = 0; i < ctx->count; i++) { + if (!(ctx->link_mask & BIT(i))) + continue; + platform_device_unregister(ctx->pdev[i]); + } + + return 0; +} + +static struct sdw_amd_ctx *sdw_amd_probe_controller(struct sdw_amd_res *res) +{ + struct sdw_amd_ctx *ctx; + struct acpi_device *adev; + struct acp_sdw_pdata sdw_pdata[2]; + struct platform_device_info pdevinfo[2]; + u32 link_mask; + int count, index; + int ret; + + if (!res) + return NULL; + + adev = acpi_fetch_acpi_dev(res->handle); + if (!adev) + return NULL; + + if (!res->count) + return NULL; + + count = res->count; + dev_dbg(&adev->dev, "Creating %d SDW Link devices\n", count); + ret = amd_enable_sdw_pads(res->mmio_base, res->link_mask, res->parent); + if (ret) + return NULL; + + /* + * we need to alloc/free memory manually and can't use devm: + * this routine may be called from a workqueue, and not from + * the parent .probe. + * If devm_ was used, the memory might never be freed on errors. + */ + ctx = kzalloc_obj(*ctx); + if (!ctx) + return NULL; + + ctx->count = count; + ctx->link_mask = res->link_mask; + struct resource *sdw_res __free(kfree) = kzalloc_obj(*sdw_res); + if (!sdw_res) { + kfree(ctx); + return NULL; + } + sdw_res->flags = IORESOURCE_MEM; + sdw_res->start = res->addr; + sdw_res->end = res->addr + res->reg_range; + memset(&pdevinfo, 0, sizeof(pdevinfo)); + link_mask = ctx->link_mask; + for (index = 0; index < count; index++) { + if (!(link_mask & BIT(index))) + continue; + + sdw_pdata[index].instance = index; + sdw_pdata[index].acp_sdw_lock = res->acp_lock; + sdw_pdata[index].acp_rev = res->acp_rev; + pdevinfo[index].name = "amd_sdw_manager"; + pdevinfo[index].id = index; + pdevinfo[index].parent = res->parent; + pdevinfo[index].num_res = 1; + pdevinfo[index].res = sdw_res; + pdevinfo[index].data = &sdw_pdata[index]; + pdevinfo[index].size_data = sizeof(struct acp_sdw_pdata); + pdevinfo[index].fwnode = acpi_fwnode_handle(adev); + ctx->pdev[index] = platform_device_register_full(&pdevinfo[index]); + if (IS_ERR(ctx->pdev[index])) + goto err; + } + return ctx; +err: + while (index--) { + if (!(link_mask & BIT(index))) + continue; + + platform_device_unregister(ctx->pdev[index]); + } + + kfree(ctx); + return NULL; +} + +static int sdw_amd_startup(struct sdw_amd_ctx *ctx) +{ + struct amd_sdw_manager *amd_manager; + int i, ret; + + /* Startup SDW Manager devices */ + for (i = 0; i < ctx->count; i++) { + if (!(ctx->link_mask & BIT(i))) + continue; + amd_manager = dev_get_drvdata(&ctx->pdev[i]->dev); + ret = amd_sdw_manager_start(amd_manager); + if (ret) + return ret; + } + + return 0; +} + +int sdw_amd_probe(struct sdw_amd_res *res, struct sdw_amd_ctx **sdw_ctx) +{ + *sdw_ctx = sdw_amd_probe_controller(res); + if (!*sdw_ctx) + return -ENODEV; + + return sdw_amd_startup(*sdw_ctx); +} +EXPORT_SYMBOL_NS(sdw_amd_probe, "SOUNDWIRE_AMD_INIT"); + +void sdw_amd_exit(struct sdw_amd_ctx *ctx) +{ + sdw_amd_cleanup(ctx); + kfree(ctx->peripherals); + kfree(ctx); +} +EXPORT_SYMBOL_NS(sdw_amd_exit, "SOUNDWIRE_AMD_INIT"); + +int sdw_amd_get_slave_info(struct sdw_amd_ctx *ctx) +{ + struct amd_sdw_manager *amd_manager; + struct sdw_bus *bus; + struct sdw_slave *slave; + struct list_head *node; + int index; + int i = 0; + int num_slaves = 0; + + for (index = 0; index < ctx->count; index++) { + if (!(ctx->link_mask & BIT(index))) + continue; + amd_manager = dev_get_drvdata(&ctx->pdev[index]->dev); + if (!amd_manager) + return -ENODEV; + bus = &amd_manager->bus; + /* Calculate number of slaves */ + list_for_each(node, &bus->slaves) + num_slaves++; + } + + ctx->peripherals = kmalloc_flex(*ctx->peripherals, array, num_slaves); + if (!ctx->peripherals) + return -ENOMEM; + ctx->peripherals->num_peripherals = num_slaves; + for (index = 0; index < ctx->count; index++) { + if (!(ctx->link_mask & BIT(index))) + continue; + amd_manager = dev_get_drvdata(&ctx->pdev[index]->dev); + if (amd_manager) { + bus = &amd_manager->bus; + list_for_each_entry(slave, &bus->slaves, node) { + ctx->peripherals->array[i] = slave; + i++; + } + } + } + return 0; +} +EXPORT_SYMBOL_NS(sdw_amd_get_slave_info, "SOUNDWIRE_AMD_INIT"); + +MODULE_AUTHOR("Vijendar.Mukunda@amd.com"); +MODULE_DESCRIPTION("AMD SoundWire Init Library"); +MODULE_LICENSE("Dual BSD/GPL"); -- cgit v1.3.1