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/parisc/wax.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 drivers/parisc/wax.c (limited to 'drivers/parisc/wax.c') diff --git a/drivers/parisc/wax.c b/drivers/parisc/wax.c new file mode 100644 index 000000000..a82a5e88e --- /dev/null +++ b/drivers/parisc/wax.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * WAX Device Driver + * + * (c) Copyright 2000 The Puffin Group Inc. + * + * (c) 2000-2023 by Helge Deller + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "gsc.h" + +#define WAX_GSC_IRQ 7 /* Hardcoded Interrupt for GSC */ + +static void wax_choose_irq(struct parisc_device *dev, void *ctrl) +{ + int irq; + + switch (dev->id.sversion) { + case 0x73: irq = 1; break; /* i8042 General */ + case 0x8c: irq = 6; break; /* Serial */ + case 0x90: irq = 10; break; /* EISA */ + default: return; /* Unknown */ + } + + gsc_asic_assign_irq(ctrl, irq, &dev->irq); + + switch (dev->id.sversion) { + case 0x73: irq = 2; break; /* i8042 High-priority */ + case 0x90: irq = 0; break; /* EISA NMI */ + default: return; /* No secondary IRQ */ + } + + gsc_asic_assign_irq(ctrl, irq, &dev->aux_irq); +} + +static void __init +wax_init_irq(struct gsc_asic *wax) +{ + unsigned long base = wax->hpa; + + /* Wax-off */ + gsc_writel(0x00000000, base+OFFSET_IMR); + + /* clear pending interrupts */ + gsc_readl(base+OFFSET_IRR); + + /* We're not really convinced we want to reset the onboard + * devices. Firmware does it for us... + */ + + /* Resets */ +// gsc_writel(0xFFFFFFFF, base+0x1000); /* HIL */ +// gsc_writel(0xFFFFFFFF, base+0x2000); /* RS232-B on Wax */ +} + +static int __init wax_init_chip(struct parisc_device *dev) +{ + struct gsc_asic *wax; + struct parisc_device *parent; + int ret; + + wax = kzalloc_obj(*wax); + if (!wax) + return -ENOMEM; + + wax->name = "wax"; + wax->hpa = dev->hpa.start; + + wax->version = 0; /* gsc_readb(wax->hpa+WAX_VER); */ + printk(KERN_INFO "%s at 0x%lx found.\n", wax->name, wax->hpa); + + /* Stop wax hissing for a bit */ + wax_init_irq(wax); + + /* the IRQ wax should use */ + dev->irq = gsc_claim_irq(&wax->gsc_irq, WAX_GSC_IRQ); + if (dev->irq < 0) { + printk(KERN_ERR "%s(): cannot get GSC irq\n", + __func__); + kfree(wax); + return -EBUSY; + } + + wax->eim = ((u32) wax->gsc_irq.txn_addr) | wax->gsc_irq.txn_data; + + ret = request_irq(wax->gsc_irq.irq, gsc_asic_intr, 0, "wax", wax); + if (ret < 0) { + kfree(wax); + return ret; + } + + /* enable IRQ's for devices below WAX */ + gsc_writel(wax->eim, wax->hpa + OFFSET_IAR); + + /* Done init'ing, register this driver */ + ret = gsc_common_setup(dev, wax); + if (ret) { + kfree(wax); + return ret; + } + + gsc_fixup_irqs(dev, wax, wax_choose_irq); + /* On 715-class machines, Wax EISA is a sibling of Wax, not a child. */ + parent = parisc_parent(dev); + if (parent->id.hw_type != HPHW_IOA) { + gsc_fixup_irqs(parent, wax, wax_choose_irq); + } + + return ret; +} + +static const struct parisc_device_id wax_tbl[] __initconst = { + { HPHW_BA, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x0008e }, + { 0, } +}; + +MODULE_DEVICE_TABLE(parisc, wax_tbl); + +static struct parisc_driver wax_driver __refdata = { + .name = "wax", + .id_table = wax_tbl, + .probe = wax_init_chip, +}; + +static int __init wax_init(void) +{ + return register_parisc_driver(&wax_driver); +} +arch_initcall(wax_init); -- cgit v1.3.1