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 --- arch/arc/mm/init.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 178 insertions(+) create mode 100644 arch/arc/mm/init.c (limited to 'arch/arc/mm/init.c') diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c new file mode 100644 index 000000000..d6b5c27a0 --- /dev/null +++ b/arch/arc/mm/init.c @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + */ + +#include +#include +#include +#ifdef CONFIG_BLK_DEV_INITRD +#include +#endif +#include +#include +#include +#include +#include +#include +#include +#include + +pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE); + +static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE; +static unsigned long low_mem_sz; + +#ifdef CONFIG_HIGHMEM +static unsigned long min_high_pfn, max_high_pfn; +static phys_addr_t high_mem_start; +static phys_addr_t high_mem_sz; +unsigned long arch_pfn_offset; +EXPORT_SYMBOL(arch_pfn_offset); +#endif + +long __init arc_get_mem_sz(void) +{ + return low_mem_sz; +} + +/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */ +static int __init setup_mem_sz(char *str) +{ + low_mem_sz = memparse(str, NULL) & PAGE_MASK; + + /* early console might not be setup yet - it will show up later */ + pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(low_mem_sz)); + + return 0; +} +early_param("mem", setup_mem_sz); + +void __init early_init_dt_add_memory_arch(u64 base, u64 size) +{ + int in_use = 0; + + if (!low_mem_sz) { + if (base != low_mem_start) + panic("CONFIG_LINUX_RAM_BASE != DT memory { }"); + + low_mem_sz = size; + in_use = 1; + memblock_add_node(base, size, 0, MEMBLOCK_NONE); + } else { +#ifdef CONFIG_HIGHMEM + high_mem_start = base; + high_mem_sz = size; + in_use = 1; + memblock_add_node(base, size, 1, MEMBLOCK_NONE); + memblock_reserve(base, size); +#endif + } + + pr_info("Memory @ %llx [%lldM] %s\n", + base, TO_MB(size), !in_use ? "Not used":""); +} + +void __init arch_zone_limits_init(unsigned long *max_zone_pfn) +{ + /*----------------- node/zones setup --------------------------*/ + max_zone_pfn[ZONE_NORMAL] = max_low_pfn; + +#ifdef CONFIG_HIGHMEM + /* + * max_high_pfn should be ok here for both HIGHMEM and HIGHMEM+PAE. + * For HIGHMEM without PAE max_high_pfn should be less than + * min_low_pfn to guarantee that these two regions don't overlap. + * For PAE case highmem is greater than lowmem, so it is natural + * to use max_high_pfn. + * + * In both cases, holes should be handled by pfn_valid(). + */ + max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn; +#endif +} + +/* + * First memory setup routine called from setup_arch() + * 1. setup swapper's mm @init_mm + * 2. Count the pages we have and setup bootmem allocator + * 3. zone setup + */ +void __init setup_arch_memory(void) +{ + setup_initial_init_mm(_text, _etext, _edata, _end); + + /* first page of system - kernel .vector starts here */ + min_low_pfn = virt_to_pfn((void *)CONFIG_LINUX_RAM_BASE); + + /* Last usable page of low mem */ + max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz); + + /*------------- bootmem allocator setup -----------------------*/ + + /* + * seed the bootmem allocator after any DT memory node parsing or + * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz + * + * Only low mem is added, otherwise we have crashes when allocating + * mem_map[] itself. NO_BOOTMEM allocates mem_map[] at the end of + * avail memory, ending in highmem with a > 32-bit address. However + * it then tries to memset it with a truncaed 32-bit handle, causing + * the crash + */ + + memblock_reserve(CONFIG_LINUX_LINK_BASE, + __pa(_end) - CONFIG_LINUX_LINK_BASE); + +#ifdef CONFIG_BLK_DEV_INITRD + if (phys_initrd_size) { + memblock_reserve(phys_initrd_start, phys_initrd_size); + initrd_start = (unsigned long)__va(phys_initrd_start); + initrd_end = initrd_start + phys_initrd_size; + } +#endif + + early_init_fdt_reserve_self(); + early_init_fdt_scan_reserved_mem(); + + memblock_dump_all(); + +#ifdef CONFIG_HIGHMEM + /* + * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based) + * than addresses in normal aka low memory (0x8000_0000 based). + * Even with PAE, the huge peripheral space hole would waste a lot of + * mem with single contiguous mem_map[]. + * Thus when HIGHMEM on ARC is enabled the memory map corresponding + * to the hole is freed and ARC specific version of pfn_valid() + * handles the hole in the memory map. + */ + + min_high_pfn = PFN_DOWN(high_mem_start); + max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz); + + arch_pfn_offset = min(min_low_pfn, min_high_pfn); + kmap_init(); +#endif /* CONFIG_HIGHMEM */ +} + +void __init arch_mm_preinit(void) +{ +#ifdef CONFIG_HIGHMEM + memblock_phys_free(high_mem_start, high_mem_sz); +#endif + + BUILD_BUG_ON((PTRS_PER_PGD * sizeof(pgd_t)) > PAGE_SIZE); + BUILD_BUG_ON((PTRS_PER_PUD * sizeof(pud_t)) > PAGE_SIZE); + BUILD_BUG_ON((PTRS_PER_PMD * sizeof(pmd_t)) > PAGE_SIZE); + BUILD_BUG_ON((PTRS_PER_PTE * sizeof(pte_t)) > PAGE_SIZE); +} + +#ifdef CONFIG_HIGHMEM +int pfn_valid(unsigned long pfn) +{ + return (pfn >= min_high_pfn && pfn <= max_high_pfn) || + (pfn >= min_low_pfn && pfn <= max_low_pfn); +} +EXPORT_SYMBOL(pfn_valid); +#endif -- cgit v1.3.1