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/mips/mm/cache.c | 218 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 218 insertions(+) create mode 100644 arch/mips/mm/cache.c (limited to 'arch/mips/mm/cache.c') diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c new file mode 100644 index 000000000..ad9b0430a --- /dev/null +++ b/arch/mips/mm/cache.c @@ -0,0 +1,218 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1994 - 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org) + * Copyright (C) 2007 MIPS Technologies, Inc. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +/* Cache operations. */ +void (*flush_cache_all)(void); +void (*__flush_cache_all)(void); +EXPORT_SYMBOL_GPL(__flush_cache_all); +void (*flush_cache_mm)(struct mm_struct *mm); +void (*flush_cache_range)(struct vm_area_struct *vma, unsigned long start, + unsigned long end); +void (*flush_cache_page)(struct vm_area_struct *vma, unsigned long page, + unsigned long pfn); +void (*flush_icache_range)(unsigned long start, unsigned long end); +EXPORT_SYMBOL_GPL(flush_icache_range); +void (*local_flush_icache_range)(unsigned long start, unsigned long end); +EXPORT_SYMBOL_GPL(local_flush_icache_range); +void (*__flush_icache_user_range)(unsigned long start, unsigned long end); +void (*__local_flush_icache_user_range)(unsigned long start, unsigned long end); +EXPORT_SYMBOL_GPL(__local_flush_icache_user_range); + +void (*__flush_cache_vmap)(void); +void (*__flush_cache_vunmap)(void); + +void (*__flush_kernel_vmap_range)(unsigned long vaddr, int size); +EXPORT_SYMBOL_GPL(__flush_kernel_vmap_range); + +/* MIPS specific cache operations */ +void (*flush_data_cache_page)(unsigned long addr); +void (*flush_icache_all)(void); + +EXPORT_SYMBOL(flush_data_cache_page); +EXPORT_SYMBOL(flush_icache_all); + +/* + * Dummy cache handling routine + */ + +void cache_noop(void) {} + +#ifdef CONFIG_BOARD_SCACHE + +static struct bcache_ops no_sc_ops = { + .bc_enable = (void *)cache_noop, + .bc_disable = (void *)cache_noop, + .bc_wback_inv = (void *)cache_noop, + .bc_inv = (void *)cache_noop +}; + +struct bcache_ops *bcops = &no_sc_ops; +#endif + +#ifdef CONFIG_DMA_NONCOHERENT + +/* DMA cache operations. */ +void (*_dma_cache_wback_inv)(unsigned long start, unsigned long size); +void (*_dma_cache_wback)(unsigned long start, unsigned long size); +void (*_dma_cache_inv)(unsigned long start, unsigned long size); + +#endif /* CONFIG_DMA_NONCOHERENT */ + +/* + * We could optimize the case where the cache argument is not BCACHE but + * that seems very atypical use ... + */ +SYSCALL_DEFINE3(cacheflush, unsigned long, addr, unsigned long, bytes, + unsigned int, cache) +{ + if (bytes == 0) + return 0; + if (!access_ok((void __user *) addr, bytes)) + return -EFAULT; + + __flush_icache_user_range(addr, addr + bytes); + + return 0; +} + +void __flush_dcache_folio_pages(struct folio *folio, struct page *page, + unsigned int nr) +{ + struct address_space *mapping = folio_flush_mapping(folio); + unsigned long addr; + unsigned int i; + + if (mapping && !mapping_mapped(mapping)) { + folio_set_dcache_dirty(folio); + return; + } + + /* + * We could delay the flush for the !folio_mapping case too. But that + * case is for exec env/arg pages and those are %99 certainly going to + * get faulted into the tlb (and thus flushed) anyways. + */ + for (i = 0; i < nr; i++) { + addr = (unsigned long)kmap_local_page(page + i); + flush_data_cache_page(addr); + kunmap_local((void *)addr); + } +} +EXPORT_SYMBOL(__flush_dcache_folio_pages); + +void __flush_anon_page(struct page *page, unsigned long vmaddr) +{ + unsigned long addr = (unsigned long) page_address(page); + struct folio *folio = page_folio(page); + + if (pages_do_alias(addr, vmaddr)) { + if (folio_mapped(folio) && !folio_test_dcache_dirty(folio)) { + void *kaddr; + + kaddr = kmap_coherent(page, vmaddr); + flush_data_cache_page((unsigned long)kaddr); + kunmap_coherent(); + } else + flush_data_cache_page(addr); + } +} + +EXPORT_SYMBOL(__flush_anon_page); + +void __update_cache(unsigned long address, pte_t pte) +{ + struct folio *folio; + unsigned long pfn, addr; + int exec = !pte_no_exec(pte) && !cpu_has_ic_fills_f_dc; + unsigned int i; + + pfn = pte_pfn(pte); + if (unlikely(!pfn_valid(pfn))) + return; + + folio = page_folio(pfn_to_page(pfn)); + address &= PAGE_MASK; + address -= offset_in_folio(folio, pfn << PAGE_SHIFT); + + if (folio_test_dcache_dirty(folio)) { + for (i = 0; i < folio_nr_pages(folio); i++) { + addr = (unsigned long)kmap_local_folio(folio, i); + + if (exec || pages_do_alias(addr, address)) + flush_data_cache_page(addr); + kunmap_local((void *)addr); + address += PAGE_SIZE; + } + folio_clear_dcache_dirty(folio); + } +} + +unsigned long _page_cachable_default; +EXPORT_SYMBOL(_page_cachable_default); + +#define PM(p) __pgprot(_page_cachable_default | (p)) + +static pgprot_t protection_map[16] __ro_after_init; +DECLARE_VM_GET_PAGE_PROT + +static inline void setup_protection_map(void) +{ + protection_map[0] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[1] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[2] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[3] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[4] = PM(_PAGE_PRESENT); + protection_map[5] = PM(_PAGE_PRESENT); + protection_map[6] = PM(_PAGE_PRESENT); + protection_map[7] = PM(_PAGE_PRESENT); + + protection_map[8] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[9] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[10] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | + _PAGE_NO_READ); + protection_map[11] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); + protection_map[12] = PM(_PAGE_PRESENT); + protection_map[13] = PM(_PAGE_PRESENT); + protection_map[14] = PM(_PAGE_PRESENT | _PAGE_WRITE); + protection_map[15] = PM(_PAGE_PRESENT | _PAGE_WRITE); +} + +#undef PM + +void cpu_cache_init(void) +{ + if (IS_ENABLED(CONFIG_CPU_R3000) && cpu_has_3k_cache) + r3k_cache_init(); + if ((IS_ENABLED(CONFIG_CPU_R4K_CACHE_TLB) || + IS_ENABLED(CONFIG_CPU_SB1)) && cpu_has_4k_cache) + r4k_cache_init(); + + if (IS_ENABLED(CONFIG_CPU_CAVIUM_OCTEON) && cpu_has_octeon_cache) + octeon_cache_init(); + + setup_protection_map(); +} -- cgit v1.3.1