diff options
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r-- | arch/arm64/kernel/signal32.c | 3 | ||||
-rw-r--r-- | arch/arm64/kernel/vdso.c | 116 |
2 files changed, 90 insertions, 29 deletions
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index cb7800acd19f..caea6e25db2a 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -403,8 +403,7 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, if (ka->sa.sa_flags & SA_SIGINFO) idx += 3; - retcode = AARCH32_VECTORS_BASE + - AARCH32_KERN_SIGRET_CODE_OFFSET + + retcode = (unsigned long)current->mm->context.vdso + (idx << 2) + thumb; } diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 42b7082029e1..6bb7038dc96c 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -1,5 +1,5 @@ /* - * VDSO implementation for AArch64 and vector page setup for AArch32. + * VDSO implementations. * * Copyright (C) 2012 ARM Limited * @@ -53,61 +53,123 @@ struct vdso_data *vdso_data = &vdso_data_store.data; /* * Create and map the vectors page for AArch32 tasks. */ -static struct page *vectors_page[1] __ro_after_init; +#define C_VECTORS 0 +#define C_SIGPAGE 1 +#define C_PAGES (C_SIGPAGE + 1) +static struct page *aarch32_vdso_pages[C_PAGES] __ro_after_init; +static const struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = { + { + .name = "[vectors]", /* ABI */ + .pages = &aarch32_vdso_pages[C_VECTORS], + }, + { + .name = "[sigpage]", /* ABI */ + .pages = &aarch32_vdso_pages[C_SIGPAGE], + }, +}; -static int __init alloc_vectors_page(void) +static int __init aarch32_alloc_vdso_pages(void) { extern char __kuser_helper_start[], __kuser_helper_end[]; extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; int kuser_sz = __kuser_helper_end - __kuser_helper_start; int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; - unsigned long vpage; + unsigned long vdso_pages[C_PAGES]; - vpage = get_zeroed_page(GFP_ATOMIC); + vdso_pages[C_VECTORS] = get_zeroed_page(GFP_ATOMIC); + if (!vdso_pages[C_VECTORS]) + return -ENOMEM; - if (!vpage) + vdso_pages[C_SIGPAGE] = get_zeroed_page(GFP_ATOMIC); + if (!vdso_pages[C_SIGPAGE]) { + free_page(vdso_pages[C_VECTORS]); return -ENOMEM; + } /* kuser helpers */ - memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, - kuser_sz); + memcpy((void *)(vdso_pages[C_VECTORS] + 0x1000 - kuser_sz), + __kuser_helper_start, + kuser_sz); /* sigreturn code */ - memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, - __aarch32_sigret_code_start, sigret_sz); + memcpy((void *)vdso_pages[C_SIGPAGE], __aarch32_sigret_code_start, + sigret_sz); + + flush_icache_range(vdso_pages[C_VECTORS], + vdso_pages[C_VECTORS] + PAGE_SIZE); + flush_icache_range(vdso_pages[C_SIGPAGE], + vdso_pages[C_SIGPAGE] + PAGE_SIZE); - flush_icache_range(vpage, vpage + PAGE_SIZE); - vectors_page[0] = virt_to_page(vpage); + aarch32_vdso_pages[C_VECTORS] = virt_to_page(vdso_pages[C_VECTORS]); + aarch32_vdso_pages[C_SIGPAGE] = virt_to_page(vdso_pages[C_SIGPAGE]); return 0; } -arch_initcall(alloc_vectors_page); +arch_initcall(aarch32_alloc_vdso_pages); -int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) +static int aarch32_kuser_helpers_setup(struct mm_struct *mm) { - struct mm_struct *mm = current->mm; - unsigned long addr = AARCH32_VECTORS_BASE; - static const struct vm_special_mapping spec = { - .name = "[vectors]", - .pages = vectors_page, + void *ret; + + /* + * Avoid VM_MAYWRITE for compatibility with arch/arm/, where it's + * not safe to CoW the page containing the CPU exception vectors. + */ + ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE, + VM_READ | VM_EXEC | + VM_MAYREAD | VM_MAYEXEC, + &aarch32_vdso_spec[C_VECTORS]); + + return PTR_ERR_OR_ZERO(ret); +} - }; +static int aarch32_sigreturn_setup(struct mm_struct *mm) +{ + unsigned long addr; void *ret; - if (down_write_killable(&mm->mmap_sem)) - return -EINTR; - current->mm->context.vdso = (void *)addr; + addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0); + if (IS_ERR_VALUE(addr)) { + ret = ERR_PTR(addr); + goto out; + } - /* Map vectors page at the high address. */ + /* + * VM_MAYWRITE is required to allow gdb to Copy-on-Write and + * set breakpoints. + */ ret = _install_special_mapping(mm, addr, PAGE_SIZE, - VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, - &spec); + VM_READ | VM_EXEC | VM_MAYREAD | + VM_MAYWRITE | VM_MAYEXEC, + &aarch32_vdso_spec[C_SIGPAGE]); + if (IS_ERR(ret)) + goto out; - up_write(&mm->mmap_sem); + mm->context.vdso = (void *)addr; +out: return PTR_ERR_OR_ZERO(ret); } + +int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + int ret; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + ret = aarch32_kuser_helpers_setup(mm); + if (ret) + goto out; + + ret = aarch32_sigreturn_setup(mm); + +out: + up_write(&mm->mmap_sem); + return ret; +} #endif /* CONFIG_COMPAT */ static int vdso_mremap(const struct vm_special_mapping *sm, |