From eb59a9a561c4e4d6edaa87205a33f294a606403e Mon Sep 17 00:00:00 2001 From: Kevin Brodsky Date: Thu, 8 Sep 2016 14:25:04 +0100 Subject: [PATCH] FROMLIST: [PATCH 5/6] arm64: compat: 32-bit vDSO setup (cherry pick from url https://patchwork.kernel.org/patch/10060459/) If the compat vDSO is enabled, install it in compat processes. In this case, the compat vDSO replaces the sigreturn page (it provides its own sigreturn trampolines). Signed-off-by: Kevin Brodsky Signed-off-by: Mark Salyzyn Cc: Catalin Marinas Cc: Will Deacon Cc: Dave Martin Cc: "Eric W. Biederman" Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Bug: 63737556 Bug: 20045882 Change-Id: Ia6acf4c3ffea636bc750ac00853ea762c182e5b5 --- arch/arm64/kernel/vdso.c | 55 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 4a75e8cbd3ed..913983464e74 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -58,6 +58,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data; /* * Create and map the vectors page for AArch32 tasks. */ +#if !defined(CONFIG_VDSO32) || defined(CONFIG_KUSER_HELPERS) static struct page *vectors_page[] __ro_after_init; static const struct vm_special_mapping compat_vdso_spec[] = { { @@ -73,6 +74,7 @@ static const struct vm_special_mapping compat_vdso_spec[] = { #endif }; static struct page *vectors_page[ARRAY_SIZE(compat_vdso_spec)] __ro_after_init; +#endif static int __init alloc_vectors_page(void) { @@ -82,6 +84,7 @@ static int __init alloc_vectors_page(void) unsigned long kuser_vpage; #endif +#ifndef CONFIG_VDSO32 extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; size_t sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; @@ -90,19 +93,24 @@ static int __init alloc_vectors_page(void) sigret_vpage = get_zeroed_page(GFP_ATOMIC); if (!sigret_vpage) return -ENOMEM; +#endif #ifdef CONFIG_KUSER_HELPERS kuser_vpage = get_zeroed_page(GFP_ATOMIC); if (!kuser_vpage) { +#ifndef CONFIG_VDSO32 free_page(sigret_vpage); +#endif return -ENOMEM; } #endif +#ifndef CONFIG_VDSO32 /* sigreturn code */ memcpy((void *)sigret_vpage, __aarch32_sigret_code_start, sigret_sz); flush_icache_range(sigret_vpage, sigret_vpage + PAGE_SIZE); vectors_page[0] = virt_to_page(sigret_vpage); +#endif #ifdef CONFIG_KUSER_HELPERS /* kuser helpers */ @@ -116,6 +124,7 @@ static int __init alloc_vectors_page(void) } arch_initcall(alloc_vectors_page); +#ifndef CONFIG_VDSO32 int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) { struct mm_struct *mm = current->mm; @@ -151,6 +160,7 @@ out: return PTR_ERR_OR_ZERO(ret); } +#endif /* !CONFIG_VDSO32 */ #endif /* CONFIG_COMPAT */ static int __init vdso_mappings_init(const char *name, @@ -206,6 +216,23 @@ static int __init vdso_mappings_init(const char *name, return 0; } +#ifdef CONFIG_COMPAT +#ifdef CONFIG_VDSO32 + +static struct vdso_mappings vdso32_mappings __ro_after_init; + +static int __init vdso32_init(void) +{ + extern char vdso32_start[], vdso32_end[]; + + return vdso_mappings_init("vdso32", vdso32_start, vdso32_end, + &vdso32_mappings); +} +arch_initcall(vdso32_init); + +#endif /* CONFIG_VDSO32 */ +#endif /* CONFIG_COMPAT */ + static struct vdso_mappings vdso_mappings __ro_after_init; static int __init vdso_init(void) @@ -248,6 +275,34 @@ static int vdso_setup(struct mm_struct *mm, return PTR_ERR_OR_ZERO(ret); } +#ifdef CONFIG_COMPAT +#ifdef CONFIG_VDSO32 +int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + void *ret; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + ret = ERR_PTR(vdso_setup(mm, &vdso32_mappings)); +#ifdef CONFIG_KUSER_HELPERS + if (!IS_ERR(ret)) + /* Map the kuser helpers at the ABI-defined high address. */ + ret = _install_special_mapping(mm, AARCH32_KUSER_HELPERS_BASE, + PAGE_SIZE, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYEXEC, + &compat_vdso_spec[1]); +#endif + + up_write(&mm->mmap_sem); + + return PTR_ERR_OR_ZERO(ret); +} +#endif /* CONFIG_VDSO32 */ +#endif /* CONFIG_COMPAT */ + int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { struct mm_struct *mm = current->mm; -- 2.20.1