1 files changed, 256 insertions, 165 deletions

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 2d419006ad43..78ddf6bdecad 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -1,20 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
- * VDSO implementation for AArch64 and vector page setup for AArch32.
+ * VDSO implementations.
  *
  * Copyright (C) 2012 ARM Limited
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
  * Author: Will Deacon <will.deacon@arm.com>
  */
 
@@ -29,228 +18,330 @@
 #include <linux/sched.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
-#include <linux/timekeeper_internal.h>
+#include <linux/vdso_datastore.h>
 #include <linux/vmalloc.h>
+#include <vdso/datapage.h>
+#include <vdso/helpers.h>
+#include <vdso/vsyscall.h>
 
 #include <asm/cacheflush.h>
 #include <asm/signal32.h>
 #include <asm/vdso.h>
-#include <asm/vdso_datapage.h>
-
-extern char vdso_start[], vdso_end[];
-static unsigned long vdso_pages __ro_after_init;
-
-/*
- * The vDSO data page.
- */
-static union {
-	struct vdso_data	data;
-	u8			page[PAGE_SIZE];
-} vdso_data_store __page_aligned_data;
-struct vdso_data *vdso_data = &vdso_data_store.data;
-
-#ifdef CONFIG_COMPAT
-/*
- * Create and map the vectors page for AArch32 tasks.
- */
-static struct page *vectors_page[1] __ro_after_init;
-
-static int __init alloc_vectors_page(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;
 
-	vpage = get_zeroed_page(GFP_ATOMIC);
-
-	if (!vpage)
-		return -ENOMEM;
-
-	/* kuser helpers */
-	memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
-		kuser_sz);
-
-	/* sigreturn code */
-	memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
-               __aarch32_sigret_code_start, sigret_sz);
-
-	flush_icache_range(vpage, vpage + PAGE_SIZE);
-	vectors_page[0] = virt_to_page(vpage);
-
-	return 0;
-}
-arch_initcall(alloc_vectors_page);
-
-int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
-{
-	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;
-
-	if (down_write_killable(&mm->mmap_sem))
-		return -EINTR;
-	current->mm->context.vdso = (void *)addr;
-
-	/* Map vectors page at the high address. */
-	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
-				       VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
-				       &spec);
+enum vdso_abi {
+	VDSO_ABI_AA64,
+	VDSO_ABI_AA32,
+};
 
-	up_write(&mm->mmap_sem);
+struct vdso_abi_info {
+	const char *name;
+	const char *vdso_code_start;
+	const char *vdso_code_end;
+	unsigned long vdso_pages;
+	/* Code Mapping */
+	struct vm_special_mapping *cm;
+};
 
-	return PTR_ERR_OR_ZERO(ret);
-}
-#endif /* CONFIG_COMPAT */
+static struct vdso_abi_info vdso_info[] __ro_after_init = {
+	[VDSO_ABI_AA64] = {
+		.name = "vdso",
+		.vdso_code_start = vdso_start,
+		.vdso_code_end = vdso_end,
+	},
+#ifdef CONFIG_COMPAT_VDSO
+	[VDSO_ABI_AA32] = {
+		.name = "vdso32",
+		.vdso_code_start = vdso32_start,
+		.vdso_code_end = vdso32_end,
+	},
+#endif /* CONFIG_COMPAT_VDSO */
+};
 
 static int vdso_mremap(const struct vm_special_mapping *sm,
 		struct vm_area_struct *new_vma)
 {
-	unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
-	unsigned long vdso_size = vdso_end - vdso_start;
-
-	if (vdso_size != new_size)
-		return -EINVAL;
-
 	current->mm->context.vdso = (void *)new_vma->vm_start;
 
 	return 0;
 }
 
-static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
-	{
-		.name	= "[vvar]",
-	},
-	{
-		.name	= "[vdso]",
-		.mremap = vdso_mremap,
-	},
-};
-
-static int __init vdso_init(void)
+static int __init __vdso_init(enum vdso_abi abi)
 {
 	int i;
 	struct page **vdso_pagelist;
 	unsigned long pfn;
 
-	if (memcmp(vdso_start, "\177ELF", 4)) {
+	if (memcmp(vdso_info[abi].vdso_code_start, "\177ELF", 4)) {
 		pr_err("vDSO is not a valid ELF object!\n");
 		return -EINVAL;
 	}
 
-	vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
-	pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
-		vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);
+	vdso_info[abi].vdso_pages = (
+			vdso_info[abi].vdso_code_end -
+			vdso_info[abi].vdso_code_start) >>
+			PAGE_SHIFT;
 
-	/* Allocate the vDSO pagelist, plus a page for the data. */
-	vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
+	vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages,
+				sizeof(struct page *),
 				GFP_KERNEL);
 	if (vdso_pagelist == NULL)
 		return -ENOMEM;
 
-	/* Grab the vDSO data page. */
-	vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data));
-
-
 	/* Grab the vDSO code pages. */
-	pfn = sym_to_pfn(vdso_start);
+	pfn = sym_to_pfn(vdso_info[abi].vdso_code_start);
 
-	for (i = 0; i < vdso_pages; i++)
-		vdso_pagelist[i + 1] = pfn_to_page(pfn + i);
+	for (i = 0; i < vdso_info[abi].vdso_pages; i++)
+		vdso_pagelist[i] = pfn_to_page(pfn + i);
 
-	vdso_spec[0].pages = &vdso_pagelist[0];
-	vdso_spec[1].pages = &vdso_pagelist[1];
+	vdso_info[abi].cm->pages = vdso_pagelist;
 
 	return 0;
 }
-arch_initcall(vdso_init);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm,
-				int uses_interp)
+static int __setup_additional_pages(enum vdso_abi abi,
+				    struct mm_struct *mm,
+				    struct linux_binprm *bprm,
+				    int uses_interp)
 {
-	struct mm_struct *mm = current->mm;
 	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
+	unsigned long gp_flags = 0;
 	void *ret;
 
-	vdso_text_len = vdso_pages << PAGE_SHIFT;
+	BUILD_BUG_ON(VDSO_NR_PAGES != __VDSO_PAGES);
+
+	vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT;
 	/* Be sure to map the data page */
-	vdso_mapping_len = vdso_text_len + PAGE_SIZE;
+	vdso_mapping_len = vdso_text_len + VDSO_NR_PAGES * PAGE_SIZE;
 
-	if (down_write_killable(&mm->mmap_sem))
-		return -EINTR;
 	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
 	if (IS_ERR_VALUE(vdso_base)) {
 		ret = ERR_PTR(vdso_base);
 		goto up_fail;
 	}
-	ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
-				       VM_READ|VM_MAYREAD,
-				       &vdso_spec[0]);
+
+	ret = vdso_install_vvar_mapping(mm, vdso_base);
 	if (IS_ERR(ret))
 		goto up_fail;
 
-	vdso_base += PAGE_SIZE;
+	if (system_supports_bti_kernel())
+		gp_flags = VM_ARM64_BTI;
+
+	vdso_base += VDSO_NR_PAGES * PAGE_SIZE;
 	mm->context.vdso = (void *)vdso_base;
 	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
-				       VM_READ|VM_EXEC|
-				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				       &vdso_spec[1]);
+				       VM_READ|VM_EXEC|gp_flags|
+				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
+				       VM_SEALED_SYSMAP,
+				       vdso_info[abi].cm);
 	if (IS_ERR(ret))
 		goto up_fail;
 
-
-	up_write(&mm->mmap_sem);
 	return 0;
 
 up_fail:
 	mm->context.vdso = NULL;
-	up_write(&mm->mmap_sem);
 	return PTR_ERR(ret);
 }
 
+#ifdef CONFIG_COMPAT
 /*
- * Update the vDSO data page to keep in sync with kernel timekeeping.
+ * Create and map the vectors page for AArch32 tasks.
  */
-void update_vsyscall(struct timekeeper *tk)
+enum aarch32_map {
+	AA32_MAP_VECTORS, /* kuser helpers */
+	AA32_MAP_SIGPAGE,
+	AA32_MAP_VDSO,
+};
+
+static struct page *aarch32_vectors_page __ro_after_init;
+static struct page *aarch32_sig_page __ro_after_init;
+
+static int aarch32_sigpage_mremap(const struct vm_special_mapping *sm,
+				  struct vm_area_struct *new_vma)
+{
+	current->mm->context.sigpage = (void *)new_vma->vm_start;
+
+	return 0;
+}
+
+static struct vm_special_mapping aarch32_vdso_maps[] = {
+	[AA32_MAP_VECTORS] = {
+		.name	= "[vectors]", /* ABI */
+		.pages	= &aarch32_vectors_page,
+	},
+	[AA32_MAP_SIGPAGE] = {
+		.name	= "[sigpage]", /* ABI */
+		.pages	= &aarch32_sig_page,
+		.mremap	= aarch32_sigpage_mremap,
+	},
+	[AA32_MAP_VDSO] = {
+		.name = "[vdso]",
+		.mremap = vdso_mremap,
+	},
+};
+
+static int aarch32_alloc_kuser_vdso_page(void)
+{
+	extern char __kuser_helper_start[], __kuser_helper_end[];
+	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
+	unsigned long vdso_page;
+
+	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
+		return 0;
+
+	vdso_page = get_zeroed_page(GFP_KERNEL);
+	if (!vdso_page)
+		return -ENOMEM;
+
+	memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
+	       kuser_sz);
+	aarch32_vectors_page = virt_to_page((void *)vdso_page);
+	return 0;
+}
+
+#define COMPAT_SIGPAGE_POISON_WORD	0xe7fddef1
+static int aarch32_alloc_sigpage(void)
+{
+	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
+	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
+	__le32 poison = cpu_to_le32(COMPAT_SIGPAGE_POISON_WORD);
+	void *sigpage;
+
+	sigpage = (void *)__get_free_page(GFP_KERNEL);
+	if (!sigpage)
+		return -ENOMEM;
+
+	memset32(sigpage, (__force u32)poison, PAGE_SIZE / sizeof(poison));
+	memcpy(sigpage, __aarch32_sigret_code_start, sigret_sz);
+	aarch32_sig_page = virt_to_page(sigpage);
+	return 0;
+}
+
+static int __init __aarch32_alloc_vdso_pages(void)
+{
+
+	if (!IS_ENABLED(CONFIG_COMPAT_VDSO))
+		return 0;
+
+	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];
+
+	return __vdso_init(VDSO_ABI_AA32);
+}
+
+static int __init aarch32_alloc_vdso_pages(void)
+{
+	int ret;
+
+	ret = __aarch32_alloc_vdso_pages();
+	if (ret)
+		return ret;
+
+	ret = aarch32_alloc_sigpage();
+	if (ret)
+		return ret;
+
+	return aarch32_alloc_kuser_vdso_page();
+}
+arch_initcall(aarch32_alloc_vdso_pages);
+
+static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
+{
+	void *ret;
+
+	if (!IS_ENABLED(CONFIG_KUSER_HELPERS))
+		return 0;
+
+	/*
+	 * 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 |
+				       VM_SEALED_SYSMAP,
+				       &aarch32_vdso_maps[AA32_MAP_VECTORS]);
+
+	return PTR_ERR_OR_ZERO(ret);
+}
+
+static int aarch32_sigreturn_setup(struct mm_struct *mm)
 {
-	u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
-
-	++vdso_data->tb_seq_count;
-	smp_wmb();
-
-	vdso_data->use_syscall			= use_syscall;
-	vdso_data->xtime_coarse_sec		= tk->xtime_sec;
-	vdso_data->xtime_coarse_nsec		= tk->tkr_mono.xtime_nsec >>
-							tk->tkr_mono.shift;
-	vdso_data->wtm_clock_sec		= tk->wall_to_monotonic.tv_sec;
-	vdso_data->wtm_clock_nsec		= tk->wall_to_monotonic.tv_nsec;
-
-	if (!use_syscall) {
-		/* tkr_mono.cycle_last == tkr_raw.cycle_last */
-		vdso_data->cs_cycle_last	= tk->tkr_mono.cycle_last;
-		vdso_data->raw_time_sec         = tk->raw_sec;
-		vdso_data->raw_time_nsec        = tk->tkr_raw.xtime_nsec;
-		vdso_data->xtime_clock_sec	= tk->xtime_sec;
-		vdso_data->xtime_clock_nsec	= tk->tkr_mono.xtime_nsec;
-		vdso_data->cs_mono_mult		= tk->tkr_mono.mult;
-		vdso_data->cs_raw_mult		= tk->tkr_raw.mult;
-		/* tkr_mono.shift == tkr_raw.shift */
-		vdso_data->cs_shift		= tk->tkr_mono.shift;
+	unsigned long addr;
+	void *ret;
+
+	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
+	if (IS_ERR_VALUE(addr)) {
+		ret = ERR_PTR(addr);
+		goto out;
 	}
 
-	smp_wmb();
-	++vdso_data->tb_seq_count;
+	/*
+	 * 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_MAYWRITE | VM_MAYEXEC |
+				       VM_SEALED_SYSMAP,
+				       &aarch32_vdso_maps[AA32_MAP_SIGPAGE]);
+	if (IS_ERR(ret))
+		goto out;
+
+	mm->context.sigpage = (void *)addr;
+
+out:
+	return PTR_ERR_OR_ZERO(ret);
 }
 
-void update_vsyscall_tz(void)
+int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
-	vdso_data->tz_minuteswest	= sys_tz.tz_minuteswest;
-	vdso_data->tz_dsttime		= sys_tz.tz_dsttime;
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	ret = aarch32_kuser_helpers_setup(mm);
+	if (ret)
+		goto out;
+
+	if (IS_ENABLED(CONFIG_COMPAT_VDSO)) {
+		ret = __setup_additional_pages(VDSO_ABI_AA32, mm, bprm,
+					       uses_interp);
+		if (ret)
+			goto out;
+	}
+
+	ret = aarch32_sigreturn_setup(mm);
+out:
+	mmap_write_unlock(mm);
+	return ret;
+}
+#endif /* CONFIG_COMPAT */
+
+static struct vm_special_mapping aarch64_vdso_map __ro_after_init = {
+	.name	= "[vdso]",
+	.mremap = vdso_mremap,
+};
+
+static int __init vdso_init(void)
+{
+	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_map;
+
+	return __vdso_init(VDSO_ABI_AA64);
+}
+arch_initcall(vdso_init);
+
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	ret = __setup_additional_pages(VDSO_ABI_AA64, mm, bprm, uses_interp);
+	mmap_write_unlock(mm);
+
+	return ret;
 }