1 files changed, 146 insertions, 72 deletions

diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 0f1af58b036a..de096777172f 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -1,109 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * 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) 2009, 2010 Cavium Networks, Inc.
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
  */
 
-
-#include <linux/kernel.h>
-#include <linux/err.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/init.h>
 #include <linux/binfmts.h>
 #include <linux/elf.h>
-#include <linux/vmalloc.h>
-#include <linux/unistd.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vdso_datastore.h>
 
+#include <asm/abi.h>
+#include <asm/mips-cps.h>
+#include <asm/page.h>
 #include <asm/vdso.h>
-#include <asm/uasm.h>
+#include <vdso/helpers.h>
+#include <vdso/vsyscall.h>
 
-/*
- * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
- */
-#define __NR_O32_sigreturn		4119
-#define __NR_O32_rt_sigreturn		4193
-#define __NR_N32_rt_sigreturn		6211
+static_assert(VDSO_NR_PAGES == __VDSO_PAGES);
 
-static struct page *vdso_page;
-
-static void __init install_trampoline(u32 *tramp, unsigned int sigreturn)
+static void __init init_vdso_image(struct mips_vdso_image *image)
 {
-	uasm_i_addiu(&tramp, 2, 0, sigreturn);	/* li v0, sigreturn */
-	uasm_i_syscall(&tramp, 0);
+	unsigned long num_pages, i;
+	unsigned long data_pfn;
+
+	BUG_ON(!PAGE_ALIGNED(image->data));
+	BUG_ON(!PAGE_ALIGNED(image->size));
+
+	num_pages = image->size / PAGE_SIZE;
+
+	data_pfn = __phys_to_pfn(__pa_symbol(image->data));
+	for (i = 0; i < num_pages; i++)
+		image->mapping.pages[i] = pfn_to_page(data_pfn + i);
 }
 
 static int __init init_vdso(void)
 {
-	struct mips_vdso *vdso;
-
-	vdso_page = alloc_page(GFP_KERNEL);
-	if (!vdso_page)
-		panic("Cannot allocate vdso");
-
-	vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
-	if (!vdso)
-		panic("Cannot map vdso");
-	clear_page(vdso);
-
-	install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn);
-#ifdef CONFIG_32BIT
-	install_trampoline(vdso->signal_trampoline, __NR_sigreturn);
-#else
-	install_trampoline(vdso->n32_rt_signal_trampoline,
-			   __NR_N32_rt_sigreturn);
-	install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn);
-	install_trampoline(vdso->o32_rt_signal_trampoline,
-			   __NR_O32_rt_sigreturn);
+	init_vdso_image(&vdso_image);
+
+#ifdef CONFIG_MIPS32_O32
+	init_vdso_image(&vdso_image_o32);
 #endif
 
-	vunmap(vdso);
+#ifdef CONFIG_MIPS32_N32
+	init_vdso_image(&vdso_image_n32);
+#endif
 
 	return 0;
 }
 subsys_initcall(init_vdso);
 
-static unsigned long vdso_addr(unsigned long start)
+static unsigned long vdso_base(void)
 {
-	return STACK_TOP;
+	unsigned long base = STACK_TOP;
+
+	if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
+		/* Skip the delay slot emulation page */
+		base += PAGE_SIZE;
+	}
+
+	if (current->flags & PF_RANDOMIZE) {
+		base += get_random_u32_below(VDSO_RANDOMIZE_SIZE);
+		base = PAGE_ALIGN(base);
+	}
+
+	return base;
 }
 
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
-	int ret;
-	unsigned long addr;
+	struct mips_vdso_image *image = current->thread.abi->vdso;
 	struct mm_struct *mm = current->mm;
+	unsigned long gic_size, size, base, data_addr, vdso_addr, gic_pfn, gic_base;
+	struct vm_area_struct *vma;
+	int ret;
 
-	down_write(&mm->mmap_sem);
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
 
-	addr = vdso_addr(mm->start_stack);
+	if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
+		unsigned long unused;
 
-	addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0);
-	if (IS_ERR_VALUE(addr)) {
-		ret = addr;
-		goto up_fail;
+		/* Map delay slot emulation page */
+		base = do_mmap(NULL, STACK_TOP, PAGE_SIZE, PROT_READ | PROT_EXEC,
+			       MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, 0, 0, &unused,
+			       NULL);
+		if (IS_ERR_VALUE(base)) {
+			ret = base;
+			goto out;
+		}
 	}
 
-	ret = install_special_mapping(mm, addr, PAGE_SIZE,
-				      VM_READ|VM_EXEC|
-				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				      &vdso_page);
+	/*
+	 * Determine total area size. This includes the VDSO data itself, the
+	 * data page, and the GIC user page if present. Always create a mapping
+	 * for the GIC user area if the GIC is present regardless of whether it
+	 * is the current clocksource, in case it comes into use later on. We
+	 * only map a page even though the total area is 64K, as we only need
+	 * the counter registers at the start.
+	 */
+	gic_size = mips_gic_present() ? PAGE_SIZE : 0;
+	size = gic_size + VDSO_NR_PAGES * PAGE_SIZE + image->size;
+
+	/*
+	 * Find a region that's large enough for us to perform the
+	 * colour-matching alignment below.
+	 */
+	if (cpu_has_dc_aliases)
+		size += shm_align_mask + 1;
+
+	base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
+	if (IS_ERR_VALUE(base)) {
+		ret = base;
+		goto out;
+	}
 
-	if (ret)
-		goto up_fail;
+	/*
+	 * If we suffer from dcache aliasing, ensure that the VDSO data page
+	 * mapping is coloured the same as the kernel's mapping of that memory.
+	 * This ensures that when the kernel updates the VDSO data userland
+	 * will observe it without requiring cache invalidations.
+	 */
+	if (cpu_has_dc_aliases) {
+		base = __ALIGN_MASK(base, shm_align_mask);
+		base += ((unsigned long)vdso_k_time_data - gic_size) & shm_align_mask;
+	}
 
-	mm->context.vdso = (void *)addr;
+	data_addr = base + gic_size;
+	vdso_addr = data_addr + VDSO_NR_PAGES * PAGE_SIZE;
 
-up_fail:
-	up_write(&mm->mmap_sem);
-	return ret;
-}
+	vma = vdso_install_vvar_mapping(mm, data_addr);
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto out;
+	}
 
-const char *arch_vma_name(struct vm_area_struct *vma)
-{
-	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
-		return "[vdso]";
-	return NULL;
+	/* Map GIC user page. */
+	if (gic_size) {
+		gic_base = (unsigned long)mips_gic_base + MIPS_GIC_USER_OFS;
+		gic_pfn = PFN_DOWN(__pa(gic_base));
+		static const struct vm_special_mapping gic_mapping = {
+			.name	= "[gic]",
+			.pages	= (struct page **) { NULL },
+		};
+
+		vma = _install_special_mapping(mm, base, gic_size, VM_READ | VM_MAYREAD,
+					       &gic_mapping);
+		if (IS_ERR(vma)) {
+			ret = PTR_ERR(vma);
+			goto out;
+		}
+
+		ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
+					 pgprot_noncached(vma->vm_page_prot));
+		if (ret)
+			goto out;
+	}
+
+	/* Map VDSO image. */
+	vma = _install_special_mapping(mm, vdso_addr, image->size,
+				       VM_READ | VM_EXEC |
+				       VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+				       &image->mapping);
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto out;
+	}
+
+	mm->context.vdso = (void *)vdso_addr;
+	ret = 0;
+
+out:
+	mmap_write_unlock(mm);
+	return ret;
 }