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authorGreentime Hu <greentime@andestech.com>2017-10-25 05:16:56 +0200
committerGreentime Hu <greentime@andestech.com>2018-02-22 03:44:33 +0100
commiteefacd1dfe38a3334d2e1c44fee0d7b0fdd5d252 (patch)
treeecc49e54c9a797a7f402c39da9a2d7f25cd1c104 /arch/nds32/kernel/vdso.c
parentnds32: System calls handling (diff)
downloadlinux-eefacd1dfe38a3334d2e1c44fee0d7b0fdd5d252.tar.xz
linux-eefacd1dfe38a3334d2e1c44fee0d7b0fdd5d252.zip
nds32: VDSO support
This patch adds VDSO support. The VDSO code is currently used for sys_rt_sigreturn() and optimised gettimeofday() (using the SoC timer counter). Signed-off-by: Vincent Chen <vincentc@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/nds32/kernel/vdso.c')
-rw-r--r--arch/nds32/kernel/vdso.c230
1 files changed, 230 insertions, 0 deletions
diff --git a/arch/nds32/kernel/vdso.c b/arch/nds32/kernel/vdso.c
new file mode 100644
index 000000000000..f1198d7a5654
--- /dev/null
+++ b/arch/nds32/kernel/vdso.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2012 ARM Limited
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/cache.h>
+#include <linux/clocksource.h>
+#include <linux/elf.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/vmalloc.h>
+#include <linux/random.h>
+
+#include <asm/cacheflush.h>
+#include <asm/vdso.h>
+#include <asm/vdso_datapage.h>
+#include <asm/vdso_timer_info.h>
+#include <asm/cache_info.h>
+extern struct cache_info L1_cache_info[2];
+extern char vdso_start, vdso_end;
+static unsigned long vdso_pages __ro_after_init;
+static unsigned long timer_mapping_base;
+
+struct timer_info_t timer_info = {
+ .cycle_count_down = true,
+ .mapping_base = EMPTY_TIMER_MAPPING,
+ .cycle_count_reg_offset = EMPTY_REG_OFFSET
+};
+/*
+ * The vDSO data page.
+ */
+static struct page *no_pages[] = { NULL };
+
+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;
+static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
+ {
+ .name = "[vvar]",
+ .pages = no_pages,
+ },
+ {
+ .name = "[vdso]",
+ },
+};
+
+static void get_timer_node_info(void)
+{
+ timer_mapping_base = timer_info.mapping_base;
+ vdso_data->cycle_count_offset =
+ timer_info.cycle_count_reg_offset;
+ vdso_data->cycle_count_down =
+ timer_info.cycle_count_down;
+}
+
+static int __init vdso_init(void)
+{
+ int i;
+ struct page **vdso_pagelist;
+
+ if (memcmp(&vdso_start, "\177ELF", 4)) {
+ pr_err("vDSO is not a valid ELF object!\n");
+ return -EINVAL;
+ }
+ /* Creat a timer io mapping to get clock cycles counter */
+ get_timer_node_info();
+
+ 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);
+
+ /* Allocate the vDSO pagelist */
+ vdso_pagelist = kcalloc(vdso_pages, sizeof(struct page *), GFP_KERNEL);
+ if (vdso_pagelist == NULL)
+ return -ENOMEM;
+
+ for (i = 0; i < vdso_pages; i++)
+ vdso_pagelist[i] = virt_to_page(&vdso_start + i * PAGE_SIZE);
+ vdso_spec[1].pages = &vdso_pagelist[0];
+
+ return 0;
+}
+
+arch_initcall(vdso_init);
+
+unsigned long inline vdso_random_addr(unsigned long vdso_mapping_len)
+{
+ unsigned long start = current->mm->mmap_base, end, offset, addr;
+ start = PAGE_ALIGN(start);
+
+ /* Round the lowest possible end address up to a PMD boundary. */
+ end = (start + vdso_mapping_len + PMD_SIZE - 1) & PMD_MASK;
+ if (end >= TASK_SIZE)
+ end = TASK_SIZE;
+ end -= vdso_mapping_len;
+
+ if (end > start) {
+ offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
+ addr = start + (offset << PAGE_SHIFT);
+ } else {
+ addr = start;
+ }
+ return addr;
+}
+
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
+ struct vm_area_struct *vma;
+ unsigned long addr = 0;
+ pgprot_t prot;
+ int ret, vvar_page_num = 2;
+
+ vdso_text_len = vdso_pages << PAGE_SHIFT;
+
+ if(timer_mapping_base == EMPTY_VALUE)
+ vvar_page_num = 1;
+ /* Be sure to map the data page */
+ vdso_mapping_len = vdso_text_len + vvar_page_num * PAGE_SIZE;
+#ifdef CONFIG_CPU_CACHE_ALIASING
+ vdso_mapping_len += L1_cache_info[DCACHE].aliasing_num - 1;
+#endif
+
+ if (down_write_killable(&mm->mmap_sem))
+ return -EINTR;
+
+ addr = vdso_random_addr(vdso_mapping_len);
+ vdso_base = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0);
+ if (IS_ERR_VALUE(vdso_base)) {
+ ret = vdso_base;
+ goto up_fail;
+ }
+
+#ifdef CONFIG_CPU_CACHE_ALIASING
+ {
+ unsigned int aliasing_mask =
+ L1_cache_info[DCACHE].aliasing_mask;
+ unsigned int page_colour_ofs;
+ page_colour_ofs = ((unsigned int)vdso_data & aliasing_mask) -
+ (vdso_base & aliasing_mask);
+ vdso_base += page_colour_ofs & aliasing_mask;
+ }
+#endif
+
+ vma = _install_special_mapping(mm, vdso_base, vvar_page_num * PAGE_SIZE,
+ VM_READ | VM_MAYREAD, &vdso_spec[0]);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto up_fail;
+ }
+
+ /*Map vdata to user space */
+ ret = io_remap_pfn_range(vma, vdso_base,
+ virt_to_phys(vdso_data) >> PAGE_SHIFT,
+ PAGE_SIZE, vma->vm_page_prot);
+ if (ret)
+ goto up_fail;
+
+ /*Map timer to user space */
+ vdso_base += PAGE_SIZE;
+ prot = __pgprot(_PAGE_V | _PAGE_M_UR_KR | _PAGE_D | _PAGE_C_DEV);
+ ret = io_remap_pfn_range(vma, vdso_base, timer_mapping_base >> PAGE_SHIFT,
+ PAGE_SIZE, prot);
+ if (ret)
+ goto up_fail;
+
+ /*Map vdso to user space */
+ vdso_base += PAGE_SIZE;
+ mm->context.vdso = (void *)vdso_base;
+ vma = _install_special_mapping(mm, vdso_base, vdso_text_len,
+ VM_READ | VM_EXEC |
+ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+ &vdso_spec[1]);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto up_fail;
+ }
+
+ up_write(&mm->mmap_sem);
+ return 0;
+
+up_fail:
+ mm->context.vdso = NULL;
+ up_write(&mm->mmap_sem);
+ return ret;
+}
+
+static void vdso_write_begin(struct vdso_data *vdata)
+{
+ ++vdso_data->seq_count;
+ smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */
+}
+
+static void vdso_write_end(struct vdso_data *vdata)
+{
+ smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */
+ ++vdso_data->seq_count;
+}
+
+void update_vsyscall(struct timekeeper *tk)
+{
+ vdso_write_begin(vdso_data);
+ vdso_data->cs_mask = tk->tkr_mono.mask;
+ vdso_data->cs_mult = tk->tkr_mono.mult;
+ vdso_data->cs_shift = tk->tkr_mono.shift;
+ vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
+ vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
+ vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
+ vdso_data->xtime_clock_sec = tk->xtime_sec;
+ vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
+ vdso_data->xtime_coarse_sec = tk->xtime_sec;
+ vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>
+ tk->tkr_mono.shift;
+ vdso_write_end(vdso_data);
+}
+
+void update_vsyscall_tz(void)
+{
+ vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data->tz_dsttime = sys_tz.tz_dsttime;
+}