linux/arch/riscv/kernel/vdso.c
Linus Torvalds cd16ed33c3 RISC-V Patches for the 5.8 Merge Window, Part 2
* Select statements are now sorted alphanumerically.
 * Our first-level interrupts are now handled via a full irqchip driver.
 * CPU hotplug is fixed.
 * Our vDSO calls now use the common vDSO infrastructure.
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Merge tag 'riscv-for-linus-5.8-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:

 - Kconfig select statements are now sorted alphanumerically

 - first-level interrupts are now handled via a full irqchip driver

 - CPU hotplug is fixed

 - vDSO calls now use the common vDSO infrastructure

* tag 'riscv-for-linus-5.8-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: set the permission of vdso_data to read-only
  riscv: use vDSO common flow to reduce the latency of the time-related functions
  riscv: fix build warning of missing prototypes
  RISC-V: Don't mark init section as non-executable
  RISC-V: Force select RISCV_INTC for CONFIG_RISCV
  RISC-V: Remove do_IRQ() function
  clocksource/drivers/timer-riscv: Use per-CPU timer interrupt
  irqchip: RISC-V per-HART local interrupt controller driver
  RISC-V: Rename and move plic_find_hart_id() to arch directory
  RISC-V: self-contained IPI handling routine
  RISC-V: Sort select statements alphanumerically
2020-06-11 12:55:20 -07:00

112 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
* <benh@kernel.crashing.org>
* Copyright (C) 2012 ARM Limited
* Copyright (C) 2015 Regents of the University of California
*/
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/err.h>
#include <asm/page.h>
#ifdef GENERIC_TIME_VSYSCALL
#include <vdso/datapage.h>
#else
#include <asm/vdso.h>
#endif
extern char vdso_start[], vdso_end[];
static unsigned int vdso_pages;
static struct page **vdso_pagelist;
/*
* 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;
static int __init vdso_init(void)
{
unsigned int i;
vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
vdso_pagelist =
kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
if (unlikely(vdso_pagelist == NULL)) {
pr_err("vdso: pagelist allocation failed\n");
return -ENOMEM;
}
for (i = 0; i < vdso_pages; i++) {
struct page *pg;
pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
vdso_pagelist[i] = pg;
}
vdso_pagelist[i] = virt_to_page(vdso_data);
return 0;
}
arch_initcall(vdso_init);
int arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp)
{
struct mm_struct *mm = current->mm;
unsigned long vdso_base, vdso_len;
int ret;
vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
mmap_write_lock(mm);
vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
if (IS_ERR_VALUE(vdso_base)) {
ret = vdso_base;
goto end;
}
/*
* Put vDSO base into mm struct. We need to do this before calling
* install_special_mapping or the perf counter mmap tracking code
* will fail to recognise it as a vDSO (since arch_vma_name fails).
*/
mm->context.vdso = (void *)vdso_base;
ret =
install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
(VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
vdso_pagelist);
if (unlikely(ret)) {
mm->context.vdso = NULL;
goto end;
}
vdso_base += (vdso_pages << PAGE_SHIFT);
ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
(VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
if (unlikely(ret))
mm->context.vdso = NULL;
end:
mmap_write_unlock(mm);
return ret;
}
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]";
if (vma->vm_mm && (vma->vm_start ==
(long)vma->vm_mm->context.vdso + PAGE_SIZE))
return "[vdso_data]";
return NULL;
}