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    Subject[PATCH V7 09/20] csky: VDSO and rt_sigreturn
    Date
    This patch adds files related to VDSO and our VDSO only support
    rt_sigreturn.

    Signed-off-by: Guo Ren <ren_guo@c-sky.com>
    ---
    arch/csky/abiv1/inc/abi/vdso.h | 17 +++++++++
    arch/csky/abiv2/inc/abi/vdso.h | 23 +++++++++++
    arch/csky/include/asm/vdso.h | 12 ++++++
    arch/csky/kernel/vdso.c | 86 ++++++++++++++++++++++++++++++++++++++++++
    4 files changed, 138 insertions(+)
    create mode 100644 arch/csky/abiv1/inc/abi/vdso.h
    create mode 100644 arch/csky/abiv2/inc/abi/vdso.h
    create mode 100644 arch/csky/include/asm/vdso.h
    create mode 100644 arch/csky/kernel/vdso.c

    diff --git a/arch/csky/abiv1/inc/abi/vdso.h b/arch/csky/abiv1/inc/abi/vdso.h
    new file mode 100644
    index 0000000..14352f5
    --- /dev/null
    +++ b/arch/csky/abiv1/inc/abi/vdso.h
    @@ -0,0 +1,17 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +
    +#include <linux/uaccess.h>
    +
    +static inline int setup_vdso_page(unsigned short *ptr)
    +{
    + int err = 0;
    +
    + /* movi r1, 127 */
    + err |= __put_user(0x67f1, ptr + 0);
    + /* addi r1, (139 - 127) */
    + err |= __put_user(0x20b1, ptr + 1);
    + /* trap 0 */
    + err |= __put_user(0x0008, ptr + 2);
    +
    + return err;
    +}
    diff --git a/arch/csky/abiv2/inc/abi/vdso.h b/arch/csky/abiv2/inc/abi/vdso.h
    new file mode 100644
    index 0000000..b60d4a0
    --- /dev/null
    +++ b/arch/csky/abiv2/inc/abi/vdso.h
    @@ -0,0 +1,23 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +
    +#ifndef __ABI_CSKY_VDSO_H
    +#define __ABI_CSKY_VDSO_H
    +
    +#include <linux/uaccess.h>
    +
    +static inline int setup_vdso_page(unsigned short *ptr)
    +{
    + int err = 0;
    +
    + /* movi r7, 173 */
    + err |= __put_user(0xea07, ptr);
    + err |= __put_user(0x008b, ptr+1);
    +
    + /* trap 0 */
    + err |= __put_user(0xc000, ptr+2);
    + err |= __put_user(0x2020, ptr+3);
    +
    + return err;
    +}
    +
    +#endif /* __ABI_CSKY_STRING_H */
    diff --git a/arch/csky/include/asm/vdso.h b/arch/csky/include/asm/vdso.h
    new file mode 100644
    index 0000000..d963d69
    --- /dev/null
    +++ b/arch/csky/include/asm/vdso.h
    @@ -0,0 +1,12 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +
    +#ifndef __ASM_CSKY_VDSO_H
    +#define __ASM_CSKY_VDSO_H
    +
    +#include <abi/vdso.h>
    +
    +struct csky_vdso {
    + unsigned short rt_signal_retcode[4];
    +};
    +
    +#endif /* __ASM_CSKY_VDSO_H */
    diff --git a/arch/csky/kernel/vdso.c b/arch/csky/kernel/vdso.c
    new file mode 100644
    index 0000000..60ff7ad
    --- /dev/null
    +++ b/arch/csky/kernel/vdso.c
    @@ -0,0 +1,86 @@
    +// SPDX-License-Identifier: GPL-2.0
    +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
    +
    +#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/uaccess.h>
    +
    +#include <asm/vdso.h>
    +#include <asm/cacheflush.h>
    +
    +static struct page *vdso_page;
    +
    +static int __init init_vdso(void)
    +{
    + struct csky_vdso *vdso;
    + int err = 0;
    +
    + 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);
    +
    + err = setup_vdso_page(vdso->rt_signal_retcode);
    + if (err)
    + panic("Cannot set signal return code, err: %x.", err);
    +
    + dcache_wb_range((unsigned long)vdso, (unsigned long)vdso + 16);
    +
    + vunmap(vdso);
    +
    + return 0;
    +}
    +subsys_initcall(init_vdso);
    +
    +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
    +{
    + int ret;
    + unsigned long addr;
    + struct mm_struct *mm = current->mm;
    +
    + down_write(&mm->mmap_sem);
    +
    + addr = get_unmapped_area(NULL, STACK_TOP, PAGE_SIZE, 0, 0);
    + if (IS_ERR_VALUE(addr)) {
    + ret = addr;
    + goto up_fail;
    + }
    +
    + ret = install_special_mapping(
    + mm,
    + addr,
    + PAGE_SIZE,
    + VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
    + &vdso_page);
    + if (ret)
    + goto up_fail;
    +
    + mm->context.vdso = (void *)addr;
    +
    +up_fail:
    + up_write(&mm->mmap_sem);
    + return ret;
    +}
    +
    +const char *arch_vma_name(struct vm_area_struct *vma)
    +{
    + if (vma->vm_mm == NULL)
    + return NULL;
    +
    + if (vma->vm_start == (long)vma->vm_mm->context.vdso)
    + return "[vdso]";
    + else
    + return NULL;
    +}
    --
    2.7.4
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