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    Subject[patch V2 27/52] x86/fpu: Deduplicate copy_uabi_from_user/kernel_to_xstate()
    copy_uabi_from_user_to_xstate() and copy_uabi_from_kernel_to_xstate() are
    almost identical except for the copy function.

    Unify them.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Acked-by: Andy Lutomirski <luto@kernel.org>
    ---
    arch/x86/kernel/fpu/xstate.c | 84 +++++++++++++++----------------------------
    1 file changed, 30 insertions(+), 54 deletions(-)

    --- a/arch/x86/kernel/fpu/xstate.c
    +++ b/arch/x86/kernel/fpu/xstate.c
    @@ -1076,20 +1076,30 @@ void copy_uabi_xstate_to_membuf(struct m
    membuf_zero(&to, to.left);
    }

    -/*
    - * Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S] format
    - * and copy to the target thread. This is called from xstateregs_set().
    - */
    -int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
    +static int copy_from_buffer(void *dst, unsigned int offset, unsigned int size,
    + const void *kbuf, const void __user *ubuf)
    +{
    + if (kbuf) {
    + memcpy(dst, kbuf + offset, size);
    + } else {
    + if (copy_from_user(dst, ubuf + offset, size))
    + return -EFAULT;
    + }
    + return 0;
    +}
    +
    +static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf,
    + const void __user *ubuf)
    {
    unsigned int offset, size;
    - int i;
    struct xstate_header hdr;
    + int i;

    offset = offsetof(struct xregs_state, header);
    size = sizeof(hdr);

    - memcpy(&hdr, kbuf + offset, size);
    + if (copy_from_buffer(&hdr, offset, size, kbuf, ubuf))
    + return -EFAULT;

    if (validate_user_xstate_header(&hdr))
    return -EINVAL;
    @@ -1111,7 +1121,8 @@ int copy_uabi_from_kernel_to_xstate(stru
    offset = xstate_offsets[i];
    size = xstate_sizes[i];

    - memcpy(dst, kbuf + offset, size);
    + if (copy_from_buffer(dst, offset, size, kbuf, ubuf))
    + return -EFAULT;
    }
    }

    @@ -1136,6 +1147,16 @@ int copy_uabi_from_kernel_to_xstate(stru
    }

    /*
    + * Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S]
    + * format and copy to the target thread. This is called from
    + * xstateregs_set().
    + */
    +int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
    +{
    + return copy_uabi_to_xstate(xsave, kbuf, NULL);
    +}
    +
    +/*
    * Convert from a sigreturn standard-format user-space buffer to kernel
    * XSAVE[S] format and copy to the target thread. This is called from the
    * sigreturn() and rt_sigreturn() system calls.
    @@ -1143,52 +1164,7 @@ int copy_uabi_from_kernel_to_xstate(stru
    int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave,
    const void __user *ubuf)
    {
    - unsigned int offset, size;
    - int i;
    - struct xstate_header hdr;
    -
    - offset = offsetof(struct xregs_state, header);
    - size = sizeof(hdr);
    -
    - if (copy_from_user(&hdr, ubuf + offset, size))
    - return -EFAULT;
    -
    - if (validate_user_xstate_header(&hdr))
    - return -EINVAL;
    -
    - for (i = 0; i < XFEATURE_MAX; i++) {
    - u64 mask = ((u64)1 << i);
    -
    - if (hdr.xfeatures & mask) {
    - void *dst = __raw_xsave_addr(xsave, i);
    -
    - offset = xstate_offsets[i];
    - size = xstate_sizes[i];
    -
    - if (copy_from_user(dst, ubuf + offset, size))
    - return -EFAULT;
    - }
    - }
    -
    - if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
    - offset = offsetof(struct fxregs_state, mxcsr);
    - size = MXCSR_AND_FLAGS_SIZE;
    - if (copy_from_user(&xsave->i387.mxcsr, ubuf + offset, size))
    - return -EFAULT;
    - }
    -
    - /*
    - * The state that came in from userspace was user-state only.
    - * Mask all the user states out of 'xfeatures':
    - */
    - xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL;
    -
    - /*
    - * Add back in the features that came in from userspace:
    - */
    - xsave->header.xfeatures |= hdr.xfeatures;
    -
    - return 0;
    + return copy_uabi_to_xstate(xsave, NULL, ubuf);
    }

    /**
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