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33385150ac
Hook up the generic vDSO implementation to the x86 vDSO data page. Since the existing vDSO infrastructure is heavily based on the timekeeping functionality, which works over arrays of bases, a new macro is introduced for vvars that are not arrays. The vDSO function requires a ChaCha20 implementation that does not write to the stack, yet can still do an entire ChaCha20 permutation, so provide this using SSE2, since this is userland code that must work on all x86-64 processors. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Samuel Neves <sneves@dei.uc.pt> # for vgetrandom-chacha.S Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
72 lines
2.0 KiB
C
72 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* vvar.h: Shared vDSO/kernel variable declarations
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* Copyright (c) 2011 Andy Lutomirski
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*
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* A handful of variables are accessible (read-only) from userspace
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* code in the vsyscall page and the vdso. They are declared here.
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* Some other file must define them with DEFINE_VVAR.
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*
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* In normal kernel code, they are used like any other variable.
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* In user code, they are accessed through the VVAR macro.
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*
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* These variables live in a page of kernel data that has an extra RO
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* mapping for userspace. Each variable needs a unique offset within
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* that page; specify that offset with the DECLARE_VVAR macro. (If
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* you mess up, the linker will catch it.)
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*/
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#ifndef _ASM_X86_VVAR_H
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#define _ASM_X86_VVAR_H
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#ifdef EMIT_VVAR
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/*
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* EMIT_VVAR() is used by the kernel linker script to put vvars in the
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* right place. Also, it's used by kernel code to import offsets values.
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*/
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#define DECLARE_VVAR(offset, type, name) \
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EMIT_VVAR(name, offset)
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#define DECLARE_VVAR_SINGLE(offset, type, name) \
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EMIT_VVAR(name, offset)
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#else
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extern char __vvar_page;
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#define DECLARE_VVAR(offset, type, name) \
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extern type vvar_ ## name[CS_BASES] \
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__attribute__((visibility("hidden"))); \
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extern type timens_ ## name[CS_BASES] \
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__attribute__((visibility("hidden"))); \
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#define DECLARE_VVAR_SINGLE(offset, type, name) \
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extern type vvar_ ## name \
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__attribute__((visibility("hidden"))); \
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#define VVAR(name) (vvar_ ## name)
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#define TIMENS(name) (timens_ ## name)
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#define DEFINE_VVAR(type, name) \
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type name[CS_BASES] \
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__attribute__((section(".vvar_" #name), aligned(16))) __visible
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#define DEFINE_VVAR_SINGLE(type, name) \
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type name \
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__attribute__((section(".vvar_" #name), aligned(16))) __visible
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#endif
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/* DECLARE_VVAR(offset, type, name) */
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DECLARE_VVAR(128, struct vdso_data, _vdso_data)
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#if !defined(_SINGLE_DATA)
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#define _SINGLE_DATA
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DECLARE_VVAR_SINGLE(640, struct vdso_rng_data, _vdso_rng_data)
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#endif
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#undef DECLARE_VVAR
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#undef DECLARE_VVAR_SINGLE
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#endif
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