mk-rootfs.sh

hc

2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376

 kernel/Documentation/userspace-api/spec_ctrl.rst
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 which is selected with arg2 of prctl(2). The return value uses bits 0-3 with
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 the following meaning:
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-==== ===================== ===================================================
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-Bit  Define                Description
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-==== ===================== ===================================================
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-0    PR_SPEC_PRCTL         Mitigation can be controlled per task by
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-                           PR_SET_SPECULATION_CTRL.
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-1    PR_SPEC_ENABLE        The speculation feature is enabled, mitigation is
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-                           disabled.
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-2    PR_SPEC_DISABLE       The speculation feature is disabled, mitigation is
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-                           enabled.
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-3    PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A
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-                           subsequent prctl(..., PR_SPEC_ENABLE) will fail.
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-==== ===================== ===================================================
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+==== ====================== ==================================================
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+Bit  Define                 Description
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+==== ====================== ==================================================
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+0    PR_SPEC_PRCTL          Mitigation can be controlled per task by
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+                            PR_SET_SPECULATION_CTRL.
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+1    PR_SPEC_ENABLE         The speculation feature is enabled, mitigation is
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+                            disabled.
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+2    PR_SPEC_DISABLE        The speculation feature is disabled, mitigation is
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+                            enabled.
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+3    PR_SPEC_FORCE_DISABLE  Same as PR_SPEC_DISABLE, but cannot be undone. A
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+                            subsequent prctl(..., PR_SPEC_ENABLE) will fail.
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+4    PR_SPEC_DISABLE_NOEXEC Same as PR_SPEC_DISABLE, but the state will be
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+                            cleared on :manpage:`execve(2)`.
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+==== ====================== ==================================================
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 If all bits are 0 the CPU is not affected by the speculation misfeature.
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    * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_ENABLE, 0, 0);
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    * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_DISABLE, 0, 0);
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    * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_FORCE_DISABLE, 0, 0);
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+   * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_DISABLE_NOEXEC, 0, 0);
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 - PR_SPEC_INDIR_BRANCH: Indirect Branch Speculation in User Processes
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                         (Mitigate Spectre V2 style attacks against user processes)