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-rw-r--r--common/recipes-kernel/linux/linux-yocto-4.9.21/0050-prctl-Add-force-disable-speculation.patch218
1 files changed, 0 insertions, 218 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0050-prctl-Add-force-disable-speculation.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0050-prctl-Add-force-disable-speculation.patch
deleted file mode 100644
index acdc260b..00000000
--- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0050-prctl-Add-force-disable-speculation.patch
+++ /dev/null
@@ -1,218 +0,0 @@
-From 6eca73ee80c5d8b6f8c3d294b3f97b7c8da67791 Mon Sep 17 00:00:00 2001
-From: Thomas Gleixner <tglx@linutronix.de>
-Date: Thu, 3 May 2018 22:09:15 +0200
-Subject: [PATCH 50/93] prctl: Add force disable speculation
-
-commit 356e4bfff2c5489e016fdb925adbf12a1e3950ee upstream
-
-For certain use cases it is desired to enforce mitigations so they cannot
-be undone afterwards. That's important for loader stubs which want to
-prevent a child from disabling the mitigation again. Will also be used for
-seccomp(). The extra state preserving of the prctl state for SSB is a
-preparatory step for EBPF dymanic speculation control.
-
-Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- Documentation/spec_ctrl.txt | 34 +++++++++++++++++++++-------------
- arch/x86/kernel/cpu/bugs.c | 35 +++++++++++++++++++++++++----------
- fs/proc/array.c | 3 +++
- include/linux/sched.h | 9 +++++++++
- include/uapi/linux/prctl.h | 1 +
- 5 files changed, 59 insertions(+), 23 deletions(-)
-
-diff --git a/Documentation/spec_ctrl.txt b/Documentation/spec_ctrl.txt
-index ddbebcd..1b3690d 100644
---- a/Documentation/spec_ctrl.txt
-+++ b/Documentation/spec_ctrl.txt
-@@ -25,19 +25,21 @@ PR_GET_SPECULATION_CTRL
- -----------------------
-
- PR_GET_SPECULATION_CTRL returns the state of the speculation misfeature
--which is selected with arg2 of prctl(2). The return value uses bits 0-2 with
-+which is selected with arg2 of prctl(2). The return value uses bits 0-3 with
- the following meaning:
-
--==== ================ ===================================================
--Bit Define Description
--==== ================ ===================================================
--0 PR_SPEC_PRCTL Mitigation can be controlled per task by
-- PR_SET_SPECULATION_CTRL
--1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is
-- disabled
--2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is
-- enabled
--==== ================ ===================================================
-+==== ===================== ===================================================
-+Bit Define Description
-+==== ===================== ===================================================
-+0 PR_SPEC_PRCTL Mitigation can be controlled per task by
-+ PR_SET_SPECULATION_CTRL
-+1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is
-+ disabled
-+2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is
-+ enabled
-+3 PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A
-+ subsequent prctl(..., PR_SPEC_ENABLE) will fail.
-+==== ===================== ===================================================
-
- If all bits are 0 the CPU is not affected by the speculation misfeature.
-
-@@ -47,9 +49,11 @@ misfeature will fail.
-
- PR_SET_SPECULATION_CTRL
- -----------------------
-+
- PR_SET_SPECULATION_CTRL allows to control the speculation misfeature, which
- is selected by arg2 of :manpage:`prctl(2)` per task. arg3 is used to hand
--in the control value, i.e. either PR_SPEC_ENABLE or PR_SPEC_DISABLE.
-+in the control value, i.e. either PR_SPEC_ENABLE or PR_SPEC_DISABLE or
-+PR_SPEC_FORCE_DISABLE.
-
- Common error codes
- ------------------
-@@ -70,10 +74,13 @@ Value Meaning
- 0 Success
-
- ERANGE arg3 is incorrect, i.e. it's neither PR_SPEC_ENABLE nor
-- PR_SPEC_DISABLE
-+ PR_SPEC_DISABLE nor PR_SPEC_FORCE_DISABLE
-
- ENXIO Control of the selected speculation misfeature is not possible.
- See PR_GET_SPECULATION_CTRL.
-+
-+EPERM Speculation was disabled with PR_SPEC_FORCE_DISABLE and caller
-+ tried to enable it again.
- ======= =================================================================
-
- Speculation misfeature controls
-@@ -84,3 +91,4 @@ Speculation misfeature controls
- * prctl(PR_GET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, 0, 0, 0);
- * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_ENABLE, 0, 0);
- * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_DISABLE, 0, 0);
-+ * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_FORCE_DISABLE, 0, 0);
-diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
-index 65114d2..fdbd8e5 100644
---- a/arch/x86/kernel/cpu/bugs.c
-+++ b/arch/x86/kernel/cpu/bugs.c
-@@ -532,21 +532,37 @@ static void ssb_select_mitigation()
-
- static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl)
- {
-- bool rds = !!test_tsk_thread_flag(task, TIF_RDS);
-+ bool update;
-
- if (ssb_mode != SPEC_STORE_BYPASS_PRCTL)
- return -ENXIO;
-
-- if (ctrl == PR_SPEC_ENABLE)
-- clear_tsk_thread_flag(task, TIF_RDS);
-- else
-- set_tsk_thread_flag(task, TIF_RDS);
-+ switch (ctrl) {
-+ case PR_SPEC_ENABLE:
-+ /* If speculation is force disabled, enable is not allowed */
-+ if (task_spec_ssb_force_disable(task))
-+ return -EPERM;
-+ task_clear_spec_ssb_disable(task);
-+ update = test_and_clear_tsk_thread_flag(task, TIF_RDS);
-+ break;
-+ case PR_SPEC_DISABLE:
-+ task_set_spec_ssb_disable(task);
-+ update = !test_and_set_tsk_thread_flag(task, TIF_RDS);
-+ break;
-+ case PR_SPEC_FORCE_DISABLE:
-+ task_set_spec_ssb_disable(task);
-+ task_set_spec_ssb_force_disable(task);
-+ update = !test_and_set_tsk_thread_flag(task, TIF_RDS);
-+ break;
-+ default:
-+ return -ERANGE;
-+ }
-
- /*
- * If being set on non-current task, delay setting the CPU
- * mitigation until it is next scheduled.
- */
-- if (task == current && rds != !!test_tsk_thread_flag(task, TIF_RDS))
-+ if (task == current && update)
- speculative_store_bypass_update();
-
- return 0;
-@@ -558,7 +574,9 @@ static int ssb_prctl_get(struct task_struct *task)
- case SPEC_STORE_BYPASS_DISABLE:
- return PR_SPEC_DISABLE;
- case SPEC_STORE_BYPASS_PRCTL:
-- if (test_tsk_thread_flag(task, TIF_RDS))
-+ if (task_spec_ssb_force_disable(task))
-+ return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE;
-+ if (task_spec_ssb_disable(task))
- return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
- return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
- default:
-@@ -571,9 +589,6 @@ static int ssb_prctl_get(struct task_struct *task)
- int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which,
- unsigned long ctrl)
- {
-- if (ctrl != PR_SPEC_ENABLE && ctrl != PR_SPEC_DISABLE)
-- return -ERANGE;
--
- switch (which) {
- case PR_SPEC_STORE_BYPASS:
- return ssb_prctl_set(task, ctrl);
-diff --git a/fs/proc/array.c b/fs/proc/array.c
-index 64f3f20..3e37195 100644
---- a/fs/proc/array.c
-+++ b/fs/proc/array.c
-@@ -355,6 +355,9 @@ static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
- case PR_SPEC_NOT_AFFECTED:
- seq_printf(m, "not vulnerable");
- break;
-+ case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
-+ seq_printf(m, "thread force mitigated");
-+ break;
- case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
- seq_printf(m, "thread mitigated");
- break;
-diff --git a/include/linux/sched.h b/include/linux/sched.h
-index 75d9a57..8e127a3 100644
---- a/include/linux/sched.h
-+++ b/include/linux/sched.h
-@@ -2335,6 +2335,8 @@ static inline void memalloc_noio_restore(unsigned int flags)
- #define PFA_SPREAD_PAGE 1 /* Spread page cache over cpuset */
- #define PFA_SPREAD_SLAB 2 /* Spread some slab caches over cpuset */
- #define PFA_LMK_WAITING 3 /* Lowmemorykiller is waiting */
-+#define PFA_SPEC_SSB_DISABLE 4 /* Speculative Store Bypass disabled */
-+#define PFA_SPEC_SSB_FORCE_DISABLE 5 /* Speculative Store Bypass force disabled*/
-
-
- #define TASK_PFA_TEST(name, func) \
-@@ -2361,6 +2363,13 @@ TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
- TASK_PFA_TEST(LMK_WAITING, lmk_waiting)
- TASK_PFA_SET(LMK_WAITING, lmk_waiting)
-
-+TASK_PFA_TEST(SPEC_SSB_DISABLE, spec_ssb_disable)
-+TASK_PFA_SET(SPEC_SSB_DISABLE, spec_ssb_disable)
-+TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
-+
-+TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
-+TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
-+
- /*
- * task->jobctl flags
- */
-diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
-index 3b316be..64776b7 100644
---- a/include/uapi/linux/prctl.h
-+++ b/include/uapi/linux/prctl.h
-@@ -207,5 +207,6 @@ struct prctl_mm_map {
- # define PR_SPEC_PRCTL (1UL << 0)
- # define PR_SPEC_ENABLE (1UL << 1)
- # define PR_SPEC_DISABLE (1UL << 2)
-+# define PR_SPEC_FORCE_DISABLE (1UL << 3)
-
- #endif /* _LINUX_PRCTL_H */
---
-2.7.4
-
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-19 11:08:19 +0000