From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de,
luto@kernel.org
Cc: hpa@zytor.com, dave.hansen@intel.com, tony.luck@intel.com,
ak@linux.intel.com, ravi.v.shankar@intel.com,
chang.seok.bae@intel.com
Subject: [PATCH v9 12/17] x86/fsgsbase/64: Use FSGSBASE instructions on thread copy and ptrace
Date: Fri, 4 Oct 2019 11:16:04 -0700 [thread overview]
Message-ID: <1570212969-21888-13-git-send-email-chang.seok.bae@intel.com> (raw)
In-Reply-To: <1570212969-21888-1-git-send-email-chang.seok.bae@intel.com>
When FSGSBASE is enabled, copying threads and reading FS/GS base using
ptrace must read the actual values.
When copying a thread, use fsgs_save() and copy the saved values. For
ptrace, the bases must be read from memory regardless of the selector
if FSGSBASE is enabled.
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
---
Changes from v8: none
Changes from v7:
* No code change
* Massaged changelog by Andy Lutomirski
---
arch/x86/kernel/process_64.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 56c0e5b..b67f656 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -415,7 +415,8 @@ unsigned long x86_fsbase_read_task(struct task_struct *task)
if (task == current)
fsbase = x86_fsbase_read_cpu();
- else if (task->thread.fsindex == 0)
+ else if (static_cpu_has(X86_FEATURE_FSGSBASE) ||
+ (task->thread.fsindex == 0))
fsbase = task->thread.fsbase;
else
fsbase = x86_fsgsbase_read_task(task, task->thread.fsindex);
@@ -429,7 +430,8 @@ unsigned long x86_gsbase_read_task(struct task_struct *task)
if (task == current)
gsbase = x86_gsbase_read_cpu_inactive();
- else if (task->thread.gsindex == 0)
+ else if (static_cpu_has(X86_FEATURE_FSGSBASE) ||
+ (task->thread.gsindex == 0))
gsbase = task->thread.gsbase;
else
gsbase = x86_fsgsbase_read_task(task, task->thread.gsindex);
@@ -469,10 +471,11 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
p->thread.sp = (unsigned long) fork_frame;
p->thread.io_bitmap_ptr = NULL;
- savesegment(gs, p->thread.gsindex);
- p->thread.gsbase = p->thread.gsindex ? 0 : me->thread.gsbase;
- savesegment(fs, p->thread.fsindex);
- p->thread.fsbase = p->thread.fsindex ? 0 : me->thread.fsbase;
+ save_fsgs(me);
+ p->thread.fsindex = me->thread.fsindex;
+ p->thread.fsbase = me->thread.fsbase;
+ p->thread.gsindex = me->thread.gsindex;
+ p->thread.gsbase = me->thread.gsbase;
savesegment(es, p->thread.es);
savesegment(ds, p->thread.ds);
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
--
2.7.4
next prev parent reply other threads:[~2019-10-04 18:17 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 18:15 [PATCH v9 00/17] Enable FSGSBASE instructions Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 01/17] x86/ptrace: Prevent ptrace from clearing the FS/GS selector Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 02/17] selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 03/17] x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 04/17] x86/entry/64: Clean up paranoid exit Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 05/17] x86/entry/64: Switch CR3 before SWAPGS in paranoid entry Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 06/17] x86/entry/64: Introduce the FIND_PERCPU_BASE macro Chang S. Bae
2019-10-04 18:15 ` [PATCH v9 07/17] x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 08/17] x86/entry/64: Document GSBASE handling in the paranoid path Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 09/17] x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 10/17] x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 11/17] x86/fsgsbase/64: Use FSGSBASE in switch_to() if available Chang S. Bae
2019-10-04 18:16 ` Chang S. Bae [this message]
2019-10-04 18:16 ` [PATCH v9 13/17] x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 14/17] selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 15/17] x86/fsgsbase/64: Enable FSGSBASE on 64bit by default and add a chicken bit Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 16/17] x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 Chang S. Bae
2019-10-04 18:16 ` [PATCH v9 17/17] Documentation/x86/64: Add documentation for GS/FS addressing mode Chang S. Bae
2019-10-04 22:54 ` Randy Dunlap
2019-11-15 18:29 ` [PATCH v9 00/17] Enable FSGSBASE instructions Thomas Gleixner
2019-11-15 19:12 ` Andi Kleen
2019-11-29 14:56 ` Metzger, Markus T
2019-11-29 16:51 ` Andy Lutomirski
2019-12-02 8:23 ` Metzger, Markus T
2019-12-04 20:20 ` Andy Lutomirski
2019-12-10 8:27 ` Metzger, Markus T
2020-02-24 18:02 ` Bae, Chang Seok
2020-04-13 20:03 ` Sasha Levin
2020-04-14 0:32 ` Andi Kleen
2020-04-17 13:30 ` Sasha Levin
2020-04-17 15:52 ` Andy Lutomirski
2020-04-20 14:13 ` Andi Kleen
2020-04-20 17:14 ` Thomas Gleixner
2020-04-21 16:06 ` Sasha Levin
2020-04-21 16:49 ` Andy Lutomirski
2020-04-21 20:02 ` Andi Kleen
2020-04-21 17:15 ` Bae, Chang Seok
2020-04-21 19:56 ` Andi Kleen
2020-04-21 20:21 ` Andy Lutomirski
2020-04-21 20:51 ` Sasha Levin
2020-04-22 23:00 ` Andy Lutomirski
2020-04-23 4:08 ` Sasha Levin
2020-04-25 22:39 ` Thomas Gleixner
2020-04-26 2:52 ` Sasha Levin
2020-04-26 10:04 ` Thomas Gleixner
2020-04-14 15:47 ` Bae, Chang Seok
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