From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, "Andy Lutomirski" <luto@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>,
"Rik van Riel" <riel@surriel.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: [PATCH 09/29] x86/fpu: Remove fpu__restore()
Date: Wed, 28 Nov 2018 23:20:15 +0100 [thread overview]
Message-ID: <20181128222035.2996-10-bigeasy@linutronix.de> (raw)
In-Reply-To: <20181128222035.2996-1-bigeasy@linutronix.de>
There are no users of fpu__restore() so it is time to remove it.
The comment regarding fpu__restore() and TS bit is stale since commit
b3b0870ef3ffe ("i387: do not preload FPU state at task switch time")
and has no meaning since.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
Documentation/preempt-locking.txt | 1 -
arch/x86/include/asm/fpu/internal.h | 1 -
arch/x86/kernel/fpu/core.c | 24 ------------------------
arch/x86/kernel/process_32.c | 4 +---
arch/x86/kernel/process_64.c | 4 +---
5 files changed, 2 insertions(+), 32 deletions(-)
diff --git a/Documentation/preempt-locking.txt b/Documentation/preempt-locking.txt
index 509f5a422d571..dce336134e54a 100644
--- a/Documentation/preempt-locking.txt
+++ b/Documentation/preempt-locking.txt
@@ -52,7 +52,6 @@ preemption must be disabled around such regions.
Note, some FPU functions are already explicitly preempt safe. For example,
kernel_fpu_begin and kernel_fpu_end will disable and enable preemption.
-However, fpu__restore() must be called with preemption disabled.
RULE #3: Lock acquire and release must be performed by same task
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 978a1633c0698..415d43bdaaa76 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -28,7 +28,6 @@ extern void fpu__initialize(struct fpu *fpu);
extern void fpu__prepare_read(struct fpu *fpu);
extern void fpu__prepare_write(struct fpu *fpu);
extern void fpu__save(struct fpu *fpu);
-extern void fpu__restore(struct fpu *fpu);
extern int fpu__restore_sig(void __user *buf, int ia32_frame);
extern void fpu__drop(struct fpu *fpu);
extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 2e5003fef51a9..1d3ae7988f7f2 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -303,30 +303,6 @@ void fpu__prepare_write(struct fpu *fpu)
}
}
-/*
- * 'fpu__restore()' is called to copy FPU registers from
- * the FPU fpstate to the live hw registers and to activate
- * access to the hardware registers, so that FPU instructions
- * can be used afterwards.
- *
- * Must be called with kernel preemption disabled (for example
- * with local interrupts disabled, as it is in the case of
- * do_device_not_available()).
- */
-void fpu__restore(struct fpu *fpu)
-{
- fpu__initialize(fpu);
-
- /* Avoid __kernel_fpu_begin() right after fpregs_activate() */
- kernel_fpu_disable();
- trace_x86_fpu_before_restore(fpu);
- fpregs_activate(fpu);
- copy_kernel_to_fpregs(&fpu->state);
- trace_x86_fpu_after_restore(fpu);
- kernel_fpu_enable();
-}
-EXPORT_SYMBOL_GPL(fpu__restore);
-
/*
* Drops current FPU state: deactivates the fpregs and
* the fpstate. NOTE: it still leaves previous contents
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 1bf5b5830e81a..b8a935adc96fc 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -271,9 +271,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Leave lazy mode, flushing any hypercalls made here.
* This must be done before restoring TLS segments so
- * the GDT and LDT are properly updated, and must be
- * done before fpu__restore(), so the TS bit is up
- * to date.
+ * the GDT and LDT are properly updated.
*/
arch_end_context_switch(next_p);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 0e0b4288a4b2b..cf2c157714594 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -576,9 +576,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Leave lazy mode, flushing any hypercalls made here. This
* must be done after loading TLS entries in the GDT but before
- * loading segments that might reference them, and and it must
- * be done before fpu__restore(), so the TS bit is up to
- * date.
+ * loading segments that might reference them.
*/
arch_end_context_switch(next_p);
--
2.20.0.rc1
next prev parent reply other threads:[~2018-11-28 22:20 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 22:20 [PATCH v5] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 01/29] x86/fpu: Use ULL for shift in xfeature_uncompacted_offset() Sebastian Andrzej Siewior
2018-11-29 1:52 ` Rik van Riel
2018-12-03 21:00 ` [tip:x86/fpu] x86/fpu: Use unsigned long long " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 02/29] x86/entry/32: Remove asm/math_emu.h include Sebastian Andrzej Siewior
2018-11-29 1:52 ` Rik van Riel
2018-12-03 21:01 ` [tip:x86/fpu] x86/process/32: " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 03/29] x86/entry: Remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-11-29 1:53 ` Rik van Riel
2018-12-03 21:02 ` [tip:x86/fpu] x86/thread_info: " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 04/29] x86/pkeys: Make init_pkru_value static Sebastian Andrzej Siewior
2018-11-29 1:53 ` Rik van Riel
2018-12-03 21:02 ` [tip:x86/fpu] " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 05/29] x86/fpu: add might_fault() to user_insn() Sebastian Andrzej Siewior
2018-11-29 1:54 ` Rik van Riel
2018-12-03 21:03 ` [tip:x86/fpu] x86/fpu: Add " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 06/29] x86/fpu: Update comment for __raw_xsave_addr() Sebastian Andrzej Siewior
2018-11-29 1:56 ` Rik van Riel
2018-12-03 21:03 ` [tip:x86/fpu] " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 07/29] x86/fpu: don't export __kernel_fpu_{begin|end}() Sebastian Andrzej Siewior
2018-11-29 2:00 ` Rik van Riel
2018-11-29 15:02 ` [PATCH 07/29 v2] " Sebastian Andrzej Siewior
2018-12-03 21:04 ` [tip:x86/fpu] x86/fpu: Don't export __kernel_fpu_{begin,end}() tip-bot for Sebastian Andrzej Siewior
2018-12-03 21:12 ` Ard Biesheuvel
2018-12-03 22:08 ` Borislav Petkov
2018-12-04 11:39 ` Borislav Petkov
2018-12-04 12:15 ` Sebastian Andrzej Siewior
2018-12-04 12:33 ` Borislav Petkov
2018-12-04 11:45 ` tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 08/29] x86/fpu: Remove fpu->initialized usage in __fpu__restore_sig() Sebastian Andrzej Siewior
2018-12-06 20:07 ` Borislav Petkov
2018-12-07 8:17 ` Sebastian Andrzej Siewior
2018-12-07 10:19 ` Borislav Petkov
2018-11-28 22:20 ` Sebastian Andrzej Siewior [this message]
2018-11-28 22:20 ` [PATCH 10/29] x86/fpu: Remove preempt_disable() in fpu__clear() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 11/29] x86/fpu: Always init the `state' " Sebastian Andrzej Siewior
2018-12-12 17:11 ` Borislav Petkov
2018-12-13 14:35 ` Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 12/29] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 13/29] x86/fpu: Don't save fxregs for ia32 frames " Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 14/29] x86/fpu: Remove fpu->initialized Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 15/29] x86/fpu: Remove user_fpu_begin() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 16/29] x86/fpu: Add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 17/29] x86/fpu: Make __raw_xsave_addr() use feature number instead of mask Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 18/29] x86/fpu: Make get_xsave_field_ptr() and get_xsave_addr() " Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 19/29] x86/fpu: Only write PKRU if it is different from current Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 20/29] x86/pkeys: Don't check if PKRU is zero before writting it Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 21/29] x86/fpu: Eager switch PKRU state Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 22/29] x86/entry: Add TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 23/29] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 24/29] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 25/29] x86/fpu: Update xstate's PKRU value on write_pkru() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 26/29] x86/fpu: Inline copy_user_to_fpregs_zeroing() Sebastian Andrzej Siewior
2018-11-28 23:09 ` Joey Pabalinas
2018-11-28 22:20 ` [PATCH 27/29] x86/fpu: Let __fpu__restore_sig() restore the !32bit+fxsr frame from kernel memory Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 28/29] x86/fpu: Merge the two code paths in __fpu__restore_sig() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 29/29] x86/fpu: Defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-11-29 15:00 ` Sebastian Andrzej Siewior
2018-12-10 14:41 ` Sebastian Andrzej Siewior
2018-11-30 11:52 ` [PATCH v5] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
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