From: Oleg Nesterov <oleg@redhat.com>
To: Tavis Ormandy <taviso@google.com>, Borislav Petkov <bp@alien8.de>,
Ingo Molnar <mingo@kernel.org>
Cc: Rik van Riel <riel@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths
Date: Mon, 2 Mar 2015 19:32:57 +0100 [thread overview]
Message-ID: <20150302183257.GC23085@redhat.com> (raw)
In-Reply-To: <20150302183210.GA23085@redhat.com>
fx_finit() has 2 users but only fpu_finit() needs to nullify xstate,
alloc_bootmem_align() in setup_init_fpu_buf() returns zero-filled
memory.
And note that both memset()'s look confusing. Yes, offsetof() is 0
for ->fxsave or ->fsave, but it would be more clean to turn them into
a single memset() which nullifies fpu->state.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
arch/x86/include/asm/fpu-internal.h | 1 -
arch/x86/kernel/i387.c | 3 ++-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 02f2e08..8809b5a 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -107,7 +107,6 @@ static __always_inline __pure bool use_fxsr(void)
static inline void fx_finit(struct i387_fxsave_struct *fx)
{
- memset(fx, 0, xstate_size);
fx->cwd = 0x37f;
fx->mxcsr = MXCSR_DEFAULT;
}
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 4b12df8..9b7759f 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -224,11 +224,12 @@ void fpu_finit(struct fpu *fpu)
return;
}
+ memset(fpu->state, 0, xstate_size);
+
if (cpu_has_fxsr) {
fx_finit(&fpu->state->fxsave);
} else {
struct i387_fsave_struct *fp = &fpu->state->fsave;
- memset(fp, 0, xstate_size);
fp->cwd = 0xffff037fu;
fp->swd = 0xffff0000u;
fp->twd = 0xffffffffu;
--
1.5.5.1
next prev parent reply other threads:[~2015-03-02 18:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAJ_zFkJkHpU4Y8wrrZjO0VnhzUVqJfyrLmNfRsBRT29bgbDSHg@mail.gmail.com>
[not found] ` <20150301184650.GA12758@redhat.com>
[not found] ` <20150301185943.GA14318@redhat.com>
[not found] ` <20150302174818.GA16886@redhat.com>
2015-03-02 18:32 ` [PATCH 0/2] x86/fpu: minor cleanups Oleg Nesterov
2015-03-02 18:32 ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
2015-03-03 19:23 ` Rik van Riel
2015-03-04 10:30 ` Borislav Petkov
2015-03-10 10:08 ` [tip:x86/fpu] x86/fpu: Change xstateregs_get()/set() to use -> xsave.i387 " tip-bot for Oleg Nesterov
2015-03-02 18:32 ` Oleg Nesterov [this message]
2015-03-03 22:01 ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Rik van Riel
2015-03-04 11:38 ` Borislav Petkov
2015-03-10 10:08 ` [tip:x86/fpu] x86/fpu: Factor out memset(xstate, 0) in fpu_finit( ) paths tip-bot for Oleg Nesterov
2015-03-09 18:08 [GIT PULL] x86/fpu cleanups Borislav Petkov
2015-03-10 6:06 ` [PATCH 1/2] x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave Borislav Petkov
2015-03-10 6:06 ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Borislav Petkov
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