From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755898AbbHFRyt (ORCPT ); Thu, 6 Aug 2015 13:54:49 -0400 Received: from mx2.suse.de ([195.135.220.15]:52774 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755829AbbHFRyr (ORCPT ); Thu, 6 Aug 2015 13:54:47 -0400 From: Juergen Gross To: billm@melbpc.org.au, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, luto@kernel.org Cc: Juergen Gross , Subject: [Patch V4] x86/ldt: correct fpu emulation access to ldt Date: Thu, 6 Aug 2015 19:54:34 +0200 Message-Id: <1438883674-1240-1-git-send-email-jgross@suse.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 37868fe113ff ("x86/ldt: Make modify_ldt synchronous") introduced a new struct ldt_struct anchored at mm->context.ldt. Adapt the x86 fpu emulation to use that new structure. Cc: # 37868fe113ff: x86/ldt: Make modify_ldt synchronous Cc: # a5b9e5a2f14f: x86/ldt: Make modify_ldt optional Signed-off-by: Juergen Gross --- arch/x86/math-emu/fpu_entry.c | 3 +-- arch/x86/math-emu/fpu_system.h | 21 ++++++++++++++++++--- arch/x86/math-emu/get_address.c | 3 +-- 3 files changed, 20 insertions(+), 7 deletions(-) diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index f37e84a..3d8f2e4 100644 --- a/arch/x86/math-emu/fpu_entry.c +++ b/arch/x86/math-emu/fpu_entry.c @@ -29,7 +29,6 @@ #include #include -#include #include #include @@ -181,7 +180,7 @@ void math_emulate(struct math_emu_info *info) math_abort(FPU_info, SIGILL); } - code_descriptor = LDT_DESCRIPTOR(FPU_CS); + code_descriptor = FPU_get_ldt_descriptor(FPU_CS); if (SEG_D_SIZE(code_descriptor)) { /* The above test may be wrong, the book is not clear */ /* Segmented 32 bit protected mode */ diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h index 9ccecb6..5e044d5 100644 --- a/arch/x86/math-emu/fpu_system.h +++ b/arch/x86/math-emu/fpu_system.h @@ -16,9 +16,24 @@ #include #include -/* s is always from a cpu register, and the cpu does bounds checking - * during register load --> no further bounds checks needed */ -#define LDT_DESCRIPTOR(s) (((struct desc_struct *)current->mm->context.ldt)[(s) >> 3]) +#include +#include + +static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg) +{ + static struct desc_struct zero_desc; + struct desc_struct ret = zero_desc; + +#ifdef CONFIG_MODIFY_LDT_SYSCALL + seg >>= 3; + mutex_lock(¤t->mm->context.lock); + if (current->mm->context.ldt && seg < current->mm->context.ldt->size) + ret = current->mm->context.ldt->entries[seg]; + mutex_unlock(¤t->mm->context.lock); +#endif + return ret; +} + #define SEG_D_SIZE(x) ((x).b & (3 << 21)) #define SEG_G_BIT(x) ((x).b & (1 << 23)) #define SEG_GRANULARITY(x) (((x).b & (1 << 23)) ? 4096 : 1) diff --git a/arch/x86/math-emu/get_address.c b/arch/x86/math-emu/get_address.c index 6ef5e99..d13cab2 100644 --- a/arch/x86/math-emu/get_address.c +++ b/arch/x86/math-emu/get_address.c @@ -20,7 +20,6 @@ #include #include -#include #include "fpu_system.h" #include "exception.h" @@ -158,7 +157,7 @@ static long pm_address(u_char FPU_modrm, u_char segment, addr->selector = PM_REG_(segment); } - descriptor = LDT_DESCRIPTOR(PM_REG_(segment)); + descriptor = FPU_get_ldt_descriptor(segment); base_address = SEG_BASE_ADDR(descriptor); address = base_address + offset; limit = base_address -- 2.1.4