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Message-Id: <9eeb4be3c4e91d4155d0c4c234858f4259c5993d.1466974736.git.luto@kernel.org>
Date: Sun, 26 Jun 2016 14:55:44 -0700
From: Andy Lutomirski <luto@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
Borislav Petkov <bp@...en8.de>,
Nadav Amit <nadav.amit@...il.com>,
Kees Cook <keescook@...omium.org>,
Brian Gerst <brgerst@...il.com>,
"kernel-hardening@...ts.openwall.com"
<kernel-hardening@...ts.openwall.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Jann Horn <jann@...jh.net>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v4 22/29] x86/asm: Move 'status' from struct thread_info to struct thread_struct
Becuase sched.h and thread_info.h are a tangled mess, I turned
in_compat_syscall into a macro. If we had current_thread_struct()
or similar and we could use it from thread_info.h, then this would
be a bit cleaner.
Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
arch/x86/entry/common.c | 4 ++--
arch/x86/include/asm/processor.h | 12 ++++++++++++
arch/x86/include/asm/syscall.h | 23 +++++------------------
arch/x86/include/asm/thread_info.h | 23 ++++-------------------
arch/x86/kernel/asm-offsets.c | 1 -
arch/x86/kernel/fpu/init.c | 1 -
arch/x86/kernel/process_64.c | 4 ++--
arch/x86/kernel/ptrace.c | 2 +-
8 files changed, 26 insertions(+), 44 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index ec138e538c44..c4150bec7982 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -271,7 +271,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
* syscalls. The fixup is exercised by the ptrace_syscall_32
* selftest.
*/
- ti->status &= ~TS_COMPAT;
+ current->thread.status &= ~TS_COMPAT;
#endif
user_enter();
@@ -369,7 +369,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
unsigned int nr = (unsigned int)regs->orig_ax;
#ifdef CONFIG_IA32_EMULATION
- ti->status |= TS_COMPAT;
+ current->thread.status |= TS_COMPAT;
#endif
if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a2e20d6d01fe..a75e720f6402 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -388,6 +388,9 @@ struct thread_struct {
unsigned short fsindex;
unsigned short gsindex;
#endif
+
+ u32 status; /* thread synchronous flags */
+
#ifdef CONFIG_X86_32
unsigned long ip;
#endif
@@ -437,6 +440,15 @@ struct thread_struct {
};
/*
+ * Thread-synchronous status.
+ *
+ * This is different from the flags in that nobody else
+ * ever touches our thread-synchronous status, so we don't
+ * have to worry about atomic accesses.
+ */
+#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/
+
+/*
* Set IOPL bits in EFLAGS from given mask
*/
static inline void native_set_iopl_mask(unsigned mask)
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 999b7cd2e78c..17229e7e2a1c 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -60,7 +60,7 @@ static inline long syscall_get_error(struct task_struct *task,
* TS_COMPAT is set for 32-bit syscall entries and then
* remains set until we return to user mode.
*/
- if (task_thread_info(task)->status & TS_COMPAT)
+ if (task->thread.status & TS_COMPAT)
/*
* Sign-extend the value so (int)-EFOO becomes (long)-EFOO
* and will match correctly in comparisons.
@@ -116,7 +116,7 @@ static inline void syscall_get_arguments(struct task_struct *task,
unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
- if (task_thread_info(task)->status & TS_COMPAT)
+ if (task->thread.status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
@@ -177,7 +177,7 @@ static inline void syscall_set_arguments(struct task_struct *task,
const unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
- if (task_thread_info(task)->status & TS_COMPAT)
+ if (task->thread.status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
@@ -234,21 +234,8 @@ static inline void syscall_set_arguments(struct task_struct *task,
static inline int syscall_get_arch(void)
{
-#ifdef CONFIG_IA32_EMULATION
- /*
- * TS_COMPAT is set for 32-bit syscall entry and then
- * remains set until we return to user mode.
- *
- * TIF_IA32 tasks should always have TS_COMPAT set at
- * system call time.
- *
- * x32 tasks should be considered AUDIT_ARCH_X86_64.
- */
- if (task_thread_info(current)->status & TS_COMPAT)
- return AUDIT_ARCH_I386;
-#endif
- /* Both x32 and x86_64 are considered "64-bit". */
- return AUDIT_ARCH_X86_64;
+ /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
+ return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
}
#endif /* CONFIG_X86_32 */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index b45ffdda3549..7b42c1e462ac 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -55,7 +55,6 @@ struct task_struct;
struct thread_info {
struct task_struct *task; /* main task structure */
__u32 flags; /* low level flags */
- __u32 status; /* thread synchronous flags */
__u32 cpu; /* current CPU */
};
@@ -211,28 +210,14 @@ static inline unsigned long current_stack_pointer(void)
#endif
-/*
- * Thread-synchronous status.
- *
- * This is different from the flags in that nobody else
- * ever touches our thread-synchronous status, so we don't
- * have to worry about atomic accesses.
- */
-#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/
-
#ifndef __ASSEMBLY__
-static inline bool in_ia32_syscall(void)
-{
#ifdef CONFIG_X86_32
- return true;
-#endif
-#ifdef CONFIG_IA32_EMULATION
- if (current_thread_info()->status & TS_COMPAT)
- return true;
+#define in_ia32_syscall() true
+#else
+#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
+ current->thread.status & TS_COMPAT)
#endif
- return false;
-}
/*
* Force syscall return via IRET by making it look as if there was
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 2bd5c6ff7ee7..a91a6ead24a2 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -30,7 +30,6 @@
void common(void) {
BLANK();
OFFSET(TI_flags, thread_info, flags);
- OFFSET(TI_status, thread_info, status);
BLANK();
OFFSET(TASK_addr_limit, task_struct, thread.addr_limit);
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index aacfd7a82cec..4579c1544ed1 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -327,7 +327,6 @@ static void __init fpu__init_system_ctx_switch(void)
on_boot_cpu = 0;
WARN_ON_FPU(current->thread.fpu.fpstate_active);
- current_thread_info()->status = 0;
if (boot_cpu_has(X86_FEATURE_XSAVEOPT) && eagerfpu != DISABLE)
eagerfpu = ENABLE;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6e789ca1f841..e6d53b641ef0 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -511,7 +511,7 @@ void set_personality_ia32(bool x32)
current->personality &= ~READ_IMPLIES_EXEC;
/* in_compat_syscall() uses the presence of the x32
syscall bit flag to determine compat status */
- current_thread_info()->status &= ~TS_COMPAT;
+ current->thread.status &= ~TS_COMPAT;
} else {
set_thread_flag(TIF_IA32);
clear_thread_flag(TIF_X32);
@@ -519,7 +519,7 @@ void set_personality_ia32(bool x32)
current->mm->context.ia32_compat = TIF_IA32;
current->personality |= force_personality32;
/* Prepare the first "return" to user space */
- current_thread_info()->status |= TS_COMPAT;
+ current->thread.status |= TS_COMPAT;
}
}
EXPORT_SYMBOL_GPL(set_personality_ia32);
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 600edd225e81..4f03301ecfbe 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -931,7 +931,7 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value)
*/
regs->orig_ax = value;
if (syscall_get_nr(child, regs) >= 0)
- task_thread_info(child)->status |= TS_COMPAT;
+ child->thread.status |= TS_COMPAT;
break;
case offsetof(struct user32, regs.eflags):
--
2.7.4
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