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Subject[PATCH 08/11] x86: Move uaccess_err and sig_on_uaccess_err to thread_struct
Date
thread_info is a legacy mess.  To prepare for its partial removal,
move the uaccess control fields out -- they're straightforward.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/vsyscall/vsyscall_64.c | 6 +++---
arch/x86/include/asm/processor.h | 3 +++
arch/x86/include/asm/thread_info.h | 2 --
arch/x86/include/asm/uaccess.h | 4 ++--
arch/x86/mm/extable.c | 2 +-
arch/x86/mm/fault.c | 2 +-
6 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 174c2549939d..3aba2b043050 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -221,8 +221,8 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
* With a real vsyscall, page faults cause SIGSEGV. We want to
* preserve that behavior to make writing exploits harder.
*/
- prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
- current_thread_info()->sig_on_uaccess_error = 1;
+ prev_sig_on_uaccess_error = current->thread.sig_on_uaccess_error;
+ current->thread.sig_on_uaccess_error = 1;

ret = -EFAULT;
switch (vsyscall_nr) {
@@ -243,7 +243,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
break;
}

- current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
+ current->thread.sig_on_uaccess_error = prev_sig_on_uaccess_error;

check_fault:
if (ret == -EFAULT) {
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 62c6cc3cc5d3..f53ae57bd985 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -419,6 +419,9 @@ struct thread_struct {
/* Max allowed port in the bitmap, in bytes: */
unsigned io_bitmap_max;

+ unsigned int sig_on_uaccess_error:1;
+ unsigned int uaccess_err:1; /* uaccess failed */
+
/* Floating point and extended processor state */
struct fpu fpu;
/*
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 30c133ac05cd..7c47bb659ecd 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -58,8 +58,6 @@ struct thread_info {
__u32 status; /* thread synchronous flags */
__u32 cpu; /* current CPU */
mm_segment_t addr_limit;
- unsigned int sig_on_uaccess_error:1;
- unsigned int uaccess_err:1; /* uaccess failed */
};

#define INIT_THREAD_INFO(tsk) \
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 2982387ba817..4d2a726e8e6d 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -468,13 +468,13 @@ struct __large_struct { unsigned long buf[100]; };
* uaccess_try and catch
*/
#define uaccess_try do { \
- current_thread_info()->uaccess_err = 0; \
+ current->thread.uaccess_err = 0; \
__uaccess_begin(); \
barrier();

#define uaccess_catch(err) \
__uaccess_end(); \
- (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \
+ (err) |= (current->thread.uaccess_err ? -EFAULT : 0); \
} while (0)

/**
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 4bb53b89f3c5..0f90cc218d04 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -37,7 +37,7 @@ bool ex_handler_ext(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
/* Special hack for uaccess_err */
- current_thread_info()->uaccess_err = 1;
+ current->thread.uaccess_err = 1;
regs->ip = ex_fixup_addr(fixup);
return true;
}
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index ca44e2e7fd00..69be03d4aca6 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -737,7 +737,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
* In this case we need to make sure we're not recursively
* faulting through the emulate_vsyscall() logic.
*/
- if (current_thread_info()->sig_on_uaccess_error && signal) {
+ if (current->thread.sig_on_uaccess_error && signal) {
tsk->thread.trap_nr = X86_TRAP_PF;
tsk->thread.error_code = error_code | PF_USER;
tsk->thread.cr2 = address;
--
2.7.4
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