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[PATCH v5 16/32] x86: Move uaccess_err and sig_on_uaccess_err to thread_struct

From Andy Lutomirski <luto@kernel.org>
Newsgroups linux.kernel
Subject [PATCH v5 16/32] x86: Move uaccess_err and sig_on_uaccess_err to thread_struct
Date 2016-07-11 23:00 +0200
Message-ID <rTQt5-3Fx-57@gated-at.bofh.it> (permalink)
References <rTQt3-3Fx-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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 76c58fdcfb29..c4c8b4938e93 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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Thread

[PATCH v5 00/32] virtually mapped stacks and thread_info cleanup Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 18/32] signal: Consolidate {TS,TLF}_RESTORE_SIGMASK code Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
    Re: [PATCH v5 18/32] signal: Consolidate {TS,TLF}_RESTORE_SIGMASK code Brian Gerst <brgerst@gmail.com> - 2016-07-12 14:00 +0200
      Re: [PATCH v5 18/32] signal: Consolidate {TS,TLF}_RESTORE_SIGMASK code Andy Lutomirski <luto@amacapital.net> - 2016-07-13 01:10 +0200
  [PATCH v5 08/32] dma-api: Teach the "DMA-from-stack" check about vmapped stacks Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 32/32] fork: Cache two thread stacks per cpu if CONFIG_VMAP_STACK is set Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 27/32] x86: Move thread_info into task_struct Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 31/32] sched: Free the stack early if CONFIG_THREAD_INFO_IN_TASK Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 23/32] printk: When dumping regs, show the stack, not thread_info Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 19/32] x86/smp: Remove stack_smp_processor_id() Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 20/32] x86/smp: Remove unnecessary initialization of thread_info::cpu Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 16/32] x86: Move uaccess_err and sig_on_uaccess_err to thread_struct Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:00 +0200
  [PATCH v5 04/32] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 01/32] bluetooth: Switch SMP to crypto_cipher_encrypt_one() Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
    Re: [PATCH v5 01/32] bluetooth: Switch SMP to crypto_cipher_encrypt_one() Andy Lutomirski <luto@amacapital.net> - 2016-07-14 21:20 +0200
      Re: [PATCH v5 01/32] bluetooth: Switch SMP to crypto_cipher_encrypt_one() Marcel Holtmann <marcel@holtmann.org> - 2016-07-14 22:40 +0200
      Re: [PATCH v5 01/32] bluetooth: Switch SMP to  crypto_cipher_encrypt_one() David Miller <davem@davemloft.net> - 2016-07-14 22:50 +0200
  [PATCH v5 05/32] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 12/32] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 06/32] mm: Fix memcg stack accounting for sub-page stacks Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 03/32] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
    Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Valdis.Kletnieks@vt.edu - 2016-07-22 06:50 +0200
      Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd,  don't set the pgd entry until it's populated Andy Lutomirski <luto@kernel.org> - 2016-07-22 07:40 +0200
        Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd,  don't set the pgd entry until it's populated Ingo Molnar <mingo@kernel.org> - 2016-07-22 12:30 +0200
          Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd,  don't set the pgd entry until it's populated Andy Lutomirski <luto@amacapital.net> - 2016-07-22 20:30 +0200
            Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd,  don't set the pgd entry until it's populated Andy Lutomirski <luto@amacapital.net> - 2016-07-22 20:40 +0200
            Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd,  don't set the pgd entry until it's populated Ingo Molnar <mingo@kernel.org> - 2016-07-22 22:20 +0200
        Re: [kernel-hardening] [PATCH v5 03/32] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Nicolai Stange <nicstange@gmail.com> - 2016-07-23 17:00 +0200
  [PATCH v5 10/32] x86/dumpstack: Honor supplied @regs arg Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 02/32] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 15/32] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  [PATCH v5 11/32] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski <luto@kernel.org> - 2016-07-11 23:10 +0200
  Re: [PATCH v5 00/32] virtually mapped stacks and thread_info cleanup Herbert Xu <herbert@gondor.apana.org.au> - 2016-07-12 11:00 +0200
  Re: [PATCH v5 00/32] virtually mapped stacks and thread_info cleanup Christian Borntraeger <borntraeger@de.ibm.com> - 2016-07-13 11:00 +0200
    Re: [PATCH v5 00/32] virtually mapped stacks and thread_info cleanup Andy Lutomirski <luto@amacapital.net> - 2016-07-13 20:40 +0200
      Re: [PATCH v5 00/32] virtually mapped stacks and thread_info cleanup Christian Borntraeger <borntraeger@de.ibm.com> - 2016-07-13 21:00 +0200

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