Commit 5a1dc78a authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: Support thread fault code encoding. 



This provides a simple interface modelled after sparc64/m32r to encode
the error code in the upper byte of thread_info for finer-grained
handling in the page fault path.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent f007688a

arch/sh/include/asm/thread_info.h

+36 −10
Original line number Diff line number Diff line
@@ -10,8 +10,18 @@ 
 *  - Incorporating suggestions made by Linus Torvalds and Dave Miller

 */

#ifdef __KERNEL__



#include <asm/page.h>



/*

 * Page fault error code bits

 */

#define FAULT_CODE_WRITE	(1 << 0)	/* write access */

#define FAULT_CODE_INITIAL	(1 << 1)	/* initial page write */

#define FAULT_CODE_ITLB		(1 << 2)	/* ITLB miss */

#define FAULT_CODE_PROT		(1 << 3)	/* protection fault */

#define FAULT_CODE_USER		(1 << 4)	/* user-mode access */



#ifndef __ASSEMBLY__

#include <asm/processor.h>
@@ -107,10 +117,13 @@ extern void init_thread_xstate(void); 
#endif /* __ASSEMBLY__ */



/*

 * thread information flags

 * - these are process state flags that various assembly files may need to access

 * - pending work-to-be-done flags are in LSW

 * - other flags in MSW

 * Thread information flags

 *

 * - Limited to 24 bits, upper byte used for fault code encoding.

 *

 * - _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or

 *   we blow the tst immediate size constraints and need to fix up

 *   arch/sh/kernel/entry-common.S.

 */

#define TIF_SYSCALL_TRACE	0	/* syscall trace active */

#define TIF_SIGPENDING		1	/* signal pending */
@@ -133,12 +146,6 @@ extern void init_thread_xstate(void); 
#define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)

#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)



/*

 * _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or we

 * blow the tst immediate size constraints and need to fix up

 * arch/sh/kernel/entry-common.S.

 */



/* work to do in syscall trace */

#define _TIF_WORK_SYSCALL_MASK	(_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \

				 _TIF_SYSCALL_AUDIT | _TIF_SECCOMP    | \
@@ -165,6 +172,7 @@ extern void init_thread_xstate(void); 
#define TS_USEDFPU		0x0002	/* FPU used by this task this quantum */



#ifndef __ASSEMBLY__



#define HAVE_SET_RESTORE_SIGMASK	1

static inline void set_restore_sigmask(void)

{
@@ -172,6 +180,24 @@ static inline void set_restore_sigmask(void) 
	ti->status |= TS_RESTORE_SIGMASK;

	set_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags);

}



#define TI_FLAG_FAULT_CODE_SHIFT	24



/*

 * Additional thread flag encoding

 */

static inline void set_thread_fault_code(unsigned int val)

{

	struct thread_info *ti = current_thread_info();

	ti->flags = (ti->flags & (~0 >> (32 - TI_FLAG_FAULT_CODE_SHIFT)))

		| (val << TI_FLAG_FAULT_CODE_SHIFT);

}



static inline unsigned int get_thread_fault_code(void)

{

	struct thread_info *ti = current_thread_info();

	return ti->flags >> TI_FLAG_FAULT_CODE_SHIFT;

}

#endif	/* !__ASSEMBLY__ */



#endif /* __KERNEL__ */

arch/sh/kernel/cpu/sh3/entry.S

+6 −5
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 * arch/sh/kernel/cpu/sh3/entry.S

 *

 *  Copyright (C) 1999, 2000, 2002  Niibe Yutaka

 *  Copyright (C) 2003 - 2006  Paul Mundt

 *  Copyright (C) 2003 - 2012  Paul Mundt

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive
@@ -17,6 +17,7 @@ 
#include <cpu/mmu_context.h>

#include <asm/page.h>

#include <asm/cache.h>

#include <asm/thread_info.h>



! NOTE:

! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
@@ -114,22 +115,22 @@ ENTRY(tlb_miss_load) 
	.align	2

ENTRY(tlb_miss_store)

	bra	call_handle_tlbmiss

	 mov	#1, r5

	 mov	#FAULT_CODE_WRITE, r5



	.align	2

ENTRY(initial_page_write)

	bra	call_handle_tlbmiss

	 mov	#2, r5

	 mov	#FAULT_CODE_INITIAL, r5



	.align	2

ENTRY(tlb_protection_violation_load)

	bra	call_do_page_fault

	 mov	#0, r5

	 mov	#FAULT_CODE_PROT, r5



	.align	2

ENTRY(tlb_protection_violation_store)

	bra	call_do_page_fault

	 mov	#1, r5

	 mov	#(FAULT_CODE_PROT | FAULT_CODE_WRITE), r5



call_handle_tlbmiss:

	mov.l	1f, r0

arch/sh/mm/fault_32.c

+36 −32
Original line number Diff line number Diff line
@@ -211,7 +211,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long address) 
}



static noinline void

no_context(struct pt_regs *regs, unsigned long writeaccess,

no_context(struct pt_regs *regs, unsigned long error_code,

	   unsigned long address)

{

	/* Are we prepared to handle this kernel fault?  */
@@ -229,13 +229,13 @@ no_context(struct pt_regs *regs, unsigned long writeaccess, 


	show_fault_oops(regs, address);



	die("Oops", regs, writeaccess);

	die("Oops", regs, error_code);

	bust_spinlocks(0);

	do_exit(SIGKILL);

}



static void

__bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,

__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,

		       unsigned long address, int si_code)

{

	struct task_struct *tsk = current;
@@ -252,18 +252,18 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess, 
		return;

	}



	no_context(regs, writeaccess, address);

	no_context(regs, error_code, address);

}



static noinline void

bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,

bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,

		     unsigned long address)

{

	__bad_area_nosemaphore(regs, writeaccess, address, SEGV_MAPERR);

	__bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);

}



static void

__bad_area(struct pt_regs *regs, unsigned long writeaccess,

__bad_area(struct pt_regs *regs, unsigned long error_code,

	   unsigned long address, int si_code)

{

	struct mm_struct *mm = current->mm;
@@ -274,20 +274,20 @@ __bad_area(struct pt_regs *regs, unsigned long writeaccess, 
	 */

	up_read(&mm->mmap_sem);



	__bad_area_nosemaphore(regs, writeaccess, address, si_code);

	__bad_area_nosemaphore(regs, error_code, address, si_code);

}



static noinline void

bad_area(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)

bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)

{

	__bad_area(regs, writeaccess, address, SEGV_MAPERR);

	__bad_area(regs, error_code, address, SEGV_MAPERR);

}



static noinline void

bad_area_access_error(struct pt_regs *regs, unsigned long writeaccess,

bad_area_access_error(struct pt_regs *regs, unsigned long error_code,

		      unsigned long address)

{

	__bad_area(regs, writeaccess, address, SEGV_ACCERR);

	__bad_area(regs, error_code, address, SEGV_ACCERR);

}



static void out_of_memory(void)
@@ -302,7 +302,7 @@ static void out_of_memory(void) 
}



static void

do_sigbus(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)

do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)

{

	struct task_struct *tsk = current;

	struct mm_struct *mm = tsk->mm;
@@ -311,13 +311,13 @@ do_sigbus(struct pt_regs *regs, unsigned long writeaccess, unsigned long address 


	/* Kernel mode? Handle exceptions or die: */

	if (!user_mode(regs))

		no_context(regs, writeaccess, address);

		no_context(regs, error_code, address);



	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);

}



static noinline int

mm_fault_error(struct pt_regs *regs, unsigned long writeaccess,

mm_fault_error(struct pt_regs *regs, unsigned long error_code,

	       unsigned long address, unsigned int fault)

{

	/*
@@ -328,7 +328,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long writeaccess, 
		if (!(fault & VM_FAULT_RETRY))

			up_read(&current->mm->mmap_sem);

		if (!user_mode(regs))

			no_context(regs, writeaccess, address);

			no_context(regs, error_code, address);

		return 1;

	}
@@ -339,14 +339,14 @@ mm_fault_error(struct pt_regs *regs, unsigned long writeaccess, 
		/* Kernel mode? Handle exceptions or die: */

		if (!user_mode(regs)) {

			up_read(&current->mm->mmap_sem);

			no_context(regs, writeaccess, address);

			no_context(regs, error_code, address);

			return 1;

		}



		out_of_memory();

	} else {

		if (fault & VM_FAULT_SIGBUS)

			do_sigbus(regs, writeaccess, address);

			do_sigbus(regs, error_code, address);

		else

			BUG();

	}
@@ -381,7 +381,7 @@ static int fault_in_kernel_space(unsigned long address) 
 * routines.

 */

asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,

					unsigned long writeaccess,

					unsigned long error_code,

					unsigned long address)

{

	unsigned long vec;
@@ -389,8 +389,9 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	struct mm_struct *mm;

	struct vm_area_struct * vma;

	int fault;

	int write = error_code & FAULT_CODE_WRITE;

	unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |

			      (writeaccess ? FAULT_FLAG_WRITE : 0));

			      (write ? FAULT_FLAG_WRITE : 0));



	tsk = current;

	mm = tsk->mm;
@@ -411,7 +412,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
		if (notify_page_fault(regs, vec))

			return;



		bad_area_nosemaphore(regs, writeaccess, address);

		bad_area_nosemaphore(regs, error_code, address);

		return;

	}
@@ -429,7 +430,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	 * in an atomic region then we must not take the fault:

	 */

	if (unlikely(in_atomic() || !mm)) {

		bad_area_nosemaphore(regs, writeaccess, address);

		bad_area_nosemaphore(regs, error_code, address);

		return;

	}
@@ -438,17 +439,17 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 


	vma = find_vma(mm, address);

	if (unlikely(!vma)) {

		bad_area(regs, writeaccess, address);

		bad_area(regs, error_code, address);

		return;

	}

	if (likely(vma->vm_start <= address))

		goto good_area;

	if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {

		bad_area(regs, writeaccess, address);

		bad_area(regs, error_code, address);

		return;

	}

	if (unlikely(expand_stack(vma, address))) {

		bad_area(regs, writeaccess, address);

		bad_area(regs, error_code, address);

		return;

	}
@@ -457,11 +458,13 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	 * we can handle it..

	 */

good_area:

	if (unlikely(access_error(writeaccess, vma))) {

		bad_area_access_error(regs, writeaccess, address);

	if (unlikely(access_error(error_code, vma))) {

		bad_area_access_error(regs, error_code, address);

		return;

	}



	set_thread_fault_code(error_code);



	/*

	 * If for any reason at all we couldn't handle the fault,

	 * make sure we exit gracefully rather than endlessly redo
@@ -470,7 +473,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	fault = handle_mm_fault(mm, vma, address, flags);



	if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))

		if (mm_fault_error(regs, writeaccess, address, fault))

		if (mm_fault_error(regs, error_code, address, fault))

			return;



	if (flags & FAULT_FLAG_ALLOW_RETRY) {
@@ -502,7 +505,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
 * Called with interrupts disabled.

 */

asmlinkage int __kprobes

handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,

handle_tlbmiss(struct pt_regs *regs, unsigned long error_code,

	       unsigned long address)

{

	pgd_t *pgd;
@@ -535,10 +538,10 @@ handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess, 
	entry = *pte;

	if (unlikely(pte_none(entry) || pte_not_present(entry)))

		return 1;

	if (unlikely(writeaccess && !pte_write(entry)))

	if (unlikely(error_code && !pte_write(entry)))

		return 1;



	if (writeaccess)

	if (error_code)

		entry = pte_mkdirty(entry);

	entry = pte_mkyoung(entry);
@@ -550,10 +553,11 @@ handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess, 
	 * the case of an initial page write exception, so we need to

	 * flush it in order to avoid potential TLB entry duplication.

	 */

	if (writeaccess == 2)

	if (error_code == FAULT_CODE_INITIAL)

		local_flush_tlb_one(get_asid(), address & PAGE_MASK);

#endif



	set_thread_fault_code(error_code);

	update_mmu_cache(NULL, address, pte);



	return 0;