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: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt
Родитель
f007688a50
Коммит
5a1dc78a38
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@ -10,8 +10,18 @@
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* - Incorporating suggestions made by Linus Torvalds and Dave Miller
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*/
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#ifdef __KERNEL__
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#include <asm/page.h>
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/*
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* Page fault error code bits
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*/
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#define FAULT_CODE_WRITE (1 << 0) /* write access */
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#define FAULT_CODE_INITIAL (1 << 1) /* initial page write */
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#define FAULT_CODE_ITLB (1 << 2) /* ITLB miss */
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#define FAULT_CODE_PROT (1 << 3) /* protection fault */
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#define FAULT_CODE_USER (1 << 4) /* user-mode access */
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#ifndef __ASSEMBLY__
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#include <asm/processor.h>
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@ -107,10 +117,13 @@ extern void init_thread_xstate(void);
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#endif /* __ASSEMBLY__ */
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/*
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* thread information flags
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* - these are process state flags that various assembly files may need to access
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* - pending work-to-be-done flags are in LSW
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* - other flags in MSW
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* Thread information flags
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*
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* - Limited to 24 bits, upper byte used for fault code encoding.
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*
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* - _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or
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* we blow the tst immediate size constraints and need to fix up
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* arch/sh/kernel/entry-common.S.
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*/
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#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
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#define TIF_SIGPENDING 1 /* signal pending */
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@ -133,12 +146,6 @@ extern void init_thread_xstate(void);
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#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
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#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
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/*
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* _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or we
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* blow the tst immediate size constraints and need to fix up
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* arch/sh/kernel/entry-common.S.
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*/
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/* work to do in syscall trace */
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#define _TIF_WORK_SYSCALL_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
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_TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
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@ -165,6 +172,7 @@ extern void init_thread_xstate(void);
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#define TS_USEDFPU 0x0002 /* FPU used by this task this quantum */
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#ifndef __ASSEMBLY__
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#define HAVE_SET_RESTORE_SIGMASK 1
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static inline void set_restore_sigmask(void)
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{
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@ -172,6 +180,24 @@ static inline void set_restore_sigmask(void)
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ti->status |= TS_RESTORE_SIGMASK;
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set_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags);
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}
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#define TI_FLAG_FAULT_CODE_SHIFT 24
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/*
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* Additional thread flag encoding
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*/
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static inline void set_thread_fault_code(unsigned int val)
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{
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struct thread_info *ti = current_thread_info();
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ti->flags = (ti->flags & (~0 >> (32 - TI_FLAG_FAULT_CODE_SHIFT)))
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| (val << TI_FLAG_FAULT_CODE_SHIFT);
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}
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static inline unsigned int get_thread_fault_code(void)
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{
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struct thread_info *ti = current_thread_info();
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return ti->flags >> TI_FLAG_FAULT_CODE_SHIFT;
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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@ -2,7 +2,7 @@
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* arch/sh/kernel/cpu/sh3/entry.S
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*
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* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
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* Copyright (C) 2003 - 2006 Paul Mundt
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* Copyright (C) 2003 - 2012 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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@ -17,6 +17,7 @@
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#include <cpu/mmu_context.h>
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#include <asm/page.h>
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#include <asm/cache.h>
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#include <asm/thread_info.h>
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! NOTE:
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! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
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@ -114,22 +115,22 @@ ENTRY(tlb_miss_load)
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.align 2
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ENTRY(tlb_miss_store)
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bra call_handle_tlbmiss
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mov #1, r5
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mov #FAULT_CODE_WRITE, r5
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.align 2
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ENTRY(initial_page_write)
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bra call_handle_tlbmiss
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mov #2, r5
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mov #FAULT_CODE_INITIAL, r5
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.align 2
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ENTRY(tlb_protection_violation_load)
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bra call_do_page_fault
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mov #0, r5
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mov #FAULT_CODE_PROT, r5
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.align 2
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ENTRY(tlb_protection_violation_store)
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bra call_do_page_fault
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mov #1, r5
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mov #(FAULT_CODE_PROT | FAULT_CODE_WRITE), r5
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call_handle_tlbmiss:
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mov.l 1f, r0
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@ -211,7 +211,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long address)
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}
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static noinline void
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no_context(struct pt_regs *regs, unsigned long writeaccess,
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no_context(struct pt_regs *regs, unsigned long error_code,
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unsigned long address)
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{
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/* Are we prepared to handle this kernel fault? */
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@ -229,13 +229,13 @@ no_context(struct pt_regs *regs, unsigned long writeaccess,
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show_fault_oops(regs, address);
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die("Oops", regs, writeaccess);
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die("Oops", regs, error_code);
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bust_spinlocks(0);
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do_exit(SIGKILL);
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}
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static void
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__bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
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__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
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unsigned long address, int si_code)
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{
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struct task_struct *tsk = current;
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@ -252,18 +252,18 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
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return;
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}
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no_context(regs, writeaccess, address);
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no_context(regs, error_code, address);
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}
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static noinline void
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bad_area_nosemaphore(struct pt_regs *regs, unsigned long writeaccess,
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bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
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unsigned long address)
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{
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__bad_area_nosemaphore(regs, writeaccess, address, SEGV_MAPERR);
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__bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
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}
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static void
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__bad_area(struct pt_regs *regs, unsigned long writeaccess,
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__bad_area(struct pt_regs *regs, unsigned long error_code,
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unsigned long address, int si_code)
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{
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struct mm_struct *mm = current->mm;
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@ -274,20 +274,20 @@ __bad_area(struct pt_regs *regs, unsigned long writeaccess,
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*/
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up_read(&mm->mmap_sem);
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__bad_area_nosemaphore(regs, writeaccess, address, si_code);
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__bad_area_nosemaphore(regs, error_code, address, si_code);
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}
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static noinline void
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bad_area(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
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bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
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{
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__bad_area(regs, writeaccess, address, SEGV_MAPERR);
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__bad_area(regs, error_code, address, SEGV_MAPERR);
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}
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static noinline void
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bad_area_access_error(struct pt_regs *regs, unsigned long writeaccess,
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bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
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unsigned long address)
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{
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__bad_area(regs, writeaccess, address, SEGV_ACCERR);
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__bad_area(regs, error_code, address, SEGV_ACCERR);
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}
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static void out_of_memory(void)
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@ -302,7 +302,7 @@ static void out_of_memory(void)
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}
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static void
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do_sigbus(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
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do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
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{
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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@ -311,13 +311,13 @@ do_sigbus(struct pt_regs *regs, unsigned long writeaccess, unsigned long address
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/* Kernel mode? Handle exceptions or die: */
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if (!user_mode(regs))
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no_context(regs, writeaccess, address);
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no_context(regs, error_code, address);
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force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
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}
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static noinline int
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mm_fault_error(struct pt_regs *regs, unsigned long writeaccess,
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mm_fault_error(struct pt_regs *regs, unsigned long error_code,
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unsigned long address, unsigned int fault)
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{
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/*
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@ -328,7 +328,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long writeaccess,
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if (!(fault & VM_FAULT_RETRY))
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up_read(¤t->mm->mmap_sem);
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if (!user_mode(regs))
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no_context(regs, writeaccess, address);
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no_context(regs, error_code, address);
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return 1;
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}
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@ -339,14 +339,14 @@ mm_fault_error(struct pt_regs *regs, unsigned long writeaccess,
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/* Kernel mode? Handle exceptions or die: */
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if (!user_mode(regs)) {
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up_read(¤t->mm->mmap_sem);
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no_context(regs, writeaccess, address);
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no_context(regs, error_code, address);
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return 1;
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}
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out_of_memory();
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} else {
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if (fault & VM_FAULT_SIGBUS)
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do_sigbus(regs, writeaccess, address);
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do_sigbus(regs, error_code, address);
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else
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BUG();
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}
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@ -381,7 +381,7 @@ static int fault_in_kernel_space(unsigned long address)
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* routines.
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*/
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asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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unsigned long writeaccess,
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unsigned long error_code,
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unsigned long address)
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{
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unsigned long vec;
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@ -389,8 +389,9 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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struct mm_struct *mm;
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struct vm_area_struct * vma;
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int fault;
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int write = error_code & FAULT_CODE_WRITE;
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unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
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(writeaccess ? FAULT_FLAG_WRITE : 0));
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(write ? FAULT_FLAG_WRITE : 0));
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tsk = current;
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mm = tsk->mm;
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@ -411,7 +412,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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if (notify_page_fault(regs, vec))
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return;
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bad_area_nosemaphore(regs, writeaccess, address);
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bad_area_nosemaphore(regs, error_code, address);
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return;
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}
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@ -429,7 +430,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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* in an atomic region then we must not take the fault:
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*/
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if (unlikely(in_atomic() || !mm)) {
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bad_area_nosemaphore(regs, writeaccess, address);
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bad_area_nosemaphore(regs, error_code, address);
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return;
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}
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@ -438,17 +439,17 @@ retry:
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vma = find_vma(mm, address);
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if (unlikely(!vma)) {
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bad_area(regs, writeaccess, address);
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bad_area(regs, error_code, address);
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return;
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}
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if (likely(vma->vm_start <= address))
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goto good_area;
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if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
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bad_area(regs, writeaccess, address);
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bad_area(regs, error_code, address);
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return;
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}
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if (unlikely(expand_stack(vma, address))) {
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bad_area(regs, writeaccess, address);
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bad_area(regs, error_code, address);
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return;
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}
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@ -457,11 +458,13 @@ retry:
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* we can handle it..
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*/
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good_area:
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if (unlikely(access_error(writeaccess, vma))) {
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bad_area_access_error(regs, writeaccess, address);
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if (unlikely(access_error(error_code, vma))) {
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bad_area_access_error(regs, error_code, address);
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return;
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}
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set_thread_fault_code(error_code);
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/*
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* If for any reason at all we couldn't handle the fault,
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* make sure we exit gracefully rather than endlessly redo
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@ -470,7 +473,7 @@ good_area:
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fault = handle_mm_fault(mm, vma, address, flags);
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if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
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if (mm_fault_error(regs, writeaccess, address, fault))
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if (mm_fault_error(regs, error_code, address, fault))
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return;
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if (flags & FAULT_FLAG_ALLOW_RETRY) {
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@ -502,7 +505,7 @@ good_area:
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* Called with interrupts disabled.
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*/
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asmlinkage int __kprobes
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handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,
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handle_tlbmiss(struct pt_regs *regs, unsigned long error_code,
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unsigned long address)
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{
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pgd_t *pgd;
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@ -535,10 +538,10 @@ handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,
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entry = *pte;
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if (unlikely(pte_none(entry) || pte_not_present(entry)))
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return 1;
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if (unlikely(writeaccess && !pte_write(entry)))
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if (unlikely(error_code && !pte_write(entry)))
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return 1;
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if (writeaccess)
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if (error_code)
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entry = pte_mkdirty(entry);
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entry = pte_mkyoung(entry);
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@ -550,10 +553,11 @@ handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,
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* the case of an initial page write exception, so we need to
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* flush it in order to avoid potential TLB entry duplication.
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*/
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if (writeaccess == 2)
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if (error_code == FAULT_CODE_INITIAL)
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local_flush_tlb_one(get_asid(), address & PAGE_MASK);
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#endif
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set_thread_fault_code(error_code);
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update_mmu_cache(NULL, address, pte);
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return 0;
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