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Date: Fri, 10 Apr 2009 12:15:39 -0700
From: Ying Han <yinghan@...gle.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@...el.com>,
Andrew Morton <akpm@...ux-foundation.org>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Ingo Molnar <mingo@...e.hu>, Mike Waychison <mikew@...gle.com>,
Rohit Seth <rohitseth@...gle.com>,
Hugh Dickins <hugh@...itas.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
"H. Peter Anvin" <hpa@...or.com>,
Török Edwin <edwintorok@...il.com>,
Lee Schermerhorn <lee.schermerhorn@...com>,
Nick Piggin <npiggin@...e.de>
Subject: Re: [PATCH 2/2] Move FAULT_FLAG_xyz into handle_mm_fault() callers
2009/4/10 Linus Torvalds <torvalds@...ux-foundation.org>:
>
> From: Linus Torvalds <torvalds@...ux-foundation.org>
> Date: Fri, 10 Apr 2009 09:01:23 -0700
>
> This allows the callers to now pass down the full set of FAULT_FLAG_xyz
> flags to handle_mm_fault(). All callers have been (mechanically)
> converted to the new calling convention, there's almost certainly room
> for architectures to clean up their code and then add FAULT_FLAG_RETRY
> when that support is added.
>
> Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
> ---
>
> Again - untested. Not compiled. Might well rape your pets and just
> otherwise act badly. It's also a very mechanical conversion, ie I
> explicitly did
>
> - fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
> + fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & (1 << 11)) ? FAULT_FLAG_WRITE : 0);
>
> rather than doing some cleanup while there.
>
> The point is, once we do this, now you really pass FAULT_FLAG_xyz
> everywhere, and now it's trivial to add FAULT_FLAG_RETRY without horribly
> ugly or hacky code.
>
> For example, before, I think Wu's code would have failed on ARM if
> FAULT_FLAG_RETRY just happened to be (1 << 11), because back when we
> passed in "zero or non-zero", ARM would literally pass in (1 << 11) or 0
> for "write_access".
>
> Now we explicitly pass in a nice FAULT_FLAG_WRITE or 0.
>
> arch/alpha/mm/fault.c | 2 +-
> arch/arm/mm/fault.c | 2 +-
> arch/avr32/mm/fault.c | 2 +-
> arch/cris/mm/fault.c | 2 +-
> arch/frv/mm/fault.c | 2 +-
> arch/ia64/mm/fault.c | 2 +-
> arch/m32r/mm/fault.c | 2 +-
> arch/m68k/mm/fault.c | 2 +-
> arch/mips/mm/fault.c | 2 +-
> arch/mn10300/mm/fault.c | 2 +-
> arch/parisc/mm/fault.c | 2 +-
> arch/powerpc/mm/fault.c | 2 +-
> arch/powerpc/platforms/cell/spu_fault.c | 2 +-
> arch/s390/lib/uaccess_pt.c | 2 +-
> arch/s390/mm/fault.c | 2 +-
> arch/sh/mm/fault_32.c | 2 +-
> arch/sh/mm/tlbflush_64.c | 2 +-
> arch/sparc/mm/fault_32.c | 4 ++--
> arch/sparc/mm/fault_64.c | 2 +-
> arch/um/kernel/trap.c | 2 +-
> arch/x86/mm/fault.c | 2 +-
> arch/xtensa/mm/fault.c | 2 +-
> include/linux/mm.h | 4 ++--
> mm/memory.c | 8 ++++----
> 24 files changed, 29 insertions(+), 29 deletions(-)
>
> diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
> index 4829f96..00a31de 100644
> --- a/arch/alpha/mm/fault.c
> +++ b/arch/alpha/mm/fault.c
> @@ -146,7 +146,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
> /* If for any reason at all we couldn't handle the fault,
> make sure we exit gracefully rather than endlessly redo
> the fault. */
> - fault = handle_mm_fault(mm, vma, address, cause > 0);
> + fault = handle_mm_fault(mm, vma, address, cause > 0 ? FAULT_FLAG_WRITE : 0);
> up_read(&mm->mmap_sem);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
> index 0455557..6fdcbb7 100644
> --- a/arch/arm/mm/fault.c
> +++ b/arch/arm/mm/fault.c
> @@ -208,7 +208,7 @@ good_area:
> * than endlessly redo the fault.
> */
> survive:
> - fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
> + fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & (1 << 11)) ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
> index 62d4abb..b61d86d 100644
> --- a/arch/avr32/mm/fault.c
> +++ b/arch/avr32/mm/fault.c
> @@ -133,7 +133,7 @@ good_area:
> * fault.
> */
> survive:
> - fault = handle_mm_fault(mm, vma, address, writeaccess);
> + fault = handle_mm_fault(mm, vma, address, writeaccess ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c
> index c4c76db..f925115 100644
> --- a/arch/cris/mm/fault.c
> +++ b/arch/cris/mm/fault.c
> @@ -163,7 +163,7 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
> * the fault.
> */
>
> - fault = handle_mm_fault(mm, vma, address, writeaccess & 1);
> + fault = handle_mm_fault(mm, vma, address, (writeaccess & 1) ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/frv/mm/fault.c b/arch/frv/mm/fault.c
> index 05093d4..30f5d10 100644
> --- a/arch/frv/mm/fault.c
> +++ b/arch/frv/mm/fault.c
> @@ -163,7 +163,7 @@ asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear
> * make sure we exit gracefully rather than endlessly redo
> * the fault.
> */
> - fault = handle_mm_fault(mm, vma, ear0, write);
> + fault = handle_mm_fault(mm, vma, ear0, write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
> index 23088be..19261a9 100644
> --- a/arch/ia64/mm/fault.c
> +++ b/arch/ia64/mm/fault.c
> @@ -154,7 +154,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
> * sure we exit gracefully rather than endlessly redo the
> * fault.
> */
> - fault = handle_mm_fault(mm, vma, address, (mask & VM_WRITE) != 0);
> + fault = handle_mm_fault(mm, vma, address, (mask & VM_WRITE) ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> /*
> * We ran out of memory, or some other thing happened
> diff --git a/arch/m32r/mm/fault.c b/arch/m32r/mm/fault.c
> index 4a71df4..7274b47 100644
> --- a/arch/m32r/mm/fault.c
> +++ b/arch/m32r/mm/fault.c
> @@ -196,7 +196,7 @@ survive:
> */
> addr = (address & PAGE_MASK);
> set_thread_fault_code(error_code);
> - fault = handle_mm_fault(mm, vma, addr, write);
> + fault = handle_mm_fault(mm, vma, addr, write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
> index f493f03..d0e35cf 100644
> --- a/arch/m68k/mm/fault.c
> +++ b/arch/m68k/mm/fault.c
> @@ -155,7 +155,7 @@ good_area:
> */
>
> survive:
> - fault = handle_mm_fault(mm, vma, address, write);
> + fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
> #ifdef DEBUG
> printk("handle_mm_fault returns %d\n",fault);
> #endif
> diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
> index 55767ad..6751ce9 100644
> --- a/arch/mips/mm/fault.c
> +++ b/arch/mips/mm/fault.c
> @@ -102,7 +102,7 @@ good_area:
> * make sure we exit gracefully rather than endlessly redo
> * the fault.
> */
> - fault = handle_mm_fault(mm, vma, address, write);
> + fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c
> index 33cf250..a62e1e1 100644
> --- a/arch/mn10300/mm/fault.c
> +++ b/arch/mn10300/mm/fault.c
> @@ -258,7 +258,7 @@ good_area:
> * make sure we exit gracefully rather than endlessly redo
> * the fault.
> */
> - fault = handle_mm_fault(mm, vma, address, write);
> + fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
> index 92c7fa4..bfb6dd6 100644
> --- a/arch/parisc/mm/fault.c
> +++ b/arch/parisc/mm/fault.c
> @@ -202,7 +202,7 @@ good_area:
> * fault.
> */
>
> - fault = handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0);
> + fault = handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> /*
> * We hit a shared mapping outside of the file, or some
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index 7699394..e2bf1ee 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -299,7 +299,7 @@ good_area:
> * the fault.
> */
> survive:
> - ret = handle_mm_fault(mm, vma, address, is_write);
> + ret = handle_mm_fault(mm, vma, address, is_write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(ret & VM_FAULT_ERROR)) {
> if (ret & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/powerpc/platforms/cell/spu_fault.c b/arch/powerpc/platforms/cell/spu_fault.c
> index 95d8dad..d06ba87 100644
> --- a/arch/powerpc/platforms/cell/spu_fault.c
> +++ b/arch/powerpc/platforms/cell/spu_fault.c
> @@ -70,7 +70,7 @@ int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
> }
>
> ret = 0;
> - *flt = handle_mm_fault(mm, vma, ea, is_write);
> + *flt = handle_mm_fault(mm, vma, ea, is_write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(*flt & VM_FAULT_ERROR)) {
> if (*flt & VM_FAULT_OOM) {
> ret = -ENOMEM;
> diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
> index b0b84c3..cb5d59e 100644
> --- a/arch/s390/lib/uaccess_pt.c
> +++ b/arch/s390/lib/uaccess_pt.c
> @@ -66,7 +66,7 @@ static int __handle_fault(struct mm_struct *mm, unsigned long address,
> }
>
> survive:
> - fault = handle_mm_fault(mm, vma, address, write_access);
> + fault = handle_mm_fault(mm, vma, address, write_access ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
> index 833e836..31456fa 100644
> --- a/arch/s390/mm/fault.c
> +++ b/arch/s390/mm/fault.c
> @@ -351,7 +351,7 @@ good_area:
> * make sure we exit gracefully rather than endlessly redo
> * the fault.
> */
> - fault = handle_mm_fault(mm, vma, address, write);
> + fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM) {
> up_read(&mm->mmap_sem);
> diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c
> index 31a33eb..09ef52a 100644
> --- a/arch/sh/mm/fault_32.c
> +++ b/arch/sh/mm/fault_32.c
> @@ -133,7 +133,7 @@ good_area:
> * the fault.
> */
> survive:
> - fault = handle_mm_fault(mm, vma, address, writeaccess);
> + fault = handle_mm_fault(mm, vma, address, writeaccess ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/sh/mm/tlbflush_64.c b/arch/sh/mm/tlbflush_64.c
> index 7876997..fcbb6e1 100644
> --- a/arch/sh/mm/tlbflush_64.c
> +++ b/arch/sh/mm/tlbflush_64.c
> @@ -187,7 +187,7 @@ good_area:
> * the fault.
> */
> survive:
> - fault = handle_mm_fault(mm, vma, address, writeaccess);
> + fault = handle_mm_fault(mm, vma, address, writeaccess ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
> index 12e447f..a5e30c6 100644
> --- a/arch/sparc/mm/fault_32.c
> +++ b/arch/sparc/mm/fault_32.c
> @@ -241,7 +241,7 @@ good_area:
> * make sure we exit gracefully rather than endlessly redo
> * the fault.
> */
> - fault = handle_mm_fault(mm, vma, address, write);
> + fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> @@ -484,7 +484,7 @@ good_area:
> if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
> goto bad_area;
> }
> - switch (handle_mm_fault(mm, vma, address, write)) {
> + switch (handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0)) {
> case VM_FAULT_SIGBUS:
> case VM_FAULT_OOM:
> goto do_sigbus;
> diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
> index 4ab8993..e5620b2 100644
> --- a/arch/sparc/mm/fault_64.c
> +++ b/arch/sparc/mm/fault_64.c
> @@ -398,7 +398,7 @@ good_area:
> goto bad_area;
> }
>
> - fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE));
> + fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE) ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
> index 7384d8a..637c650 100644
> --- a/arch/um/kernel/trap.c
> +++ b/arch/um/kernel/trap.c
> @@ -65,7 +65,7 @@ good_area:
> do {
> int fault;
>
> - fault = handle_mm_fault(mm, vma, address, is_write);
> + fault = handle_mm_fault(mm, vma, address, is_write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM) {
> goto out_of_memory;
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index a03b727..65a07ba 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -1130,7 +1130,7 @@ good_area:
> * make sure we exit gracefully rather than endlessly redo
> * the fault:
> */
> - fault = handle_mm_fault(mm, vma, address, write);
> + fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
>
> if (unlikely(fault & VM_FAULT_ERROR)) {
> mm_fault_error(regs, error_code, address, fault);
> diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
> index bdd860d..bc07333 100644
> --- a/arch/xtensa/mm/fault.c
> +++ b/arch/xtensa/mm/fault.c
> @@ -106,7 +106,7 @@ good_area:
> * the fault.
> */
> survive:
> - fault = handle_mm_fault(mm, vma, address, is_write);
> + fault = handle_mm_fault(mm, vma, address, is_write ? FAULT_FLAG_WRITE : 0);
> if (unlikely(fault & VM_FAULT_ERROR)) {
> if (fault & VM_FAULT_OOM)
> goto out_of_memory;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index bff1f0d..3f207d1 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -810,11 +810,11 @@ extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
>
> #ifdef CONFIG_MMU
> extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> - unsigned long address, int write_access);
> + unsigned long address, unsigned int flags);
> #else
> static inline int handle_mm_fault(struct mm_struct *mm,
> struct vm_area_struct *vma, unsigned long address,
> - int write_access)
> + unsigned int flags)
> {
> /* should never happen if there's no MMU */
> BUG();
> diff --git a/mm/memory.c b/mm/memory.c
> index 9050bae..383dc0b 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1310,8 +1310,9 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
> cond_resched();
> while (!(page = follow_page(vma, start, foll_flags))) {
> int ret;
> - ret = handle_mm_fault(mm, vma, start,
> - foll_flags & FOLL_WRITE);
> +
> + /* FOLL_WRITE matches FAULT_FLAG_WRITE! */
> + ret = handle_mm_fault(mm, vma, start, foll_flags & FOLL_WRITE);
> if (ret & VM_FAULT_ERROR) {
> if (ret & VM_FAULT_OOM)
> return i ? i : -ENOMEM;
> @@ -2864,13 +2865,12 @@ unlock:
> * By the time we get here, we already hold the mm semaphore
> */
> int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> - unsigned long address, int write_access)
> + unsigned long address, unsigned int flags)
> {
> pgd_t *pgd;
> pud_t *pud;
> pmd_t *pmd;
> pte_t *pte;
> - unsigned int flags = write_access ? FAULT_FLAG_WRITE : 0;
>
> __set_current_state(TASK_RUNNING);
>
> --
> 1.6.2.2.471.g6da14.dirty
>
>
How about something like this for x86? If it looks sane, i will apply
to other arches.
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 8bcb6f4..f3b6ee4 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -584,11 +584,12 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigne
struct mm_struct *mm;
struct vm_area_struct *vma;
unsigned long address;
- int write, si_code;
+ int si_code;
int fault;
#ifdef CONFIG_X86_64
unsigned long flags;
#endif
+ unsigned int fault_flags |= FAULT_FLAG_RETRY;
/*
* We can fault from pretty much anywhere, with unknown IRQ state.
@@ -722,14 +723,13 @@ again:
*/
good_area:
si_code = SEGV_ACCERR;
- write = 0;
switch (error_code & (PF_PROT|PF_WRITE)) {
default: /* 3: write, present */
/* fall through */
case PF_WRITE: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
- write++;
+ fault_flags |= FAULT_FLAG_WRITE;
break;
case PF_PROT: /* read, present */
goto bad_area;
@@ -746,7 +746,7 @@ survive:
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
- fault = handle_mm_fault(mm, vma, address, write);
+ fault = handle_mm_fault(mm, vma, address, fault_flags);
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
--Ying
--
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