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Unverified Commit 561478b6 authored by Minchan Kim's avatar Minchan Kim Committed by Alexander Winkowski
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Revert "arm64/mm: add speculative page fault" 



This reverts commit ad3023ac.

Bug: 128240262
Change-Id: I80f12ab9b25478a13b69d9c8fe7b46b3f65b1197
Signed-off-by: default avatarMinchan Kim <minchan@google.com>
[dereference23: Forward port to msm-5.4]
Signed-off-by: default avatarAlexander Winkowski <dereference23@outlook.com>
parent 37d40ca0

arch/arm64/mm/fault.c

+3 −23
Original line number Diff line number Diff line
@@ -410,9 +410,10 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re 
#define VM_FAULT_BADMAP		((__force vm_fault_t)0x010000)

#define VM_FAULT_BADACCESS	((__force vm_fault_t)0x020000)



static int __do_page_fault(struct vm_area_struct *vma, unsigned long addr,

static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,

			   unsigned int mm_flags, unsigned long vm_flags)

{

	struct vm_area_struct *vma = find_vma(mm, addr);



	if (unlikely(!vma))

		return VM_FAULT_BADMAP;
@@ -459,7 +460,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
	vm_fault_t fault, major = 0;

	unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC;

	unsigned int mm_flags = FAULT_FLAG_DEFAULT;

	struct vm_area_struct *vma = NULL;



	if (kprobe_page_fault(regs, esr))

		return 0;
@@ -499,14 +499,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 


	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);



	/*

	 * let's try a speculative page fault without grabbing the

	 * mmap_sem.

	 */

	fault = handle_speculative_fault(mm, addr, mm_flags, &vma);

	if (fault != VM_FAULT_RETRY)

		goto done;



	/*

	 * As per x86, we may deadlock here. However, since the kernel only

	 * validly references user space from well defined areas of the code,
@@ -531,10 +523,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
#endif

	}



	if (!vma || !can_reuse_spf_vma(vma, addr))

		vma = find_vma(mm, addr);



	fault = __do_page_fault(vma, addr, mm_flags, vm_flags);

	fault = __do_page_fault(mm, addr, mm_flags, vm_flags);

	major |= fault & VM_FAULT_MAJOR;



	/* Quick path to respond to signals */
@@ -547,20 +536,11 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
	if (fault & VM_FAULT_RETRY) {

		if (mm_flags & FAULT_FLAG_ALLOW_RETRY) {

			mm_flags |= FAULT_FLAG_TRIED;



			/*

			 * Do not try to reuse this vma and fetch it

			 * again since we will release the mmap_sem.

			 */

			vma = NULL;



			goto retry;

		}

	}

	up_read(&mm->mmap_sem);



done:



	/*

	 * Handle the "normal" (no error) case first.

	 */