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Commit 67ce16ec authored by Kristina Martsenko's avatar Kristina Martsenko Committed by Will Deacon
Browse files

arm64: mm: print out correct page table entries 



When we take a fault that can't be handled, we print out the page table
entries associated with the faulting address. In some cases we currently
print out the wrong entries. For a faulting TTBR1 address, we sometimes
print out TTBR0 table entries instead, and for a faulting TTBR0 address
we sometimes print out TTBR1 table entries. Fix this by choosing the
tables based on the faulting address.

Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarKristina Martsenko <kristina.martsenko@arm.com>
[will: zero-extend addrs to 64-bit, don't walk swapper w/ TTBR0 addr]
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent e71a4e1b

arch/arm64/include/asm/system_misc.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -40,7 +40,7 @@ void hook_debug_fault_code(int nr, int (*fn)(unsigned long, unsigned int, 
			   int sig, int code, const char *name);

			   int sig, int code, const char *name);





struct mm_struct;

struct mm_struct;

extern void show_pte(struct mm_struct *mm, unsigned long addr);

extern void show_pte(unsigned long addr);

extern void __show_regs(struct pt_regs *);

extern void __show_regs(struct pt_regs *);





extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);

extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);

arch/arm64/mm/fault.c

+25 −11
Original line number Original line Diff line number Diff line
@@ -80,18 +80,33 @@ static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) 
#endif

#endif





/*

/*

 * Dump out the page tables associated with 'addr' in mm 'mm'.

 * Dump out the page tables associated with 'addr' in the currently active mm.

 */

 */

void show_pte(struct mm_struct *mm, unsigned long addr)

void show_pte(unsigned long addr)

{

{

	struct mm_struct *mm;

	pgd_t *pgd;

	pgd_t *pgd;





	if (!mm)

	if (addr < TASK_SIZE) {

		/* TTBR0 */

		mm = current->active_mm;

		if (mm == &init_mm) {

			pr_alert("[%016lx] user address but active_mm is swapper\n",

				 addr);

			return;

		}

	} else if (addr >= VA_START) {

		/* TTBR1 */

		mm = &init_mm;

		mm = &init_mm;

	} else {

		pr_alert("[%016lx] address between user and kernel address ranges\n",

			 addr);

		return;

	}





	pr_alert("pgd = %p\n", mm->pgd);

	pr_alert("pgd = %p\n", mm->pgd);

	pgd = pgd_offset(mm, addr);

	pgd = pgd_offset(mm, addr);

	pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd));

	pr_alert("[%016lx] *pgd=%016llx", addr, pgd_val(*pgd));





	do {

	do {

		pud_t *pud;

		pud_t *pud;
@@ -196,8 +211,8 @@ static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs, 
/*

/*

 * The kernel tried to access some page that wasn't present.

 * The kernel tried to access some page that wasn't present.

 */

 */

static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,

static void __do_kernel_fault(unsigned long addr, unsigned int esr,

			      unsigned int esr, struct pt_regs *regs)

			      struct pt_regs *regs)

{

{

	const char *msg;

	const char *msg;
@@ -227,7 +242,7 @@ static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, 
	pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg,

	pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg,

		 addr);

		 addr);





	show_pte(mm, addr);

	show_pte(addr);

	die("Oops", regs, esr);

	die("Oops", regs, esr);

	bust_spinlocks(0);

	bust_spinlocks(0);

	do_exit(SIGKILL);

	do_exit(SIGKILL);
@@ -249,7 +264,7 @@ static void __do_user_fault(struct task_struct *tsk, unsigned long addr, 
		pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n",

		pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n",

			tsk->comm, task_pid_nr(tsk), inf->name, sig,

			tsk->comm, task_pid_nr(tsk), inf->name, sig,

			addr, esr);

			addr, esr);

		show_pte(tsk->mm, addr);

		show_pte(addr);

		__show_regs(regs);

		__show_regs(regs);

	}

	}
@@ -265,7 +280,6 @@ static void __do_user_fault(struct task_struct *tsk, unsigned long addr, 
static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)

static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)

{

{

	struct task_struct *tsk = current;

	struct task_struct *tsk = current;

	struct mm_struct *mm = tsk->active_mm;

	const struct fault_info *inf;

	const struct fault_info *inf;





	/*

	/*
@@ -276,7 +290,7 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re 
		inf = esr_to_fault_info(esr);

		inf = esr_to_fault_info(esr);

		__do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs);

		__do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs);

	} else

	} else

		__do_kernel_fault(mm, addr, esr, regs);

		__do_kernel_fault(addr, esr, regs);

}

}





#define VM_FAULT_BADMAP		0x010000

#define VM_FAULT_BADMAP		0x010000
@@ -475,7 +489,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
	return 0;

	return 0;





no_context:

no_context:

	__do_kernel_fault(mm, addr, esr, regs);

	__do_kernel_fault(addr, esr, regs);

	return 0;

	return 0;

}

}