From 67ce16ec15ce9d97d3d85e72beabbc5d7017193e Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Fri, 9 Jun 2017 16:35:52 +0100 Subject: [PATCH] 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: Mark Rutland Signed-off-by: Kristina Martsenko [will: zero-extend addrs to 64-bit, don't walk swapper w/ TTBR0 addr] Signed-off-by: Will Deacon --- arch/arm64/include/asm/system_misc.h | 2 +- arch/arm64/mm/fault.c | 36 +++++++++++++++++++++++++----------- 2 files changed, 26 insertions(+), 12 deletions(-) diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h index bc81243..d0beefe 100644 --- a/arch/arm64/include/asm/system_misc.h +++ b/arch/arm64/include/asm/system_misc.h @@ -40,7 +40,7 @@ void hook_debug_fault_code(int nr, int (*fn)(unsigned long, unsigned int, int sig, int code, const char *name); 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 (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c3f2b10..9d27b17 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -80,18 +80,33 @@ static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) #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; - 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; + } else { + pr_alert("[%016lx] address between user and kernel address ranges\n", + addr); + return; + } pr_alert("pgd = %p\n", mm->pgd); pgd = pgd_offset(mm, addr); - pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd)); + pr_alert("[%016lx] *pgd=%016llx", addr, pgd_val(*pgd)); do { 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. */ -static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, - unsigned int esr, struct pt_regs *regs) +static void __do_kernel_fault(unsigned long addr, unsigned int esr, + struct pt_regs *regs) { 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, addr); - show_pte(mm, addr); + show_pte(addr); die("Oops", regs, esr); bust_spinlocks(0); 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", tsk->comm, task_pid_nr(tsk), inf->name, sig, addr, esr); - show_pte(tsk->mm, addr); + show_pte(addr); __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) { struct task_struct *tsk = current; - struct mm_struct *mm = tsk->active_mm; 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); __do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs); } else - __do_kernel_fault(mm, addr, esr, regs); + __do_kernel_fault(addr, esr, regs); } #define VM_FAULT_BADMAP 0x010000 @@ -475,7 +489,7 @@ retry: return 0; no_context: - __do_kernel_fault(mm, addr, esr, regs); + __do_kernel_fault(addr, esr, regs); return 0; } -- 2.7.4