From: Kristina Martsenko kristina.martsenko@arm.com
commit 67ce16ec15ce9d97d3d85e72beabbc5d7017193e upstream.
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 mark.rutland@arm.com Signed-off-by: Kristina Martsenko kristina.martsenko@arm.com [will: zero-extend addrs to 64-bit, don't walk swapper w/ TTBR0 addr] Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Andrey Konovalov andreyknvl@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/include/asm/system_misc.h | 2 - arch/arm64/mm/fault.c | 36 ++++++++++++++++++++++++----------- 2 files changed, 26 insertions(+), 12 deletions(-)
--- 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 ( 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); --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -79,18 +79,33 @@ static inline int notify_page_fault(stru #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; @@ -176,8 +191,8 @@ static bool is_el1_instruction_abort(uns /* * 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) { /* * Are we prepared to handle this kernel fault? @@ -194,7 +209,7 @@ static void __do_kernel_fault(struct mm_ (addr < PAGE_SIZE) ? "NULL pointer dereference" : "paging request", addr);
- show_pte(mm, addr); + show_pte(addr); die("Oops", regs, esr); bust_spinlocks(0); do_exit(SIGKILL); @@ -216,7 +231,7 @@ static void __do_user_fault(struct task_ 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); }
@@ -232,7 +247,6 @@ static void __do_user_fault(struct task_ 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;
/* @@ -243,7 +257,7 @@ static void do_bad_area(unsigned long ad 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 @@ -454,7 +468,7 @@ retry: return 0;
no_context: - __do_kernel_fault(mm, addr, esr, regs); + __do_kernel_fault(addr, esr, regs); return 0; }