From 3b7df3421f8813ce3b0eedf3d1d9c247c38e3c39 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 7 Apr 2014 10:20:40 +0200 Subject: [PATCH] s390/mm: print control registers and page table walk on crash Print extra debugging information to the console if the kernel or a user space process crashed (with user space debugging enabled): - contents of control register 7 and 13 - failing address and translation exception identification - page table walk for the failing address Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/mm/fault.c | 140 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 135 insertions(+), 5 deletions(-) diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 19f623f1f21c..2f51a998a67e 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -126,6 +126,133 @@ static inline int user_space_fault(struct pt_regs *regs) return 0; } +static int bad_address(void *p) +{ + unsigned long dummy; + + return probe_kernel_address((unsigned long *)p, dummy); +} + +#ifdef CONFIG_64BIT +static void dump_pagetable(unsigned long asce, unsigned long address) +{ + unsigned long *table = __va(asce & PAGE_MASK); + + pr_alert("AS:%016lx ", asce); + switch (asce & _ASCE_TYPE_MASK) { + case _ASCE_TYPE_REGION1: + table = table + ((address >> 53) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("R1:%016lx ", *table); + if (*table & _REGION_ENTRY_INVALID) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + /* fallthrough */ + case _ASCE_TYPE_REGION2: + table = table + ((address >> 42) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("R2:%016lx ", *table); + if (*table & _REGION_ENTRY_INVALID) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + /* fallthrough */ + case _ASCE_TYPE_REGION3: + table = table + ((address >> 31) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("R3:%016lx ", *table); + if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + /* fallthrough */ + case _ASCE_TYPE_SEGMENT: + table = table + ((address >> 20) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont(KERN_CONT "S:%016lx ", *table); + if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) + goto out; + table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); + } + table = table + ((address >> 12) & 0xff); + if (bad_address(table)) + goto bad; + pr_cont("P:%016lx ", *table); +out: + pr_cont("\n"); + return; +bad: + pr_cont("BAD\n"); +} + +#else /* CONFIG_64BIT */ + +static void dump_pagetable(unsigned long asce, unsigned long address) +{ + unsigned long *table = __va(asce & PAGE_MASK); + + pr_alert("AS:%08lx ", asce); + table = table + ((address >> 20) & 0x7ff); + if (bad_address(table)) + goto bad; + pr_cont("S:%08lx ", *table); + if (*table & _SEGMENT_ENTRY_INVALID) + goto out; + table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); + table = table + ((address >> 12) & 0xff); + if (bad_address(table)) + goto bad; + pr_cont("P:%08lx ", *table); +out: + pr_cont("\n"); + return; +bad: + pr_cont("BAD\n"); +} + +#endif /* CONFIG_64BIT */ + +static void dump_fault_info(struct pt_regs *regs) +{ + unsigned long asce; + + pr_alert("Fault in "); + switch (regs->int_parm_long & 3) { + case 3: + pr_cont("home space "); + break; + case 2: + pr_cont("secondary space "); + break; + case 1: + pr_cont("access register "); + break; + case 0: + pr_cont("primary space "); + break; + } + pr_cont("mode while using "); + if (!user_space_fault(regs)) { + asce = S390_lowcore.kernel_asce; + pr_cont("kernel "); + } +#ifdef CONFIG_PGSTE + else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { + struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; + asce = gmap->asce; + pr_cont("gmap "); + } +#endif + else { + asce = S390_lowcore.user_asce; + pr_cont("user "); + } + pr_cont("ASCE.\n"); + dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); +} + static inline void report_user_fault(struct pt_regs *regs, long signr) { if ((task_pid_nr(current) > 1) && !show_unhandled_signals) @@ -138,8 +265,9 @@ static inline void report_user_fault(struct pt_regs *regs, long signr) regs->int_code); print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); printk(KERN_CONT "\n"); - printk(KERN_ALERT "failing address: %lX\n", - regs->int_parm_long & __FAIL_ADDR_MASK); + printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", + regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); + dump_fault_info(regs); show_regs(regs); } @@ -177,11 +305,13 @@ static noinline void do_no_context(struct pt_regs *regs) address = regs->int_parm_long & __FAIL_ADDR_MASK; if (!user_space_fault(regs)) printk(KERN_ALERT "Unable to handle kernel pointer dereference" - " at virtual kernel address %p\n", (void *)address); + " in virtual kernel address space\n"); else printk(KERN_ALERT "Unable to handle kernel paging request" - " at virtual user address %p\n", (void *)address); - + " in virtual user address space\n"); + printk(KERN_ALERT "failing address: %016lx TEID: %016lx\n", + regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); + dump_fault_info(regs); die(regs, "Oops"); do_exit(SIGKILL); } -- 2.20.1