From 45c0e0e25eae2c5e8bb9e2dfaf73afb396e0928d Mon Sep 17 00:00:00 2001 From: Stuart Menefy Date: Thu, 19 Apr 2012 17:25:03 +0900 Subject: [PATCH] sh: Improve oops error reporting In some cases the opps error reporting doesn't give enough information to diagnose the problem, only printing information if it is thought to be valid. Replace the current code with more detailed output. This code is based on the ARM reporting, with minor changes for the SH. [lethal@linux-sh.org: fixed up for 64-bit PTEs and pte_offset_kernel()] Signed-off-by: Stuart Menefy Signed-off-by: Paul Mundt --- arch/sh/mm/fault_32.c | 97 +++++++++++++++++++++++++++++++++---------- 1 file changed, 74 insertions(+), 23 deletions(-) diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c index e99b104d967a..c5cd87868c73 100644 --- a/arch/sh/mm/fault_32.c +++ b/arch/sh/mm/fault_32.c @@ -35,6 +35,74 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap) return ret; } +/* + * This is useful to dump out the page tables associated with + * 'addr' in mm 'mm'. + */ +static void show_pte(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + + if (mm) + pgd = mm->pgd; + else + pgd = get_TTB(); + + printk(KERN_ALERT "pgd = %p\n", pgd); + pgd += pgd_index(addr); + printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr, + sizeof(*pgd) * 2, (u64)pgd_val(*pgd)); + + do { + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + if (pgd_none(*pgd)) + break; + + if (pgd_bad(*pgd)) { + printk("(bad)"); + break; + } + + pud = pud_offset(pgd, addr); + if (PTRS_PER_PUD != 1) + printk(", *pud=%0*Lx", sizeof(*pud) * 2, + (u64)pud_val(*pud)); + + if (pud_none(*pud)) + break; + + if (pud_bad(*pud)) { + printk("(bad)"); + break; + } + + pmd = pmd_offset(pud, addr); + if (PTRS_PER_PMD != 1) + printk(", *pmd=%0*Lx", sizeof(*pmd) * 2, + (u64)pmd_val(*pmd)); + + if (pmd_none(*pmd)) + break; + + if (pmd_bad(*pmd)) { + printk("(bad)"); + break; + } + + /* We must not map this if we have highmem enabled */ + if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT))) + break; + + pte = pte_offset_kernel(pmd, addr); + printk(", *pte=%0*Lx", sizeof(*pte) * 2, (u64)pte_val(*pte)); + } while (0); + + printk("\n"); +} + static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address) { unsigned index = pgd_index(address); @@ -254,29 +322,12 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, bust_spinlocks(1); if (oops_may_print()) { - unsigned long page; - - if (address < PAGE_SIZE) - printk(KERN_ALERT "Unable to handle kernel NULL " - "pointer dereference"); - else - printk(KERN_ALERT "Unable to handle kernel paging " - "request"); - printk(" at virtual address %08lx\n", address); - printk(KERN_ALERT "pc = %08lx\n", regs->pc); - page = (unsigned long)get_TTB(); - if (page) { - page = ((__typeof__(page) *)page)[address >> PGDIR_SHIFT]; - printk(KERN_ALERT "*pde = %08lx\n", page); - if (page & _PAGE_PRESENT) { - page &= PAGE_MASK; - address &= 0x003ff000; - page = ((__typeof__(page) *) - __va(page))[address >> - PAGE_SHIFT]; - printk(KERN_ALERT "*pte = %08lx\n", page); - } - } + printk(KERN_ALERT + "Unable to handle kernel %s at virtual address %08lx\n", + (address < PAGE_SIZE) ? "NULL pointer dereference" : + "paging request", address); + + show_pte(mm, address); } die("Oops", regs, writeaccess); -- GitLab