From 7ceb3a1040524c32aa71df8807427e348fac49da Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 13 Jun 2016 11:15:15 +0100 Subject: [PATCH] arm64: simplify dump_mem Currently dump_mem attempts to dump memory in 64-bit chunks when reporting a failure in 64-bit code, or 32-bit chunks when reporting a failure in 32-bit code. We added code to handle these two cases separately in commit e147ae6d7f908412 ("arm64: modify the dump mem for 64 bit addresses"). However, in all cases dump_mem is called, the failing context is a kernel rather than user context. Additionally dump_mem is assumed to only be used for kernel contexts, as internally it switches to KERNEL_DS, and its callers pass kernel stack bounds. This patch removes the redundant 32-bit chunk logic and associated compat parameter, largely reverting the aforementioned commit. For the call in __die(), the check of in_interrupt() is removed also, as __die() is only called in response to faults from the kernel's exception level, and thus the !user_mode(regs) check is sufficient. Were this not the case, the used of task_stack_page(tsk) to generate the stack bounds would be erroneous. Signed-off-by: Mark Rutland Cc: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/traps.c | 31 +++++++++++-------------------- 1 file changed, 11 insertions(+), 20 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 2a43012616b7..d9da2c56e4f8 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -52,15 +52,14 @@ static const char *handler[]= { int show_unhandled_signals = 1; /* - * Dump out the contents of some memory nicely... + * Dump out the contents of some kernel memory nicely... */ static void dump_mem(const char *lvl, const char *str, unsigned long bottom, - unsigned long top, bool compat) + unsigned long top) { unsigned long first; mm_segment_t fs; int i; - unsigned int width = compat ? 4 : 8; /* * We need to switch to kernel mode so that we can use __get_user @@ -78,22 +77,15 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom, memset(str, ' ', sizeof(str)); str[sizeof(str) - 1] = '\0'; - for (p = first, i = 0; i < (32 / width) - && p < top; i++, p += width) { + for (p = first, i = 0; i < (32 / 8) + && p < top; i++, p += 8) { if (p >= bottom && p < top) { unsigned long val; - if (width == 8) { - if (__get_user(val, (unsigned long *)p) == 0) - sprintf(str + i * 17, " %016lx", val); - else - sprintf(str + i * 17, " ????????????????"); - } else { - if (__get_user(val, (unsigned int *)p) == 0) - sprintf(str + i * 9, " %08lx", val); - else - sprintf(str + i * 9, " ????????"); - } + if (__get_user(val, (unsigned long *)p) == 0) + sprintf(str + i * 17, " %016lx", val); + else + sprintf(str + i * 17, " ????????????????"); } } printk("%s%04lx:%s\n", lvl, first & 0xffff, str); @@ -216,7 +208,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr); dump_mem("", "Exception stack", stack, - stack + sizeof(struct pt_regs), false); + stack + sizeof(struct pt_regs)); } } } @@ -254,10 +246,9 @@ static int __die(const char *str, int err, struct thread_info *thread, pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); - if (!user_mode(regs) || in_interrupt()) { + if (!user_mode(regs)) { dump_mem(KERN_EMERG, "Stack: ", regs->sp, - THREAD_SIZE + (unsigned long)task_stack_page(tsk), - compat_user_mode(regs)); + THREAD_SIZE + (unsigned long)task_stack_page(tsk)); dump_backtrace(regs, tsk); dump_instr(KERN_EMERG, regs); } -- 2.30.2