forked from luck/tmp_suning_uos_patched
e996e58133
- If system panics then cpu register states are captured through funciton crash_get_current_regs(). This is not a inline function hence a stack frame is pushed on to the stack and then cpu register state is captured. Later this frame is popped and new frames are pushed (machine_kexec). - In theory this is not very right as we are capturing register states for a frame and that frame is no more valid. This seems to have created back trace problems for ppc64. - This patch fixes it up. The very first thing it does after entering crash_kexec() is to capture the register states. Anyway we don't want the back trace beyond crash_kexec(). crash_get_current_regs() has been made inline - crash_setup_regs() is the top architecture dependent function which should be responsible for capturing the register states as well as to do some architecture dependent tricks. For ex. fixing up ss and esp for i386. crash_setup_regs() has also been made inline to ensure no new call frame is pushed onto stack. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
76 lines
2.7 KiB
C
76 lines
2.7 KiB
C
#ifndef _I386_KEXEC_H
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#define _I386_KEXEC_H
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#include <asm/fixmap.h>
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#include <asm/ptrace.h>
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/*
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* KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return.
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* I.e. Maximum page that is mapped directly into kernel memory,
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* and kmap is not required.
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*
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* Someone correct me if FIXADDR_START - PAGEOFFSET is not the correct
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* calculation for the amount of memory directly mappable into the
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* kernel memory space.
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*/
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/* Maximum physical address we can use pages from */
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#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
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/* Maximum address we can reach in physical address mode */
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#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
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/* Maximum address we can use for the control code buffer */
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#define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
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#define KEXEC_CONTROL_CODE_SIZE 4096
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/* The native architecture */
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#define KEXEC_ARCH KEXEC_ARCH_386
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#define MAX_NOTE_BYTES 1024
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/* CPU does not save ss and esp on stack if execution is already
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* running in kernel mode at the time of NMI occurrence. This code
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* fixes it.
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*/
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static inline void crash_fixup_ss_esp(struct pt_regs *newregs,
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struct pt_regs *oldregs)
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{
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memcpy(newregs, oldregs, sizeof(*newregs));
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newregs->esp = (unsigned long)&(oldregs->esp);
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__asm__ __volatile__(
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"xorl %%eax, %%eax\n\t"
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"movw %%ss, %%ax\n\t"
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:"=a"(newregs->xss));
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}
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/*
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* This function is responsible for capturing register states if coming
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* via panic otherwise just fix up the ss and esp if coming via kernel
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* mode exception.
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*/
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static inline void crash_setup_regs(struct pt_regs *newregs,
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struct pt_regs *oldregs)
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{
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if (oldregs)
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crash_fixup_ss_esp(newregs, oldregs);
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else {
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__asm__ __volatile__("movl %%ebx,%0" : "=m"(newregs->ebx));
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__asm__ __volatile__("movl %%ecx,%0" : "=m"(newregs->ecx));
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__asm__ __volatile__("movl %%edx,%0" : "=m"(newregs->edx));
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__asm__ __volatile__("movl %%esi,%0" : "=m"(newregs->esi));
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__asm__ __volatile__("movl %%edi,%0" : "=m"(newregs->edi));
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__asm__ __volatile__("movl %%ebp,%0" : "=m"(newregs->ebp));
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__asm__ __volatile__("movl %%eax,%0" : "=m"(newregs->eax));
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__asm__ __volatile__("movl %%esp,%0" : "=m"(newregs->esp));
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__asm__ __volatile__("movw %%ss, %%ax;" :"=a"(newregs->xss));
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__asm__ __volatile__("movw %%cs, %%ax;" :"=a"(newregs->xcs));
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__asm__ __volatile__("movw %%ds, %%ax;" :"=a"(newregs->xds));
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__asm__ __volatile__("movw %%es, %%ax;" :"=a"(newregs->xes));
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__asm__ __volatile__("pushfl; popl %0" :"=m"(newregs->eflags));
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newregs->eip = (unsigned long)current_text_addr();
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}
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}
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#endif /* _I386_KEXEC_H */
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