From ec9ce0dbaa734bc95ec73cf5c13f202f1adb219d Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Mon, 9 Jan 2006 20:51:49 -0800 Subject: [PATCH] kdump: x86_64 save cpu registers upon crash - Saving the cpu registers of all cpus before booting in to the crash kernel. - crash_setup_regs will save the registers of the cpu on which panic has occured. One of the concerns ppc64 folks raised is that after capturing the register states, one should not pop the current call frame and push new one. Hence it has been inlined. More call frames later get pushed on to stack (machine_crash_shutdown() and machine_kexec()), but one will not want to backtrace those. - Not very sure about the CFI annotations. With this patch I am getting decent backtrace with gdb. Assuming, compiler has generated enough debugging information for crash_kexec(). Coding crash_setup_regs() in pure assembly makes it tricky because then it can not be inlined and we don't want to return back after capturing register states we don't want to pop this call frame. - Saving the non-panicing cpus registers will be done in the NMI handler while shooting down them in machine_crash_shutdown. - Introducing CRASH_DUMP option in Kconfig for x86_64. Signed-off-by: Murali M Chakravarthy Signed-off-by: Vivek Goyal Cc: Andi Kleen Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-x86_64/kexec.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'include') diff --git a/include/asm-x86_64/kexec.h b/include/asm-x86_64/kexec.h index cea78543a57..ae28cd44bcd 100644 --- a/include/asm-x86_64/kexec.h +++ b/include/asm-x86_64/kexec.h @@ -3,6 +3,7 @@ #include #include +#include /* * KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return. @@ -27,4 +28,39 @@ #define MAX_NOTE_BYTES 1024 +/* + * Saving the registers of the cpu on which panic occured in + * crash_kexec to save a valid sp. The registers of other cpus + * will be saved in machine_crash_shutdown while shooting down them. + */ + +static inline void crash_setup_regs(struct pt_regs *newregs, + struct pt_regs *oldregs) +{ + if (oldregs) + memcpy(newregs, oldregs, sizeof(*newregs)); + else { + __asm__ __volatile__("movq %%rbx,%0" : "=m"(newregs->rbx)); + __asm__ __volatile__("movq %%rcx,%0" : "=m"(newregs->rcx)); + __asm__ __volatile__("movq %%rdx,%0" : "=m"(newregs->rdx)); + __asm__ __volatile__("movq %%rsi,%0" : "=m"(newregs->rsi)); + __asm__ __volatile__("movq %%rdi,%0" : "=m"(newregs->rdi)); + __asm__ __volatile__("movq %%rbp,%0" : "=m"(newregs->rbp)); + __asm__ __volatile__("movq %%rax,%0" : "=m"(newregs->rax)); + __asm__ __volatile__("movq %%rsp,%0" : "=m"(newregs->rsp)); + __asm__ __volatile__("movq %%r8,%0" : "=m"(newregs->r8)); + __asm__ __volatile__("movq %%r9,%0" : "=m"(newregs->r9)); + __asm__ __volatile__("movq %%r10,%0" : "=m"(newregs->r10)); + __asm__ __volatile__("movq %%r11,%0" : "=m"(newregs->r11)); + __asm__ __volatile__("movq %%r12,%0" : "=m"(newregs->r12)); + __asm__ __volatile__("movq %%r13,%0" : "=m"(newregs->r13)); + __asm__ __volatile__("movq %%r14,%0" : "=m"(newregs->r14)); + __asm__ __volatile__("movq %%r15,%0" : "=m"(newregs->r15)); + __asm__ __volatile__("movl %%ss, %%eax;" :"=a"(newregs->ss)); + __asm__ __volatile__("movl %%cs, %%eax;" :"=a"(newregs->cs)); + __asm__ __volatile__("pushfq; popq %0" :"=m"(newregs->eflags)); + + newregs->rip = (unsigned long)current_text_addr(); + } +} #endif /* _X86_64_KEXEC_H */ -- cgit v1.2.3