diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-05-07 23:25:54 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-06-25 10:23:47 +0200 |
| commit | 3c88c692c28746473791276f8b42d2c989d6cbe6 (patch) | |
| tree | 51cb03ef4cbb611f42ea43c8737be894991b656b /arch/x86/include/asm/kexec.h | |
| parent | x86/stackframe, x86/ftrace: Add pt_regs frame annotations (diff) | |
| download | linux-3c88c692c28746473791276f8b42d2c989d6cbe6.tar.xz linux-3c88c692c28746473791276f8b42d2c989d6cbe6.zip | |
x86/stackframe/32: Provide consistent pt_regs
Currently pt_regs on x86_32 has an oddity in that kernel regs
(!user_mode(regs)) are short two entries (esp/ss). This means that any
code trying to use them (typically: regs->sp) needs to jump through
some unfortunate hoops.
Change the entry code to fix this up and create a full pt_regs frame.
This then simplifies various trampolines in ftrace and kprobes, the
stack unwinder, ptrace, kdump and kgdb.
Much thanks to Josh for help with the cleanups!
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/kexec.h')
| -rw-r--r-- | arch/x86/include/asm/kexec.h | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index 003f2daa3b0f..5e7d6b46de97 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -71,22 +71,6 @@ struct kimage; #define KEXEC_BACKUP_SRC_END (640 * 1024UL - 1) /* 640K */ /* - * CPU does not save ss and sp on stack if execution is already - * running in kernel mode at the time of NMI occurrence. This code - * fixes it. - */ -static inline void crash_fixup_ss_esp(struct pt_regs *newregs, - struct pt_regs *oldregs) -{ -#ifdef CONFIG_X86_32 - newregs->sp = (unsigned long)&(oldregs->sp); - asm volatile("xorl %%eax, %%eax\n\t" - "movw %%ss, %%ax\n\t" - :"=a"(newregs->ss)); -#endif -} - -/* * This function is responsible for capturing register states if coming * via panic otherwise just fix up the ss and sp if coming via kernel * mode exception. @@ -96,7 +80,6 @@ static inline void crash_setup_regs(struct pt_regs *newregs, { if (oldregs) { memcpy(newregs, oldregs, sizeof(*newregs)); - crash_fixup_ss_esp(newregs, oldregs); } else { #ifdef CONFIG_X86_32 asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); |