linux/arch/x86/kernel/cpu/mcheck/winchip.c
Andy Lutomirski 8c84014f3b x86/entry: Remove exception_enter() from most trap handlers
On 64-bit kernels, we don't need it any more: we handle context
tracking directly on entry from user mode and exit to user mode.

On 32-bit kernels, we don't support context tracking at all, so
these callbacks had no effect.

Note: this doesn't change do_page_fault().  Before we do that,
we need to make sure that there is no code that can page fault
from kernel mode with CONTEXT_USER.  The 32-bit fast system call
stack argument code is the only offender I'm aware of right now.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/ae22f4dfebd799c916574089964592be218151f9.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-07 10:59:09 +02:00

45 lines
1.1 KiB
C

/*
* IDT Winchip specific Machine Check Exception Reporting
* (C) Copyright 2002 Alan Cox <alan@lxorguk.ukuu.org.uk>
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <asm/processor.h>
#include <asm/traps.h>
#include <asm/tlbflush.h>
#include <asm/mce.h>
#include <asm/msr.h>
/* Machine check handler for WinChip C6: */
static void winchip_machine_check(struct pt_regs *regs, long error_code)
{
ist_enter(regs);
printk(KERN_EMERG "CPU0: Machine Check Exception.\n");
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
ist_exit(regs);
}
/* Set up machine check reporting on the Winchip C6 series */
void winchip_mcheck_init(struct cpuinfo_x86 *c)
{
u32 lo, hi;
machine_check_vector = winchip_machine_check;
/* Make sure the vector pointer is visible before we enable MCEs: */
wmb();
rdmsr(MSR_IDT_FCR1, lo, hi);
lo |= (1<<2); /* Enable EIERRINT (int 18 MCE) */
lo &= ~(1<<4); /* Enable MCE */
wrmsr(MSR_IDT_FCR1, lo, hi);
cr4_set_bits(X86_CR4_MCE);
printk(KERN_INFO
"Winchip machine check reporting enabled on CPU#0.\n");
}