7fb983b4dd
A future patch will move SYSENTER_stack to the beginning of cpu_tss to help detect overflow. Before this can happen, fix several code paths that hardcode assumptions about the old layout. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Dave Hansen <dave.hansen@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bpetkov@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Link: https://lkml.kernel.org/r/20171204150605.722425540@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
84 lines
2.0 KiB
C
84 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/mm.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sched/debug.h>
|
|
#include <linux/init_task.h>
|
|
#include <linux/fs.h>
|
|
|
|
#include <linux/uaccess.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/desc.h>
|
|
|
|
#ifdef CONFIG_X86_32
|
|
|
|
#define DOUBLEFAULT_STACKSIZE (1024)
|
|
static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
|
|
#define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
|
|
|
|
#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)
|
|
|
|
static void doublefault_fn(void)
|
|
{
|
|
struct desc_ptr gdt_desc = {0, 0};
|
|
unsigned long gdt, tss;
|
|
|
|
native_store_gdt(&gdt_desc);
|
|
gdt = gdt_desc.address;
|
|
|
|
printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
|
|
|
|
if (ptr_ok(gdt)) {
|
|
gdt += GDT_ENTRY_TSS << 3;
|
|
tss = get_desc_base((struct desc_struct *)gdt);
|
|
printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
|
|
|
|
if (ptr_ok(tss)) {
|
|
struct x86_hw_tss *t = (struct x86_hw_tss *)tss;
|
|
|
|
printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
|
|
t->ip, t->sp);
|
|
|
|
printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
|
|
t->ax, t->bx, t->cx, t->dx);
|
|
printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
|
|
t->si, t->di);
|
|
}
|
|
}
|
|
|
|
for (;;)
|
|
cpu_relax();
|
|
}
|
|
|
|
struct x86_hw_tss doublefault_tss __cacheline_aligned = {
|
|
.sp0 = STACK_START,
|
|
.ss0 = __KERNEL_DS,
|
|
.ldt = 0,
|
|
.io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
|
|
|
|
.ip = (unsigned long) doublefault_fn,
|
|
/* 0x2 bit is always set */
|
|
.flags = X86_EFLAGS_SF | 0x2,
|
|
.sp = STACK_START,
|
|
.es = __USER_DS,
|
|
.cs = __KERNEL_CS,
|
|
.ss = __KERNEL_DS,
|
|
.ds = __USER_DS,
|
|
.fs = __KERNEL_PERCPU,
|
|
|
|
.__cr3 = __pa_nodebug(swapper_pg_dir),
|
|
};
|
|
|
|
/* dummy for do_double_fault() call */
|
|
void df_debug(struct pt_regs *regs, long error_code) {}
|
|
|
|
#else /* !CONFIG_X86_32 */
|
|
|
|
void df_debug(struct pt_regs *regs, long error_code)
|
|
{
|
|
pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
|
|
show_regs(regs);
|
|
panic("Machine halted.");
|
|
}
|
|
#endif
|