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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
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/init_task.h>
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#include <linux/fs.h>
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#include <linux/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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#include <asm/desc.h>
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#ifdef CONFIG_X86_32
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#define DOUBLEFAULT_STACKSIZE (1024)
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static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
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#define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
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#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)
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static void doublefault_fn(void)
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{
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struct desc_ptr gdt_desc = {0, 0};
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unsigned long gdt, tss;
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native_store_gdt(&gdt_desc);
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gdt = gdt_desc.address;
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printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
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if (ptr_ok(gdt)) {
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gdt += GDT_ENTRY_TSS << 3;
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tss = get_desc_base((struct desc_struct *)gdt);
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printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
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if (ptr_ok(tss)) {
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struct x86_hw_tss *t = (struct x86_hw_tss *)tss;
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printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
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t->ip, t->sp);
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printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
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t->ax, t->bx, t->cx, t->dx);
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printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
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t->si, t->di);
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}
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}
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for (;;)
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cpu_relax();
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}
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struct x86_hw_tss doublefault_tss __cacheline_aligned = {
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.sp0 = STACK_START,
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.ss0 = __KERNEL_DS,
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.ldt = 0,
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.io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
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.ip = (unsigned long) doublefault_fn,
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/* 0x2 bit is always set */
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.flags = X86_EFLAGS_SF | 0x2,
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.sp = STACK_START,
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.es = __USER_DS,
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.cs = __KERNEL_CS,
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.ss = __KERNEL_DS,
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.ds = __USER_DS,
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.fs = __KERNEL_PERCPU,
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.__cr3 = __pa_nodebug(swapper_pg_dir),
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};
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/* dummy for do_double_fault() call */
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void df_debug(struct pt_regs *regs, long error_code) {}
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#else /* !CONFIG_X86_32 */
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void df_debug(struct pt_regs *regs, long error_code)
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{
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pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
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show_regs(regs);
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panic("Machine halted.");
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}
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#endif
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