Skip to content

L
linux

xiphi1978 / linux

通知 2
Star 0
Fork 0
L
linux

体验新版 GitCode，发现更多精彩内容 >>

切换分支/标签
  1. 02 4月, 2015 2 次提交
    • S
      kgdb/x86: Fix reporting of 'si' in kgdb on x86_64 · f59df35f
      由 Steffen Liebergeld 提交于 
      This patch fixes an error in kgdb for x86_64 which would report
the value of dx when asked to give the value of si.
Signed-off-by: NSteffen Liebergeld <steffen.liebergeld@kernkonzept.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      f59df35f
    • A
      x86/asm/entry/64: Disable opportunistic SYSRET if regs->flags has TF set · 7ea24169
      由 Andy Lutomirski 提交于 
      When I wrote the opportunistic SYSRET code, I missed an important difference
between SYSRET and IRET.

Both instructions are capable of setting EFLAGS.TF, but they behave differently
when doing so:

 - IRET will not issue a #DB trap after execution when it sets TF.
   This is critical -- otherwise you'd never be able to make forward progress when
   returning to userspace.

 - SYSRET, on the other hand, will trap with #DB immediately after
   returning to CPL3, and the next instruction will never execute.

This breaks anything that opportunistically SYSRETs to a user
context with TF set.  For example, running this code with TF set
and a SIGTRAP handler loaded never gets past 'post_nop':

	extern unsigned char post_nop[];
	asm volatile ("pushfq\n\t"
		      "popq %%r11\n\t"
		      "nop\n\t"
		      "post_nop:"
		      : : "c" (post_nop) : "r11");

In my defense, I can't find this documented in the AMD or Intel manual.

Fix it by using IRET to restore TF.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2a23c6b8 ("x86_64, entry: Use sysret to return to userspace when possible")
Link: http://lkml.kernel.org/r/9472f1ca4c19a38ecda45bba9c91b7168135fcfa.1427923514.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      7ea24169
  3. 01 4月, 2015 1 次提交
    • S
      x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk · 80313b30
      由 Stefan Lippers-Hollmann 提交于 
      The ASRock Q1900DC-ITX mainboard (Baytrail-D) hangs randomly in
both BIOS and UEFI mode while rebooting unless reboot=pci is
used. Add a quirk to reboot via the pci method.

The problem is very intermittent and hard to debug, it might succeed
rebooting just fine 40 times in a row - but fails half a dozen times
the next day. It seems to be slightly less common in BIOS CSM mode
than native UEFI (with the CSM disabled), but it does happen in either
mode. Since I've started testing this patch in late january, rebooting
has been 100% reliable.

Most of the time it already hangs during POST, but occasionally it
might even make it through the bootloader and the kernel might even
start booting, but then hangs before the mode switch. The same symptoms
occur with grub-efi, gummiboot and grub-pc, just as well as (at least)
kernel 3.16-3.19 and 4.0-rc6 (I haven't tried older kernels than 3.16).
Upgrading to the most current mainboard firmware of the ASRock
Q1900DC-ITX, version 1.20, does not improve the situation.

( Searching the web seems to suggest that other Bay Trail-D mainboards
  might be affected as well. )
--
Signed-off-by: NStefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: <stable@vger.kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150330224427.0fb58e42@mirSigned-off-by: NIngo Molnar <mingo@kernel.org>
      80313b30
  5. 31 3月, 2015 2 次提交
  7. 30 3月, 2015 7 次提交
  9. 29 3月, 2015 9 次提交
  11. 28 3月, 2015 2 次提交
  13. 27 3月, 2015 10 次提交
  15. 26 3月, 2015 7 次提交