From: "Fernando Luis Vázquez Cao" <fernando_b1@lab.ntt.co.jp>
To: "H. Peter Anvin" <hpa@linux.intel.com>, Yinghai Lu <yinghai@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] x86, 64bit: do not assume CPU is NX capable when setting early page tables
Date: Thu, 02 May 2013 15:40:50 +0900 [thread overview]
Message-ID: <1367476850.5660.2.camel@nexus> (raw)
The kernel sets the NX bit in the early page tables without checking whether
the CPU actually supports this feature. If it doesn't the first attempt to use
them will cause a kernel hang. Since these are temporary page tables marked as
initdata this fix takes the approach of not bothering with the NX bit at all.
Noticed when my AMD machine that happened to have the NX feature disabled by
the BIOS failed to boot after the update to 3.9.
Cc: stable@vger.kernel.org
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
---
diff -urNp linux-3.9/arch/x86/kernel/head64.c linux-3.9-fix/arch/x86/kernel/head64.c
--- linux-3.9/arch/x86/kernel/head64.c 2013-04-29 09:36:01.000000000 +0900
+++ linux-3.9-fix/arch/x86/kernel/head64.c 2013-05-02 14:38:52.589276092 +0900
@@ -99,7 +99,7 @@ again:
pmd_p[i] = 0;
*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
}
- pmd = (physaddr & PMD_MASK) + (__PAGE_KERNEL_LARGE & ~_PAGE_GLOBAL);
+ pmd = (physaddr & PMD_MASK) + (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL);
pmd_p[pmd_index(address)] = pmd;
return 0;
next reply other threads:[~2013-05-02 6:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-02 6:40 Fernando Luis Vázquez Cao [this message]
2013-05-02 18:33 ` [tip:x86/urgent] x86-64, init: Do not set NX bits on non-NX capable hardware tip-bot for H. Peter Anvin
2013-05-11 5:57 ` Yuhong Bao
2013-05-11 14:55 ` H. Peter Anvin
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