From: Andy Lutomirski <luto@kernel.org>
To: X86 ML <x86@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v3 11/19] x86/espfix/64: Stop assuming that pt_regs is on the entry stack
Date: Thu, 23 Nov 2017 20:32:57 -0800 [thread overview]
Message-ID: <b1ef4136616c6bd2a75d1fd2736d1d54437d65a8.1511497875.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1511497874.git.luto@kernel.org>
In-Reply-To: <cover.1511497874.git.luto@kernel.org>
When we start using an entry trampoline, a #GP from userspace will
be delivered on the entry stack, not on the task stack. Fix the
espfix64 #DF fixup to set up #GP according to TSS.SP0, rather than
assuming that pt_regs + 1 == SP0. This won't change anything
without an entry stack, but it will make the code continue to work
when an entry stack is added.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/traps.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 2008dd0f8ccb..1bd43f044c62 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -359,7 +359,8 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
regs->cs == __KERNEL_CS &&
regs->ip == (unsigned long)native_irq_return_iret)
{
- struct pt_regs *normal_regs = task_pt_regs(current);
+ struct pt_regs *normal_regs =
+ (struct pt_regs *)this_cpu_read(cpu_tss.x86_tss.sp0) - 1;
/* Fake a #GP(0) from userspace. */
memmove(&normal_regs->ip, (void *)regs->sp, 5*8);
@@ -390,7 +391,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
*
* Processors update CR2 whenever a page fault is detected. If a
* second page fault occurs while an earlier page fault is being
- * deliv- ered, the faulting linear address of the second fault will
+ * delivered, the faulting linear address of the second fault will
* overwrite the contents of CR2 (replacing the previous
* address). These updates to CR2 occur even if the page fault
* results in a double fault or occurs during the delivery of a
--
2.13.6
next prev parent reply other threads:[~2017-11-24 4:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-24 4:32 [PATCH v3 00/19] Entry stack switching Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 01/19] x86/asm/64: Allocate and enable the SYSENTER stack Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 02/19] x86/dumpstack: Add get_stack_info() support for " Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 03/19] x86/gdt: Put per-cpu GDT remaps in ascending order Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 04/19] x86/fixmap: Generalize the GDT fixmap mechanism Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 05/19] x86/kasan/64: Teach KASAN about the cpu_entry_area Andy Lutomirski
2017-11-24 13:16 ` Andrey Ryabinin
2017-11-24 16:27 ` Andy Lutomirski
2017-11-24 17:21 ` [PATCH v4] x86/mm/kasan: " Andrey Ryabinin
2017-11-24 19:26 ` Andy Lutomirski
2017-11-24 17:26 ` [PATCH v3 05/19] x86/kasan/64: " Andrey Ryabinin
2017-11-24 4:32 ` [PATCH v3 06/19] x86/asm: Fix assumptions that the HW TSS is at the beginning of cpu_tss Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 07/19] x86/dumpstack: Handle stack overflow on all stacks Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 08/19] x86/asm: Move SYSENTER_stack to the beginning of struct tss_struct Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 09/19] x86/asm: Remap the TSS into the cpu entry area Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 10/19] x86/asm/64: Separate cpu_current_top_of_stack from TSS.sp0 Andy Lutomirski
2017-11-24 4:32 ` Andy Lutomirski [this message]
2017-11-24 4:32 ` [PATCH v3 12/19] x86/asm/64: Use a percpu trampoline stack for IDT entries Andy Lutomirski
2017-11-24 4:32 ` [PATCH v3 13/19] x86/asm/64: Return to userspace from the trampoline stack Andy Lutomirski
2017-11-24 4:33 ` [PATCH v3 14/19] x86/entry/64: Create a percpu SYSCALL entry trampoline Andy Lutomirski
2017-11-24 11:39 ` David Laight
2017-12-01 5:56 ` Andy Lutomirski
2017-11-24 4:33 ` [PATCH v3 15/19] x86/irq: Remove an old outdated comment about context tracking races Andy Lutomirski
2017-11-24 4:33 ` [PATCH v3 16/19] x86/irq/64: In the stack overflow warning, print the offending IP Andy Lutomirski
2017-11-24 4:33 ` [PATCH v3 17/19] x86/entry/64: Move the IST stacks into cpu_entry_area Andy Lutomirski
2017-11-24 4:33 ` [PATCH v3 18/19] x86/entry/64: Remove the SYSENTER stack canary Andy Lutomirski
2017-11-24 4:33 ` [PATCH v3 19/19] x86/entry: Clean up SYSENTER_stack code Andy Lutomirski
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