kernel.git/arch/x86/kernel/traps.c, branch linux-3.11.y

x86: Make sure IDT is page aligned

2013-07-16T22:14:48Z

Since the IDT is referenced from a fixmap, make sure it is page aligned. Merge with 32-bit one, since it was already aligned to deal with F00F bug. Since bss is cleared before IDT setup, it can live there. This also moves the other *_idt_table variables into common locations. This avoids the risk of the IDT ever being moved in the bss and having the mapping be offset, resulting in calling incorrect handlers. In the current upstream kernel this is not a manifested bug, but heavily patched kernels (such as those using the PaX patch series) did encounter this bug. The tables other than idt_table technically do not need to be page aligned, at least not at the current time, but using a common declaration avoids mistakes. On 64 bits the table is exactly one page long, anyway. Signed-off-by: Kees Cook Link: http://lkml.kernel.org/r/20130716183441.GA14232@www.outflux.net Reported-by: PaX Team Signed-off-by: H. Peter Anvin

Merge branch 'x86-tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-07-02T23:31:49Z

Pull x86 tracing updates from Ingo Molnar: "This tree adds IRQ vector tracepoints that are named after the handler and which output the vector #, based on a zero-overhead approach that relies on changing the IDT entries, by Seiji Aguchi. The new tracepoints look like this: # perf list | grep -i irq_vector irq_vectors:local_timer_entry [Tracepoint event] irq_vectors:local_timer_exit [Tracepoint event] irq_vectors:reschedule_entry [Tracepoint event] irq_vectors:reschedule_exit [Tracepoint event] irq_vectors:spurious_apic_entry [Tracepoint event] irq_vectors:spurious_apic_exit [Tracepoint event] irq_vectors:error_apic_entry [Tracepoint event] irq_vectors:error_apic_exit [Tracepoint event] [...]" * 'x86-tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tracing: Add config option checking to the definitions of mce handlers trace,x86: Do not call local_irq_save() in load_current_idt() trace,x86: Move creation of irq tracepoints from apic.c to irq.c x86, trace: Add irq vector tracepoints x86: Rename variables for debugging x86, trace: Introduce entering/exiting_irq() tracing: Add DEFINE_EVENT_FN() macro

Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-07-02T23:25:06Z

Pull x86 debug update from Ingo Molnar: "Misc debuggability improvements: - Optimize the x86 CPU register printout a bit - Expose the tboot TXT log via debugfs - Small do_debug() cleanup" * 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tboot: Provide debugfs interfaces to access TXT log x86: Remove weird PTR_ERR() in do_debug x86/debug: Only print out DR registers if they are not power-on defaults

x86: Rename variables for debugging

2013-06-21T05:25:13Z

Rename variables for debugging to describe meaning of them precisely. Also, introduce a generic way to switch IDT by checking a current state, debug on/off. Signed-off-by: Seiji Aguchi Link: http://lkml.kernel.org/r/51C323A8.7050905@hds.com Signed-off-by: H. Peter Anvin Cc: Steven Rostedt

x86: Remove weird PTR_ERR() in do_debug

2013-06-19T13:01:36Z

62edab905 changed the argument to notify_die() from dr6 to &dr6, but weirdly, used PTR_ERR() to cast it to a long. Since dr6 is on the stack, this is an abuse of PTR_ERR(). Cast to long, as per kernel standard. Signed-off-by: Rusty Russell Cc: K.Prasad Link: http://lkml.kernel.org/r/1371357768-4968-8-git-send-email-rusty@rustcorp.com.au Signed-off-by: Ingo Molnar

x86: Extend #DF debugging aid to 64-bit

2013-05-13T20:42:44Z

It is sometimes very helpful to be able to pinpoint the location which causes a double fault before it turns into a triple fault and the machine reboots. We have this for 32-bit already so extend it to 64-bit. On 64-bit we get the register snapshot at #DF time and not from the first exception which actually causes the #DF. It should be close enough, though. [ hpa: and definitely better than nothing, which is what we have now. ] Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1368093749-31296-1-git-send-email-bp@alien8.de Signed-off-by: H. Peter Anvin

Merge branch 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-04-30T15:37:24Z

Pull perparatory x86 kasrl changes from Ingo Molnar: "This contains changes from the ongoing KASLR work, by Kees Cook. The main changes are the use of a read-only IDT on x86 (which decouples the userspace visible virtual IDT address from the physical address), and a rework of ELF relocation support, in preparation of random, boot-time kernel image relocation." * 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, relocs: Refactor the relocs tool to merge 32- and 64-bit ELF x86, relocs: Build separate 32/64-bit tools x86, relocs: Add 64-bit ELF support to relocs tool x86, relocs: Consolidate processing logic x86, relocs: Generalize ELF structure names x86: Use a read-only IDT alias on all CPUs

x86: Use a read-only IDT alias on all CPUs

2013-04-11T20:53:19Z

Make a copy of the IDT (as seen via the "sidt" instruction) read-only. This primarily removes the IDT from being a target for arbitrary memory write attacks, and has the added benefit of also not leaking the kernel base offset, if it has been relocated. We already did this on vendor == Intel and family == 5 because of the F0 0F bug -- regardless of if a particular CPU had the F0 0F bug or not. Since the workaround was so cheap, there simply was no reason to be very specific. This patch extends the readonly alias to all CPUs, but does not activate the #PF to #UD conversion code needed to deliver the proper exception in the F0 0F case except on Intel family 5 processors. Signed-off-by: Kees Cook Link: http://lkml.kernel.org/r/20130410192422.GA17344@www.outflux.net Cc: Eric Northup Signed-off-by: H. Peter Anvin

context_tracking: Restore correct previous context state on exception exit

2013-03-07T16:10:11Z

On exception exit, we restore the previous context tracking state based on the regs of the interrupted frame. Iff that frame is in user mode as stated by user_mode() helper, we restore the context tracking user mode. However there is a tiny chunck of low level arch code after we pass through user_enter() and until the CPU eventually resumes userspace. If an exception happens in this tiny area, exception_enter() correctly exits the context tracking user mode but exception_exit() won't restore it because of the value returned by user_mode(regs). As a result we may return to userspace with the wrong context tracking state. To fix this, change exception_enter() to return the context tracking state prior to its call and pass this saved state to exception_exit(). This restores the real context tracking state of the interrupted frame. (May be this patch was suggested to me, I don't recall exactly. If so, sorry for the missing credit). Signed-off-by: Frederic Weisbecker Cc: Li Zhong Cc: Kevin Hilman Cc: Mats Liljegren Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Steven Rostedt Cc: Namhyung Kim Cc: Andrew Morton Cc: Thomas Gleixner Cc: Paul E. McKenney

context_tracking: Move exception handling to generic code

2013-03-07T16:09:25Z

Exceptions handling on context tracking should share common treatment: on entry we exit user mode if the exception triggered in that context. Then on exception exit we return to that previous context. Generalize this to avoid duplication across archs. Signed-off-by: Frederic Weisbecker Cc: Li Zhong Cc: Kevin Hilman Cc: Mats Liljegren Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Steven Rostedt Cc: Namhyung Kim Cc: Andrew Morton Cc: Thomas Gleixner Cc: Paul E. McKenney