- 30 Jan, 2008 40 commits
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Bernhard Kaindl authored
This patch adds a new configuration option, which adds support for a new early_param which gets checked in arch/x86/kernel/setup_{32,64}.c:setup_arch() to decide wether OHCI-1394 FireWire controllers should be initialized and enabled for physical DMA access to allow remote debugging of early problems like issues ACPI or other subsystems which are executed very early. If the config option is not enabled, no code is changed, and if the boot paramenter is not given, no new code is executed, and independent of that, all new code is freed after boot, so the config option can be even enabled in standard, non-debug kernels. With specialized tools, it is then possible to get debugging information from machines which have no serial ports (notebooks) such as the printk buffer contents, or any data which can be referenced from global pointers, if it is stored below the 4GB limit and even memory dumps of of the physical RAM region below the 4GB limit can be taken without any cooperation from the CPU of the host, so the machine can be crashed early, it does not matter. In the extreme, even kernel debuggers can be accessed in this way. I wrote a small kgdb module and an accompanying gdb stub for FireWire which allows to gdb to talk to kgdb using remote remory reads and writes over FireWire. An version of the gdb stub fore FireWire is able to read all global data from a system which is running a a normal kernel without any kernel debugger, without any interruption or support of the system's CPU. That way, e.g. the task struct and so on can be read and even manipulated when the physical DMA access is granted. A HOWTO is included in this patch, in Documentation/debugging-via-ohci1394.txt and I've put a copy online at ftp://ftp.suse.de/private/bk/firewire/docs/debugging-via-ohci1394.txt It also has links to all the tools which are available to make use of it another copy of it is online at: ftp://ftp.suse.de/private/bk/firewire/kernel/ohci1394_dma_early-v2.diffSigned-Off-By:Bernhard Kaindl <bk@suse.de> Tested-By:
Thomas Renninger <trenn@suse.de> Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de>
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Jeremy Fitzhardinge authored
In x86 PAE mode, stop treating pmds as a special case. Previously they were always allocated and freed with the pgd. The modifies the code to be the same as 64-bit mode, where they are allocated on demand. This is a step on the way to unifying 32/64-bit pagetable allocation as much as possible. There is a complicating wart, however. When you install a new reference to a pmd in the pgd, the processor isn't guaranteed to see it unless you reload cr3. Since reloading cr3 also has the side-effect of flushing the tlb, this is an expense that we want to avoid whereever possible. This patch simply avoids reloading cr3 unless the update is to the current pagetable. Later patches will optimise this further. Signed-off-by:
Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: William Irwin <wli@holomorphy.com> Signed-off-by:
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Harvey Harrison authored
The change from current to tsk in do_page_fault is safe as this is set at the very beginning of the function. Removes a likely() annotation from the 64-bit version, this could have instead been added to 32-bit. Signed-off-by:
Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by:
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Jeremy Fitzhardinge authored
When changing a kernel page from RO->RW, it's OK to leave stale TLB entries around, since doing a global flush is expensive and they pose no security problem. They can, however, generate a spurious fault, which we should catch and simply return from (which will have the side-effect of reloading the TLB to the current PTE). This can occur when running under Xen, because it frequently changes kernel pages from RW->RO->RW to implement Xen's pagetable semantics. It could also occur when using CONFIG_DEBUG_PAGEALLOC, since it avoids doing a global TLB flush after changing page permissions. Signed-off-by:
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Harvey Harrison authored
On !PAE 32-bit, _PAGE_NX will be 0, making is_prefetch always return early. The test is sufficient on PAE as __supported_pte_mask is updated in the same places as nx_enabled in init_32.c which also takes disable_nx into account. Signed-off-by:
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Harvey Harrison authored
Unify includes in moved fault.c. Modify Makefiles to pick up unified file. Signed-off-by:
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Harvey Harrison authored
Elimination of these ifdefs can be done in a unified file. Signed-off-by:
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Harvey Harrison authored
It's about time to get on with unifying these files, elimination of the ugly ifdefs can occur in the unified file. Signed-off-by:
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Ingo Molnar authored
printk fixes. NOP in terms of functionality, but strings got a bit larger due to the KERN_ markers that were added. Signed-off-by:
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Ingo Molnar authored
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Ingo Molnar authored
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Thomas Gleixner authored
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Huang, Ying authored
This patch fixes some bugs of EFI memory handing code. - On x86_64, it is possible that EFI memory map can not be mapped via identity map, so efi_map_memmap is removed, just use early_ioremap. - On i386, the EFI memory map mapping take effect cross paging_init, so it is not necessary to use efi_map_memmap. - EFI memory map is unmapped in efi_enter_virtual_mode to avoid early_ioremap leak. Signed-off-by:
Huang Ying <ying.huang@intel.com> Signed-off-by:
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Huang, Ying authored
This patch makes reboot_type of BOOT_EFI is used on i386 too. Because correpsonding reboot code of i386 and x86_64 is merged. Signed-off-by:
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Harvey Harrison authored
This changes the oops dumping format for page faults to be similar between X86_32 and 64. This is the first user of printk_address on X86_32. Signed-off-by:
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Harvey Harrison authored
This will help when unifying the oops dumping code on 32/64 bit. No functional changes. Signed-off-by:
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Harvey Harrison authored
Further towards unifying these files, add another helper in same spirit as is_errata93. Signed-off-by:
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Harvey Harrison authored
Further towards unifying these files, add another helper in same spirit as is_errata93. Signed-off-by:
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Ingo Molnar authored
Yes! A mere 120 c_p_a() fixing and rewriting patches later, we are now confident that we can enable UC by default for ioremap(), on x86 too. Every other architectures was doing this already. Doing so makes Linux more robust against MTRR mixups (which might go unnoticed if BIOS writers test other OSs only - where PAT might override bad MTRRs defaults). Signed-off-by:
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Thomas Gleixner authored
Cleanup the address calculations, which are necessary to identify the high/low alias mappings of the kernel on 64 bit machines. Instead of calling __pa/__va back and forth, calculate the physical address once and base the other calculations on it. Add understandable constants so we can use the already available within() helper. Also add comments, which help mere mortals to understand what this code does. Signed-off-by:
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Ingo Molnar authored
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Ingo Molnar authored
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Ingo Molnar authored
make CONFIG_DEBUG_PAGEALLOC universally available. CONFIG_HIBERNATION and CONFIG_HUGETLBFS was disabling it, for no particular reason. If there are any unfixed bugs here we'll fix it, but do not disable vital debugging facilities like that .. Signed-off-by:
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Ingo Molnar authored
debug incorrect/late access to init memory, by permanently unmapping the init memory ranges. Depends on CONFIG_DEBUG_PAGEALLOC=y. Signed-off-by:
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Arjan van de Ven authored
It looks like a mismerge put the rodata self-check in the wrong spot; move it to the right place after marking the .rodata section read only. Signed-off-by:
Arjan van de Ven <arjan@linux.intel.com> Signed-off-by:
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Ingo Molnar authored
only present ptes must be flushed. Signed-off-by:
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Thomas Gleixner authored
clflush is sufficient to be issued on one CPU. The invalidation is broadcast throughout the coherence domain. Signed-off-by:
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Thomas Gleixner authored
clflush is an unordered operation with respect to other memory traffic, including other CLFLUSH instructions. This needs proper fencing with mfence. Signed-off-by:
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Thomas Gleixner authored
The function name global_flush_tlb() suggests something different from what the function really does. Rename it to cpa_flush_all(), which is an understandable counterpart to cpa_flush_range(). no global visibility of the old API anymore. Signed-off-by:
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Thomas Gleixner authored
Use clflush on CPUs which support this. clflush is only used when the page attribute operation has been successful. On CPUs which do not support clflush and in the case of error the old fashioned global_flush_tlb() is called. Signed-off-by:
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Thomas Gleixner authored
Convert cpa_set and cpa_clear to call the new set_clr function. Seperate out the debug helpers. Signed-off-by:
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Thomas Gleixner authored
Create a set_and_clr function to avoid the duplicate loops. Allows also to do combined operations for optimization. Signed-off-by:
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Thomas Gleixner authored
To avoid the modification of the flush code for the clflush implementation, move the flush into the set and clear functions and provide helper functions for the debugging code. Signed-off-by:
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Arjan van de Ven authored
Latest update; I now have 4 NX tests, but 2 fail so they're #if 0'd. I also cleaned up the NX test code quite a bit, and got rid of the ugly exception table sorting stuff. From: Arjan van de Ven <arjan@linux.intel.com> This patch adds testcases for the CONFIG_DEBUG_RODATA configuration option as well as the NX CPU feature/mappings. Both testcases can move to tests/ once that patch gets merged into mainline. (I'm half considering moving the rodata test into mm/init.c but I'll wait with that until init.c is unified) As part of this I had to fix a not-quite-right alignment in the vmlinux.lds.h for the RODATA sections, which lead to 1 page less being marked read only. Signed-off-by:
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Ingo Molnar authored
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Thomas Gleixner authored
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Ingo Molnar authored
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Thomas Gleixner authored
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Arjan van de Ven authored
When we free initmem, various rodata and CPA checks may have left memory read only.. this patch ensures that the memory is writable before we free it. Signed-off-by:
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Arjan van de Ven authored
In Ingo's testing, he found a bug in the CPA selftest code. What would happen is that the test would call change_page_attr_addr on a range of memory, part of which was read only, part of which was writable. The only thing the test wanted to change was the global bit... What actually happened was that the selftest would take the permissions of the first page, and then the change_page_attr_addr call would then set the permissions of the entire range to this first page. In the rodata section case, this resulted in pages after the .rodata becoming read only... which made the kernel rather unhappy in many interesting ways. This is just another example of how dangerous the cpa API is (was); this patch changes the test to use the incremental clear/set APIs instead, and it changes the clear/set implementation to work on a 1 page at a time basis. Signed-off-by:
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