user/sven/linux.git/arch/powerpc/lib/code-patching.c, branch v4.9.220

powerpc/lib: fix book3s/32 boot failure due to code patching

2019-05-16T17:43:47Z

commit b45ba4a51cde29b2939365ef0c07ad34c8321789 upstream. Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections") accesses 'init_mem_is_free' flag too early, before the kernel is relocated. This provokes early boot failure (before the console is active). As it is not necessary to do this verification that early, this patch moves the test into patch_instruction() instead of __patch_instruction(). This modification also has the advantage of avoiding unnecessary remappings. Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections") Cc: stable@vger.kernel.org # 4.13+ Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/asm: Add a patch_site macro & helpers for patching instructions

2019-04-17T06:36:41Z

commit 06d0bbc6d0f56dacac3a79900e9a9a0d5972d818 upstream. Add a macro and some helper C functions for patching single asm instructions. The gas macro means we can do something like: 1: nop patch_site 1b, patch__foo Which is less visually distracting than defining a GLOBAL symbol at 1, and also doesn't pollute the symbol table which can confuse eg. perf. These are obviously similar to our existing feature sections, but are not automatically patched based on CPU/MMU features, rather they are designed to be manually patched by C code at some arbitrary point. Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc: Avoid code patching freed init sections

2019-04-17T06:36:40Z

commit 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 upstream. This stops us from doing code patching in init sections after they've been freed. In this chain: kvm_guest_init() -> kvm_use_magic_page() -> fault_in_pages_readable() -> __get_user() -> __get_user_nocheck() -> barrier_nospec(); We have a code patching location at barrier_nospec() and kvm_guest_init() is an init function. This whole chain gets inlined, so when we free the init section (hence kvm_guest_init()), this code goes away and hence should no longer be patched. We seen this as userspace memory corruption when using a memory checker while doing partition migration testing on powervm (this starts the code patching post migration via /sys/kernel/mobility/migration). In theory, it could also happen when using /sys/kernel/debug/powerpc/barrier_nospec. Cc: stable@vger.kernel.org # 4.13+ Signed-off-by: Michael Neuling Reviewed-by: Nicholas Piggin Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/modules: Don't try to restore r2 after a sibling call

2018-03-22T08:17:57Z

[ Upstream commit b9eab08d012fa093947b230f9a87257c27fb829b ] When attempting to load a livepatch module, I got the following error: module_64: patch_module: Expect noop after relocate, got 3c820000 The error was triggered by the following code in unregister_netdevice_queue(): 14c: 00 00 00 48 b 14c 14c: R_PPC64_REL24 net_set_todo 150: 00 00 82 3c addis r4,r2,0 GCC didn't insert a nop after the branch to net_set_todo() because it's a sibling call, so it never returns. The nop isn't needed after the branch in that case. Signed-off-by: Josh Poimboeuf Acked-by: Naveen N. Rao Reviewed-and-tested-by: Kamalesh Babulal Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

powerpc: Move the patch_exception to a common place

2013-12-02T03:06:54Z

So that it can be used by other codes. No function change. Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt

powerpc: Don't use __put_user() in patch_instruction

2012-09-05T06:05:23Z

patch_instruction() can be called very early on ppc32, when the kernel isn't yet running at it's linked address. That can cause the ! is_kernel_addr() test in __put_user() to trip and call might_sleep() which is very bad at that point during boot. Use a lower level function instead for now, at least until we get to rework ppc32 boot process to do the code patching later, like ppc64 does. Signed-off-by: Benjamin Herrenschmidt

powerpc: Have patch_instruction detect faults

2012-07-03T04:14:38Z

For ftrace to use the patch_instruction code, it needs to check for faults on write. Ftrace updates code all over the kernel, and we need to know if code is updated or not due to protections that are placed on some portions of the kernel. If ftrace does not detect a fault, it will error later on, and it will be much more difficult to find the problem. By changing patch_instruction() to detect faults, then ftrace will be able to make use of it too. Signed-off-by: Steven Rostedt Signed-off-by: Benjamin Herrenschmidt

PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures

2008-07-24T17:47:21Z

On 32-bit architectures PAGE_ALIGN() truncates 64-bit values to the 32-bit boundary. For example: u64 val = PAGE_ALIGN(size); always returns a value < 4GB even if size is greater than 4GB. The problem resides in PAGE_MASK definition (from include/asm-x86/page.h for example): #define PAGE_SHIFT 12 #define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT) #define PAGE_MASK (~(PAGE_SIZE-1)) ... #define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) The "~" is performed on a 32-bit value, so everything in "and" with PAGE_MASK greater than 4GB will be truncated to the 32-bit boundary. Using the ALIGN() macro seems to be the right way, because it uses typeof(addr) for the mask. Also move the PAGE_ALIGN() definitions out of include/asm-*/page.h in include/linux/mm.h. See also lkml discussion: http://lkml.org/lkml/2008/6/11/237 [akpm@linux-foundation.org: fix drivers/media/video/uvc/uvc_queue.c] [akpm@linux-foundation.org: fix v850] [akpm@linux-foundation.org: fix powerpc] [akpm@linux-foundation.org: fix arm] [akpm@linux-foundation.org: fix mips] [akpm@linux-foundation.org: fix drivers/media/video/pvrusb2/pvrusb2-dvb.c] [akpm@linux-foundation.org: fix drivers/mtd/maps/uclinux.c] [akpm@linux-foundation.org: fix powerpc] Signed-off-by: Andrea Righi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc: Add tests of the code patching routines

2008-07-01T01:28:22Z

Add tests of the existing code patching routines, as well as the new routines added in the last commit. The self-tests are run late in boot when CONFIG_CODE_PATCHING_SELFTEST=y, which depends on DEBUG_KERNEL=y. Signed-off-by: Michael Ellerman Acked-by: Kumar Gala Signed-off-by: Paul Mackerras

powerpc: Add new code patching routines

2008-07-01T01:28:21Z

This commit adds some new routines for patching code, which will be used in a following commit. Signed-off-by: Michael Ellerman Signed-off-by: Paul Mackerras