This is a note to let you know that I've just added the patch titled
powerpc/nohash: Fix use of mmu_has_feature() in setup_initial_memory_limit()
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: powerpc-nohash-fix-use-of-mmu_has_feature-in-setup_initial_memory_limit.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Sun Mar 18 16:55:33 CET 2018
From: Michael Ellerman mpe@ellerman.id.au Date: Mon, 3 Apr 2017 12:05:55 +1000 Subject: powerpc/nohash: Fix use of mmu_has_feature() in setup_initial_memory_limit()
From: Michael Ellerman mpe@ellerman.id.au
[ Upstream commit 4868e3508d1934d28961f940ed6b9f1e347ab52c ]
setup_initial_memory_limit() is called from early_init_devtree(), which runs prior to feature patching. If the kernel is built with CONFIG_JUMP_LABEL=y and CONFIG_JUMP_LABEL_FEATURE_CHECKS=y then we will potentially get the wrong value.
If we also have CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG=y we get a warning and backtrace:
Warning! mmu_has_feature() used prior to jump label init! CPU: 0 PID: 0 Comm: swapper Not tainted 4.11.0-rc4-gccN-next-20170331-g6af2434 #1 Call Trace: [c000000000fc3d50] [c000000000a26c30] .dump_stack+0xa8/0xe8 (unreliable) [c000000000fc3de0] [c00000000002e6b8] .setup_initial_memory_limit+0xa4/0x104 [c000000000fc3e60] [c000000000d5c23c] .early_init_devtree+0xd0/0x2f8 [c000000000fc3f00] [c000000000d5d3b0] .early_setup+0x90/0x11c [c000000000fc3f90] [c000000000000520] start_here_multiplatform+0x68/0x80
Fix it by using early_mmu_has_feature().
Fixes: c12e6f24d413 ("powerpc: Add option to use jump label for mmu_has_feature()") Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/mm/tlb_nohash.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/powerpc/mm/tlb_nohash.c +++ b/arch/powerpc/mm/tlb_nohash.c @@ -751,7 +751,7 @@ void setup_initial_memory_limit(phys_add * avoid going over total available memory just in case... */ #ifdef CONFIG_PPC_FSL_BOOK3E - if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) { + if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E)) { unsigned long linear_sz; unsigned int num_cams;
Patches currently in stable-queue which might be from mpe@ellerman.id.au are
queue-4.9/powerpc-nohash-fix-use-of-mmu_has_feature-in-setup_initial_memory_limit.patch queue-4.9/powerpc-avoid-taking-a-data-miss-on-every-userspace-instruction-miss.patch queue-4.9/powerpc-modules-don-t-try-to-restore-r2-after-a-sibling-call.patch queue-4.9/powerpc-xmon-fix-an-unexpected-xmon-on-off-state-change.patch queue-4.9/powerpc-mm-hugetlb-filter-out-hugepage-size-not-supported-by-page-table-layout.patch