4.9-stable review patch. If anyone has any objections, please let me know.
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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;