From 2c43838c99d9d23f17eb2bdadafcb2879cca6995 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 14 Dec 2017 19:18:26 +0100 Subject: sched/isolation: Enable CONFIG_CPU_ISOLATION=y by default The "isolcpus=" boot parameter support was always built-in before we moved the related code under CONFIG_CPU_ISOLATION. Having it disabled by default is very confusing for people accustomed to use this parameter. So enable it by dafault to keep the previous behaviour but keep it optable for those who want to tinify their kernels. Signed-off-by: Frederic Weisbecker Cc: Chris Metcalf Cc: Christoph Lameter Cc: John Stultz Cc: Linus Torvalds Cc: Luiz Capitulino Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Wanpeng Li Cc: kernel test robot Link: http://lkml.kernel.org/r/1513275507-29200-3-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar --- init/Kconfig | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 2934249fba46..690a381adee0 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -461,10 +461,14 @@ endmenu # "CPU/Task time and stats accounting" config CPU_ISOLATION bool "CPU isolation" + default y help Make sure that CPUs running critical tasks are not disturbed by any source of "noise" such as unbound workqueues, timers, kthreads... - Unbound jobs get offloaded to housekeeping CPUs. + Unbound jobs get offloaded to housekeeping CPUs. This is driven by + the "isolcpus=" boot parameter. + + Say Y if unsure. source "kernel/rcu/Kconfig" -- cgit From 613e396bc0d4c7604fba23256644e78454c68cf6 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 17 Dec 2017 10:56:29 +0100 Subject: init: Invoke init_espfix_bsp() from mm_init() init_espfix_bsp() needs to be invoked before the page table isolation initialization. Move it into mm_init() which is the place where pti_init() will be added. While at it get rid of the #ifdeffery and provide proper stub functions. Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- init/main.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'init') diff --git a/init/main.c b/init/main.c index 0ee9c6866ada..8a390f60ec81 100644 --- a/init/main.c +++ b/init/main.c @@ -504,6 +504,8 @@ static void __init mm_init(void) pgtable_init(); vmalloc_init(); ioremap_huge_init(); + /* Should be run before the first non-init thread is created */ + init_espfix_bsp(); } asmlinkage __visible void __init start_kernel(void) @@ -673,10 +675,6 @@ asmlinkage __visible void __init start_kernel(void) #ifdef CONFIG_X86 if (efi_enabled(EFI_RUNTIME_SERVICES)) efi_enter_virtual_mode(); -#endif -#ifdef CONFIG_X86_ESPFIX64 - /* Should be run before the first non-init thread is created */ - init_espfix_bsp(); #endif thread_stack_cache_init(); cred_init(); -- cgit From aa8c6248f8c75acfd610fe15d8cae23cf70d9d09 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 4 Dec 2017 15:07:36 +0100 Subject: x86/mm/pti: Add infrastructure for page table isolation Add the initial files for kernel page table isolation, with a minimal init function and the boot time detection for this misfeature. Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Signed-off-by: Ingo Molnar --- init/main.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'init') diff --git a/init/main.c b/init/main.c index 8a390f60ec81..b32ec72cdf3d 100644 --- a/init/main.c +++ b/init/main.c @@ -75,6 +75,7 @@ #include #include #include +#include #include #include #include @@ -506,6 +507,8 @@ static void __init mm_init(void) ioremap_huge_init(); /* Should be run before the first non-init thread is created */ init_espfix_bsp(); + /* Should be run after espfix64 is set up. */ + pti_init(); } asmlinkage __visible void __init start_kernel(void) -- cgit From 414a2dc138838642d28938506e31ad461648b898 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 2 Jan 2018 12:13:10 +0100 Subject: sched/isolation: Make CONFIG_CPU_ISOLATION=y depend on SMP or COMPILE_TEST On uniprocessor systems, critical and non-critical tasks cannot be isolated, as there is only a single CPU core. Hence enabling CPU isolation by default on such systems does not make much sense. Instead of changing the default for !SMP, fix this by making the feature depend on SMP, with an override for compile-testing. Note that its sole selector (NO_HZ_FULL) already depends on SMP. This decreases kernel size for a default uniprocessor kernel by ca. 1 KiB. Signed-off-by: Geert Uytterhoeven Acked-by: Nicolas Pitre Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 2c43838c99d9d23f ("sched/isolation: Enable CONFIG_CPU_ISOLATION=y by default") Link: http://lkml.kernel.org/r/1514891590-20782-1-git-send-email-geert@linux-m68k.org Signed-off-by: Ingo Molnar --- init/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 690a381adee0..c1221332e128 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -461,6 +461,7 @@ endmenu # "CPU/Task time and stats accounting" config CPU_ISOLATION bool "CPU isolation" + depends on SMP || COMPILE_TEST default y help Make sure that CPUs running critical tasks are not disturbed by -- cgit From 290af86629b25ffd1ed6232c4e9107da031705cb Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 9 Jan 2018 10:04:29 -0800 Subject: bpf: introduce BPF_JIT_ALWAYS_ON config The BPF interpreter has been used as part of the spectre 2 attack CVE-2017-5715. A quote from goolge project zero blog: "At this point, it would normally be necessary to locate gadgets in the host kernel code that can be used to actually leak data by reading from an attacker-controlled location, shifting and masking the result appropriately and then using the result of that as offset to an attacker-controlled address for a load. But piecing gadgets together and figuring out which ones work in a speculation context seems annoying. So instead, we decided to use the eBPF interpreter, which is built into the host kernel - while there is no legitimate way to invoke it from inside a VM, the presence of the code in the host kernel's text section is sufficient to make it usable for the attack, just like with ordinary ROP gadgets." To make attacker job harder introduce BPF_JIT_ALWAYS_ON config option that removes interpreter from the kernel in favor of JIT-only mode. So far eBPF JIT is supported by: x64, arm64, arm32, sparc64, s390, powerpc64, mips64 The start of JITed program is randomized and code page is marked as read-only. In addition "constant blinding" can be turned on with net.core.bpf_jit_harden v2->v3: - move __bpf_prog_ret0 under ifdef (Daniel) v1->v2: - fix init order, test_bpf and cBPF (Daniel's feedback) - fix offloaded bpf (Jakub's feedback) - add 'return 0' dummy in case something can invoke prog->bpf_func - retarget bpf tree. For bpf-next the patch would need one extra hunk. It will be sent when the trees are merged back to net-next Considered doing: int bpf_jit_enable __read_mostly = BPF_EBPF_JIT_DEFAULT; but it seems better to land the patch as-is and in bpf-next remove bpf_jit_enable global variable from all JITs, consolidate in one place and remove this jit_init() function. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- init/Kconfig | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 2934249fba46..5e2a4a391ba9 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1392,6 +1392,13 @@ config BPF_SYSCALL Enable the bpf() system call that allows to manipulate eBPF programs and maps via file descriptors. +config BPF_JIT_ALWAYS_ON + bool "Permanently enable BPF JIT and remove BPF interpreter" + depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT + help + Enables BPF JIT and removes BPF interpreter to avoid + speculative execution of BPF instructions by the interpreter + config USERFAULTFD bool "Enable userfaultfd() system call" select ANON_INODES -- cgit