From 404f6aac9b3ef595735feca99979db084ea48315 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 8 Aug 2016 16:29:06 -0700 Subject: x86: Apply more __ro_after_init and const Guided by grsecurity's analogous __read_only markings in arch/x86, this applies several uses of __ro_after_init to structures that are only updated during __init, and const for some structures that are never updated. Additionally extends __init markings to some functions that are only used during __init, and cleans up some missing C99 style static initializers. Signed-off-by: Kees Cook Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brad Spengler Cc: Brian Gerst Cc: David Brown Cc: Denys Vlasenko Cc: Emese Revfy Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Mathias Krause Cc: Michael Ellerman Cc: PaX Team Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: kernel-hardening@lists.openwall.com Link: http://lkml.kernel.org/r/20160808232906.GA29731@www.outflux.net Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'arch/x86/kernel/cpu/common.c') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 809eda03c527..d3b91be4873b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1265,9 +1265,14 @@ static __init int setup_disablecpuid(char *arg) __setup("clearcpuid=", setup_disablecpuid); #ifdef CONFIG_X86_64 -struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table }; -struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1, - (unsigned long) debug_idt_table }; +struct desc_ptr idt_descr __ro_after_init = { + .size = NR_VECTORS * 16 - 1, + .address = (unsigned long) idt_table, +}; +const struct desc_ptr debug_idt_descr = { + .size = NR_VECTORS * 16 - 1, + .address = (unsigned long) debug_idt_table, +}; DEFINE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __aligned(PAGE_SIZE) __visible; -- cgit v1.2.3 From 4950d6d48a0c43cc61d0bbb76fb10e0214b79c66 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 18 Aug 2016 10:59:08 -0500 Subject: x86/dumpstack: Remove 64-byte gap at end of irq stack There has been a 64-byte gap at the end of the irq stack for at least 12 years. It predates git history, and I can't find any good reason for it. Remove it. What's the worst that could happen? Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/14f9281c5475cc44af95945ea7546bff2e3836db.1471535549.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/cpu/common.c') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 809eda03c527..6ef55e83fb8a 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1281,7 +1281,7 @@ DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = EXPORT_PER_CPU_SYMBOL(current_task); DEFINE_PER_CPU(char *, irq_stack_ptr) = - init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64; + init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE; DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1; -- cgit v1.2.3 From 556b6723689694ac9134bcc36a07828168e057f4 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Tue, 23 Aug 2016 19:23:56 +0200 Subject: x86/entry: Remove outdated comment about SYSCALL targets The comment probably meant some old AMD64 incarnation which most likely never saw the light of day. STAR and LSTAR are two different registers and STAR sets CS/SS(DS) selectors for *all* modes, not only 32-bit. So simply remove that comment. Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20160823172356.15879-1-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'arch/x86/kernel/cpu/common.c') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 6ef55e83fb8a..e374c19b9ddc 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1305,11 +1305,6 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks /* May not be marked __init: used by software suspend */ void syscall_init(void) { - /* - * LSTAR and STAR live in a bit strange symbiosis. - * They both write to the same internal register. STAR allows to - * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip. - */ wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); -- cgit v1.2.3