From 7974891db234467eaf1fec613ec0129cb4ac2332 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 28 Jun 2010 14:15:54 +0200 Subject: x86: Always use irq stacks IRQ stacks provide much better safety against unexpected stack use from interrupts, at the minimal downside of slightly higher memory usage. Enable irq stacks also for the default 8k stack on 32-bit kernels to minimize the problem of stack overflows through interrupt activity. This is what the 64-bit kernel and various other architectures already do. Signed-off-by: Christoph Hellwig LKML-Reference: <20100628121554.GA6605@lst.de> Signed-off-by: Thomas Gleixner --- arch/x86/kernel/irq_32.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c index 10709f29d16..67f5f9f5299 100644 --- a/arch/x86/kernel/irq_32.c +++ b/arch/x86/kernel/irq_32.c @@ -49,7 +49,6 @@ static inline int check_stack_overflow(void) { return 0; } static inline void print_stack_overflow(void) { } #endif -#ifdef CONFIG_4KSTACKS /* * per-CPU IRQ handling contexts (thread information and stack) */ @@ -187,11 +186,6 @@ asmlinkage void do_softirq(void) local_irq_restore(flags); } -#else -static inline int -execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; } -#endif - bool handle_irq(unsigned irq, struct pt_regs *regs) { struct irq_desc *desc; -- cgit v1.2.3-18-g5258 From 25897374297906eeebef8864299406bdcb5859c3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 27 Jul 2010 14:13:13 +0200 Subject: x86-32: Align IRQ stacks properly As suggested by Steven Rostedt we need to align the IRQ stacks to the stack size, not just the page size to make them work for stack traces and other things that depend on finding the stack slot itself with 8k stacks. Signed-off-by: Christoph Hellwig LKML-Reference: <20100727121313.GA19976@lst.de> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/irq_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c index 67f5f9f5299..3b5609f54c4 100644 --- a/arch/x86/kernel/irq_32.c +++ b/arch/x86/kernel/irq_32.c @@ -55,7 +55,7 @@ static inline void print_stack_overflow(void) { } union irq_ctx { struct thread_info tinfo; u32 stack[THREAD_SIZE/sizeof(u32)]; -} __attribute__((aligned(PAGE_SIZE))); +} __attribute__((aligned(THREAD_SIZE))); static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx); static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx); -- cgit v1.2.3-18-g5258 From fe8e0c25cad28e8858ecfa5863333c70685a6811 Mon Sep 17 00:00:00 2001 From: Alexander van Heukelum Date: Mon, 6 Sep 2010 20:53:42 +0200 Subject: x86, 32-bit: Align percpu area and irq stacks to THREAD_SIZE The irq stacks, located in the percpu-area, need to be THREAD_SIZE aligned. Add the infrastucture to align percpu variables to larger-than-pagesize amounts within the percpu area, and use it to specify the alignment for the irq stacks. Also align the percpu area itself to THREAD_SIZE. This should make irq stacks work with 8K THREAD_SIZE. Signed-off-by: Alexander van Heukelum Cc: Tejun Heo Cc: hch@lst.de LKML-Reference: <1283799222.15941.1393621887@webmail.messagingengine.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/irq_32.c | 4 ++-- arch/x86/kernel/vmlinux.lds.S | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c index 3b5609f54c4..50fbbe60e50 100644 --- a/arch/x86/kernel/irq_32.c +++ b/arch/x86/kernel/irq_32.c @@ -60,8 +60,8 @@ union irq_ctx { static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx); static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx); -static DEFINE_PER_CPU_PAGE_ALIGNED(union irq_ctx, hardirq_stack); -static DEFINE_PER_CPU_PAGE_ALIGNED(union irq_ctx, softirq_stack); +static DEFINE_PER_CPU_MULTIPAGE_ALIGNED(union irq_ctx, hardirq_stack, THREAD_SIZE); +static DEFINE_PER_CPU_MULTIPAGE_ALIGNED(union irq_ctx, softirq_stack, THREAD_SIZE); static void call_on_stack(void *func, void *stack) { diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index d0bb52296fa..bb899475355 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -273,7 +273,7 @@ SECTIONS } #if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) - PERCPU(PAGE_SIZE) + PERCPU(THREAD_SIZE) #endif . = ALIGN(PAGE_SIZE); -- cgit v1.2.3-18-g5258