From 2fbb6773e3a6d5d18e84b0ac79b645147fbf0d66 Mon Sep 17 00:00:00 2001 From: Kyösti Mälkki Date: Tue, 15 May 2018 19:50:20 +0300 Subject: arch/x86: Enforce CPU stack alignment MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When rmodule is loaded CPU stack alignment is only guaranteed to 4kiB. Implementation of cpu_info() requires that each CPU sees its stack aligned to CONFIG_STACK_SIZE. Add one spare CPU for the stack reserve, such that alignment can be enforced runtime. Change-Id: Ie04956c64df0dc7bb156002d3d4f2629f92b340e Signed-off-by: Kyösti Mälkki Reviewed-on: https://review.coreboot.org/c/26302 Reviewed-by: Stefan Reinauer Reviewed-by: Aaron Durbin Tested-by: build bot (Jenkins) --- src/arch/x86/c_start.S | 7 +++++-- src/cpu/x86/lapic/lapic_cpu_init.c | 22 +++++++++++----------- src/cpu/x86/mp_init.c | 9 +++++---- 3 files changed, 21 insertions(+), 17 deletions(-) (limited to 'src') diff --git a/src/arch/x86/c_start.S b/src/arch/x86/c_start.S index 3fbdac11b3..86147ecdc7 100644 --- a/src/arch/x86/c_start.S +++ b/src/arch/x86/c_start.S @@ -19,9 +19,11 @@ .global _stack .global _estack +/* Stack alignment is not enforced with rmodule loader, reserve one + * extra CPU such that alignment can be enforced on entry. */ .align CONFIG_STACK_SIZE _stack: -.space CONFIG_MAX_CPUS*CONFIG_STACK_SIZE +.space (CONFIG_MAX_CPUS+1)*CONFIG_STACK_SIZE _estack: #if IS_ENABLED(CONFIG_COOP_MULTITASKING) .global thread_stacks @@ -70,8 +72,9 @@ _start: rep stosl - /* set new stack */ + /* Set new stack with enforced alignment. */ movl $_estack, %esp + andl $(~(CONFIG_STACK_SIZE-1)), %esp #if IS_ENABLED(CONFIG_COOP_MULTITASKING) /* Push the thread pointer. */ diff --git a/src/cpu/x86/lapic/lapic_cpu_init.c b/src/cpu/x86/lapic/lapic_cpu_init.c index 4498b97b1c..7daca0ac67 100644 --- a/src/cpu/x86/lapic/lapic_cpu_init.c +++ b/src/cpu/x86/lapic/lapic_cpu_init.c @@ -263,8 +263,8 @@ volatile unsigned int secondary_cpu_index; int start_cpu(struct device *cpu) { struct cpu_info *info; - unsigned long stack_end; - unsigned long stack_base; + uintptr_t stack_top; + uintptr_t stack_base; unsigned long apicid; unsigned int index; unsigned long count; @@ -278,23 +278,23 @@ int start_cpu(struct device *cpu) /* Get an index for the new processor */ index = ++last_cpu_index; - /* Find end of the new processor's stack */ - stack_end = ((unsigned long)_estack) - (CONFIG_STACK_SIZE*index) - - sizeof(struct cpu_info); - - stack_base = ((unsigned long)_estack) - (CONFIG_STACK_SIZE*(index+1)); - printk(BIOS_SPEW, "CPU%d: stack_base %p, stack_end %p\n", index, - (void *)stack_base, (void *)stack_end); + /* Find boundaries of the new processor's stack */ + stack_top = ALIGN_DOWN((uintptr_t)_estack, CONFIG_STACK_SIZE); + stack_top -= (CONFIG_STACK_SIZE*index); + stack_base = stack_top - CONFIG_STACK_SIZE; + stack_top -= sizeof(struct cpu_info); + printk(BIOS_SPEW, "CPU%d: stack_base %p, stack_top %p\n", index, + (void *)stack_base, (void *)stack_top); stacks[index] = (void *)stack_base; /* Record the index and which CPU structure we are using */ - info = (struct cpu_info *)stack_end; + info = (struct cpu_info *)stack_top; info->index = index; info->cpu = cpu; thread_init_cpu_info_non_bsp(info); /* Advertise the new stack and index to start_cpu */ - secondary_stack = stack_end; + secondary_stack = stack_top; secondary_cpu_index = index; /* Until the CPU starts up report the CPU is not enabled */ diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c index 9526824976..3889c7d28e 100644 --- a/src/cpu/x86/mp_init.c +++ b/src/cpu/x86/mp_init.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -229,11 +230,11 @@ static void asmlinkage ap_init(unsigned int cpu) static void setup_default_sipi_vector_params(struct sipi_params *sp) { - sp->gdt = (uint32_t)&gdt; - sp->gdtlimit = (uint32_t)&gdt_end - (u32)&gdt - 1; - sp->idt_ptr = (uint32_t)&idtarg; + sp->gdt = (uintptr_t)&gdt; + sp->gdtlimit = (uintptr_t)&gdt_end - (uintptr_t)&gdt - 1; + sp->idt_ptr = (uintptr_t)&idtarg; sp->stack_size = CONFIG_STACK_SIZE; - sp->stack_top = (uint32_t)&_estack; + sp->stack_top = ALIGN_DOWN((uintptr_t)&_estack, CONFIG_STACK_SIZE); /* Adjust the stack top to take into account cpu_info. */ sp->stack_top -= sizeof(struct cpu_info); } -- cgit v1.2.3