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arch/x86: Enforce CPU stack alignment 

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 <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/26302
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Kyösti Mälkki 2018-05-15 19:50:20 +03:00 committed by Patrick Georgi
parent b318be2218
commit 2fbb6773e3
3 changed files with 21 additions and 17 deletions
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7
src/arch/x86/c_start.S
View File

@ -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. */

22
src/cpu/x86/lapic/lapic_cpu_init.c
View File

@ -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 */

9
src/cpu/x86/mp_init.c
View File

@ -18,6 +18,7 @@
#include <stdint.h>
#include <rmodule.h>
#include <arch/cpu.h>
#include <commonlib/helpers.h>
#include <cpu/cpu.h>
#include <cpu/intel/microcode.h>
#include <cpu/x86/cache.h>
@ -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);
}