From 4d75dbd1c1d6362c002a26a5c4e6de74b2816cdf Mon Sep 17 00:00:00 2001 From: Arthur Heymans Date: Tue, 1 Nov 2022 23:57:24 +0100 Subject: cpu/x86: Set up a separate stack for APs APs use a lot less stack, so set up a separate stack for those in .bss. Now that CPU_INFO_V2 is the only code path that is used, there is no need to align stacks in c_start.S. Change-Id: I7a681a2e3003da0400843daa5d6d6180d952abf5 Signed-off-by: Arthur Heymans Reviewed-on: https://review.coreboot.org/c/coreboot/+/69123 Tested-by: build bot (Jenkins) Reviewed-by: Angel Pons Reviewed-by: Werner Zeh --- src/arch/x86/c_start.S | 8 +++----- src/cpu/x86/Kconfig | 7 +++++++ src/cpu/x86/mp_init.c | 6 ++++-- 3 files changed, 14 insertions(+), 7 deletions(-) (limited to 'src') diff --git a/src/arch/x86/c_start.S b/src/arch/x86/c_start.S index 5b7052ef58..52aeb19b57 100644 --- a/src/arch/x86/c_start.S +++ b/src/arch/x86/c_start.S @@ -10,11 +10,9 @@ .global _estack .global _stack_size -/* Stack alignment is not enforced with rmodule loader, reserve one - * extra CPU such that alignment can be enforced on entry. */ -.align CONFIG_STACK_SIZE +.align 16 _stack: -.space (CONFIG_MAX_CPUS+1)*CONFIG_STACK_SIZE +.space CONFIG_STACK_SIZE _estack: .set _stack_size, _estack - _stack @@ -75,7 +73,7 @@ _start: /* Set new stack with enforced alignment. */ movl $_estack, %esp - andl $(~(CONFIG_STACK_SIZE-1)), %esp + andl $(0xfffffff0), %esp /* * Now we are finished. Memory is up, data is copied and diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig index 2253e18ade..7e5817537e 100644 --- a/src/cpu/x86/Kconfig +++ b/src/cpu/x86/Kconfig @@ -202,4 +202,11 @@ config RESERVE_MTRRS_FOR_OS However, modern OSes use PAT to control cacheability instead of using MTRRs. +config AP_STACK_SIZE + hex + default 0x800 + help + This is the amount of stack each AP needs. The BSP stack size can be + larger and is set with STACK_SIZE. + endif # ARCH_X86 diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c index f00418547e..507da7d1be 100644 --- a/src/cpu/x86/mp_init.c +++ b/src/cpu/x86/mp_init.c @@ -215,6 +215,8 @@ static asmlinkage void ap_init(unsigned int index) park_this_cpu(NULL); } +static __aligned(16) uint8_t ap_stack[CONFIG_AP_STACK_SIZE * CONFIG_MAX_CPUS]; + static void setup_default_sipi_vector_params(struct sipi_params *sp) { sp->gdt = (uintptr_t)&gdt; @@ -222,8 +224,8 @@ static void setup_default_sipi_vector_params(struct sipi_params *sp) sp->idt_ptr = (uintptr_t)&idtarg; sp->per_cpu_segment_descriptors = (uintptr_t)&per_cpu_segment_descriptors; sp->per_cpu_segment_selector = per_cpu_segment_selector; - sp->stack_size = CONFIG_STACK_SIZE; - sp->stack_top = ALIGN_DOWN((uintptr_t)&_estack, CONFIG_STACK_SIZE); + sp->stack_size = CONFIG_AP_STACK_SIZE; + sp->stack_top = (uintptr_t)ap_stack + ARRAY_SIZE(ap_stack); } static const unsigned int fixed_mtrrs[NUM_FIXED_MTRRS] = { -- cgit v1.2.3