diff options
| -rw-r--r-- | src/arch/x86/c_start.S | 35 | ||||
| -rw-r--r-- | src/arch/x86/include/arch/cpu.h | 29 | ||||
| -rw-r--r-- | src/cpu/x86/Kconfig | 8 | ||||
| -rw-r--r-- | src/cpu/x86/cpu_info.S.inc | 47 | ||||
| -rw-r--r-- | src/cpu/x86/mp_init.c | 16 | ||||
| -rw-r--r-- | src/cpu/x86/sipi_vector.S | 22 | ||||
| -rw-r--r-- | src/cpu/x86/smm/smm_stub.S | 30 | ||||
| -rw-r--r-- | src/include/cpu/x86/gdt.h | 2 |
8 files changed, 186 insertions, 3 deletions
diff --git a/src/arch/x86/c_start.S b/src/arch/x86/c_start.S index cb7d5045ff..9e718fcab0 100644 --- a/src/arch/x86/c_start.S +++ b/src/arch/x86/c_start.S @@ -80,6 +80,20 @@ _start: push_cpu_info +#if CONFIG(CPU_INFO_V2) + /* Allocate the per_cpu_segment_data on the stack */ + push_per_cpu_segment_data + + /* + * Update the BSP's per_cpu_segment_descriptor to point to the + * per_cpu_segment_data that was allocated on the stack. + */ + set_segment_descriptor_base $per_cpu_segment_descriptors, %esp + + mov per_cpu_segment_selector, %eax + mov %eax, %gs +#endif + /* * Now we are finished. Memory is up, data is copied and * bss is cleared. Now we call the main routine and @@ -127,6 +141,7 @@ gdb_stub_breakpoint: #endif .globl gdt, gdt_end + .global per_cpu_segment_descriptors, per_cpu_segment_selector gdtaddr: .word gdt_end - gdt - 1 @@ -136,7 +151,7 @@ gdtaddr: .long gdt /* we know the offset */ #endif - .data + .data /* This is the gdt for GCC part of coreboot. * It is different from the gdt in ASM part of coreboot @@ -206,8 +221,26 @@ gdt: .word 0xffff, 0x0000 .byte 0x00, 0x9b, 0xaf, 0x00 #endif +#if CONFIG(CPU_INFO_V2) +per_cpu_segment_descriptors: + .rept CONFIG_MAX_CPUS + /* flat data segment */ + .word 0xffff, 0x0000 +#if ENV_X86_64 + .byte 0x00, 0x92, 0xcf, 0x00 +#else + .byte 0x00, 0x93, 0xcf, 0x00 +#endif + .endr +#endif /* CPU_INFO_V2 */ gdt_end: +#if CONFIG(CPU_INFO_V2) +/* Segment selector pointing to the first per_cpu_segment_descriptor. */ +per_cpu_segment_selector: + .long per_cpu_segment_descriptors - gdt +#endif /* CPU_INFO_V2 */ + .section ".text._start", "ax", @progbits #if ENV_X86_64 SetCodeSelector: diff --git a/src/arch/x86/include/arch/cpu.h b/src/arch/x86/include/arch/cpu.h index f736a147fe..8e96fae2c2 100644 --- a/src/arch/x86/include/arch/cpu.h +++ b/src/arch/x86/include/arch/cpu.h @@ -236,11 +236,40 @@ struct cpu_info { #endif }; +/* + * This structure describes the data allocated in the %gs segment for each CPU. + * In order to read from this structure you will need to use assembly to + * reference the segment. + * + * e.g., Reading the cpu_info pointer: + * %%gs:0 + */ +struct per_cpu_segment_data { + /* + * Instead of keeping a `struct cpu_info`, we actually keep a pointer + * pointing to the cpu_info struct located in %ds. This prevents + * needing specific access functions to read the fields in the cpu_info. + */ + struct cpu_info *cpu_info; +}; + static inline struct cpu_info *cpu_info(void) { +/* We use a #if because we don't want to mess with the &s below. */ +#if CONFIG(CPU_INFO_V2) + struct cpu_info *ci = NULL; + + __asm__("mov %%gs:%c[offset], %[ci]" + : [ci] "=r" (ci) + : [offset] "i" (offsetof(struct per_cpu_segment_data, cpu_info)) + ); + + return ci; +#else char s; uintptr_t info = ALIGN_UP((uintptr_t)&s, CONFIG_STACK_SIZE) - sizeof(struct cpu_info); return (struct cpu_info *)info; +#endif /* CPU_INFO_V2 */ } struct cpuinfo_x86 { diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig index a5c2a4df47..99e33bb570 100644 --- a/src/cpu/x86/Kconfig +++ b/src/cpu/x86/Kconfig @@ -193,3 +193,11 @@ config RESERVE_MTRRS_FOR_OS the system BIOS and the last 2 are to be reserved for OS usage. However, modern OSes use PAT to control cacheability instead of using MTRRs. + +config CPU_INFO_V2 + bool + depends on PARALLEL_MP + help + Enables the new method of locating struct cpu_info. This new method + uses the %gs segment to locate the cpu_info pointer. The old method + relied on the stack being CONFIG_STACK_SIZE aligned. diff --git a/src/cpu/x86/cpu_info.S.inc b/src/cpu/x86/cpu_info.S.inc index 62b47ca52a..dffd1bc346 100644 --- a/src/cpu/x86/cpu_info.S.inc +++ b/src/cpu/x86/cpu_info.S.inc @@ -8,3 +8,50 @@ push \index /* index */ push $0 /* *cpu */ .endm + +/* Push struct per_cpu_segment_data */ +.macro push_per_cpu_segment_data cpu_info_pointer=%esp + push \cpu_info_pointer /* *cpu_info */ +.endm + +/* + * Sets the base address in the segment descriptor array. + * + * A segment descriptor has the following structure: + * struct { + * uint16_t segment_limit_0_15; + * uint16_t base_address_0_15; + * uint8_t base_address_16_23; + * uint8_t attrs[2]; + * uint8_t base_address_24_31; + * }; + * + * @desc_array: Address of the descriptor table + * @base: Address to set in the descriptor + * @desc_index: Index of the descriptor in the table. Defaults to 0. Must be a + * register if specified. + * + * Clobbers %eax. + */ +.macro set_segment_descriptor_base desc_array:req, base:req, desc_index + mov \base, %eax + + push %ebx /* preserve ebx */ + mov \desc_array, %ebx + +.ifb \desc_index + movw %ax, 2(%ebx) + shr $16, %eax + movb %al, 4(%ebx) + shr $8, %eax + movb %al, 7(%ebx) +.else + movw %ax, 2(%ebx, \desc_index, 8) + shr $16, %eax + movb %al, 4(%ebx, \desc_index, 8) + shr $8, %eax + movb %al, 7(%ebx, \desc_index, 8) +.endif + + pop %ebx +.endm diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c index 93c143ec85..123b2b5eb5 100644 --- a/src/cpu/x86/mp_init.c +++ b/src/cpu/x86/mp_init.c @@ -89,6 +89,8 @@ struct sipi_params { uint32_t gdt; uint16_t unused; uint32_t idt_ptr; + uint32_t per_cpu_segment_descriptors; + uint32_t per_cpu_segment_selector; uint32_t stack_top; uint32_t stack_size; uint32_t microcode_lock; /* 0xffffffff means parallel loading. */ @@ -215,10 +217,20 @@ static void setup_default_sipi_vector_params(struct sipi_params *sp) sp->gdt = (uintptr_t)&gdt; sp->gdtlimit = (uintptr_t)&gdt_end - (uintptr_t)&gdt - 1; sp->idt_ptr = (uintptr_t)&idtarg; + if (CONFIG(CPU_INFO_V2)) { + 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); - /* Adjust the stack top to take into account cpu_info. */ - sp->stack_top -= sizeof(struct cpu_info); + /* + * In the CPU_INFO_V2 case, we don't need to pre-allocate the space on the stack. + * Instead we push them onto the top of the stack in the sipi vector. + */ + if (!CONFIG(CPU_INFO_V2)) { + /* Adjust the stack top to take into account cpu_info. */ + sp->stack_top -= sizeof(struct cpu_info); + } } #define NUM_FIXED_MTRRS 11 diff --git a/src/cpu/x86/sipi_vector.S b/src/cpu/x86/sipi_vector.S index 496fd345eb..491f1de435 100644 --- a/src/cpu/x86/sipi_vector.S +++ b/src/cpu/x86/sipi_vector.S @@ -1,5 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0-only */ +#include <cpu/x86/cpu_info.S.inc> #include <cpu/x86/cr.h> #include <cpu/amd/mtrr.h> #include <cpu/x86/msr.h> @@ -19,6 +20,10 @@ gdtaddr: .word 0 /* unused */ idt_ptr: .long 0 +per_cpu_segment_descriptors: +.long 0 +per_cpu_segment_selector: +.long 0 stack_top: .long 0 stack_size: @@ -98,6 +103,23 @@ _start: movl stack_top, %edx subl %eax, %edx mov %edx, %esp + +#if CONFIG(CPU_INFO_V2) + push_cpu_info index=%ecx + push_per_cpu_segment_data + + /* + * Update the AP's per_cpu_segment_descriptor to point to the + * per_cpu_segment_data that was allocated on the stack. + */ + set_segment_descriptor_base per_cpu_segment_descriptors, %esp, %ecx + + mov %ecx, %eax + shl $3, %eax /* The index is << 3 in the segment selector */ + add per_cpu_segment_selector, %eax + mov %eax, %gs +#endif + andl $0xfffffff0, %esp /* ensure stack alignment */ /* Save CPU number. */ diff --git a/src/cpu/x86/smm/smm_stub.S b/src/cpu/x86/smm/smm_stub.S index aa48ab69ec..e409983eae 100644 --- a/src/cpu/x86/smm/smm_stub.S +++ b/src/cpu/x86/smm/smm_stub.S @@ -9,6 +9,7 @@ * found in smm.h. */ +#include <cpu/x86/cpu_info.S.inc> #include <cpu/x86/cr.h> #include <cpu/x86/msr.h> #include <cpu/x86/lapic_def.h> @@ -82,8 +83,21 @@ smm_relocate_gdt: /* gdt selector 0x20 tss segment */ .word 0xffff, 0x0000 .byte 0x00, 0x8b, 0x80, 0x00 + +#if CONFIG(CPU_INFO_V2) +per_cpu_segment_descriptors: + .rept CONFIG_MAX_CPUS + /* selgdt 0x28, flat data segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x93, 0xcf, 0x00 + .endr +#endif /* CPU_INFO_V2 */ smm_relocate_gdt_end: +#if CONFIG(CPU_INFO_V2) +.set per_cpu_segment_selector, per_cpu_segment_descriptors - smm_relocate_gdt +#endif /* CPU_INFO_V2 */ + .align 4 .code32 .global smm_trampoline32 @@ -153,6 +167,22 @@ apicid_end: movl $0, 4(%ebx) #endif +#if CONFIG(CPU_INFO_V2) + push_cpu_info index=%ecx + push_per_cpu_segment_data + + /* + * Update the AP's per_cpu_segment_descriptor to point to the + * per_cpu_segment_data that was allocated on the stack. + */ + set_segment_descriptor_base $per_cpu_segment_descriptors, %esp, %ecx + + mov %ecx, %eax + shl $3, %eax /* The index is << 3 in the segment selector */ + add $per_cpu_segment_selector, %eax + mov %eax, %gs +#endif + /* Create stack frame by pushing a NULL stack base pointer */ pushl $0x0 mov %esp, %ebp diff --git a/src/include/cpu/x86/gdt.h b/src/include/cpu/x86/gdt.h index bc4eaad0ca..27a863ee33 100644 --- a/src/include/cpu/x86/gdt.h +++ b/src/include/cpu/x86/gdt.h @@ -5,6 +5,8 @@ /* These symbols are defined in c_start.S. */ extern char gdt[]; +extern char per_cpu_segment_descriptors[]; +extern uint32_t per_cpu_segment_selector; extern char gdt_end[]; extern char idtarg[]; |