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cpu/x86/smm: Drop fxsave/fxrstor logic 

Since we now explicitly compile both ramstage and smihandler code
without floating point operations and associated registers we don't need
to save/restore floating point registers.

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: I180b9781bf5849111501ae8e9806554a7851c0da
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75317
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>
This commit is contained in:
Arthur Heymans 2023-05-17 18:10:47 +02:00 committed by Martin L Roth
parent b992df9891
commit 1efca4d570
3 changed files with 15 additions and 74 deletions
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36
src/cpu/x86/smm/smm_module_loader.c
View File

@ -13,13 +13,7 @@
#include <string.h>
#include <types.h>
#define FXSAVE_SIZE 512
#define SMM_CODE_SEGMENT_SIZE 0x10000
/* FXSAVE area during relocation. While it may not be strictly needed the
SMM stub code relies on the FXSAVE area being non-zero to enable SSE
instructions within SMM mode. */
static uint8_t fxsave_area_relocation[CONFIG_MAX_CPUS][FXSAVE_SIZE]
__attribute__((aligned(16)));
/*
* Components that make up the SMRAM:
@ -56,7 +50,7 @@ struct cpu_smm_info cpus[CONFIG_MAX_CPUS] = { 0 };
* developer's manuals (volume 3, chapter 34). SMRAM is divided up into the
* following regions:
* +-----------------+ Top of SMRAM
* | | <- MSEG, FXSAVE
* | MSEG |
* +-----------------+
* | common |
* | smi handler | 64K
@ -240,8 +234,7 @@ static void smm_stub_place_staggered_entry_points(const struct smm_loader_params
* by the permanent handler can be used during relocation.
*/
static int smm_module_setup_stub(const uintptr_t smbase, const size_t smm_size,
struct smm_loader_params *params,
void *const fxsave_area)
struct smm_loader_params *params)
{
struct rmodule smm_stub;
if (rmodule_parse(&_binary_smmstub_start, &smm_stub)) {
@ -266,8 +259,6 @@ static int smm_module_setup_stub(const uintptr_t smbase, const size_t smm_size,
stub_params->stack_top = stack_top;
stub_params->stack_size = g_stack_size;
stub_params->c_handler = (uintptr_t)params->handler;
stub_params->fxsave_area = (uintptr_t)fxsave_area;
stub_params->fxsave_area_size = FXSAVE_SIZE;
/* This runs on the BSP. All the APs are its siblings */
struct cpu_info *info = cpu_info();
@ -322,8 +313,7 @@ int smm_setup_relocation_handler(struct smm_loader_params *params)
params->num_cpus = CONFIG_MAX_CPUS;
printk(BIOS_SPEW, "%s: exit\n", __func__);
return smm_module_setup_stub(smram, SMM_DEFAULT_SIZE,
params, fxsave_area_relocation);
return smm_module_setup_stub(smram, SMM_DEFAULT_SIZE, params);
}
static void setup_smihandler_params(struct smm_runtime *mod_params,
@ -363,8 +353,8 @@ static void print_region(const char *name, const struct region region)
region_end(&region));
}
/* STM + FX_SAVE + Handler + (Stub + Save state) * CONFIG_MAX_CPUS + stacks */
#define SMM_REGIONS_ARRAY_SIZE (1 + 1 + 1 + CONFIG_MAX_CPUS * 2 + 1)
/* STM + Handler + (Stub + Save state) * CONFIG_MAX_CPUS + stacks */
#define SMM_REGIONS_ARRAY_SIZE (1 + 1 + CONFIG_MAX_CPUS * 2 + 1)
static int append_and_check_region(const struct region smram,
const struct region region,
@ -406,8 +396,6 @@ static int append_and_check_region(const struct region smram,
* | BIOS resource |
* | list (STM) |
* +-----------------+
* | fxsave area |
* +-----------------+
* | smi handler |
* | ... |
* +-----------------+ <- cpu0
@ -453,19 +441,10 @@ int smm_load_module(const uintptr_t smram_base, const size_t smram_size,
printk(BIOS_DEBUG, "BIOS res list 0x%x\n", CONFIG_BIOS_RESOURCE_LIST_SIZE);
}
const size_t fx_save_area_size = CONFIG(SSE) ? FXSAVE_SIZE * params->num_cpus : 0;
struct region fx_save = {};
if (CONFIG(SSE)) {
fx_save.offset = smram_top - stm_size - fx_save_area_size;
fx_save.size = fx_save_area_size;
if (append_and_check_region(smram, fx_save, region_list, "FX_SAVE"))
return -1;
}
const size_t handler_size = rmodule_memory_size(&smi_handler);
const size_t handler_alignment = rmodule_load_alignment(&smi_handler);
const uintptr_t handler_base =
ALIGN_DOWN(smram_top - stm_size - fx_save_area_size - handler_size,
ALIGN_DOWN(smram_top - stm_size - handler_size,
handler_alignment);
struct region handler = {
.offset = handler_base,
@ -506,6 +485,5 @@ int smm_load_module(const uintptr_t smram_base, const size_t smram_size,
params->handler = rmodule_entry(&smi_handler);
setup_smihandler_params(smihandler_params, smram_base, smram_size, params);
return smm_module_setup_stub(stub_segment_base, smram_size, params,
(void *)region_offset(&fx_save));
return smm_module_setup_stub(stub_segment_base, smram_size, params);
}

51
src/cpu/x86/smm/smm_stub.S
View File

@ -22,10 +22,6 @@ stack_top:
.long 0
c_handler:
.long 0
fxsave_area:
.long 0
fxsave_area_size:
.long 0
/* apic_to_cpu_num is a table mapping the default APIC id to CPU num. If the
* APIC id is found at the given index, the contiguous CPU number is index
* into the table. */
@ -171,9 +167,7 @@ apicid_end:
* not be assigned. Use the fallback stack and check this condition in
* C handler. */
movl $(fallback_stack_top), %esp
/* Clear fxsave location as there will be no saving/restoring. */
xor %edi, %edi
jmp 2f
jmp align_stack
1:
movl stack_size, %eax
mul %ecx /* %eax(stack_size) * %ecx(cpu) = %eax(offset) */
@ -193,32 +187,10 @@ apicid_end:
pushl $0x0
mov %esp, %ebp
/* Allocate locals (fxsave, efer_backup) */
subl $0xc, %esp
/* Allocate locals (efer_backup) */
subl $0x8, %esp
/* calculate fxsave location */
mov fxsave_area, %edi
test %edi, %edi
jz 2f
movl fxsave_area_size, %eax
mul %ecx
add %eax, %edi
2:
/* Save location of fxsave area. */
mov %edi, -4(%ebp)
test %edi, %edi
jz 1f
/* Enable sse instructions. */
mov %cr4, %eax
orl $(CR4_OSFXSR | CR4_OSXMMEXCPT), %eax
mov %eax, %cr4
/* Save FP state. */
fxsave (%edi)
1:
align_stack:
/* Align stack to 16 bytes. Another 32 bytes are pushed below. */
andl $0xfffffff0, %esp
@ -227,8 +199,8 @@ apicid_end:
/* Backup IA32_EFER. Preserves ebx. */
movl $(IA32_EFER), %ecx
rdmsr
movl %eax, -0x8(%ebp)
movl %edx, -0xc(%ebp)
movl %eax, -0x4(%ebp)
movl %edx, -0x8(%ebp)
/* entry64.inc preserves ebx, esi, edi, ebp */
#include <cpu/x86/64bit/entry64.inc>
@ -262,8 +234,8 @@ apicid_end:
/* Restore IA32_EFER as RSM doesn't restore MSRs. */
movl $(IA32_EFER), %ecx
rdmsr
movl -0x8(%ebp), %eax
movl -0xc(%ebp), %edx
movl -0x4(%ebp), %eax
movl -0x8(%ebp), %edx
wrmsr
@ -275,13 +247,6 @@ apicid_end:
mov c_handler, %eax
call *%eax
#endif
/* Retrieve fxsave location. */
mov -4(%ebp), %edi
test %edi, %edi
jz 1f
/* Restore FP state. */
fxrstor (%edi)
1:
/* Exit from SM mode. */

2
src/include/cpu/x86/smm.h
View File

@ -98,8 +98,6 @@ struct smm_stub_params {
u32 stack_size;
u32 stack_top;
u32 c_handler;
u32 fxsave_area;
u32 fxsave_area_size;
/* The apic_id_to_cpu provides a mapping from APIC id to CPU number.
* The CPU number is indicated by the index into the array by matching
* the default APIC id and value at the index. The stub loader