diff options
Diffstat (limited to 'src/cpu')
| -rw-r--r-- | src/cpu/x86/Kconfig | 18 | ||||
| -rw-r--r-- | src/cpu/x86/smm/Makefile.inc | 46 | ||||
| -rw-r--r-- | src/cpu/x86/smm/smm_module_handler.c | 171 | ||||
| -rw-r--r-- | src/cpu/x86/smm/smm_module_header.c | 24 | ||||
| -rw-r--r-- | src/cpu/x86/smm/smm_module_loader.c | 371 | ||||
| -rw-r--r-- | src/cpu/x86/smm/smm_stub.S | 145 |
6 files changed, 775 insertions, 0 deletions
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig index ae3241e8b3..62d78b5436 100644 --- a/src/cpu/x86/Kconfig +++ b/src/cpu/x86/Kconfig @@ -66,3 +66,21 @@ config SMM_TSEG config SMM_TSEG_SIZE hex default 0 + +config SMM_MODULES + bool + default n + depends on HAVE_SMI_HANDLER + select RELOCATABLE_MODULES + help + If SMM_MODULES is selected then SMM handlers are built as modules. + A SMM stub along with a SMM loader/relocator. All the handlers are + written in C with stub being the only assembly. + +config SMM_MODULE_HEAP_SIZE + hex + default 0x4000 + depends on SMM_MODULES + help + This option determines the size of the heap within the SMM handler + modules. diff --git a/src/cpu/x86/smm/Makefile.inc b/src/cpu/x86/smm/Makefile.inc index 405cf891ad..ee4dbeaae0 100644 --- a/src/cpu/x86/smm/Makefile.inc +++ b/src/cpu/x86/smm/Makefile.inc @@ -17,6 +17,51 @@ ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA ## +ifeq ($(CONFIG_SMM_MODULES),y) + +smmstub-y += smm_stub.S +smmstub-y += smm_module_header.c + +smm-y += smiutil.c +smm-y += smm_module_header.c +smm-y += smm_module_handler.c + +ramstage-y += smm_module_loader.c + +ramstage-srcs += $(obj)/cpu/x86/smm/smm +ramstage-srcs += $(obj)/cpu/x86/smm/smmstub + +# SMM Stub Module. The stub is used as a trampoline for relocation and normal +# SMM handling. +$(obj)/cpu/x86/smm/smmstub.o: $$(smmstub-objs) + $(CC) $(LDFLAGS) -nostdlib -r -o $@ $^ + +# Link the SMM stub module with a 0-byte heap. +$(eval $(call rmodule_link,$(obj)/cpu/x86/smm/smmstub.elf, $(obj)/cpu/x86/smm/smmstub.o, 0)) + +$(obj)/cpu/x86/smm/smmstub: $(obj)/cpu/x86/smm/smmstub.elf + $(OBJCOPY) -O binary $< $@ + +$(obj)/cpu/x86/smm/smmstub.ramstage.o: $(obj)/cpu/x86/smm/smmstub + @printf " OBJCOPY $(subst $(obj)/,,$(@))\n" + cd $(dir $@); $(OBJCOPY) -I binary $(notdir $<) -O elf32-i386 -B i386 $(notdir $@) + +# C-based SMM handler. + +$(obj)/cpu/x86/smm/smm.o: $$(smm-objs) + $(CC) $(LDFLAGS) -nostdlib -r -o $@ $^ + +$(eval $(call rmodule_link,$(obj)/cpu/x86/smm/smm.elf, $(obj)/cpu/x86/smm/smm.o, $(CONFIG_SMM_MODULE_HEAP_SIZE))) + +$(obj)/cpu/x86/smm/smm: $(obj)/cpu/x86/smm/smm.elf + $(OBJCOPY) -O binary $< $@ + +$(obj)/cpu/x86/smm/smm.ramstage.o: $(obj)/cpu/x86/smm/smm + @printf " OBJCOPY $(subst $(obj)/,,$(@))\n" + cd $(dir $@); $(OBJCOPY) -I binary $(notdir $<) -O elf32-i386 -B i386 $(notdir $@) + +else # CONFIG_SMM_MODULES + ramstage-$(CONFIG_HAVE_SMI_HANDLER) += smmrelocate.S ifeq ($(CONFIG_HAVE_SMI_HANDLER),y) ramstage-srcs += $(obj)/cpu/x86/smm/smm_wrap @@ -50,3 +95,4 @@ $(obj)/cpu/x86/smm/smm_wrap.ramstage.o: $(obj)/cpu/x86/smm/smm_wrap @printf " OBJCOPY $(subst $(obj)/,,$(@))\n" cd $(obj)/cpu/x86/smm; $(OBJCOPY) -I binary smm -O elf32-i386 -B i386 smm_wrap.ramstage.o +endif # CONFIG_SMM_MODULES diff --git a/src/cpu/x86/smm/smm_module_handler.c b/src/cpu/x86/smm/smm_module_handler.c new file mode 100644 index 0000000000..67802d6431 --- /dev/null +++ b/src/cpu/x86/smm/smm_module_handler.c @@ -0,0 +1,171 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2013 ChromeOS Authors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <arch/io.h> +#include <arch/romcc_io.h> +#include <console/console.h> +#include <cpu/x86/smm.h> + +typedef enum { SMI_LOCKED, SMI_UNLOCKED } smi_semaphore; + +/* SMI multiprocessing semaphore */ +static volatile +smi_semaphore smi_handler_status __attribute__ ((aligned (4))) = SMI_UNLOCKED; + +static int smi_obtain_lock(void) +{ + u8 ret = SMI_LOCKED; + + asm volatile ( + "movb %2, %%al\n" + "xchgb %%al, %1\n" + "movb %%al, %0\n" + : "=g" (ret), "=m" (smi_handler_status) + : "g" (SMI_LOCKED) + : "eax" + ); + + return (ret == SMI_UNLOCKED); +} + +static void smi_release_lock(void) +{ + asm volatile ( + "movb %1, %%al\n" + "xchgb %%al, %0\n" + : "=m" (smi_handler_status) + : "g" (SMI_UNLOCKED) + : "eax" + ); +} + +void io_trap_handler(int smif) +{ + /* If a handler function handled a given IO trap, it + * shall return a non-zero value + */ + printk(BIOS_DEBUG, "SMI function trap 0x%x: ", smif); + + if (southbridge_io_trap_handler(smif)) + return; + + if (mainboard_io_trap_handler(smif)) + return; + + printk(BIOS_DEBUG, "Unknown function\n"); +} + +/** + * @brief Set the EOS bit + */ +static void smi_set_eos(void) +{ + southbridge_smi_set_eos(); +} + + +static u32 pci_orig; + +/** + * @brief Backup PCI address to make sure we do not mess up the OS + */ +static void smi_backup_pci_address(void) +{ + pci_orig = inl(0xcf8); +} + +/** + * @brief Restore PCI address previously backed up + */ +static void smi_restore_pci_address(void) +{ + outl(pci_orig, 0xcf8); +} + + +static const struct smm_runtime *smm_runtime; + +void *smm_get_save_state(int cpu) +{ + char *base; + + /* This function assumes all save states start at top of default + * SMRAM size space and are staggered down by save state size. */ + base = (void *)smm_runtime->smbase; + base += SMM_DEFAULT_SIZE; + base -= (cpu + 1) * smm_runtime->save_state_size; + + return base; +} + +void smm_handler_start(void *arg, int cpu, const struct smm_runtime *runtime) +{ + /* Make sure to set the global runtime. It's OK to race as the value + * will be the same across CPUs as well as multiple SMIs. */ + if (smm_runtime == NULL) + smm_runtime = runtime; + + if (cpu >= CONFIG_MAX_CPUS) { + console_init(); + printk(BIOS_CRIT, + "Invalid CPU number assigned in SMM stub: %d\n", cpu); + return; + } + + /* Are we ok to execute the handler? */ + if (!smi_obtain_lock()) { + /* For security reasons we don't release the other CPUs + * until the CPU with the lock is actually done */ + while (smi_handler_status == SMI_LOCKED) { + asm volatile ( + ".byte 0xf3, 0x90\n" /* PAUSE */ + ); + } + return; + } + + smi_backup_pci_address(); + + console_init(); + + printk(BIOS_SPEW, "\nSMI# #%d\n", cpu); + + cpu_smi_handler(); + northbridge_smi_handler(); + southbridge_smi_handler(); + + smi_restore_pci_address(); + + smi_release_lock(); + + /* De-assert SMI# signal to allow another SMI */ + smi_set_eos(); +} + +/* Provide a default implementation for all weak handlers so that relocation + * entries in the modules make sense. Without default implementations the + * weak relocations w/o a symbol have a 0 address which is where the modules + * are linked at. */ +int __attribute__((weak)) mainboard_io_trap_handler(int smif) { return 0; } +void __attribute__((weak)) cpu_smi_handler(void) {} +void __attribute__((weak)) northbridge_smi_handler() {} +void __attribute__((weak)) southbridge_smi_handler() {} +void __attribute__((weak)) mainboard_smi_gpi(u16 gpi_sts) {} +int __attribute__((weak)) mainboard_smi_apmc(u8 data) { return 0; } +void __attribute__((weak)) mainboard_smi_sleep(u8 slp_typ) {} diff --git a/src/cpu/x86/smm/smm_module_header.c b/src/cpu/x86/smm/smm_module_header.c new file mode 100644 index 0000000000..3ee654f6cd --- /dev/null +++ b/src/cpu/x86/smm/smm_module_header.c @@ -0,0 +1,24 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2013 ChromeOS Authors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <rmodule.h> + +extern char smm_handler_start[]; + +DEFINE_RMODULE_HEADER(smm_module, smm_handler_start, RMODULE_TYPE_SMM); diff --git a/src/cpu/x86/smm/smm_module_loader.c b/src/cpu/x86/smm/smm_module_loader.c new file mode 100644 index 0000000000..5eb4c5a0a2 --- /dev/null +++ b/src/cpu/x86/smm/smm_module_loader.c @@ -0,0 +1,371 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2012 ChromeOS Authors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <string.h> +#include <rmodule.h> +#include <cpu/x86/smm.h> +#include <cpu/x86/cache.h> +#include <console/console.h> + +/* + * Compoments that make up the SMRAM: + * 1. Save state - the total save state memory used + * 2. Stack - stacks for the CPUs in the SMM handler + * 3. Stub - SMM stub code for calling into handler + * 4. Handler - C-based SMM handler. + * + * The compoents are assumed to consist of one consecutive region. + */ + +/* These paramters are used by the SMM stub code. A pointer to the params + * is also passed to the C-base handler. */ +struct smm_stub_params { + u32 stack_size; + u32 stack_top; + u32 c_handler; + u32 c_handler_arg; + struct smm_runtime runtime; +} __attribute__ ((packed)); + +/* + * The stub is the entry point that sets up protected mode and stacks for each + * cpu. It then calls into the SMM handler module. It is encoded as an rmodule. + */ +extern unsigned char _binary_smmstub_start[]; + +/* This is the SMM handler that the stub calls. It is encoded as an rmodule. */ +extern unsigned char _binary_smm_start[]; + +/* Per cpu minimum stack size. */ +#define SMM_MINIMUM_STACK_SIZE 32 + +/* + * The smm_entry_ins consists of 3 bytes. It is used when staggering SMRAM entry + * addresses across CPUs. + * + * 0xe9 <16-bit relative target> ; jmp <relative-offset> + */ +struct smm_entry_ins { + char jmp_rel; + uint16_t rel16; +} __attribute__ ((packed)); + +/* + * Place the entry instructions for num entries beginning at entry_start with + * a given stride. The entry_start is the highest entry point's address. All + * other entry points are stride size below the previous. + */ +static void smm_place_jmp_instructions(void *entry_start, int stride, int num, + void *jmp_target) +{ + int i; + char *cur; + struct smm_entry_ins entry = { .jmp_rel = 0xe9 }; + + /* Each entry point has an IP value of 0x8000. The SMBASE for each + * cpu is different so the effective address of the entry instruction + * is different. Therefore, the relative displacment for each entry + * instruction needs to be updated to reflect the current effective + * IP. Additionally, the IP result from the jmp instruction is + * calculated using the next instruction's address so the size of + * the jmp instruction needs to be taken into account. */ + cur = entry_start; + for (i = 0; i < num; i++) { + uint32_t disp = (uint32_t)jmp_target; + + disp -= sizeof(entry) + (uint32_t)cur; + printk(BIOS_DEBUG, + "SMM Module: placing jmp sequence at %p rel16 0x%04x\n", + cur, disp); + entry.rel16 = disp; + memcpy(cur, &entry, sizeof(entry)); + cur -= stride; + } +} + +/* Place stacks in base -> base + size region, but ensure the stacks don't + * overlap the staggered entry points. */ +static void *smm_stub_place_stacks(char *base, int size, + struct smm_loader_params *params) +{ + int total_stack_size; + char *stacks_top; + + if (params->stack_top != NULL) + return params->stack_top; + + /* If stack space is requested assume the space lives in the lower + * half of SMRAM. */ + total_stack_size = params->per_cpu_stack_size * + params->num_concurrent_stacks; + + /* There has to be at least one stack user. */ + if (params->num_concurrent_stacks < 1) + return NULL; + + /* Total stack size cannot fit. */ + if (total_stack_size > size) + return NULL; + + /* Stacks extend down to SMBASE */ + stacks_top = &base[total_stack_size]; + + return stacks_top; +} + +/* Place the staggered entry points for each CPU. The entry points are + * staggered by the per cpu SMM save state size extending down from + * SMM_ENTRY_OFFSET. */ +static void smm_stub_place_staggered_entry_points(char *base, + const struct smm_loader_params *params, const struct rmodule *smm_stub) +{ + int stub_entry_offset; + + stub_entry_offset = rmodule_entry_offset(smm_stub); + + /* If there are staggered entry points or the stub is not located + * at the SMM entry point then jmp instructionss need to be placed. */ + if (params->num_concurrent_save_states > 1 || stub_entry_offset != 0) { + int num_entries; + + base += SMM_ENTRY_OFFSET; + num_entries = params->num_concurrent_save_states; + /* Adjust beginning entry and number of entries down since + * the initial entry point doesn't need a jump sequence. */ + if (stub_entry_offset == 0) { + base -= params->per_cpu_save_state_size; + num_entries--; + } + smm_place_jmp_instructions(base, + params->per_cpu_save_state_size, + num_entries, + rmodule_entry(smm_stub)); + } +} + +/* + * The stub setup code assumes it is completely contained within the + * default SMRAM size (0x10000). There are potentially 3 regions to place + * within the default SMRAM size: + * 1. Save state areas + * 2. Stub code + * 3. Stack areas + * + * The save state and stack areas are treated as contiguous for the number of + * concurrent areas requested. The save state always lives at the top of SMRAM + * space, and the entry point is at offset 0x8000. + */ +static int smm_module_setup_stub(void *smbase, struct smm_loader_params *params) +{ + int total_save_state_size; + int smm_stub_size; + int stub_entry_offset; + char *smm_stub_loc; + void *stacks_top; + int size; + char *base; + int i; + struct smm_stub_params *stub_params; + struct rmodule smm_stub; + + base = smbase; + size = SMM_DEFAULT_SIZE; + + /* The number of concurrent stacks cannot exceed CONFIG_MAX_CPUS. */ + if (params->num_concurrent_stacks > CONFIG_MAX_CPUS) + return -1; + + /* Fail if can't parse the smm stub rmodule. */ + if (rmodule_parse(&_binary_smmstub_start, &smm_stub)) + return -1; + + /* Adjust remaining size to account for save state. */ + total_save_state_size = params->per_cpu_save_state_size * + params->num_concurrent_save_states; + size -= total_save_state_size; + + /* The save state size encroached over the first SMM entry point. */ + if (size <= SMM_ENTRY_OFFSET) + return -1; + + /* Need a minimum stack size and alignment. */ + if (params->per_cpu_stack_size <= SMM_MINIMUM_STACK_SIZE || + (params->per_cpu_stack_size & 3) != 0) + return -1; + + smm_stub_loc = NULL; + smm_stub_size = rmodule_memory_size(&smm_stub); + stub_entry_offset = rmodule_entry_offset(&smm_stub); + + /* Assume the stub is always small enough to live within upper half of + * SMRAM region after the save state space has been allocated. */ + smm_stub_loc = &base[SMM_ENTRY_OFFSET]; + + /* Adjust for jmp instruction sequence. */ + if (stub_entry_offset != 0) { + int entry_sequence_size = sizeof(struct smm_entry_ins); + /* Align up to 16 bytes. */ + entry_sequence_size += 15; + entry_sequence_size &= ~15; + smm_stub_loc += entry_sequence_size; + smm_stub_size += entry_sequence_size; + } + + /* Stub is too big to fit. */ + if (smm_stub_size > (size - SMM_ENTRY_OFFSET)) + return -1; + + /* The stacks, if requested, live in the lower half of SMRAM space. */ + size = SMM_ENTRY_OFFSET; + + /* Ensure stacks don't encroach onto staggered SMM + * entry points. The staggered entry points extend + * below SMM_ENTRY_OFFSET by the number of concurrent + * save states - 1 and save state size. */ + if (params->num_concurrent_save_states > 1) { + size -= total_save_state_size; + size += params->per_cpu_save_state_size; + } + + /* Place the stacks in the lower half of SMRAM. */ + stacks_top = smm_stub_place_stacks(base, size, params); + if (stacks_top == NULL) + return -1; + + /* Load the stub. */ + if (rmodule_load(smm_stub_loc, &smm_stub)) + return -1; + + /* Place staggered entry points. */ + smm_stub_place_staggered_entry_points(base, params, &smm_stub); + + /* Setup the parameters for the stub code. */ + stub_params = rmodule_parameters(&smm_stub); + stub_params->stack_top = (u32)stacks_top; + stub_params->stack_size = params->per_cpu_stack_size; + stub_params->c_handler = (u32)params->handler; + stub_params->c_handler_arg = (u32)params->handler_arg; + stub_params->runtime.smbase = (u32)smbase; + stub_params->runtime.save_state_size = params->per_cpu_save_state_size; + + /* Initialize the APIC id to cpu number table to be 1:1 */ + for (i = 0; i < params->num_concurrent_stacks; i++) + stub_params->runtime.apic_id_to_cpu[i] = i; + + /* Allow the initiator to manipulate SMM stub parameters. */ + params->runtime = &stub_params->runtime; + + printk(BIOS_DEBUG, "SMM Module: stub loaded at %p. Will call %p(%p)\n", + smm_stub_loc, params->handler, params->handler_arg); + + return 0; +} + +/* + * smm_setup_relocation_handler assumes the callback is already loaded in + * memory. i.e. Another SMM module isn't chained to the stub. The other + * assumption is that the stub will be entered from the default SMRAM + * location: 0x30000 -> 0x40000. + */ +int smm_setup_relocation_handler(struct smm_loader_params *params) +{ + void *smram = (void *)SMM_DEFAULT_BASE; + + /* There can't be more than 1 concurrent save state for the relocation + * handler because all CPUs default to 0x30000 as SMBASE. */ + if (params->num_concurrent_save_states > 1) + return -1; + + /* A handler has to be defined to call for relocation. */ + if (params->handler == NULL) + return -1; + + /* Since the relocation handler always uses stack, adjust the number + * of conccurent stack users to be CONFIG_MAX_CPUS. */ + if (params->num_concurrent_stacks == 0) + params->num_concurrent_stacks = CONFIG_MAX_CPUS; + + return smm_module_setup_stub(smram, params); +} + +/* The SMM module is placed within the provided region in the following + * manner: + * +-----------------+ <- smram + size + * | stacks | + * +-----------------+ <- smram + size - total_stack_size + * | ... | + * +-----------------+ <- smram + handler_size + SMM_DEFAULT_SIZE + * | handler | + * +-----------------+ <- smram + SMM_DEFAULT_SIZE + * | stub code | + * +-----------------+ <- smram + * + * It should be noted that this algorithm will not work for + * SMM_DEFAULT_SIZE SMRAM regions such as the A segment. This algorithm + * expectes a region large enough to encompass the handler and stacks + * as well as the SMM_DEFAULT_SIZE. + */ +int smm_load_module(void *smram, int size, struct smm_loader_params *params) +{ + struct rmodule smm_mod; + int total_stack_size; + int handler_size; + int module_alignment; + int alignment_size; + char *base; + + if (size <= SMM_DEFAULT_SIZE) + return -1; + + /* Fail if can't parse the smm rmodule. */ + if (rmodule_parse(&_binary_smm_start, &smm_mod)) + return -1; + + total_stack_size = params->per_cpu_stack_size * + params->num_concurrent_stacks; + + /* Stacks start at the top of the region. */ + base = smram; + base += size; + params->stack_top = base; + + /* SMM module starts at offset SMM_DEFAULT_SIZE with the load alignment + * taken into account. */ + base = smram; + base += SMM_DEFAULT_SIZE; + handler_size = rmodule_memory_size(&smm_mod); + module_alignment = rmodule_load_alignment(&smm_mod); + alignment_size = module_alignment - ((u32)base % module_alignment); + if (alignment_size != module_alignment) { + handler_size += alignment_size; + base += alignment_size; + } + + /* Does the required amount of memory exceed the SMRAM region size? */ + if ((total_stack_size + handler_size + SMM_DEFAULT_SIZE) > size) + return -1; + + if (rmodule_load(base, &smm_mod)) + return -1; + + params->handler = rmodule_entry(&smm_mod); + params->handler_arg = rmodule_parameters(&smm_mod); + + return smm_module_setup_stub(smram, params); +} diff --git a/src/cpu/x86/smm/smm_stub.S b/src/cpu/x86/smm/smm_stub.S new file mode 100644 index 0000000000..07eb5dcb6d --- /dev/null +++ b/src/cpu/x86/smm/smm_stub.S @@ -0,0 +1,145 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2012 ChromeOS Authors + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; version 2 of + * the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, + * MA 02110-1301 USA + */ + +/* + * The stub is a generic wrapper for bootstrapping a C-based SMM handler. Its + * primary purpose is to put the CPU into protected mode with a stack and call + * into the C handler. + * + * The stub_entry_params structure needs to correspond to the C structure + * found in smm.h. + */ + +.code32 +.section ".module_parameters", "aw", @progbits +stub_entry_params: +stack_size: +.long 0 +stack_top: +.long 0 +c_handler: +.long 0 +c_handler_arg: +.long 0 +/* struct smm_runtime begins here. */ +smm_runtime: +smbase: +.long 0 +save_state_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. */ +apic_to_cpu_num: +.fill CONFIG_MAX_CPUS,1,0xff +/* end struct smm_runtime */ + +.data +/* Provide fallback stack to use when a valid cpu number cannot be found. */ +fallback_stack_bottom: +.skip 128 +fallback_stack_top: + +.text +.code16 +.global smm_handler_start +smm_handler_start: + movl $(smm_relocate_gdt), %ebx + data32 lgdt (%ebx) + + movl %cr0, %eax + andl $0x1FFAFFD1, %eax /* CD,NW,PG,AM,WP,NE,TS,EM,MP = 0 */ + orl $0x1, %eax /* PE = 1 */ + movl %eax, %cr0 + + /* Enable protected mode */ + data32 ljmp $0x8, $smm_trampoline32 + +.align 4 +smm_relocate_gdt: + /* The first GDT entry is used for the lgdt instruction. */ + .word smm_relocate_gdt_end - smm_relocate_gdt - 1 + .long smm_relocate_gdt + .word 0x0000 + + /* gdt selector 0x08, flat code segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x9b, 0xcf, 0x00 /* G=1 and 0x0f, 4GB limit */ + + /* gdt selector 0x10, flat data segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x93, 0xcf, 0x00 +smm_relocate_gdt_end: + +.align 4 +.code32 +.global smm_trampoline32 +smm_trampoline32: + /* Use flat data segment */ + movw $0x10, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %ss + movw %ax, %fs + movw %ax, %gs + + /* The CPU number is calculated by reading the initial APIC id. Since + * the OS can maniuplate the APIC id use the non-changing cpuid result + * for APIC id (ebx[31:24]). A table is used to handle a discontiguous + * APIC id space. */ + mov $1, %eax + cpuid + bswap %ebx /* Default APIC id in bl. */ + mov $(apic_to_cpu_num), %eax + xor %ecx, %ecx + +1: + cmp (%eax, %ecx, 1), %bl + je 1f + inc %ecx + cmp $CONFIG_MAX_CPUS, %ecx + jne 1b + /* This is bad. One cannot find a stack entry because a cpu num could + * not be assigned. Use the fallback stack and check this condition in + * C handler. */ + movl $(fallback_stack_top), %esp + jmp 2f +1: + movl stack_size, %eax + mul %ecx + movl stack_top, %edx + subl %eax, %edx + mov %edx, %esp + +2: + /* Call into the c-based SMM relocation function with the platform + * parameters. Equivalent to: + * c_handler(c_handler_params, cpu_num, smm_runtime); + */ + push $(smm_runtime) + push %ecx + push c_handler_arg + mov c_handler, %eax + call *%eax + + /* Exit from SM mode. */ + rsm + |