cpu/x86/smm: Improve smm stack setup
Both the relocation handler and the permanent handler use the same
stacks, so things can be simplified.
Change-Id: I7bdca775550e8280757a6c5a5150a0d638d5fc2d
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58698
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index fee5940..7d0a20f 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -760,10 +760,9 @@
}
static enum cb_err install_relocation_handler(int num_cpus, size_t real_save_state_size,
- size_t save_state_size, uintptr_t perm_smbase)
+ size_t save_state_size)
{
struct smm_loader_params smm_params = {
- .per_cpu_stack_size = CONFIG_SMM_STUB_STACK_SIZE,
.num_concurrent_stacks = num_cpus,
.real_cpu_save_state_size = real_save_state_size,
.per_cpu_save_state_size = save_state_size,
@@ -771,11 +770,7 @@
.handler = smm_do_relocation,
};
- /* Allow callback to override parameters. */
- if (mp_state.ops.adjust_smm_params != NULL)
- mp_state.ops.adjust_smm_params(&smm_params, 0);
-
- if (smm_setup_relocation_handler(perm_smbase, &smm_params)) {
+ if (smm_setup_relocation_handler(&smm_params)) {
printk(BIOS_ERR, "%s: smm setup failed\n", __func__);
return CB_ERR;
}
@@ -798,17 +793,12 @@
* size and save state size for each CPU.
*/
struct smm_loader_params smm_params = {
- .per_cpu_stack_size = CONFIG_SMM_MODULE_STACK_SIZE,
.num_concurrent_stacks = num_cpus,
.real_cpu_save_state_size = real_save_state_size,
.per_cpu_save_state_size = save_state_size,
.num_concurrent_save_states = num_cpus,
};
- /* Allow callback to override parameters. */
- if (mp_state.ops.adjust_smm_params != NULL)
- mp_state.ops.adjust_smm_params(&smm_params, 1);
-
printk(BIOS_DEBUG, "Installing permanent SMM handler to 0x%08lx\n", smbase);
if (smm_load_module(smbase, smsize, &smm_params))
@@ -829,10 +819,15 @@
if (!is_smm_enabled())
return;
+ if (smm_setup_stack(mp_state.perm_smbase, mp_state.perm_smsize, mp_state.cpu_count,
+ CONFIG_SMM_MODULE_STACK_SIZE)) {
+ printk(BIOS_ERR, "Unable to install SMM relocation handler.\n");
+ smm_disable();
+ }
+
/* Install handlers. */
if (install_relocation_handler(mp_state.cpu_count, real_save_state_size,
- smm_save_state_size, mp_state.perm_smbase) !=
- CB_SUCCESS) {
+ smm_save_state_size) != CB_SUCCESS) {
printk(BIOS_ERR, "Unable to install SMM relocation handler.\n");
smm_disable();
}
diff --git a/src/cpu/x86/smm/smm_module_loader.c b/src/cpu/x86/smm/smm_module_loader.c
index ba179ca..ce7cf20 100644
--- a/src/cpu/x86/smm/smm_module_loader.c
+++ b/src/cpu/x86/smm/smm_module_loader.c
@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#include <acpi/acpi_gnvs.h>
+#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <rmodule.h>
@@ -239,32 +240,26 @@
return 1;
}
-/*
- * Place stacks in base -> base + size region, but ensure the stacks don't
- * overlap the staggered entry points.
- */
-static uintptr_t smm_stub_place_stacks(const uintptr_t base, struct smm_loader_params *params)
+static uintptr_t stack_top;
+static size_t g_stack_size;
+
+int smm_setup_stack(const uintptr_t perm_smbase, const size_t perm_smram_size,
+ const unsigned int total_cpus, const size_t stack_size)
{
- size_t total_stack_size;
- uintptr_t stacks_top;
+ /* Need a minimum stack size and alignment. */
+ if (stack_size <= SMM_MINIMUM_STACK_SIZE || (stack_size & 3) != 0) {
+ printk(BIOS_ERR, "%s: need minimum stack size\n", __func__);
+ return -1;
+ }
- /* 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;
- printk(BIOS_DEBUG, "%s: cpus: %zx : stack space: needed -> %zx\n",
- __func__, params->num_concurrent_stacks,
- total_stack_size);
-
- /* There has to be at least one stack user. */
- if (params->num_concurrent_stacks < 1)
- return 0;
-
- /* Stacks extend down to SMBASE */
- stacks_top = base + total_stack_size;
- printk(BIOS_DEBUG, "%s: exit, stack_top %lx\n", __func__, stacks_top);
-
- return stacks_top;
+ const size_t total_stack_size = total_cpus * stack_size;
+ if (total_stack_size >= perm_smram_size) {
+ printk(BIOS_ERR, "%s: Stack won't fit smram\n", __func__);
+ return -1;
+ }
+ stack_top = perm_smbase + total_stack_size;
+ g_stack_size = stack_size;
+ return 0;
}
/*
@@ -284,7 +279,7 @@
if (params->num_concurrent_save_states > 1 || stub_entry_offset != 0) {
rc = smm_place_entry_code((uintptr_t)base,
params->num_concurrent_save_states,
- (uintptr_t)params->stack_top, params);
+ stack_top, params);
}
return rc;
}
@@ -309,18 +304,15 @@
* permanent SMM handler.
* The CPU stack is decided at runtime in the stub and is treaded as a continuous
* region. As this might not fit the default SMRAM region, the same region used
- * by the permanent handler can be used during relocation. This is done via the
- * smram_start argument.
+ * 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,
- const uintptr_t smram_start)
+ void *const fxsave_area)
{
size_t total_save_state_size;
size_t smm_stub_size;
uintptr_t smm_stub_loc;
- uintptr_t stacks_top;
size_t size;
uintptr_t base;
size_t i;
@@ -361,13 +353,6 @@
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) {
- printk(BIOS_ERR, "%s: need minimum stack size\n", __func__);
- return -1;
- }
-
smm_stub_size = rmodule_memory_size(&smm_stub);
/* Put the stub at the main entry point */
@@ -379,16 +364,10 @@
return -1;
}
- /* The stacks, if requested, live in the lower half of SMRAM space
- * for default handler, but for relocated handler it lives at the beginning
- * of SMRAM which is TSEG base
- */
- stacks_top = smm_stub_place_stacks(smram_start, params);
- if (stacks_top == 0) {
+ if (stack_top == 0) {
printk(BIOS_ERR, "%s: error assigning stacks\n", __func__);
return -1;
}
- params->stack_top = stacks_top;
/* Load the stub. */
if (rmodule_load((void *)smm_stub_loc, &smm_stub)) {
printk(BIOS_ERR, "%s: load module failed\n", __func__);
@@ -402,19 +381,15 @@
/* Setup the parameters for the stub code. */
stub_params = rmodule_parameters(&smm_stub);
- stub_params->stack_top = (uintptr_t)stacks_top;
- stub_params->stack_size = params->per_cpu_stack_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;
- const size_t total_stack_size =
- params->num_concurrent_stacks * params->per_cpu_stack_size;
- printk(BIOS_DEBUG, "%s: stack_end = 0x%zx\n",
- __func__, stub_params->stack_top - total_stack_size);
printk(BIOS_DEBUG,
"%s: stack_top = 0x%x\n", __func__, stub_params->stack_top);
- printk(BIOS_DEBUG, "%s: stack_size = 0x%x\n",
+ printk(BIOS_DEBUG, "%s: per cpu stack_size = 0x%x\n",
__func__, stub_params->stack_size);
printk(BIOS_DEBUG, "%s: runtime.start32_offset = 0x%x\n", __func__,
stub_params->start32_offset);
@@ -439,7 +414,7 @@
* assumption is that the stub will be entered from the default SMRAM
* location: 0x30000 -> 0x40000.
*/
-int smm_setup_relocation_handler(const uintptr_t perm_smram, struct smm_loader_params *params)
+int smm_setup_relocation_handler(struct smm_loader_params *params)
{
uintptr_t smram = SMM_DEFAULT_BASE;
printk(BIOS_SPEW, "%s: enter\n", __func__);
@@ -459,7 +434,7 @@
printk(BIOS_SPEW, "%s: exit\n", __func__);
return smm_module_setup_stub(smram, SMM_DEFAULT_SIZE,
- params, fxsave_area_relocation, perm_smram);
+ params, fxsave_area_relocation);
}
/*
@@ -519,11 +494,9 @@
if (CONFIG(DEBUG_SMI))
memset((void *)smram_base, 0xcd, smram_size);
- total_stack_size = params->per_cpu_stack_size *
- params->num_concurrent_stacks;
+ total_stack_size = stack_top - smram_base;
total_size += total_stack_size;
/* Stacks are the base of SMRAM */
- params->stack_top = smram_base + total_stack_size;
/* MSEG starts at the top of SMRAM and works down */
if (CONFIG(STM)) {
@@ -580,8 +553,6 @@
printk(BIOS_DEBUG, "%s: smram_start: 0x%lx\n", __func__, smram_base);
printk(BIOS_DEBUG, "%s: smram_end: %lx\n", __func__, smram_base + smram_size);
- printk(BIOS_DEBUG, "%s: stack_top: %lx\n",
- __func__, params->stack_top);
printk(BIOS_DEBUG, "%s: handler start %p\n",
__func__, params->handler);
printk(BIOS_DEBUG, "%s: handler_size %zx\n",
@@ -619,5 +590,5 @@
cpus[i].ss_start + params->per_cpu_save_state_size;
}
- return smm_module_setup_stub(base, smram_size, params, fxsave_area, smram_base);
+ return smm_module_setup_stub(base, smram_size, params, fxsave_area);
}
diff --git a/src/include/cpu/x86/mp.h b/src/include/cpu/x86/mp.h
index 934d217..1b4c956 100644
--- a/src/include/cpu/x86/mp.h
+++ b/src/include/cpu/x86/mp.h
@@ -45,17 +45,6 @@
*/
void (*get_microcode_info)(const void **microcode, int *parallel);
/*
- * Optionally adjust SMM handler parameters to override the default
- * values. The is_perm variable indicates if the parameters to adjust
- * are for the relocation handler or the permanent handler. This
- * function is therefore called twice -- once for each handler.
- * By default the parameters for each SMM handler are:
- * stack_size num_concurrent_stacks num_concurrent_save_states
- * relo: save_state_size get_cpu_count() 1
- * perm: save_state_size get_cpu_count() get_cpu_count()
- */
- void (*adjust_smm_params)(struct smm_loader_params *slp, int is_perm);
- /*
* Optionally provide a callback prior to the APs starting SMM
* relocation or CPU driver initialization. However, note that
* this callback is called after SMM handlers have been loaded.
@@ -92,13 +81,11 @@
* 3. get_smm_info()
* 4. get_microcode_info()
* 5. adjust_cpu_apic_entry() for each number of get_cpu_count()
- * 6. adjust_smm_params(is_perm = 0)
- * 7. adjust_smm_params(is_perm = 1)
- * 8. pre_mp_smm_init()
- * 9. per_cpu_smm_trigger() in parallel for all cpus which calls
+ * 6. pre_mp_smm_init()
+ * 7. per_cpu_smm_trigger() in parallel for all cpus which calls
* relocation_handler() in SMM.
- * 10. mp_initialize_cpu() for each cpu
- * 11. post_mp_init()
+ * 8. mp_initialize_cpu() for each cpu
+ * 9. post_mp_init()
*/
enum cb_err mp_init_with_smm(struct bus *cpu_bus, const struct mp_ops *mp_ops);
diff --git a/src/include/cpu/x86/smm.h b/src/include/cpu/x86/smm.h
index 848996f..37247ec 100644
--- a/src/include/cpu/x86/smm.h
+++ b/src/include/cpu/x86/smm.h
@@ -120,9 +120,6 @@
/* SMM Module Loading API */
/* The smm_loader_params structure provides direction to the SMM loader:
- * - stack_top - optional external stack provided to loader. It must be at
- * least per_cpu_stack_size * num_concurrent_stacks in size.
- * - per_cpu_stack_size - stack size per CPU for smm modules.
* - num_concurrent_stacks - number of concurrent cpus in handler needing stack
* optional for setting up relocation handler.
* - per_cpu_save_state_size - the SMM save state size per cpu
@@ -135,8 +132,6 @@
* handle sparse APIC id space.
*/
struct smm_loader_params {
- uintptr_t stack_top;
- size_t per_cpu_stack_size;
size_t num_concurrent_stacks;
size_t real_cpu_save_state_size;
@@ -148,8 +143,10 @@
struct smm_stub_params *stub_params;
};
-/* Both of these return 0 on success, < 0 on failure. */
-int smm_setup_relocation_handler(const uintptr_t perm_smram, struct smm_loader_params *params);
+/* All of these return 0 on success, < 0 on failure. */
+int smm_setup_stack(const uintptr_t perm_smbase, const size_t perm_smram_size,
+ const unsigned int total_cpus, const size_t stack_size);
+int smm_setup_relocation_handler(struct smm_loader_params *params);
int smm_load_module(uintptr_t smram_base, size_t smram_size, struct smm_loader_params *params);
u32 smm_get_cpu_smbase(unsigned int cpu_num);