Kyösti Mälkki has uploaded this change for review.
arch/x86: Fix .bss section in CAR
Fix clearing CAR region, 'stosl' stores 4 bytes at a time.
Restrict the use of symbol names _car_global_[start|end]
to be used exclusively with CAR_GLOBAL_MIGRATION=y.
They just alias the start and end of .bss section in CAR.
Change-Id: I36c858a4f181516d4c61f9fd1d5005c7d2c06057
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
---
M src/arch/x86/assembly_entry.S
M src/arch/x86/car.ld
M src/arch/x86/include/arch/early_variables.h
M src/arch/x86/include/arch/symbols.h
M src/soc/intel/common/block/cpu/car/cache_as_ram_fsp.S
M src/soc/intel/quark/romstage/fsp2_0.c
6 files changed, 38 insertions(+), 22 deletions(-)
git pull ssh://review.coreboot.org:29418/coreboot refs/changes/34/35034/1
diff --git a/src/arch/x86/assembly_entry.S b/src/arch/x86/assembly_entry.S
index 4ead9ea..b3871d6 100644
--- a/src/arch/x86/assembly_entry.S
+++ b/src/arch/x86/assembly_entry.S
@@ -35,12 +35,13 @@
/* reset stack pointer to CAR stack */
mov $_car_stack_end, %esp
- /* clear CAR_GLOBAL area as it is not shared */
+ /* clear .bss section as it is not shared */
cld
xor %eax, %eax
- movl $(_car_global_end), %ecx
- movl $(_car_global_start), %edi
+ movl $(_ebss), %ecx
+ movl $(_bss), %edi
sub %edi, %ecx
+ shrl $2, %ecx
rep stosl
#if ((ENV_VERSTAGE && CONFIG(VERSTAGE_DEBUG_SPINLOOP)) \
diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld
index 822f7fd..bc0090b 100644
--- a/src/arch/x86/car.ld
+++ b/src/arch/x86/car.ld
@@ -68,11 +68,13 @@
. += 80;
_car_ehci_dbg_info_end = .;
- /* _car_global_start and _car_global_end provide symbols to per-stage
+ /* _bss and _ebss provide symbols to per-stage
* variables that are not shared like the timestamp and the pre-ram
* cbmem console. This is useful for clearing this area on a per-stage
* basis when more than one stage uses cache-as-ram for CAR_GLOBALs. */
- _car_global_start = .;
+
+ . = ALIGN(ARCH_POINTER_ALIGN_SIZE);
+ _bss = .;
#if ENV_STAGE_HAS_BSS_SECTION
/* Allow global uninitialized variables for stages without CAR teardown. */
*(.bss)
@@ -80,10 +82,12 @@
*(.sbss)
*(.sbss.*)
#else
+ _car_global_start = .;
*(.car.global_data);
+ _car_global_end = .;
#endif
. = ALIGN(ARCH_POINTER_ALIGN_SIZE);
- _car_global_end = .;
+ _ebss = .;
#if CONFIG(CAR_GLOBAL_MIGRATION)
_car_stack_start = .;
diff --git a/src/arch/x86/include/arch/early_variables.h b/src/arch/x86/include/arch/early_variables.h
index b5db194..9e0441c 100644
--- a/src/arch/x86/include/arch/early_variables.h
+++ b/src/arch/x86/include/arch/early_variables.h
@@ -22,6 +22,15 @@
#if ENV_ROMSTAGE && CONFIG(CAR_GLOBAL_MIGRATION)
+/*
+ * The _car_global_[start|end]symbols cover CAR data which is relocatable
+ * once memory comes online. Variables with CAR_GLOBAL decoration
+ * reside within this region.
+ */
+extern char _car_global_start[];
+extern char _car_global_end[];
+#define _car_global_size (_car_global_end - _car_global_start)
+
asm(".section .car.global_data,\"w\",@nobits");
asm(".previous");
#ifdef __clang__
diff --git a/src/arch/x86/include/arch/symbols.h b/src/arch/x86/include/arch/symbols.h
index 5d65a7b..3f2e978 100644
--- a/src/arch/x86/include/arch/symbols.h
+++ b/src/arch/x86/include/arch/symbols.h
@@ -27,25 +27,26 @@
#define _car_region_size (_car_region_end - _car_region_start)
/*
- * This is the stack used under CONFIG_C_ENVIRONMENT_BOOTBLOCK for
- * all stages that execute when cache-as-ram is up.
+ * This is the stack area used for all stages that execute when cache-as-ram
+ * is up. Area is not cleared in between stages.
*/
extern char _car_stack_start[];
extern char _car_stack_end[];
#define _car_stack_size (_car_stack_end - _car_stack_start)
+/*
+ * This is the .bss section cleared between each stage. It is not
+ * available in romstage if CAR_GLOBAL_MIGRATION is enabled.
+ */
+extern char _bss[];
+extern char _ebss[];
+#define _bss_size (_ebss - _bss)
+
+extern char _car_unallocated_start;
+
extern char _car_ehci_dbg_info_start[];
extern char _car_ehci_dbg_info_end[];
#define _car_ehci_dbg_info_size \
(_car_ehci_dbg_info_end - _car_ehci_dbg_info_start)
-/*
- * The _car_global_[start|end]symbols cover CAR data which is relocatable
- * once memory comes online. Variables with CAR_GLOBAL decoration
- * reside within this region.
- */
-extern char _car_global_start[];
-extern char _car_global_end[];
-#define _car_global_size (_car_global_end - _car_global_start)
-
#endif
diff --git a/src/soc/intel/common/block/cpu/car/cache_as_ram_fsp.S b/src/soc/intel/common/block/cpu/car/cache_as_ram_fsp.S
index 9a8ab5b..091fc4a 100644
--- a/src/soc/intel/common/block/cpu/car/cache_as_ram_fsp.S
+++ b/src/soc/intel/common/block/cpu/car/cache_as_ram_fsp.S
@@ -89,11 +89,11 @@
/* Setup bootblock stack */
mov %edx, %esp
- /* clear CAR_GLOBAL area as it is not shared */
+ /* clear .bss section as it is not shared */
cld
xor %eax, %eax
- movl $(_car_global_end), %ecx
- movl $(_car_global_start), %edi
+ movl $(_ebss), %ecx
+ movl $(_bss), %edi
sub %edi, %ecx
shrl $2, %ecx
rep stosl
diff --git a/src/soc/intel/quark/romstage/fsp2_0.c b/src/soc/intel/quark/romstage/fsp2_0.c
index e6da5dd..0cf2d80 100644
--- a/src/soc/intel/quark/romstage/fsp2_0.c
+++ b/src/soc/intel/quark/romstage/fsp2_0.c
@@ -14,6 +14,7 @@
*/
#include <arch/cpu.h>
+#include <arch/early_variables.h>
#include <arch/romstage.h>
#include <arch/symbols.h>
#include <console/console.h>
@@ -142,10 +143,10 @@
aupd->StackBase);
printk(BIOS_SPEW, "| |\n");
printk(BIOS_SPEW, "+-------------------+ 0x%p\n",
- _car_global_end);
+ _bss);
printk(BIOS_SPEW, "| coreboot data |\n");
printk(BIOS_SPEW, "+-------------------+ 0x%p\n",
- _car_stack_end);
+ _car_stack_start);
printk(BIOS_SPEW, "| coreboot stack |\n");
printk(BIOS_SPEW,
"+-------------------+ 0x80000000 - ESRAM start\n\n");
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