From 910490f3f48d418824276045489d1ceb221e0ba1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ky=C3=B6sti=20M=C3=A4lkki?= Date: Thu, 22 Aug 2019 12:56:22 +0300 Subject: [PATCH] arch/x86: Restrict use of _car_global[start|end] MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-on: https://review.coreboot.org/c/coreboot/+/35034 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin Reviewed-by: Marshall Dawson --- src/arch/x86/assembly_entry.S | 6 +++--- src/arch/x86/car.ld | 10 +++++++--- src/arch/x86/include/arch/early_variables.h | 9 +++++++++ src/arch/x86/include/arch/symbols.h | 13 ++----------- .../intel/common/block/cpu/car/cache_as_ram_fsp.S | 6 +++--- src/soc/intel/quark/romstage/fsp2_0.c | 2 +- 6 files changed, 25 insertions(+), 21 deletions(-) diff --git a/src/arch/x86/assembly_entry.S b/src/arch/x86/assembly_entry.S index 5e84af24a2..c36dc1cb10 100644 --- a/src/arch/x86/assembly_entry.S +++ b/src/arch/x86/assembly_entry.S @@ -32,11 +32,11 @@ _start: /* 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 diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld index a09150fcd9..6ccbd8c236 100644 --- a/src/arch/x86/car.ld +++ b/src/arch/x86/car.ld @@ -64,11 +64,13 @@ . += 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) @@ -76,10 +78,12 @@ *(.sbss) *(.sbss.*) #else + _car_global_start = .; *(.car.global_data); + _car_global_end = .; #endif . = ALIGN(ARCH_POINTER_ALIGN_SIZE); - _car_global_end = .; + _ebss = .; _car_unallocated_start = .; #if !CONFIG(C_ENVIRONMENT_BOOTBLOCK) diff --git a/src/arch/x86/include/arch/early_variables.h b/src/arch/x86/include/arch/early_variables.h index 57f4306619..b88495c85b 100644 --- a/src/arch/x86/include/arch/early_variables.h +++ b/src/arch/x86/include/arch/early_variables.h @@ -20,6 +20,15 @@ #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 a516155dec..f715e0a6d1 100644 --- a/src/arch/x86/include/arch/symbols.h +++ b/src/arch/x86/include/arch/symbols.h @@ -24,8 +24,8 @@ extern char _car_region_end[]; #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[]; @@ -38,13 +38,4 @@ 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 9a8ab5ba42..091fc4a06b 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 @@ CAR_init_done: /* 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 c999bce567..a64fed4868 100644 --- a/src/soc/intel/quark/romstage/fsp2_0.c +++ b/src/soc/intel/quark/romstage/fsp2_0.c @@ -115,7 +115,7 @@ void platform_fsp_memory_init_params_cb(FSPM_UPD *fspm_upd, uint32_t version) aupd->StackBase); printk(BIOS_SPEW, "| |\n"); printk(BIOS_SPEW, "+-------------------+ 0x%p\n", - _car_global_end); + _car_unallocated_start); printk(BIOS_SPEW, "| coreboot data |\n"); printk(BIOS_SPEW, "+-------------------+ 0x%p\n", _car_stack_end);