From 7c9a0e8a9cfa90f8f413f3b485f8103bca80fac6 Mon Sep 17 00:00:00 2001 From: Arthur Heymans Date: Wed, 23 Oct 2019 17:02:50 +0200 Subject: arch/x86: Use the stage argument to implement cbmem_top Currently all stages that need cbmem need an implementation of a cbmem_top function. On FSP and AGESA platforms this proves to be painful and a pointer to the top of lower memory if often passed via lower memory (e.g. EBDA) or via a PCI scratchpad register. The problem with writing to lower memory is that also need to be written on S3 as one cannot assume it to be still there. Writing things on S3 is always a fragile thing to do. A very generic solution is to pass cbmem_top via the program argument. It should be possible to implement this solution on every architecture. Instead trying to figure out which files can be removed from stages and which cbmem_top implementations need with preprocessor, rename all cbmem_top implementation to cbmem_top_romstage. TESTED on qemu-x86. Change-Id: I6d5a366d6f1bc76f26d459628237e6b2c8ae03ea Signed-off-by: Arthur Heymans Reviewed-on: https://review.coreboot.org/c/coreboot/+/36144 Tested-by: build bot (Jenkins) Reviewed-by: Marshall Dawson --- src/arch/x86/Kconfig | 1 + src/arch/x86/Makefile.inc | 2 -- src/arch/x86/c_start.S | 8 ++++++++ src/arch/x86/cbmem.c | 13 +------------ src/arch/x86/exit_car.S | 8 ++++++++ 5 files changed, 18 insertions(+), 14 deletions(-) (limited to 'src/arch') diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig index 502e7747f483..8ce5977fdb65 100644 --- a/src/arch/x86/Kconfig +++ b/src/arch/x86/Kconfig @@ -16,6 +16,7 @@ config ARCH_X86 default n select PCI select RELOCATABLE_MODULES + select RAMSTAGE_CBMEM_TOP_ARG # stage selectors for x86 diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc index 8d001745dbf9..447fd57a1198 100644 --- a/src/arch/x86/Makefile.inc +++ b/src/arch/x86/Makefile.inc @@ -259,7 +259,6 @@ postcar-generic-ccopts += -D__POSTCAR__ postcar-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.c postcar-y += gdt_init.S postcar-y += cbfs_and_run.c -postcar-y += cbmem.c postcar-$(CONFIG_EARLY_EBDA_INIT) += ebda.c postcar-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c postcar-$(CONFIG_IDT_IN_EVERY_STAGE) += idt.S @@ -299,7 +298,6 @@ ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi_pld.c ramstage-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.c ramstage-$(CONFIG_ACPI_BERT) += acpi_bert_storage.c ramstage-y += c_start.S -ramstage-y += cbmem.c ramstage-y += cpu.c ramstage-y += ebda.c ramstage-y += exception.c diff --git a/src/arch/x86/c_start.S b/src/arch/x86/c_start.S index 43d78020e1d1..bd99c21c91c1 100644 --- a/src/arch/x86/c_start.S +++ b/src/arch/x86/c_start.S @@ -60,6 +60,14 @@ _start: cld +#ifdef __x86_64__ + mov %rdi, _cbmem_top_ptr +#else + /* The return argument is at 0(%esp), the calling argument at 4(%esp) */ + movl 4(%esp), %eax + movl %eax, _cbmem_top_ptr +#endif + /** poison the stack. Code should not count on the * stack being full of zeros. This stack poisoning * recently uncovered a bug in the broadcast SIPI diff --git a/src/arch/x86/cbmem.c b/src/arch/x86/cbmem.c index f7c58a47ce2c..fc85bc617f88 100644 --- a/src/arch/x86/cbmem.c +++ b/src/arch/x86/cbmem.c @@ -18,19 +18,8 @@ void *cbmem_top_chipset(void) { - static void *cbmem_top_backup; - void *top_backup; - - if (ENV_RAMSTAGE && cbmem_top_backup != NULL) - return cbmem_top_backup; - /* Top of CBMEM is at highest usable DRAM address below 4GiB. */ - top_backup = (void *)restore_top_of_low_cacheable(); - - if (ENV_RAMSTAGE) - cbmem_top_backup = top_backup; - - return top_backup; + return (void *)restore_top_of_low_cacheable(); } #endif /* CBMEM_TOP_BACKUP */ diff --git a/src/arch/x86/exit_car.S b/src/arch/x86/exit_car.S index 679e335eb3fe..8c2878481b98 100644 --- a/src/arch/x86/exit_car.S +++ b/src/arch/x86/exit_car.S @@ -31,6 +31,14 @@ _start: /* Migrate GDT to this text segment */ call gdt_init +#ifdef __x86_64__ + mov %rdi, _cbmem_top_ptr +#else + /* The return argument is at 0(%esp), the calling argument at 4(%esp) */ + movl 4(%esp), %eax + movl %eax, _cbmem_top_ptr +#endif + /* chipset_teardown_car() is expected to disable cache-as-ram. */ call chipset_teardown_car -- cgit v1.2.3