diff --git a/src/arch/x86/boot/cbmem.c b/src/arch/x86/boot/cbmem.c index 9ee5db49f0..f48e46aa80 100644 --- a/src/arch/x86/boot/cbmem.c +++ b/src/arch/x86/boot/cbmem.c @@ -34,10 +34,23 @@ void __attribute__((weak)) backup_top_of_ram(uint64_t ramtop) /* Do nothing. Chipset may have implementation to save ramtop in NVRAM. */ } +static void *ramtop_pointer; + void set_top_of_ram(uint64_t ramtop) { backup_top_of_ram(ramtop); - cbmem_set_top((void*)(uintptr_t)ramtop); + ramtop_pointer = (void *)(uintptr_t)ramtop; + cbmem_set_top(ramtop_pointer); +} + +static inline void *saved_ramtop(void) +{ + return ramtop_pointer; +} +#else +static inline void *saved_ramtop(void) +{ + return NULL; } #endif /* !__PRE_RAM__ */ @@ -50,6 +63,11 @@ unsigned long __attribute__((weak)) get_top_of_ram(void) void *cbmem_top(void) { /* Top of cbmem is at lowest usable DRAM address below 4GiB. */ + void *ptr = saved_ramtop(); + + if (ptr != NULL) + return ptr; + return (void *)get_top_of_ram(); } diff --git a/src/include/cbmem.h b/src/include/cbmem.h index 20cc174d05..0a7ca89cd4 100644 --- a/src/include/cbmem.h +++ b/src/include/cbmem.h @@ -221,6 +221,9 @@ void cbmem_list(void); * early features like COLLECT_TIMESTAMPS and CBMEM_CONSOLE. */ #if IS_ENABLED(CONFIG_ARCH_X86) && IS_ENABLED(CONFIG_LATE_CBMEM_INIT) +/* Note that many of the current providers of get_top_of_ram() conditionally + * return 0 when the sleep type is non S3. i.e. cold and warm boots would + * return 0 from get_top_of_ram(). */ unsigned long get_top_of_ram(void); void set_top_of_ram(uint64_t ramtop); void backup_top_of_ram(uint64_t ramtop);