From a6c29fe6841ad5e03ddb35803943bed3bc83dfd2 Mon Sep 17 00:00:00 2001 From: Vladimir Serbinenko Date: Tue, 26 Nov 2013 17:49:29 +0100 Subject: [PATCH] amd/car/post_cache_as_ram: Switch stack in assembly rather than in C Compiler may do loads of optimisations around stack switch and so it's allowed to break stack switch as it sees fit. Do it in assembly instead. Not tested. Change-Id: I277a62a9052e8fe9b04e7c65d149e087282ac2a2 Signed-off-by: Vladimir Serbinenko Reviewed-on: http://review.coreboot.org/4286 Tested-by: build bot (Jenkins) Reviewed-by: Zheng Bao Reviewed-by: Stefan Reinauer --- src/cpu/amd/car/cache_as_ram.inc | 12 ++++++++++++ src/cpu/amd/car/post_cache_as_ram.c | 25 ++++++++++--------------- 2 files changed, 22 insertions(+), 15 deletions(-) diff --git a/src/cpu/amd/car/cache_as_ram.inc b/src/cpu/amd/car/cache_as_ram.inc index 7070cf9b10..8f0abce1a5 100644 --- a/src/cpu/amd/car/cache_as_ram.inc +++ b/src/cpu/amd/car/cache_as_ram.inc @@ -414,10 +414,22 @@ CAR_FAM10_ap_out: pushl %ebx /* Init detected. */ pushl %eax /* BIST */ call cache_as_ram_main + /* We will not go back. */ post_code(0xaf) /* Should never see this POST code. */ + .globl cache_as_ram_switch_stack + +cache_as_ram_switch_stack: + /* Return address. */ + popl %eax + /* Resume memory. */ + popl %eax + subl $(( (CONFIG_DCACHE_RAM_BASE + CONFIG_DCACHE_RAM_SIZE)- (CONFIG_RAMTOP) )), %esp + pushl %eax + call cache_as_ram_new_stack + all_mtrr_msrs: /* fixed MTRR MSRs */ .long MTRRfix64K_00000_MSR diff --git a/src/cpu/amd/car/post_cache_as_ram.c b/src/cpu/amd/car/post_cache_as_ram.c index eca7673df3..3fe496e44c 100644 --- a/src/cpu/amd/car/post_cache_as_ram.c +++ b/src/cpu/amd/car/post_cache_as_ram.c @@ -75,11 +75,11 @@ static void vErrata343(void) #endif } +void cache_as_ram_switch_stack(void *resume_backup_memory); + static void post_cache_as_ram(void) { -#if CONFIG_HAVE_ACPI_RESUME - void *resume_backup_memory; -#endif + void *resume_backup_memory = NULL; #if 1 { /* Check value of esp to verify if we have enough room for stack in Cache as RAM */ @@ -92,9 +92,6 @@ static void post_cache_as_ram(void) } #endif - unsigned testx = 0x5a5a5a5a; - print_debug_pcar("testx = ", testx); - /* copy data from cache as ram to ram need to set CONFIG_RAMTOP to 2M and use var mtrr instead. */ @@ -112,21 +109,19 @@ static void post_cache_as_ram(void) vErrata343(); memcopy((void *)((CONFIG_RAMTOP)-CONFIG_DCACHE_RAM_SIZE), (void *)CONFIG_DCACHE_RAM_BASE, CONFIG_DCACHE_RAM_SIZE); //inline + cache_as_ram_switch_stack(resume_backup_memory); +} - __asm__ volatile ( - /* set new esp */ /* before CONFIG_RAMBASE */ - "subl %0, %%esp\n\t" - ::"a"( (CONFIG_DCACHE_RAM_BASE + CONFIG_DCACHE_RAM_SIZE)- (CONFIG_RAMTOP) ) - /* discard all registers (eax is used for %0), so gcc redoes everything - after the stack is moved */ - : "cc", "memory", "%ebx", "%ecx", "%edx", "%esi", "%edi", "%ebp" - ); +void +cache_as_ram_new_stack (void *resume_backup_memory); +void +cache_as_ram_new_stack (void *resume_backup_memory __attribute__ ((unused))) +{ /* We can put data to stack again */ /* only global variable sysinfo in cache need to be offset */ print_debug("Done\n"); - print_debug_pcar("testx = ", testx); print_debug("Disabling cache as ram now \n");