Vladimir Serbinenko (phcoder@gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/4286
-gerrit
commit 2d6797b8222938f2c28e60b9d930d78bd458c431 Author: Vladimir Serbinenko phcoder@gmail.com Date: Tue Nov 26 17:49:29 2013 +0100
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 phcoder@gmail.com --- 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 7070cf9..8f0abce 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 eca7673..3fe496e 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");