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authorArthur Heymans <arthur@aheymans.xyz>2019-11-25 19:58:36 +0100
committerPatrick Georgi <pgeorgi@google.com>2020-08-17 06:22:41 +0000
commita6a2f9372c492c2e6ca4404b372054b1fd82e1ee (patch)
tree809849d881e1ec1006ed033f54edfa7eba2cc44c
parent65605276a4cd08fd2e38f87cd80e3362265f9091 (diff)
downloadcoreboot-a6a2f9372c492c2e6ca4404b372054b1fd82e1ee.tar.xz
arch/x86/exit_car.S: Make sure _cbmem_top_ptr hits dram
INVD is called below so if postcar is running in a cached environment it needs to happen. NOTE: postcar cannot execute in a cached environment if clflush is not supported! Change-Id: I37681ee1f1d2ae5f9dd824b5baf7b23b2883b1dc Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/c/coreboot/+/37212 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-by: Patrick Rudolph <siro@das-labor.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com>
-rw-r--r--src/arch/x86/exit_car.S10
-rw-r--r--src/include/cpu/x86/cache.h2
2 files changed, 11 insertions, 1 deletions
diff --git a/src/arch/x86/exit_car.S b/src/arch/x86/exit_car.S
index 806dc9c069..dc356b2cf9 100644
--- a/src/arch/x86/exit_car.S
+++ b/src/arch/x86/exit_car.S
@@ -2,6 +2,7 @@
#include <cpu/x86/mtrr.h>
#include <cpu/x86/cr.h>
+#include <cpu/x86/cache.h>
.section ".module_parameters", "aw", @progbits
/* stack_top indicates the stack to pull MTRR information from. */
@@ -54,7 +55,14 @@ _start:
movl 4(%esp), %eax
movl %eax, _cbmem_top_ptr
#endif
-
+ /* Make sure _cbmem_top_ptr hits dram before invd */
+ movl $1, %eax
+ cpuid
+ btl $CPUID_FEATURE_CLFLUSH_BIT, %edx
+ jz skip_clflush
+ clflush _cbmem_top_ptr
+
+skip_clflush:
/* chipset_teardown_car() is expected to disable cache-as-ram. */
call chipset_teardown_car
diff --git a/src/include/cpu/x86/cache.h b/src/include/cpu/x86/cache.h
index 01b202eb1a..62341104a4 100644
--- a/src/include/cpu/x86/cache.h
+++ b/src/include/cpu/x86/cache.h
@@ -8,6 +8,8 @@
#define CR0_CacheDisable (CR0_CD)
#define CR0_NoWriteThrough (CR0_NW)
+#define CPUID_FEATURE_CLFLUSH_BIT 19
+
#if !defined(__ASSEMBLER__)
static inline void wbinvd(void)