diff options
| -rw-r--r-- | src/arch/arm64/stage_entry.S | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/src/arch/arm64/stage_entry.S b/src/arch/arm64/stage_entry.S index 301711e8f9..6b8ca7b424 100644 --- a/src/arch/arm64/stage_entry.S +++ b/src/arch/arm64/stage_entry.S @@ -17,6 +17,14 @@ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ +/* + * ======================== stage_entry.S ===================================== + * This file acts as an entry point to the different stages of arm64 as well as + * for the secure monitor. They share the same process of setting up stacks and + * jumping to c code. It is important to save x25 from corruption as it contains + * the argument for secure monitor. + * ============================================================================= + */ #include <arch/asm.h> #define __ASSEMBLY__ @@ -71,6 +79,10 @@ ENDPROC(cpu_get_exception_stack) * 16-byte aligned stack. The programming enviroment uses SP_EL0 as its main * stack while keeping SP_ELx reserved for exception entry. */ +/* + * IMPORTANT: Ensure x25 is not corrupted because it saves the argument to + * secmon + */ ENTRY(arm64_c_environment) bl smp_processor_id /* x0 = cpu */ mov x24, x0 @@ -92,14 +104,22 @@ ENTRY(arm64_c_environment) mov sp, x0 /* Get entry point by dereferencing c_entry. */ - ldr x0, 1f - ldr x0, [x0] - br x0 + ldr x1, 1f + ldr x1, [x1] + /* Move back the arguments from x25 to x0 */ + mov x0, x25 + br x1 .align 3 1: .quad c_entry ENDPROC(arm64_c_environment) +ENTRY(__rmodule_entry) + /* Save the arguments to secmon in x25 */ + mov x25, x0 + b arm64_c_environment +ENDPROC(__rmodule_entry) + CPU_RESET_ENTRY(arm64_cpu_startup) read_current x0, sctlr bic x0, x0, #(1 << 25) /* Little Endian */ |