diff options
Diffstat (limited to 'payloads/libpayload/arch/arm/exception_asm.S')
| -rw-r--r-- | payloads/libpayload/arch/arm/exception_asm.S | 56 |
1 files changed, 30 insertions, 26 deletions
diff --git a/payloads/libpayload/arch/arm/exception_asm.S b/payloads/libpayload/arch/arm/exception_asm.S index 7b722cb86f..8715955de2 100644 --- a/payloads/libpayload/arch/arm/exception_asm.S +++ b/payloads/libpayload/arch/arm/exception_asm.S @@ -43,72 +43,76 @@ exception_table: b 8f 1: - mov sp, $0 + mov sp, #0 b exception_common /* Undefined Instruction (CAREFUL: the PC offset is specific to thumb mode!) */ 2: - sub lr, lr, $2 - mov sp, $1 + sub lr, lr, #2 + mov sp, #1 b exception_common /* Software Interrupt (no PC offset necessary) */ 3: - mov sp, $2 + mov sp, #2 b exception_common /* Prefetch Abort */ 4: - sub lr, lr, $4 - mov sp, $3 + sub lr, lr, #4 + mov sp, #3 b exception_common /* Data Abort */ 5: - sub lr, lr, $8 - mov sp, $4 + sub lr, lr, #8 + mov sp, #4 b exception_common /* (not used) */ 6: - mov sp, $5 + mov sp, #5 b exception_common /* Interrupt */ 7: - sub lr, lr, $4 - mov sp, $6 + sub lr, lr, #4 + mov sp, #6 b exception_common /* Fast Interrupt */ 8: - sub lr, lr, $4 - mov sp, $7 + sub lr, lr, #4 + mov sp, #7 b exception_common exception_common: str sp, exception_idx - ldr sp, exception_stack_end - push { lr } - stmfd sp, { sp, lr }^ - sub sp, sp, $8 - push { r0 - r12 } + ldr sp, exception_state_ptr + stmia sp!, { r0 - r12 } /* Save regs from bottom to top */ + stmia sp, { sp, lr }^ /* Save banked SP/LR (no writeback) */ + str lr, [sp, #(4 * 2)] /* Save PC to ®s[13] + 2 */ mrs r0, SPSR - push { r0 } - mov r0, sp - ldr r1, exception_idx + str r0, [sp, #(4 * 3)] /* Save SPSR to ®s[13] + 3 */ + ldr sp, exception_stack_end /* Point SP to the stack for C code */ + ldr r0, exception_idx blx exception_dispatch - pop { r0 } - msr SPSR_cxsf, r0 - pop { r0 - r12 } - add sp, sp, $8 - ldmfd sp!, { pc }^ + ldr sp, exception_state_ptr + ldr r0, [sp, #(4 * 16)] /* Load SPSR from ®s[0] + 16... */ + msr SPSR_cxsf, r0 /* ...and get it out of the way */ + ldmia sp!, { r0 - r12 } /* Restore regs from bottom to top */ + ldmia sp, { sp, lr }^ /* Restore SP/LR to banked location */ + add sp, sp, #8 /* Adjust SP (no writeback allowed) */ + ldmia sp!, { pc }^ /* Do exception return (mode switch) */ .align 2 .global exception_stack_end exception_stack_end: .word 0 + .global exception_state_ptr +exception_state_ptr: + .word 0 exception_idx: .word 0 |