diff options
Diffstat (limited to 'arch/arm/kernel/entry-header.S')
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 92 |
1 files changed, 87 insertions, 5 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 87ab4e157997..a4eaf4f920c5 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -36,11 +36,6 @@ #endif .endm - .macro get_thread_info, rd - mov \rd, sp, lsr #13 - mov \rd, \rd, lsl #13 - .endm - .macro alignment_trap, rtemp #ifdef CONFIG_ALIGNMENT_TRAP ldr \rtemp, .LCcralign @@ -49,6 +44,93 @@ #endif .endm + @ + @ Store/load the USER SP and LR registers by switching to the SYS + @ mode. Useful in Thumb-2 mode where "stm/ldm rd, {sp, lr}^" is not + @ available. Should only be called from SVC mode + @ + .macro store_user_sp_lr, rd, rtemp, offset = 0 + mrs \rtemp, cpsr + eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE) + msr cpsr_c, \rtemp @ switch to the SYS mode + + str sp, [\rd, #\offset] @ save sp_usr + str lr, [\rd, #\offset + 4] @ save lr_usr + + eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE) + msr cpsr_c, \rtemp @ switch back to the SVC mode + .endm + + .macro load_user_sp_lr, rd, rtemp, offset = 0 + mrs \rtemp, cpsr + eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE) + msr cpsr_c, \rtemp @ switch to the SYS mode + + ldr sp, [\rd, #\offset] @ load sp_usr + ldr lr, [\rd, #\offset + 4] @ load lr_usr + + eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE) + msr cpsr_c, \rtemp @ switch back to the SVC mode + .endm + +#ifndef CONFIG_THUMB2_KERNEL + .macro svc_exit, rpsr + msr spsr_cxsf, \rpsr + ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr + .endm + + .macro restore_user_regs, fast = 0, offset = 0 + ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr + ldr lr, [sp, #\offset + S_PC]! @ get pc + msr spsr_cxsf, r1 @ save in spsr_svc + .if \fast + ldmdb sp, {r1 - lr}^ @ get calling r1 - lr + .else + ldmdb sp, {r0 - lr}^ @ get calling r0 - lr + .endif + add sp, sp, #S_FRAME_SIZE - S_PC + movs pc, lr @ return & move spsr_svc into cpsr + .endm + + .macro get_thread_info, rd + mov \rd, sp, lsr #13 + mov \rd, \rd, lsl #13 + .endm +#else /* CONFIG_THUMB2_KERNEL */ + .macro svc_exit, rpsr + ldr r0, [sp, #S_SP] @ top of the stack + ldr r1, [sp, #S_PC] @ return address + tst r0, #4 @ orig stack 8-byte aligned? + stmdb r0, {r1, \rpsr} @ rfe context + ldmia sp, {r0 - r12} + ldr lr, [sp, #S_LR] + addeq sp, sp, #S_FRAME_SIZE - 8 @ aligned + addne sp, sp, #S_FRAME_SIZE - 4 @ not aligned + rfeia sp! + .endm + + .macro restore_user_regs, fast = 0, offset = 0 + mov r2, sp + load_user_sp_lr r2, r3, \offset + S_SP @ calling sp, lr + ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr + ldr lr, [sp, #\offset + S_PC] @ get pc + add sp, sp, #\offset + S_SP + msr spsr_cxsf, r1 @ save in spsr_svc + .if \fast + ldmdb sp, {r1 - r12} @ get calling r1 - r12 + .else + ldmdb sp, {r0 - r12} @ get calling r0 - r12 + .endif + add sp, sp, #S_FRAME_SIZE - S_SP + movs pc, lr @ return & move spsr_svc into cpsr + .endm + + .macro get_thread_info, rd + mov \rd, sp + lsr \rd, \rd, #13 + mov \rd, \rd, lsl #13 + .endm +#endif /* !CONFIG_THUMB2_KERNEL */ /* * These are the registers used in the syscall handler, and allow us to |