diff options
Diffstat (limited to 'arch/arm/kernel/entry-header.S')
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S new file mode 100644 index 00000000..9a8531ea --- /dev/null +++ b/arch/arm/kernel/entry-header.S @@ -0,0 +1,179 @@ +#include <linux/init.h> +#include <linux/linkage.h> + +#include <asm/assembler.h> +#include <asm/asm-offsets.h> +#include <asm/errno.h> +#include <asm/thread_info.h> + +@ Bad Abort numbers +@ ----------------- +@ +#define BAD_PREFETCH 0 +#define BAD_DATA 1 +#define BAD_ADDREXCPTN 2 +#define BAD_IRQ 3 +#define BAD_UNDEFINSTR 4 + +@ +@ Most of the stack format comes from struct pt_regs, but with +@ the addition of 8 bytes for storing syscall args 5 and 6. +@ This _must_ remain a multiple of 8 for EABI. +@ +#define S_OFF 8 + +/* + * The SWI code relies on the fact that R0 is at the bottom of the stack + * (due to slow/fast restore user regs). + */ +#if S_R0 != 0 +#error "Please fix" +#endif + + .macro zero_fp +#ifdef CONFIG_FRAME_POINTER + mov fp, #0 +#endif + .endm + + .macro alignment_trap, rtemp +#ifdef CONFIG_ALIGNMENT_TRAP + ldr \rtemp, .LCcralign + ldr \rtemp, [\rtemp] + mcr p15, 0, \rtemp, c1, c0 +#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 +#if defined(CONFIG_CPU_V6) + ldr r0, [sp] + strex r1, r2, [sp] @ clear the exclusive monitor + ldmib sp, {r1 - pc}^ @ load r1 - pc, cpsr +#elif defined(CONFIG_CPU_32v6K) + clrex @ clear the exclusive monitor + ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr +#else + ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr +#endif + .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 defined(CONFIG_CPU_V6) + strex r1, r2, [sp] @ clear the exclusive monitor +#elif defined(CONFIG_CPU_32v6K) + clrex @ clear the exclusive monitor +#endif + .if \fast + ldmdb sp, {r1 - lr}^ @ get calling r1 - lr + .else + ldmdb sp, {r0 - lr}^ @ get calling r0 - lr + .endif + mov r0, r0 @ ARMv5T and earlier require a nop + @ after ldm {}^ + 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 + + @ + @ 32-bit wide "mov pc, reg" + @ + .macro movw_pc, reg + mov pc, \reg + .endm +#else /* CONFIG_THUMB2_KERNEL */ + .macro svc_exit, rpsr + ldr lr, [sp, #S_SP] @ top of the stack + ldrd r0, r1, [sp, #S_LR] @ calling lr and pc + clrex @ clear the exclusive monitor + stmdb lr!, {r0, r1, \rpsr} @ calling lr and rfe context + ldmia sp, {r0 - r12} + mov sp, lr + ldr lr, [sp], #4 + rfeia sp! + .endm + + .macro restore_user_regs, fast = 0, offset = 0 + clrex @ clear the exclusive monitor + 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 + + @ + @ 32-bit wide "mov pc, reg" + @ + .macro movw_pc, reg + mov pc, \reg + nop + .endm +#endif /* !CONFIG_THUMB2_KERNEL */ + +/* + * These are the registers used in the syscall handler, and allow us to + * have in theory up to 7 arguments to a function - r0 to r6. + * + * r7 is reserved for the system call number for thumb mode. + * + * Note that tbl == why is intentional. + * + * We must set at least "tsk" and "why" when calling ret_with_reschedule. + */ +scno .req r7 @ syscall number +tbl .req r8 @ syscall table pointer +why .req r8 @ Linux syscall (!= 0) +tsk .req r9 @ current thread_info |