#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, irq = 0
.if \irq != 0
@ IRQs already off
#ifdef CONFIG_TRACE_IRQFLAGS
@ The parent context IRQs must have been enabled to get here in
@ the first place, so there's no point checking the PSR I bit.
bl trace_hardirqs_on
#endif
.else
@ IRQs off again before pulling preserved data off the stack
disable_irq_notrace
#ifdef CONFIG_TRACE_IRQFLAGS
tst \rpsr, #PSR_I_BIT
bleq trace_hardirqs_on
tst \rpsr, #PSR_I_BIT
blne trace_hardirqs_off
#endif
.endif
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, irq = 0
.if \irq != 0
@ IRQs already off
#ifdef CONFIG_TRACE_IRQFLAGS
@ The parent context IRQs must have been enabled to get here in
@ the first place, so there's no point checking the PSR I bit.
bl trace_hardirqs_on
#endif
.else
@ IRQs off again before pulling preserved data off the stack
disable_irq_notrace
#ifdef CONFIG_TRACE_IRQFLAGS
tst \rpsr, #PSR_I_BIT
bleq trace_hardirqs_on
tst \rpsr, #PSR_I_BIT
blne trace_hardirqs_off
#endif
.endif
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 */
/*
* Context tracking subsystem. Used to instrument transitions
* between user and kernel mode.
*/
.macro ct_user_exit, save = 1
#ifdef CONFIG_CONTEXT_TRACKING
.if \save
stmdb sp!, {r0-r3, ip, lr}
bl user_exit
ldmia sp!, {r0-r3, ip, lr}
.else
bl user_exit
.endif
#endif
.endm
.macro ct_user_enter, save = 1
#ifdef CONFIG_CONTEXT_TRACKING
.if \save
stmdb sp!, {r0-r3, ip, lr}
bl user_enter
ldmia sp!, {r0-r3, ip, lr}
.else
bl user_enter
.endif
#endif
.endm
/*
* 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