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/*
* (c) 1999, Eric Valette valette@crf.canon.fr
*
*
* This file contains the assembly code for the PowerPC
* exception veneers for RTEMS.
*
* $Id$
*/
#include <rtems/asm.h>
#include <rtems/score/cpu.h>
#include <bsp/vectors.h>
#include <libcpu/raw_exception.h>
#define SYNC \
sync; \
isync
PUBLIC_VAR (__rtems_start)
.section .entry_point_section,"awx",@progbits
/*
* Entry point information used by bootloader code
*/
SYM (__rtems_start):
.long __rtems_entry_point
/*
* end of special Entry point section
*/
.text
/* 603e shadows GPR0..GPR3 for certain exceptions. We must switch
* that off before we can use the stack pointer. Note that this is
* ONLY safe if the shadowing is actually active -- otherwise, r1
* is destroyed. We deliberately use r1 so problems become obvious
* if this is abused!
*/
PUBLIC_VAR(tgpr_clr_exception_vector_code_prolog)
SYM (tgpr_clr_exception_vector_code_prolog):
mfmsr r1
rlwinm r1,r1,0,15,13
mtmsr r1
isync
/* fall thru */
PUBLIC_VAR(default_exception_vector_code_prolog)
SYM (default_exception_vector_code_prolog):
/*
* let room for exception frame
*/
stw r3, GPR3_OFFSET-EXCEPTION_FRAME_END(r1)
mflr r3
stw r3, EXC_LR_OFFSET-EXCEPTION_FRAME_END(r1)
bla push_normalized_frame
/* IMPORTANT: prologue size MUST be < 32 bytes; 'altivec unavailable' exception
* is already at 0xf20 :-(
*/
PUBLIC_VAR (default_exception_vector_code_prolog_size)
PUBLIC_VAR (tgpr_clr_exception_vector_code_prolog_size)
default_exception_vector_code_prolog_size = . - default_exception_vector_code_prolog
tgpr_clr_exception_vector_code_prolog_size= . - tgpr_clr_exception_vector_code_prolog
.p2align 5
PUBLIC_VAR (push_normalized_frame)
SYM (push_normalized_frame):
stwu r1, - (EXCEPTION_FRAME_END)(r1)
mfcr r3
stw r3, EXC_CR_OFFSET(r1)
/*
* r3 = exception vector entry point
* (256 * vector number) + few instructions
*/
mflr r3
/* mask upper bits in case vectors are in the high area (psim) */
rlwinm r3, r3, 32-5, 20, 31
/*
* Remap altivec unavaliable (0xf20) to its vector number...
*/
cmplwi r3,(ASM_VEC_VECTOR_OFFSET>>5)
bne 1f
li r3,ASM_VEC_VECTOR<<3
1:
/*
* r3 = r3 >> 8 = vector #
*/
srwi r3,r3,3
stw r3, EXCEPTION_NUMBER_OFFSET(r1)
stw r0, GPR0_OFFSET(r1)
/* R2 should never change (EABI: pointer to .sdata2) - we
* save it nevertheless..
*/
stw r2, GPR2_OFFSET(r1)
mfsrr0 r3
stw r3, SRR0_FRAME_OFFSET(r1)
mfsrr1 r3
stw r3, SRR1_FRAME_OFFSET(r1)
/*
* Save general purpose registers
* Already saved in prolog : R1, R3, LR.
* Saved a few line above : R0, R2
*
* Manual says that "stmw" instruction may be slower than
* series of individual "stw" but who cares about performance
* for the DEFAULT exception handler?
*/
stmw r4, GPR4_OFFSET(r1) /* save R4->R31 */
mfctr r30
stw r30, EXC_CTR_OFFSET(r1)
mfxer r28
stw r28, EXC_XER_OFFSET(r1)
mfmsr r28
stw r28, EXC_MSR_OFFSET(r1)
mfdar r28
stw r28, EXC_DAR_OFFSET(r1)
/*
* compute SP at exception entry
*/
addi r3, r1, EXCEPTION_FRAME_END
/*
* store it at the right place
*/
stw r3, GPR1_OFFSET(r1)
/*
* Enable data and instruction address translation, exception nesting
*/
mfmsr r3
ori r3,r3, MSR_RI | MSR_IR | MSR_DR
mtmsr r3
SYNC
/*
* Call C exception handler
*/
/*
* store the execption frame address in r3 (first param)
*/
addi r3, r1, 0x8
/* clear CR[6] to make sure no varargs fn callee assumes there are FP args passed */
crxor 6,6,6
/*
* globalExceptHdl(r3)
*/
addis r4, 0, globalExceptHdl@ha
lwz r5, globalExceptHdl@l(r4)
mtlr r5
blrl
/*
* Restore registers status
*/
lwz r31, EXC_CR_OFFSET(r1)
mtcr r31
lwz r30, EXC_CTR_OFFSET(r1)
mtctr r30
lwz r29, EXC_LR_OFFSET(r1)
mtlr r29
lwz r28, EXC_XER_OFFSET(r1)
mtxer r28
lmw r4, GPR4_OFFSET(r1)
lwz r2, GPR2_OFFSET(r1)
lwz r0, GPR0_OFFSET(r1)
/*
* Disable data and instruction translation. Make path non recoverable...
*/
mfmsr r3
xori r3, r3, MSR_RI | MSR_IR | MSR_DR
mtmsr r3
SYNC
/*
* Restore rfi related settings
*/
lwz r3, SRR1_FRAME_OFFSET(r1)
mtsrr1 r3
lwz r3, SRR0_FRAME_OFFSET(r1)
mtsrr0 r3
lwz r3, GPR3_OFFSET(r1)
/* DONT add back the frame size but reload the value
* stored in the frame -- maybe the exception handler
* changed it with good reason (e.g., gdb pushed a dummy frame)
*/
lwz r1, GPR1_OFFSET(r1)
SYNC
rfi
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