diff options
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/arch/m88k/m88k/eh_common.S | 171 |
1 files changed, 60 insertions, 111 deletions
diff --git a/sys/arch/m88k/m88k/eh_common.S b/sys/arch/m88k/m88k/eh_common.S index d4e87ecc160..88dd1b194c5 100644 --- a/sys/arch/m88k/m88k/eh_common.S +++ b/sys/arch/m88k/m88k/eh_common.S @@ -1,4 +1,4 @@ -/* $OpenBSD: eh_common.S,v 1.38 2007/11/22 23:30:11 miod Exp $ */ +/* $OpenBSD: eh_common.S,v 1.39 2007/12/02 21:27:02 miod Exp $ */ /* * Mach Operating System * Copyright (c) 1993-1991 Carnegie Mellon University @@ -30,7 +30,8 @@ /* * NOTICE: This is not a standalone file. To use it, define the PFSR_SAVE - * macro and #include this file in your port's eh.S: + * macro (if supporting 88100 processors) and #include this file in your + * port's eh.S: * #include <m88k/m88k/eh_common.S> */ @@ -40,7 +41,7 @@ * (second edition). Reference in []s refer to section numbers. * * This discussion assumes that you are at least vaguely familiar with 88100 - * exception handling (chapter 6), the MACH kernel, and that you have a brain + * exception handling (chapter 6), the BSD kernel, and that you have a brain * (and use it while reading this). * * I also assume (and hope) that you're not offended by frequent misspellings. @@ -341,10 +342,10 @@ 1: bsr _ASM_LABEL(m88110_setup_phase_one) ; \ /* TMP2 now free -- use to set EF_VECTOR */ ; \ or TMP2, r0, NUM ; \ - st TMP2, r31, REG_OFF(EF_VECTOR) ; \ - /* call setup_phase_two to restart the FPU */ ; \ - /* and to save all general registers. */ ; \ - bsr _ASM_LABEL(m88110_setup_phase_two) + /* call setup_phase_two to save all general */ ; \ + /* registers. */ ; \ + bsr.n _ASM_LABEL(m88110_setup_phase_two) ; \ + st TMP2, r31, REG_OFF(EF_VECTOR) #endif /* Some defines for use with PREP88100() */ @@ -1317,7 +1318,7 @@ ASLOCAL(m88100_setup_phase_two) * * immediate goal: * restore the system to the exception-time state (except - * SR3 will be OUR stack pointer) so that we may resart the FPU. + * SR3 will be OUR stack pointer) so that we may restart the FPU. */ stcr TMP, SSBR /* done with SSBR, TMP now free */ @@ -1821,19 +1822,16 @@ ASLOCAL(m88110_setup_phase_one) * Might be at the end of R31, SR3, or the process pcb. */ - /* Check if we are coming in from a FPU restart exception. - If so, the pcb will be in SR3 */ NOP xcr r1, r1, SR2 NOP NOP NOP - bb1 FLAG_ENABLING_FPU, FLAGS, _ASM_LABEL(m88110_use_SR3_pcb) /* are we coming in from user mode? If so, pick up process pcb */ bb0 FLAG_FROM_KERNEL, FLAGS, _ASM_LABEL(m88110_pickup_stack) - /* Interrupt in kernel mode, not FPU restart */ + /* Interrupt in kernel mode */ /* * SR1: saved copy of exception-time register now holding FLAGS * SR2: return address to the calling exception handler @@ -1856,63 +1854,6 @@ ASLOCAL(m88110_setup_phase_one) br.n _ASM_LABEL(m88110_have_pcb) st r1, r31, GENREG_OFF(31) -ASLOCAL(m88110_use_SR3_pcb) - /* - * SR1: saved copy of exception-time register now holding FLAGS - * SR2: return address to the calling exception handler - * SR3: must be preserved; exception-time stack pointer - * FLAGS: CPU status flags - * - * immediate goal: - * An exception occurred while enabling the FPU. Since r31 is the - * user's r31 while enabling the FPU, we had put our pcb pointer - * into SR3, so make room from there for our stack pointer. - * We need to check if SR3 is the old stack pointer or the pointer - * off to the user pcb. If it pointing to the user pcb, we need to - * pick up the kernel stack. Otherwise we need to allocate a frame - * upon it. - * We look at the EPSR to see if it was from user mode - * Unfortunately, we have no registers free at the moment, but we - * know register 0 in the pcb frame will always be zero, so we can - * use it as scratch storage. - */ - xcr r30, r30, SR3 /* r30 = old exception frame */ - st r1, r30, GENREG_OFF(0) /* free up r1 */ - ld r1, r30, REG_OFF(EF_EPSR) /* get back the epsr */ - bb0.n PSR_SUPERVISOR_MODE_BIT, r1, 1f /* if user mode */ - ld r1, r30, GENREG_OFF(0) /* restore r1 */ - /* we were in kernel mode - dump frame upon the stack */ - st r0, r30, GENREG_OFF(0) /* repair old frame */ - subu r30, r30, SIZEOF_EF /* r30 now our E.F. */ - st FLAGS,r30, REG_OFF(EF_FLAGS) /* save flags */ - st r1, r30, GENREG_OFF(1) /* save prev. r1 (now free) */ - - st r31, r30, GENREG_OFF(31) /* save previous r31 */ - or r31, r0, r30 /* make r31 our pointer. */ - addu r30, r30, SIZEOF_EF /* r30 now has previous SR3 */ - st r30, r31, REG_OFF(EF_SR3) /* save previous SR3 */ - br.n _ASM_LABEL(m88110_have_pcb) - xcr r30, r30, SR3 /* restore r30 */ -1: - /* - * We took an exception while restarting the FPU from user space. - * Consequently, we never picked up a stack. Do so now. - * R1 is currently free (saved in the exception frame pointed at by - * r30) - */ - ldcr r1, CPU - ld r1, r1, CI_CURPCB - addu r1, r1, USIZE - SIZEOF_EF - st FLAGS,r1, REG_OFF(EF_FLAGS) /* store flags */ - st r31, r1, GENREG_OFF(31) /* store r31 - now free */ - st r30, r1, REG_OFF(EF_SR3) /* store old SR3 (pcb) */ - or r31, r1, r0 /* make r31 our exception fp */ - ld r1, r30, GENREG_OFF(0) /* restore old r1 */ - st r0, r30, GENREG_OFF(0) /* repair that frame */ - st r1, r31, GENREG_OFF(1) /* store r1 */ - br.n _ASM_LABEL(m88110_have_pcb) - xcr r30, r30, SR3 /* restore r30 */ - ASLOCAL(m88110_pickup_stack) /* * SR1: saved copy of exception-time register now holding FLAGS @@ -1935,8 +1876,7 @@ ASLOCAL(m88110_pickup_stack) /* * WARNING! Using pcb->user_state as the exception frame * AND stack pointer, means we can not afford using the stack - * until we have saved enough and can go back to the top of the u area, - * after the FPU is enabled. + * until we have saved enough and can go back to the top of the u area. */ st FLAGS,r31, REG_OFF(EF_FLAGS) /* save flags */ @@ -1956,10 +1896,6 @@ ASLOCAL(m88110_have_pcb) * Valid in the exception frame: * Exception-time r1, r31, FLAGS. * Exception SR3, if appropriate. - * - * immediate goal: - * Save the shadow registers that need to be saved to - * the exception frame. */ stcr TMP, SR3 /* free up TMP, TMP2, TMP3 */ SAVE_TMP2 @@ -2024,29 +1960,24 @@ ASLOCAL(m88110_setup_phase_two) * Exception-time TMP2, TMP3. * Exception-time espr, enip, exip. * Exception number (EF_VECTOR). - * Dmt0 - * Other data pipeline control registers, if appropriate. - * FPU control registers, if appropriate. * Exception SR3, if appropriate. * * immediate goal: * restore the system to the exception-time state (except SR3 will - * be OUR stack pointer) so that we may resart the FPU. + * be OUR stack pointer). */ RESTORE_TMP2 /* done with extra temp regs */ RESTORE_TMP3 /* done with extra temp regs */ ldcr TMP, PSR - clr TMP, TMP, 1<PSR_FPU_DISABLE_BIT> /* enable the FPU */ clr TMP, TMP, 1<PSR_SHADOW_FREEZE_BIT> /* and shadowing */ stcr TMP, EPSR - or.u TMP, r0, hi16(_ASM_LABEL(m88110_fpu_enable)) - or TMP, TMP, lo16(_ASM_LABEL(m88110_fpu_enable)) + or.u TMP, r0, hi16(_ASM_LABEL(m88110_shadow_enable)) + or TMP, TMP, lo16(_ASM_LABEL(m88110_shadow_enable)) stcr TMP, EXIP - set FLAGS, FLAGS, 1<FLAG_ENABLING_FPU> xcr FLAGS, FLAGS, SR1 st r1, r31, REG_OFF(EF_RET) /* save the return address */ ld r1, r31, GENREG_OFF(1) /* get original r1 */ @@ -2072,13 +2003,13 @@ ASLOCAL(m88110_setup_phase_two) * Return address to the calling exception handler. * * immediate goal: - * Do an RTE to restart the fpu and jump to "fpu_enable" + * Do an RTE to unfreeze the shadow registers. * Another exception (or exceptions) may be raised in - * this, which is why FLAG_ENABLING_FPU is set in SR1. + * this. */ - RTE /* jumps to "m88110_fpu_enable" to enable the FPU. */ + RTE /* jumps to "m88110_shadow_enable" */ -ASLOCAL(m88110_fpu_enable) +ASLOCAL(m88110_shadow_enable) FLUSH_PIPELINE xcr TMP, TMP, SR3 /* get E.F. pointer */ @@ -2086,13 +2017,7 @@ ASLOCAL(m88110_fpu_enable) st r31, TMP, GENREG_OFF(31) /* save previous r30, r31 */ or r31, TMP, r0 /* transfer E.F. pointer */ ld TMP, r31, REG_OFF(EF_SR3) /* get previous SR3 */ - - /* make sure that the FLAG_ENABLING_FPU bit is off */ - xcr FLAGS,FLAGS,SR1 - clr FLAGS,FLAGS,1<FLAG_ENABLING_FPU> - xcr FLAGS,FLAGS,SR1 - - xcr TMP, TMP, SR3 /* replace TMP, SR3 */ + xcr TMP, TMP, SR3 /* replace TMP, SR3 */ /* now save all regs to the exception frame. */ st r0 , r31, GENREG_OFF(0) @@ -2143,13 +2068,10 @@ ASLOCAL(m88110_fpu_enable) * Exception-time FLAGS. * Exception-time espr, enip, exip. * Exception number (EF_VECTOR). - * DSR - * Other data pipeline control registers, if appropriate. - * FPU control registers, if appropriate. + * DSR/ISR * Exception SR3, if appropriate. * * immediate goal: - * Pick up a stack if we came in from user mode. * Put a copy of the exception frame pointer into r30 * Bump the stack a doubleword and write the exception frame pointer. * If not an interrupt exception, turn on interrupts and service any @@ -2351,23 +2273,16 @@ ASGLOBAL(ast_done) FLUSH_PIPELINE /* reload the control regs*/ -#ifdef M88110 -#ifdef M88100 +#if defined(M88100) && defined(M88110) or.u r1, r0, hi16(_C_LABEL(cputyp)) ld r30, r1, lo16(_C_LABEL(cputyp)) cmp r1, r30, CPU_88110 - bb1 ne, r1, 1f -#endif - ld r30, r31, REG_OFF(EF_ENIP) - ld r1, r31, REG_OFF(EF_EXIP) - stcr r30, ENIP - stcr r1, EXIP -#ifdef M88100 - br 2f -1: -#endif + bb1 ne, r1, _ASM_LABEL(m88100_user_rte) + br _ASM_LABEL(m88110_user_rte) #endif + #ifdef M88100 +ASGLOBAL(m88100_user_rte) /* * RTE will cause execution to continue first with the * instruction pointed to by the NIP and then the FIP; @@ -2378,8 +2293,25 @@ ASGLOBAL(ast_done) ld r1, r31, REG_OFF(EF_SFIP) stcr r30, SNIP stcr r1, SFIP -2: + + ld r30, r31, REG_OFF(EF_EPSR) + stcr r30, EPSR + + /* Now restore r1, r30, and r31 */ + ld r1, r31, GENREG_OFF(1) + ld r30, r31, GENREG_OFF(30) + ld r31, r31, GENREG_OFF(31) + + RTE #endif + +#ifdef M88110 +ASGLOBAL(m88110_user_rte) + ld r30, r31, REG_OFF(EF_ENIP) + ld r1, r31, REG_OFF(EF_EXIP) + stcr r30, ENIP + stcr r1, EXIP + ld r30, r31, REG_OFF(EF_EPSR) stcr r30, EPSR @@ -2388,4 +2320,21 @@ ASGLOBAL(ast_done) ld r30, r31, GENREG_OFF(30) ld r31, r31, GENREG_OFF(31) + /* + * 88110 errata #18 (fixed in revision 5 cpus): + * ``An rte to user mode where the logical address of the rte + * instruction is within two cache lines of the logical address + * in the exip can cause the wrong instruction to be returned + * to if the rte instruction misses in the icache.'' + * + * Since we run with interrupts disabled at this point, all we + * need is make sure that the rte will not appear as the first + * instruction of a cache line. + */ + br 1f + + align 64 /* 32 might not be enough */ +1: + NOP RTE +#endif |