diff options
Diffstat (limited to 'arch/arm/vfp/vfphw.S')
| -rw-r--r-- | arch/arm/vfp/vfphw.S | 280 |
1 files changed, 193 insertions, 87 deletions
diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S index e51e6679c40..be807625ed8 100644 --- a/arch/arm/vfp/vfphw.S +++ b/arch/arm/vfp/vfphw.S @@ -14,19 +14,25 @@ * r10 points at the start of the private FP workspace in the thread structure * sp points to a struct pt_regs (as defined in include/asm/proc/ptrace.h) */ +#include <linux/init.h> +#include <linux/linkage.h> #include <asm/thread_info.h> #include <asm/vfpmacros.h> -#include "../kernel/entry-header.S" +#include <linux/kern_levels.h> +#include <asm/assembler.h> +#include <asm/asm-offsets.h> .macro DBGSTR, str #ifdef DEBUG stmfd sp!, {r0-r3, ip, lr} - add r0, pc, #4 + ldr r0, =1f bl printk - b 1f - .asciz "<7>VFP: \str\n" - .balign 4 -1: ldmfd sp!, {r0-r3, ip, lr} + ldmfd sp!, {r0-r3, ip, lr} + + .pushsection .rodata, "a" +1: .ascii KERN_DEBUG "VFP: \str\n" + .byte 0 + .previous #endif .endm @@ -34,12 +40,14 @@ #ifdef DEBUG stmfd sp!, {r0-r3, ip, lr} mov r1, \arg - add r0, pc, #4 + ldr r0, =1f bl printk - b 1f - .asciz "<7>VFP: \str\n" - .balign 4 -1: ldmfd sp!, {r0-r3, ip, lr} + ldmfd sp!, {r0-r3, ip, lr} + + .pushsection .rodata, "a" +1: .ascii KERN_DEBUG "VFP: \str\n" + .byte 0 + .previous #endif .endm @@ -49,107 +57,155 @@ mov r3, \arg3 mov r2, \arg2 mov r1, \arg1 - add r0, pc, #4 + ldr r0, =1f bl printk - b 1f - .asciz "<7>VFP: \str\n" - .balign 4 -1: ldmfd sp!, {r0-r3, ip, lr} + ldmfd sp!, {r0-r3, ip, lr} + + .pushsection .rodata, "a" +1: .ascii KERN_DEBUG "VFP: \str\n" + .byte 0 + .previous #endif .endm @ VFP hardware support entry point. @ -@ r0 = faulted instruction -@ r2 = faulted PC+4 -@ r9 = successful return +@ r0 = instruction opcode (32-bit ARM or two 16-bit Thumb) +@ r2 = PC value to resume execution after successful emulation +@ r9 = normal "successful" return address @ r10 = vfp_state union -@ lr = failure return - - .globl vfp_support_entry -vfp_support_entry: +@ r11 = CPU number +@ lr = unrecognised instruction return address +@ IRQs enabled. +ENTRY(vfp_support_entry) DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10 + ldr r3, [sp, #S_PSR] @ Neither lazy restore nor FP exceptions + and r3, r3, #MODE_MASK @ are supported in kernel mode + teq r3, #USR_MODE + bne vfp_kmode_exception @ Returns through lr + VFPFMRX r1, FPEXC @ Is the VFP enabled? DBGSTR1 "fpexc %08x", r1 - tst r1, #FPEXC_ENABLE + tst r1, #FPEXC_EN bne look_for_VFP_exceptions @ VFP is already enabled DBGSTR1 "enable %x", r10 - ldr r3, last_VFP_context_address - orr r1, r1, #FPEXC_ENABLE @ user FPEXC has the enable bit set - ldr r4, [r3] @ last_VFP_context pointer - bic r5, r1, #FPEXC_EXCEPTION @ make sure exceptions are disabled - cmp r4, r10 - beq check_for_exception @ we are returning to the same - @ process, so the registers are - @ still there. In this case, we do - @ not want to drop a pending exception. + ldr r3, vfp_current_hw_state_address + orr r1, r1, #FPEXC_EN @ user FPEXC has the enable bit set + ldr r4, [r3, r11, lsl #2] @ vfp_current_hw_state pointer + bic r5, r1, #FPEXC_EX @ make sure exceptions are disabled + cmp r4, r10 @ this thread owns the hw context? +#ifndef CONFIG_SMP + @ For UP, checking that this thread owns the hw context is + @ sufficient to determine that the hardware state is valid. + beq vfp_hw_state_valid + + @ On UP, we lazily save the VFP context. As a different + @ thread wants ownership of the VFP hardware, save the old + @ state if there was a previous (valid) owner. VFPFMXR FPEXC, r5 @ enable VFP, disable any pending @ exceptions, so we can get at the @ rest of it - @ Save out the current registers to the old thread state - DBGSTR1 "save old state %p", r4 - cmp r4, #0 - beq no_old_VFP_process + cmp r4, #0 @ if the vfp_current_hw_state is NULL + beq vfp_reload_hw @ then the hw state needs reloading + VFPFSTMIA r4, r5 @ save the working registers VFPFMRX r5, FPSCR @ current status - VFPFMRX r6, FPINST @ FPINST (always there, rev0 onwards) - tst r1, #FPEXC_FPV2 @ is there an FPINST2 to read? - VFPFMRX r8, FPINST2, NE @ FPINST2 if needed - avoids reading - @ nonexistant reg on rev0 - VFPFSTMIA r4 @ save the working registers +#ifndef CONFIG_CPU_FEROCEON + tst r1, #FPEXC_EX @ is there additional state to save? + beq 1f + VFPFMRX r6, FPINST @ FPINST (only if FPEXC.EX is set) + tst r1, #FPEXC_FP2V @ is there an FPINST2 to read? + beq 1f + VFPFMRX r8, FPINST2 @ FPINST2 if needed (and present) +1: +#endif stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2 - @ and point r4 at the word at the - @ start of the register dump +vfp_reload_hw: + +#else + @ For SMP, if this thread does not own the hw context, then we + @ need to reload it. No need to save the old state as on SMP, + @ we always save the state when we switch away from a thread. + bne vfp_reload_hw + + @ This thread has ownership of the current hardware context. + @ However, it may have been migrated to another CPU, in which + @ case the saved state is newer than the hardware context. + @ Check this by looking at the CPU number which the state was + @ last loaded onto. + ldr ip, [r10, #VFP_CPU] + teq ip, r11 + beq vfp_hw_state_valid + +vfp_reload_hw: + @ We're loading this threads state into the VFP hardware. Update + @ the CPU number which contains the most up to date VFP context. + str r11, [r10, #VFP_CPU] + + VFPFMXR FPEXC, r5 @ enable VFP, disable any pending + @ exceptions, so we can get at the + @ rest of it +#endif -no_old_VFP_process: DBGSTR1 "load state %p", r10 - str r10, [r3] @ update the last_VFP_context pointer + str r10, [r3, r11, lsl #2] @ update the vfp_current_hw_state pointer @ Load the saved state back into the VFP - VFPFLDMIA r10 @ reload the working registers while + VFPFLDMIA r10, r5 @ reload the working registers while @ FPEXC is in a safe state ldmia r10, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2 - tst r1, #FPEXC_FPV2 @ is there an FPINST2 to write? - VFPFMXR FPINST2, r8, NE @ FPINST2 if needed - avoids writing - @ nonexistant reg on rev0 - VFPFMXR FPINST, r6 +#ifndef CONFIG_CPU_FEROCEON + tst r1, #FPEXC_EX @ is there additional state to restore? + beq 1f + VFPFMXR FPINST, r6 @ restore FPINST (only if FPEXC.EX is set) + tst r1, #FPEXC_FP2V @ is there an FPINST2 to write? + beq 1f + VFPFMXR FPINST2, r8 @ FPINST2 if needed (and present) +1: +#endif VFPFMXR FPSCR, r5 @ restore status -check_for_exception: - tst r1, #FPEXC_EXCEPTION +@ The context stored in the VFP hardware is up to date with this thread +vfp_hw_state_valid: + tst r1, #FPEXC_EX bne process_exception @ might as well handle the pending @ exception before retrying branch @ out before setting an FPEXC that @ stops us reading stuff - VFPFMXR FPEXC, r1 @ restore FPEXC last - sub r2, r2, #4 - str r2, [sp, #S_PC] @ retry the instruction + VFPFMXR FPEXC, r1 @ Restore FPEXC last + sub r2, r2, #4 @ Retry current instruction - if Thumb + str r2, [sp, #S_PC] @ mode it's two 16-bit instructions, + @ else it's one 32-bit instruction, so + @ always subtract 4 from the following + @ instruction address. + dec_preempt_count_ti r10, r4 mov pc, r9 @ we think we have handled things look_for_VFP_exceptions: - tst r1, #FPEXC_EXCEPTION + @ Check for synchronous or asynchronous exception + tst r1, #FPEXC_EX | FPEXC_DEX bne process_exception + @ On some implementations of the VFP subarch 1, setting FPSCR.IXE + @ causes all the CDP instructions to be bounced synchronously without + @ setting the FPEXC.EX bit VFPFMRX r5, FPSCR - tst r5, #FPSCR_IXE @ IXE doesn't set FPEXC_EXCEPTION ! + tst r5, #FPSCR_IXE bne process_exception @ Fall into hand on to next handler - appropriate coproc instr @ not recognised by VFP DBGSTR "not VFP" + dec_preempt_count_ti r10, r4 mov pc, lr process_exception: DBGSTR "bounce" - sub r2, r2, #4 - str r2, [sp, #S_PC] @ retry the instruction on exit from - @ the imprecise exception handling in - @ the support code mov r2, sp @ nothing stacked - regdump is at TOS mov lr, r9 @ setup for a return to the user code. @@ -157,55 +213,105 @@ process_exception: @ r0 holds the trigger instruction @ r1 holds the FPEXC value @ r2 pointer to register dump - b VFP9_bounce @ we have handled this - the support + b VFP_bounce @ we have handled this - the support @ code will raise an exception if @ required. If not, the user code will @ retry the faulted instruction +ENDPROC(vfp_support_entry) -last_VFP_context_address: - .word last_VFP_context +ENTRY(vfp_save_state) + @ Save the current VFP state + @ r0 - save location + @ r1 - FPEXC + DBGSTR1 "save VFP state %p", r0 + VFPFSTMIA r0, r2 @ save the working registers + VFPFMRX r2, FPSCR @ current status + tst r1, #FPEXC_EX @ is there additional state to save? + beq 1f + VFPFMRX r3, FPINST @ FPINST (only if FPEXC.EX is set) + tst r1, #FPEXC_FP2V @ is there an FPINST2 to read? + beq 1f + VFPFMRX r12, FPINST2 @ FPINST2 if needed (and present) +1: + stmia r0, {r1, r2, r3, r12} @ save FPEXC, FPSCR, FPINST, FPINST2 + mov pc, lr +ENDPROC(vfp_save_state) + + .align +vfp_current_hw_state_address: + .word vfp_current_hw_state - .globl vfp_get_float -vfp_get_float: - add pc, pc, r0, lsl #3 + .macro tbl_branch, base, tmp, shift +#ifdef CONFIG_THUMB2_KERNEL + adr \tmp, 1f + add \tmp, \tmp, \base, lsl \shift + mov pc, \tmp +#else + add pc, pc, \base, lsl \shift mov r0, r0 +#endif +1: + .endm + +ENTRY(vfp_get_float) + tbl_branch r0, r3, #3 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 - mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0 +1: mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0 mov pc, lr - mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1 + .org 1b + 8 +1: mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1 mov pc, lr + .org 1b + 8 .endr +ENDPROC(vfp_get_float) - .globl vfp_put_float -vfp_put_float: - add pc, pc, r1, lsl #3 - mov r0, r0 +ENTRY(vfp_put_float) + tbl_branch r1, r3, #3 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 - mcr p10, 0, r0, c\dr, c0, 0 @ fmsr r0, s0 +1: mcr p10, 0, r0, c\dr, c0, 0 @ fmsr r0, s0 mov pc, lr - mcr p10, 0, r0, c\dr, c0, 4 @ fmsr r0, s1 + .org 1b + 8 +1: mcr p10, 0, r0, c\dr, c0, 4 @ fmsr r0, s1 mov pc, lr + .org 1b + 8 .endr +ENDPROC(vfp_put_float) - .globl vfp_get_double -vfp_get_double: - add pc, pc, r0, lsl #3 - mov r0, r0 +ENTRY(vfp_get_double) + tbl_branch r0, r3, #3 + .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 +1: fmrrd r0, r1, d\dr + mov pc, lr + .org 1b + 8 + .endr +#ifdef CONFIG_VFPv3 + @ d16 - d31 registers .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 - fmrrd r0, r1, d\dr +1: mrrc p11, 3, r0, r1, c\dr @ fmrrd r0, r1, d\dr mov pc, lr + .org 1b + 8 .endr +#endif - @ virtual register 16 for compare with zero + @ virtual register 16 (or 32 if VFPv3) for compare with zero mov r0, #0 mov r1, #0 mov pc, lr +ENDPROC(vfp_get_double) - .globl vfp_put_double -vfp_put_double: - add pc, pc, r2, lsl #3 - mov r0, r0 +ENTRY(vfp_put_double) + tbl_branch r2, r3, #3 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 - fmdrr d\dr, r0, r1 +1: fmdrr d\dr, r0, r1 mov pc, lr + .org 1b + 8 .endr +#ifdef CONFIG_VFPv3 + @ d16 - d31 registers + .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 +1: mcrr p11, 3, r0, r1, c\dr @ fmdrr r0, r1, d\dr + mov pc, lr + .org 1b + 8 + .endr +#endif +ENDPROC(vfp_put_double) |