mirror of
https://github.com/torvalds/linux.git
synced 2024-11-14 08:02:07 +00:00
ba00ce1d6e
A static branch hint will override dynamic branch prediction on recent POWER CPUs. Since we are about to use more altivec in the kernel remove the static hint in giveup_altivec that assumes a userspace task is using altivec. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
408 lines
8.5 KiB
ArmAsm
408 lines
8.5 KiB
ArmAsm
#include <asm/processor.h>
|
|
#include <asm/ppc_asm.h>
|
|
#include <asm/reg.h>
|
|
#include <asm/asm-offsets.h>
|
|
#include <asm/cputable.h>
|
|
#include <asm/thread_info.h>
|
|
#include <asm/page.h>
|
|
#include <asm/ptrace.h>
|
|
|
|
/*
|
|
* load_up_altivec(unused, unused, tsk)
|
|
* Disable VMX for the task which had it previously,
|
|
* and save its vector registers in its thread_struct.
|
|
* Enables the VMX for use in the kernel on return.
|
|
* On SMP we know the VMX is free, since we give it up every
|
|
* switch (ie, no lazy save of the vector registers).
|
|
*/
|
|
_GLOBAL(load_up_altivec)
|
|
mfmsr r5 /* grab the current MSR */
|
|
oris r5,r5,MSR_VEC@h
|
|
MTMSRD(r5) /* enable use of AltiVec now */
|
|
isync
|
|
|
|
/*
|
|
* For SMP, we don't do lazy VMX switching because it just gets too
|
|
* horrendously complex, especially when a task switches from one CPU
|
|
* to another. Instead we call giveup_altvec in switch_to.
|
|
* VRSAVE isn't dealt with here, that is done in the normal context
|
|
* switch code. Note that we could rely on vrsave value to eventually
|
|
* avoid saving all of the VREGs here...
|
|
*/
|
|
#ifndef CONFIG_SMP
|
|
LOAD_REG_ADDRBASE(r3, last_task_used_altivec)
|
|
toreal(r3)
|
|
PPC_LL r4,ADDROFF(last_task_used_altivec)(r3)
|
|
PPC_LCMPI 0,r4,0
|
|
beq 1f
|
|
|
|
/* Save VMX state to last_task_used_altivec's THREAD struct */
|
|
toreal(r4)
|
|
addi r4,r4,THREAD
|
|
SAVE_32VRS(0,r5,r4)
|
|
mfvscr vr0
|
|
li r10,THREAD_VSCR
|
|
stvx vr0,r10,r4
|
|
/* Disable VMX for last_task_used_altivec */
|
|
PPC_LL r5,PT_REGS(r4)
|
|
toreal(r5)
|
|
PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
lis r10,MSR_VEC@h
|
|
andc r4,r4,r10
|
|
PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
1:
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/* Hack: if we get an altivec unavailable trap with VRSAVE
|
|
* set to all zeros, we assume this is a broken application
|
|
* that fails to set it properly, and thus we switch it to
|
|
* all 1's
|
|
*/
|
|
mfspr r4,SPRN_VRSAVE
|
|
cmpwi 0,r4,0
|
|
bne+ 1f
|
|
li r4,-1
|
|
mtspr SPRN_VRSAVE,r4
|
|
1:
|
|
/* enable use of VMX after return */
|
|
#ifdef CONFIG_PPC32
|
|
mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
|
|
oris r9,r9,MSR_VEC@h
|
|
#else
|
|
ld r4,PACACURRENT(r13)
|
|
addi r5,r4,THREAD /* Get THREAD */
|
|
oris r12,r12,MSR_VEC@h
|
|
std r12,_MSR(r1)
|
|
#endif
|
|
li r4,1
|
|
li r10,THREAD_VSCR
|
|
stw r4,THREAD_USED_VR(r5)
|
|
lvx vr0,r10,r5
|
|
mtvscr vr0
|
|
REST_32VRS(0,r4,r5)
|
|
#ifndef CONFIG_SMP
|
|
/* Update last_task_used_altivec to 'current' */
|
|
subi r4,r5,THREAD /* Back to 'current' */
|
|
fromreal(r4)
|
|
PPC_STL r4,ADDROFF(last_task_used_altivec)(r3)
|
|
#endif /* CONFIG_SMP */
|
|
/* restore registers and return */
|
|
blr
|
|
|
|
/*
|
|
* giveup_altivec(tsk)
|
|
* Disable VMX for the task given as the argument,
|
|
* and save the vector registers in its thread_struct.
|
|
* Enables the VMX for use in the kernel on return.
|
|
*/
|
|
_GLOBAL(giveup_altivec)
|
|
mfmsr r5
|
|
oris r5,r5,MSR_VEC@h
|
|
SYNC
|
|
MTMSRD(r5) /* enable use of VMX now */
|
|
isync
|
|
PPC_LCMPI 0,r3,0
|
|
beqlr /* if no previous owner, done */
|
|
addi r3,r3,THREAD /* want THREAD of task */
|
|
PPC_LL r5,PT_REGS(r3)
|
|
PPC_LCMPI 0,r5,0
|
|
SAVE_32VRS(0,r4,r3)
|
|
mfvscr vr0
|
|
li r4,THREAD_VSCR
|
|
stvx vr0,r4,r3
|
|
beq 1f
|
|
PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
#ifdef CONFIG_VSX
|
|
BEGIN_FTR_SECTION
|
|
lis r3,(MSR_VEC|MSR_VSX)@h
|
|
FTR_SECTION_ELSE
|
|
lis r3,MSR_VEC@h
|
|
ALT_FTR_SECTION_END_IFSET(CPU_FTR_VSX)
|
|
#else
|
|
lis r3,MSR_VEC@h
|
|
#endif
|
|
andc r4,r4,r3 /* disable FP for previous task */
|
|
PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
1:
|
|
#ifndef CONFIG_SMP
|
|
li r5,0
|
|
LOAD_REG_ADDRBASE(r4,last_task_used_altivec)
|
|
PPC_STL r5,ADDROFF(last_task_used_altivec)(r4)
|
|
#endif /* CONFIG_SMP */
|
|
blr
|
|
|
|
#ifdef CONFIG_VSX
|
|
|
|
#ifdef CONFIG_PPC32
|
|
#error This asm code isn't ready for 32-bit kernels
|
|
#endif
|
|
|
|
/*
|
|
* load_up_vsx(unused, unused, tsk)
|
|
* Disable VSX for the task which had it previously,
|
|
* and save its vector registers in its thread_struct.
|
|
* Reuse the fp and vsx saves, but first check to see if they have
|
|
* been saved already.
|
|
*/
|
|
_GLOBAL(load_up_vsx)
|
|
/* Load FP and VSX registers if they haven't been done yet */
|
|
andi. r5,r12,MSR_FP
|
|
beql+ load_up_fpu /* skip if already loaded */
|
|
andis. r5,r12,MSR_VEC@h
|
|
beql+ load_up_altivec /* skip if already loaded */
|
|
|
|
#ifndef CONFIG_SMP
|
|
ld r3,last_task_used_vsx@got(r2)
|
|
ld r4,0(r3)
|
|
cmpdi 0,r4,0
|
|
beq 1f
|
|
/* Disable VSX for last_task_used_vsx */
|
|
addi r4,r4,THREAD
|
|
ld r5,PT_REGS(r4)
|
|
ld r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
lis r6,MSR_VSX@h
|
|
andc r6,r4,r6
|
|
std r6,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
1:
|
|
#endif /* CONFIG_SMP */
|
|
ld r4,PACACURRENT(r13)
|
|
addi r4,r4,THREAD /* Get THREAD */
|
|
li r6,1
|
|
stw r6,THREAD_USED_VSR(r4) /* ... also set thread used vsr */
|
|
/* enable use of VSX after return */
|
|
oris r12,r12,MSR_VSX@h
|
|
std r12,_MSR(r1)
|
|
#ifndef CONFIG_SMP
|
|
/* Update last_task_used_vsx to 'current' */
|
|
ld r4,PACACURRENT(r13)
|
|
std r4,0(r3)
|
|
#endif /* CONFIG_SMP */
|
|
b fast_exception_return
|
|
|
|
/*
|
|
* __giveup_vsx(tsk)
|
|
* Disable VSX for the task given as the argument.
|
|
* Does NOT save vsx registers.
|
|
* Enables the VSX for use in the kernel on return.
|
|
*/
|
|
_GLOBAL(__giveup_vsx)
|
|
mfmsr r5
|
|
oris r5,r5,MSR_VSX@h
|
|
mtmsrd r5 /* enable use of VSX now */
|
|
isync
|
|
|
|
cmpdi 0,r3,0
|
|
beqlr- /* if no previous owner, done */
|
|
addi r3,r3,THREAD /* want THREAD of task */
|
|
ld r5,PT_REGS(r3)
|
|
cmpdi 0,r5,0
|
|
beq 1f
|
|
ld r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
lis r3,MSR_VSX@h
|
|
andc r4,r4,r3 /* disable VSX for previous task */
|
|
std r4,_MSR-STACK_FRAME_OVERHEAD(r5)
|
|
1:
|
|
#ifndef CONFIG_SMP
|
|
li r5,0
|
|
ld r4,last_task_used_vsx@got(r2)
|
|
std r5,0(r4)
|
|
#endif /* CONFIG_SMP */
|
|
blr
|
|
|
|
#endif /* CONFIG_VSX */
|
|
|
|
|
|
/*
|
|
* The routines below are in assembler so we can closely control the
|
|
* usage of floating-point registers. These routines must be called
|
|
* with preempt disabled.
|
|
*/
|
|
#ifdef CONFIG_PPC32
|
|
.data
|
|
fpzero:
|
|
.long 0
|
|
fpone:
|
|
.long 0x3f800000 /* 1.0 in single-precision FP */
|
|
fphalf:
|
|
.long 0x3f000000 /* 0.5 in single-precision FP */
|
|
|
|
#define LDCONST(fr, name) \
|
|
lis r11,name@ha; \
|
|
lfs fr,name@l(r11)
|
|
#else
|
|
|
|
.section ".toc","aw"
|
|
fpzero:
|
|
.tc FD_0_0[TC],0
|
|
fpone:
|
|
.tc FD_3ff00000_0[TC],0x3ff0000000000000 /* 1.0 */
|
|
fphalf:
|
|
.tc FD_3fe00000_0[TC],0x3fe0000000000000 /* 0.5 */
|
|
|
|
#define LDCONST(fr, name) \
|
|
lfd fr,name@toc(r2)
|
|
#endif
|
|
|
|
.text
|
|
/*
|
|
* Internal routine to enable floating point and set FPSCR to 0.
|
|
* Don't call it from C; it doesn't use the normal calling convention.
|
|
*/
|
|
fpenable:
|
|
#ifdef CONFIG_PPC32
|
|
stwu r1,-64(r1)
|
|
#else
|
|
stdu r1,-64(r1)
|
|
#endif
|
|
mfmsr r10
|
|
ori r11,r10,MSR_FP
|
|
mtmsr r11
|
|
isync
|
|
stfd fr0,24(r1)
|
|
stfd fr1,16(r1)
|
|
stfd fr31,8(r1)
|
|
LDCONST(fr1, fpzero)
|
|
mffs fr31
|
|
MTFSF_L(fr1)
|
|
blr
|
|
|
|
fpdisable:
|
|
mtlr r12
|
|
MTFSF_L(fr31)
|
|
lfd fr31,8(r1)
|
|
lfd fr1,16(r1)
|
|
lfd fr0,24(r1)
|
|
mtmsr r10
|
|
isync
|
|
addi r1,r1,64
|
|
blr
|
|
|
|
/*
|
|
* Vector add, floating point.
|
|
*/
|
|
_GLOBAL(vaddfp)
|
|
mflr r12
|
|
bl fpenable
|
|
li r0,4
|
|
mtctr r0
|
|
li r6,0
|
|
1: lfsx fr0,r4,r6
|
|
lfsx fr1,r5,r6
|
|
fadds fr0,fr0,fr1
|
|
stfsx fr0,r3,r6
|
|
addi r6,r6,4
|
|
bdnz 1b
|
|
b fpdisable
|
|
|
|
/*
|
|
* Vector subtract, floating point.
|
|
*/
|
|
_GLOBAL(vsubfp)
|
|
mflr r12
|
|
bl fpenable
|
|
li r0,4
|
|
mtctr r0
|
|
li r6,0
|
|
1: lfsx fr0,r4,r6
|
|
lfsx fr1,r5,r6
|
|
fsubs fr0,fr0,fr1
|
|
stfsx fr0,r3,r6
|
|
addi r6,r6,4
|
|
bdnz 1b
|
|
b fpdisable
|
|
|
|
/*
|
|
* Vector multiply and add, floating point.
|
|
*/
|
|
_GLOBAL(vmaddfp)
|
|
mflr r12
|
|
bl fpenable
|
|
stfd fr2,32(r1)
|
|
li r0,4
|
|
mtctr r0
|
|
li r7,0
|
|
1: lfsx fr0,r4,r7
|
|
lfsx fr1,r5,r7
|
|
lfsx fr2,r6,r7
|
|
fmadds fr0,fr0,fr2,fr1
|
|
stfsx fr0,r3,r7
|
|
addi r7,r7,4
|
|
bdnz 1b
|
|
lfd fr2,32(r1)
|
|
b fpdisable
|
|
|
|
/*
|
|
* Vector negative multiply and subtract, floating point.
|
|
*/
|
|
_GLOBAL(vnmsubfp)
|
|
mflr r12
|
|
bl fpenable
|
|
stfd fr2,32(r1)
|
|
li r0,4
|
|
mtctr r0
|
|
li r7,0
|
|
1: lfsx fr0,r4,r7
|
|
lfsx fr1,r5,r7
|
|
lfsx fr2,r6,r7
|
|
fnmsubs fr0,fr0,fr2,fr1
|
|
stfsx fr0,r3,r7
|
|
addi r7,r7,4
|
|
bdnz 1b
|
|
lfd fr2,32(r1)
|
|
b fpdisable
|
|
|
|
/*
|
|
* Vector reciprocal estimate. We just compute 1.0/x.
|
|
* r3 -> destination, r4 -> source.
|
|
*/
|
|
_GLOBAL(vrefp)
|
|
mflr r12
|
|
bl fpenable
|
|
li r0,4
|
|
LDCONST(fr1, fpone)
|
|
mtctr r0
|
|
li r6,0
|
|
1: lfsx fr0,r4,r6
|
|
fdivs fr0,fr1,fr0
|
|
stfsx fr0,r3,r6
|
|
addi r6,r6,4
|
|
bdnz 1b
|
|
b fpdisable
|
|
|
|
/*
|
|
* Vector reciprocal square-root estimate, floating point.
|
|
* We use the frsqrte instruction for the initial estimate followed
|
|
* by 2 iterations of Newton-Raphson to get sufficient accuracy.
|
|
* r3 -> destination, r4 -> source.
|
|
*/
|
|
_GLOBAL(vrsqrtefp)
|
|
mflr r12
|
|
bl fpenable
|
|
stfd fr2,32(r1)
|
|
stfd fr3,40(r1)
|
|
stfd fr4,48(r1)
|
|
stfd fr5,56(r1)
|
|
li r0,4
|
|
LDCONST(fr4, fpone)
|
|
LDCONST(fr5, fphalf)
|
|
mtctr r0
|
|
li r6,0
|
|
1: lfsx fr0,r4,r6
|
|
frsqrte fr1,fr0 /* r = frsqrte(s) */
|
|
fmuls fr3,fr1,fr0 /* r * s */
|
|
fmuls fr2,fr1,fr5 /* r * 0.5 */
|
|
fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
|
|
fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
|
|
fmuls fr3,fr1,fr0 /* r * s */
|
|
fmuls fr2,fr1,fr5 /* r * 0.5 */
|
|
fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
|
|
fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
|
|
stfsx fr1,r3,r6
|
|
addi r6,r6,4
|
|
bdnz 1b
|
|
lfd fr5,56(r1)
|
|
lfd fr4,48(r1)
|
|
lfd fr3,40(r1)
|
|
lfd fr2,32(r1)
|
|
b fpdisable
|