summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/vector.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/vector.S')
-rw-r--r--arch/powerpc/kernel/vector.S354
1 files changed, 354 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
new file mode 100644
index 0000000000..80b3f6e476
--- /dev/null
+++ b/arch/powerpc/kernel/vector.S
@@ -0,0 +1,354 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/export.h>
+#include <linux/linkage.h>
+#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>
+#include <asm/asm-compat.h>
+
+/*
+ * Load state from memory into VMX registers including VSCR.
+ * Assumes the caller has enabled VMX in the MSR.
+ */
+_GLOBAL(load_vr_state)
+ li r4,VRSTATE_VSCR
+ lvx v0,r4,r3
+ mtvscr v0
+ REST_32VRS(0,r4,r3)
+ blr
+EXPORT_SYMBOL(load_vr_state)
+_ASM_NOKPROBE_SYMBOL(load_vr_state); /* used by restore_math */
+
+/*
+ * Store VMX state into memory, including VSCR.
+ * Assumes the caller has enabled VMX in the MSR.
+ */
+_GLOBAL(store_vr_state)
+ SAVE_32VRS(0, r4, r3)
+ mfvscr v0
+ li r4, VRSTATE_VSCR
+ stvx v0, r4, r3
+ lvx v0, 0, r3
+ blr
+EXPORT_SYMBOL(store_vr_state)
+
+/*
+ * 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).
+ *
+ * Note that on 32-bit this can only use registers that will be
+ * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
+ */
+_GLOBAL(load_up_altivec)
+ mfmsr r5 /* grab the current MSR */
+#ifdef CONFIG_PPC_BOOK3S_64
+ /* interrupt doesn't set MSR[RI] and HPT can fault on current access */
+ ori r5,r5,MSR_RI
+#endif
+ oris r5,r5,MSR_VEC@h
+ MTMSRD(r5) /* enable use of AltiVec now */
+ isync
+
+ /*
+ * While userspace in general ignores VRSAVE, glibc uses it as a boolean
+ * to optimise userspace context save/restore. Whenever we take an
+ * altivec unavailable exception we must set VRSAVE to something non
+ * zero. Set it to all 1s. See also the programming note in the ISA.
+ */
+ 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
+ addi r5,r2,THREAD
+ 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)
+#ifdef CONFIG_PPC_BOOK3S_64
+ li r4,0
+ stb r4,PACASRR_VALID(r13)
+#endif
+#endif
+ li r4,1
+ stb r4,THREAD_LOAD_VEC(r5)
+ addi r6,r5,THREAD_VRSTATE
+ li r10,VRSTATE_VSCR
+ stw r4,THREAD_USED_VR(r5)
+ lvx v0,r10,r6
+ mtvscr v0
+ REST_32VRS(0,r4,r6)
+ /* restore registers and return */
+ blr
+_ASM_NOKPROBE_SYMBOL(load_up_altivec)
+
+/*
+ * save_altivec(tsk)
+ * Save the vector registers to its thread_struct
+ */
+_GLOBAL(save_altivec)
+ addi r3,r3,THREAD /* want THREAD of task */
+ PPC_LL r7,THREAD_VRSAVEAREA(r3)
+ PPC_LL r5,PT_REGS(r3)
+ PPC_LCMPI 0,r7,0
+ bne 2f
+ addi r7,r3,THREAD_VRSTATE
+2: SAVE_32VRS(0,r4,r7)
+ mfvscr v0
+ li r4,VRSTATE_VSCR
+ stvx v0,r4,r7
+ lvx v0,0,r7
+ 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 */
+
+#ifdef CONFIG_PPC_BOOK3S_64
+ /* interrupt doesn't set MSR[RI] and HPT can fault on current access */
+ li r5,MSR_RI
+ mtmsrd r5,1
+#endif
+
+ 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)
+ li r4,0
+ stb r4,PACASRR_VALID(r13)
+ b fast_interrupt_return_srr
+
+#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.
+ */
+ .data
+#ifdef CONFIG_PPC32
+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
+
+fpzero:
+ .quad 0
+fpone:
+ .quad 0x3ff0000000000000 /* 1.0 */
+fphalf:
+ .quad 0x3fe0000000000000 /* 0.5 */
+
+#ifdef CONFIG_PPC_KERNEL_PCREL
+#define LDCONST(fr, name) \
+ pla r11,name@pcrel; \
+ lfd fr,0(r11)
+#else
+#define LDCONST(fr, name) \
+ addis r11,r2,name@toc@ha; \
+ lfd fr,name@toc@l(r11)
+#endif
+#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.
+ */
+SYM_FUNC_START_LOCAL(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
+SYM_FUNC_END(fpenable)
+
+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