Commit 359c2ca7 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc: Don't handle ALTIVEC/SPE in ASM in _switch(). Do it in C. 



_switch() saves and restores ALTIVEC and SPE status.
For altivec this is redundant with what __switch_to() does with
save_sprs() and restore_sprs() and giveup_all() before
calling _switch().

Add support for SPI in save_sprs() and restore_sprs() and
remove things from _switch().

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8ab21fd93d6e0047aa71e6509e5e312f14b2991b.1620998075.git.christophe.leroy@csgroup.eu
parent 4423eff7

arch/powerpc/kernel/asm-offsets.c

+0 −2
Original line number Diff line number Diff line
@@ -116,7 +116,6 @@ int main(void) 
#ifdef CONFIG_ALTIVEC

	OFFSET(THREAD_VRSTATE, thread_struct, vr_state.vr);

	OFFSET(THREAD_VRSAVEAREA, thread_struct, vr_save_area);

	OFFSET(THREAD_VRSAVE, thread_struct, vrsave);

	OFFSET(THREAD_USED_VR, thread_struct, used_vr);

	OFFSET(VRSTATE_VSCR, thread_vr_state, vscr);

	OFFSET(THREAD_LOAD_VEC, thread_struct, load_vec);
@@ -147,7 +146,6 @@ int main(void) 
#ifdef CONFIG_SPE

	OFFSET(THREAD_EVR0, thread_struct, evr[0]);

	OFFSET(THREAD_ACC, thread_struct, acc);

	OFFSET(THREAD_SPEFSCR, thread_struct, spefscr);

	OFFSET(THREAD_USED_SPE, thread_struct, used_spe);

#endif /* CONFIG_SPE */

#endif /* CONFIG_PPC64 */

arch/powerpc/kernel/entry_32.S

+0 −35
Original line number Diff line number Diff line
@@ -176,28 +176,6 @@ _GLOBAL(_switch) 
	/* r3-r12 are caller saved -- Cort */

	SAVE_NVGPRS(r1)

	stw	r0,_NIP(r1)	/* Return to switch caller */

	mfmsr	r11

	li	r0,MSR_FP	/* Disable floating-point */

#ifdef CONFIG_ALTIVEC

BEGIN_FTR_SECTION

	oris	r0,r0,MSR_VEC@h	/* Disable altivec */

	mfspr	r12,SPRN_VRSAVE	/* save vrsave register value */

	stw	r12,THREAD+THREAD_VRSAVE(r2)

END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)

#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_SPE

BEGIN_FTR_SECTION

	oris	r0,r0,MSR_SPE@h	 /* Disable SPE */

	mfspr	r12,SPRN_SPEFSCR /* save spefscr register value */

	stw	r12,THREAD+THREAD_SPEFSCR(r2)

END_FTR_SECTION_IFSET(CPU_FTR_SPE)

#endif /* CONFIG_SPE */

	and.	r0,r0,r11	/* FP or altivec or SPE enabled? */

	beq+	1f

	andc	r11,r11,r0

	mtmsr	r11

	isync

1:	stw	r11,_MSR(r1)

	mfcr	r10

	stw	r10,_CCR(r1)

	stw	r1,KSP(r3)	/* Set old stack pointer */
@@ -218,19 +196,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPE) 
	mr	r3,r2

	addi	r2,r4,-THREAD	/* Update current */



#ifdef CONFIG_ALTIVEC

BEGIN_FTR_SECTION

	lwz	r0,THREAD+THREAD_VRSAVE(r2)

	mtspr	SPRN_VRSAVE,r0		/* if G4, restore VRSAVE reg */

END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)

#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_SPE

BEGIN_FTR_SECTION

	lwz	r0,THREAD+THREAD_SPEFSCR(r2)

	mtspr	SPRN_SPEFSCR,r0		/* restore SPEFSCR reg */

END_FTR_SECTION_IFSET(CPU_FTR_SPE)

#endif /* CONFIG_SPE */



	lwz	r0,_CCR(r1)

	mtcrf	0xFF,r0

	/* r3-r12 are destroyed -- Cort */

arch/powerpc/kernel/process.c

+9 −0
Original line number Diff line number Diff line
@@ -1129,6 +1129,10 @@ static inline void save_sprs(struct thread_struct *t) 
	if (cpu_has_feature(CPU_FTR_ALTIVEC))

		t->vrsave = mfspr(SPRN_VRSAVE);

#endif

#ifdef CONFIG_SPE

	if (cpu_has_feature(CPU_FTR_SPE))

		t->spefscr = mfspr(SPRN_SPEFSCR);

#endif

#ifdef CONFIG_PPC_BOOK3S_64

	if (cpu_has_feature(CPU_FTR_DSCR))

		t->dscr = mfspr(SPRN_DSCR);
@@ -1159,6 +1163,11 @@ static inline void restore_sprs(struct thread_struct *old_thread, 
	    old_thread->vrsave != new_thread->vrsave)

		mtspr(SPRN_VRSAVE, new_thread->vrsave);

#endif

#ifdef CONFIG_SPE

	if (cpu_has_feature(CPU_FTR_SPE) &&

	    old_thread->spefscr != new_thread->spefscr)

		mtspr(SPRN_SPEFSCR, new_thread->spefscr);

#endif

#ifdef CONFIG_PPC_BOOK3S_64

	if (cpu_has_feature(CPU_FTR_DSCR)) {

		u64 dscr = get_paca()->dscr_default;