Commit bf82cb30 authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
Browse files

MIPS: Save MSA extended context around signals 



It is desirable for signal handlers to be allowed to make use of MSA,
particularly if auto vectorisation is used when compiling a program.
The MSA context must therefore be saved & restored before & after
invoking the signal handler. Make use of the extended context structs
defined in the preceding patch to save MSA context after the sigframe
when appropriate.

[ralf@linux-mips.org: Fixed conflicts.]

Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10796/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent f1fe2d21

arch/mips/kernel/r4k_fpu.S

+118 −0
Original line number Diff line number Diff line
@@ -236,6 +236,124 @@ LEAF(\name) 
	op_msa_wr	write_msa_wr_w, ld_w

	op_msa_wr	write_msa_wr_d, ld_d



#endif /* CONFIG_CPU_HAS_MSA */



#ifdef CONFIG_CPU_HAS_MSA



	.macro	save_msa_upper	wr, off, base

	.set	push

	.set	noat

#ifdef CONFIG_64BIT

	copy_u_d \wr, 1

	EX sd	$1, \off(\base)

#elif defined(CONFIG_CPU_LITTLE_ENDIAN)

	copy_u_w \wr, 2

	EX sw	$1, \off(\base)

	copy_u_w \wr, 3

	EX sw	$1, (\off+4)(\base)

#else /* CONFIG_CPU_BIG_ENDIAN */

	copy_u_w \wr, 2

	EX sw	$1, (\off+4)(\base)

	copy_u_w \wr, 3

	EX sw	$1, \off(\base)

#endif

	.set	pop

	.endm



LEAF(_save_msa_all_upper)

	save_msa_upper	0, 0x00, a0

	save_msa_upper	1, 0x08, a0

	save_msa_upper	2, 0x10, a0

	save_msa_upper	3, 0x18, a0

	save_msa_upper	4, 0x20, a0

	save_msa_upper	5, 0x28, a0

	save_msa_upper	6, 0x30, a0

	save_msa_upper	7, 0x38, a0

	save_msa_upper	8, 0x40, a0

	save_msa_upper	9, 0x48, a0

	save_msa_upper	10, 0x50, a0

	save_msa_upper	11, 0x58, a0

	save_msa_upper	12, 0x60, a0

	save_msa_upper	13, 0x68, a0

	save_msa_upper	14, 0x70, a0

	save_msa_upper	15, 0x78, a0

	save_msa_upper	16, 0x80, a0

	save_msa_upper	17, 0x88, a0

	save_msa_upper	18, 0x90, a0

	save_msa_upper	19, 0x98, a0

	save_msa_upper	20, 0xa0, a0

	save_msa_upper	21, 0xa8, a0

	save_msa_upper	22, 0xb0, a0

	save_msa_upper	23, 0xb8, a0

	save_msa_upper	24, 0xc0, a0

	save_msa_upper	25, 0xc8, a0

	save_msa_upper	26, 0xd0, a0

	save_msa_upper	27, 0xd8, a0

	save_msa_upper	28, 0xe0, a0

	save_msa_upper	29, 0xe8, a0

	save_msa_upper	30, 0xf0, a0

	save_msa_upper	31, 0xf8, a0

	jr	ra

	 li	v0, 0

	END(_save_msa_all_upper)



	.macro	restore_msa_upper	wr, off, base

	.set	push

	.set	noat

#ifdef CONFIG_64BIT

	EX ld	$1, \off(\base)

	insert_d \wr, 1

#elif defined(CONFIG_CPU_LITTLE_ENDIAN)

	EX lw	$1, \off(\base)

	insert_w \wr, 2

	EX lw	$1, (\off+4)(\base)

	insert_w \wr, 3

#else /* CONFIG_CPU_BIG_ENDIAN */

	EX lw	$1, (\off+4)(\base)

	insert_w \wr, 2

	EX lw	$1, \off(\base)

	insert_w \wr, 3

#endif

	.set	pop

	.endm



LEAF(_restore_msa_all_upper)

	restore_msa_upper	0, 0x00, a0

	restore_msa_upper	1, 0x08, a0

	restore_msa_upper	2, 0x10, a0

	restore_msa_upper	3, 0x18, a0

	restore_msa_upper	4, 0x20, a0

	restore_msa_upper	5, 0x28, a0

	restore_msa_upper	6, 0x30, a0

	restore_msa_upper	7, 0x38, a0

	restore_msa_upper	8, 0x40, a0

	restore_msa_upper	9, 0x48, a0

	restore_msa_upper	10, 0x50, a0

	restore_msa_upper	11, 0x58, a0

	restore_msa_upper	12, 0x60, a0

	restore_msa_upper	13, 0x68, a0

	restore_msa_upper	14, 0x70, a0

	restore_msa_upper	15, 0x78, a0

	restore_msa_upper	16, 0x80, a0

	restore_msa_upper	17, 0x88, a0

	restore_msa_upper	18, 0x90, a0

	restore_msa_upper	19, 0x98, a0

	restore_msa_upper	20, 0xa0, a0

	restore_msa_upper	21, 0xa8, a0

	restore_msa_upper	22, 0xb0, a0

	restore_msa_upper	23, 0xb8, a0

	restore_msa_upper	24, 0xc0, a0

	restore_msa_upper	25, 0xc8, a0

	restore_msa_upper	26, 0xd0, a0

	restore_msa_upper	27, 0xd8, a0

	restore_msa_upper	28, 0xe0, a0

	restore_msa_upper	29, 0xe8, a0

	restore_msa_upper	30, 0xf0, a0

	restore_msa_upper	31, 0xf8, a0

	jr	ra

	 li	v0, 0

	END(_restore_msa_all_upper)



#endif /* CONFIG_CPU_HAS_MSA */



	.set	reorder

arch/mips/kernel/signal-common.h

+3 −0
Original line number Diff line number Diff line
@@ -37,4 +37,7 @@ _save_fp_context(void __user *fpregs, void __user *csr); 
extern asmlinkage int

_restore_fp_context(void __user *fpregs, void __user *csr);



extern asmlinkage int _save_msa_all_upper(void __user *buf);

extern asmlinkage int _restore_msa_all_upper(void __user *buf);



#endif	/* __SIGNAL_COMMON_H */

arch/mips/kernel/signal.c

+212 −15
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <asm/vdso.h>

#include <asm/dsp.h>

#include <asm/inst.h>

#include <asm/msa.h>



#include "signal-common.h"
@@ -124,6 +125,168 @@ static int restore_hw_fp_context(void __user *sc) 
	return _restore_fp_context(fpregs, csr);

}



/*

 * Extended context handling.

 */



static inline void __user *sc_to_extcontext(void __user *sc)

{

	struct ucontext __user *uc;



	/*

	 * We can just pretend the sigcontext is always embedded in a struct

	 * ucontext here, because the offset from sigcontext to extended

	 * context is the same in the struct sigframe case.

	 */

	uc = container_of(sc, struct ucontext, uc_mcontext);

	return &uc->uc_extcontext;

}



static int save_msa_extcontext(void __user *buf)

{

	struct msa_extcontext __user *msa = buf;

	uint64_t val;

	int i, err;



	if (!thread_msa_context_live())

		return 0;



	/*

	 * Ensure that we can't lose the live MSA context between checking

	 * for it & writing it to memory.

	 */

	preempt_disable();



	if (is_msa_enabled()) {

		/*

		 * There are no EVA versions of the vector register load/store

		 * instructions, so MSA context has to be saved to kernel memory

		 * and then copied to user memory. The save to kernel memory

		 * should already have been done when handling scalar FP

		 * context.

		 */

		BUG_ON(config_enabled(CONFIG_EVA));



		err = __put_user(read_msa_csr(), &msa->csr);

		err |= _save_msa_all_upper(&msa->wr);



		preempt_enable();

	} else {

		preempt_enable();



		err = __put_user(current->thread.fpu.msacsr, &msa->csr);



		for (i = 0; i < NUM_FPU_REGS; i++) {

			val = get_fpr64(&current->thread.fpu.fpr[i], 1);

			err |= __put_user(val, &msa->wr[i]);

		}

	}



	err |= __put_user(MSA_EXTCONTEXT_MAGIC, &msa->ext.magic);

	err |= __put_user(sizeof(*msa), &msa->ext.size);



	return err ? -EFAULT : sizeof(*msa);

}



static int restore_msa_extcontext(void __user *buf, unsigned int size)

{

	struct msa_extcontext __user *msa = buf;

	unsigned long long val;

	unsigned int csr;

	int i, err;



	if (size != sizeof(*msa))

		return -EINVAL;



	err = get_user(csr, &msa->csr);

	if (err)

		return err;



	preempt_disable();



	if (is_msa_enabled()) {

		/*

		 * There are no EVA versions of the vector register load/store

		 * instructions, so MSA context has to be copied to kernel

		 * memory and later loaded to registers. The same is true of

		 * scalar FP context, so FPU & MSA should have already been

		 * disabled whilst handling scalar FP context.

		 */

		BUG_ON(config_enabled(CONFIG_EVA));



		write_msa_csr(csr);

		err |= _restore_msa_all_upper(&msa->wr);

		preempt_enable();

	} else {

		preempt_enable();



		current->thread.fpu.msacsr = csr;



		for (i = 0; i < NUM_FPU_REGS; i++) {

			err |= __get_user(val, &msa->wr[i]);

			set_fpr64(&current->thread.fpu.fpr[i], 1, val);

		}

	}



	return err;

}



static int save_extcontext(void __user *buf)

{

	int sz;



	sz = save_msa_extcontext(buf);

	if (sz < 0)

		return sz;

	buf += sz;



	/* If no context was saved then trivially return */

	if (!sz)

		return 0;



	/* Write the end marker */

	if (__put_user(END_EXTCONTEXT_MAGIC, (u32 *)buf))

		return -EFAULT;



	sz += sizeof(((struct extcontext *)NULL)->magic);

	return sz;

}



static int restore_extcontext(void __user *buf)

{

	struct extcontext ext;

	int err;



	while (1) {

		err = __get_user(ext.magic, (unsigned int *)buf);

		if (err)

			return err;



		if (ext.magic == END_EXTCONTEXT_MAGIC)

			return 0;



		err = __get_user(ext.size, (unsigned int *)(buf

			+ offsetof(struct extcontext, size)));

		if (err)

			return err;



		switch (ext.magic) {

		case MSA_EXTCONTEXT_MAGIC:

			err = restore_msa_extcontext(buf, ext.size);

			break;



		default:

			err = -EINVAL;

			break;

		}



		if (err)

			return err;



		buf += ext.size;

	}

}



/*

 * Helper routines

 */
@@ -133,20 +296,17 @@ int protected_save_fp_context(void __user *sc) 
	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;

	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;

	uint32_t __user *used_math = sc + abi->off_sc_used_math;

	unsigned int used;

	unsigned int used, ext_sz;

	int err;



	used = used_math() ? USED_FP : 0;

	if (used) {

	if (!used)

		goto fp_done;



	if (!test_thread_flag(TIF_32BIT_FPREGS))

		used |= USED_FR1;

	if (test_thread_flag(TIF_HYBRID_FPREGS))

		used |= USED_HYBRID_FPRS;

	}



	err = __put_user(used, used_math);

	if (err || !(used & USED_FP))

		return err;



	/*

	 * EVA does not have userland equivalents of ldc1 or sdc1, so
@@ -171,10 +331,16 @@ int protected_save_fp_context(void __user *sc) 
			__put_user(0, &fpregs[31]) |

			__put_user(0, csr);

		if (err)

			break;	/* really bad sigcontext */

			return err;	/* really bad sigcontext */

	}



fp_done:

	ext_sz = err = save_extcontext(sc_to_extcontext(sc));

	if (err < 0)

		return err;

	used |= ext_sz ? USED_EXTCONTEXT : 0;



	return __put_user(used, used_math);

}



int protected_restore_fp_context(void __user *sc)
@@ -184,7 +350,7 @@ int protected_restore_fp_context(void __user *sc) 
	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;

	uint32_t __user *used_math = sc + abi->off_sc_used_math;

	unsigned int used;

	int err, sig, tmp __maybe_unused;

	int err, sig = 0, tmp __maybe_unused;



	err = __get_user(used, used_math);

	conditional_used_math(used & USED_FP);
@@ -193,10 +359,12 @@ int protected_restore_fp_context(void __user *sc) 
	 * The signal handler may have used FPU; give it up if the program

	 * doesn't want it following sigreturn.

	 */

	if (err || !(used & USED_FP)) {

	if (err || !(used & USED_FP))

		lose_fpu(0);

	if (err)

		return err;

	}

	if (!(used & USED_FP))

		goto fp_done;



	err = sig = fpcsr_pending(csr);

	if (err < 0)
@@ -229,6 +397,10 @@ int protected_restore_fp_context(void __user *sc) 
			break;	/* really bad sigcontext */

	}



fp_done:

	if (used & USED_EXTCONTEXT)

		err |= restore_extcontext(sc_to_extcontext(sc));



	return err ?: sig;

}
@@ -268,6 +440,28 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 
	return err;

}



static size_t extcontext_max_size(void)

{

	size_t sz = 0;



	/*

	 * The assumption here is that between this point & the point at which

	 * the extended context is saved the size of the context should only

	 * ever be able to shrink (if the task is preempted), but never grow.

	 * That is, what this function returns is an upper bound on the size of

	 * the extended context for the current task at the current time.

	 */



	if (thread_msa_context_live())

		sz += sizeof(struct msa_extcontext);



	/* If any context is saved then we'll append the end marker */

	if (sz)

		sz += sizeof(((struct extcontext *)NULL)->magic);



	return sz;

}



int fpcsr_pending(unsigned int __user *fpcsr)

{

	int err, sig = 0;
@@ -324,6 +518,9 @@ void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, 
{

	unsigned long sp;



	/* Leave space for potential extended context */

	frame_size += extcontext_max_size();



	/* Default to using normal stack */

	sp = regs->regs[29];

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