Commit 80947e7c authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Benjamin Herrenschmidt
Browse files

powerpc: Keep track of emulated instructions 



If CONFIG_PPC_EMULATED_STATS is enabled, make available counters for the
various classes of emulated instructions under
/sys/kernel/debug/powerpc/emulated_instructions/ (assumed debugfs is mounted on
/sys/kernel/debug).  Optionally (controlled by
/sys/kernel/debug/powerpc/emulated_instructions/do_warn), rate-limited warnings
can be printed to the console when instructions are emulated.

Signed-off-by: default avatarGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent f312deb4

arch/powerpc/Kconfig.debug

+13 −0
Original line number Diff line number Diff line
@@ -41,6 +41,19 @@ config HCALL_STATS 
	  This option will add a small amount of overhead to all hypervisor

	  calls.



config PPC_EMULATED_STATS

	bool "Emulated instructions tracking"

	depends on DEBUG_FS

	help

	  Adds code to keep track of the number of instructions that are

	  emulated by the in-kernel emulator. Counters for the various classes

	  of emulated instructions are available under

	  powerpc/emulated_instructions/ in the root of the debugfs file

	  system. Optionally (controlled by

	  powerpc/emulated_instructions/do_warn in debugfs), rate-limited

	  warnings can be printed to the console when instructions are

	  emulated.



config CODE_PATCHING_SELFTEST

	bool "Run self-tests of the code-patching code."

	depends on DEBUG_KERNEL

arch/powerpc/include/asm/emulated_ops.h

0 → 100644
+73 −0
Original line number Diff line number Diff line 
/*

 *  Copyright 2007 Sony Corporation

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program.

 *  If not, see <http://www.gnu.org/licenses/>.

 */



#ifndef _ASM_POWERPC_EMULATED_OPS_H

#define _ASM_POWERPC_EMULATED_OPS_H



#include <asm/atomic.h>





#ifdef CONFIG_PPC_EMULATED_STATS



struct ppc_emulated_entry {

	const char *name;

	atomic_t val;

};



extern struct ppc_emulated {

#ifdef CONFIG_ALTIVEC

	struct ppc_emulated_entry altivec;

#endif

	struct ppc_emulated_entry dcba;

	struct ppc_emulated_entry dcbz;

	struct ppc_emulated_entry fp_pair;

	struct ppc_emulated_entry isel;

	struct ppc_emulated_entry mcrxr;

	struct ppc_emulated_entry mfpvr;

	struct ppc_emulated_entry multiple;

	struct ppc_emulated_entry popcntb;

	struct ppc_emulated_entry spe;

	struct ppc_emulated_entry string;

	struct ppc_emulated_entry unaligned;

#ifdef CONFIG_MATH_EMULATION

	struct ppc_emulated_entry math;

#elif defined(CONFIG_8XX_MINIMAL_FPEMU)

	struct ppc_emulated_entry 8xx;

#endif

#ifdef CONFIG_VSX

	struct ppc_emulated_entry vsx;

#endif

} ppc_emulated;



extern u32 ppc_warn_emulated;



extern void ppc_warn_emulated_print(const char *type);



#define PPC_WARN_EMULATED(type)						 \

	do {								 \

		atomic_inc(&ppc_emulated.type.val);			 \

		if (ppc_warn_emulated)					 \

			ppc_warn_emulated_print(ppc_emulated.type.name); \

	} while (0)



#else /* !CONFIG_PPC_EMULATED_STATS */



#define PPC_WARN_EMULATED(type)	do { } while (0)



#endif /* !CONFIG_PPC_EMULATED_STATS */



#endif /* _ASM_POWERPC_EMULATED_OPS_H */

arch/powerpc/kernel/align.c

+16 −4
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <asm/system.h>

#include <asm/cache.h>

#include <asm/cputable.h>

#include <asm/emulated_ops.h>



struct aligninfo {

	unsigned char len;
@@ -730,8 +731,10 @@ int fix_alignment(struct pt_regs *regs) 
	areg = dsisr & 0x1f;		/* register to update */



#ifdef CONFIG_SPE

	if ((instr >> 26) == 0x4)

	if ((instr >> 26) == 0x4) {

		PPC_WARN_EMULATED(spe);

		return emulate_spe(regs, reg, instr);

	}

#endif



	instr = (dsisr >> 10) & 0x7f;
@@ -783,23 +786,28 @@ int fix_alignment(struct pt_regs *regs) 
			flags |= SPLT;

			nb = 8;

		}

		PPC_WARN_EMULATED(vsx);

		return emulate_vsx(addr, reg, areg, regs, flags, nb);

	}

#endif

	/* A size of 0 indicates an instruction we don't support, with

	 * the exception of DCBZ which is handled as a special case here

	 */

	if (instr == DCBZ)

	if (instr == DCBZ) {

		PPC_WARN_EMULATED(dcbz);

		return emulate_dcbz(regs, addr);

	}

	if (unlikely(nb == 0))

		return 0;



	/* Load/Store Multiple instructions are handled in their own

	 * function

	 */

	if (flags & M)

	if (flags & M) {

		PPC_WARN_EMULATED(multiple);

		return emulate_multiple(regs, addr, reg, nb,

					flags, instr, swiz);

	}



	/* Verify the address of the operand */

	if (unlikely(user_mode(regs) &&
@@ -816,8 +824,12 @@ int fix_alignment(struct pt_regs *regs) 
	}



	/* Special case for 16-byte FP loads and stores */

	if (nb == 16)

	if (nb == 16) {

		PPC_WARN_EMULATED(fp_pair);

		return emulate_fp_pair(addr, reg, flags);

	}



	PPC_WARN_EMULATED(unaligned);



	/* If we are loading, get the data from user space, else

	 * get it from register values

arch/powerpc/kernel/traps.c

+94 −2
Original line number Diff line number Diff line
@@ -33,7 +33,9 @@ 
#include <linux/backlight.h>

#include <linux/bug.h>

#include <linux/kdebug.h>

#include <linux/debugfs.h>



#include <asm/emulated_ops.h>

#include <asm/pgtable.h>

#include <asm/uaccess.h>

#include <asm/system.h>
@@ -757,36 +759,44 @@ static int emulate_instruction(struct pt_regs *regs) 


	/* Emulate the mfspr rD, PVR. */

	if ((instword & PPC_INST_MFSPR_PVR_MASK) == PPC_INST_MFSPR_PVR) {

		PPC_WARN_EMULATED(mfpvr);

		rd = (instword >> 21) & 0x1f;

		regs->gpr[rd] = mfspr(SPRN_PVR);

		return 0;

	}



	/* Emulating the dcba insn is just a no-op.  */

	if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA)

	if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {

		PPC_WARN_EMULATED(dcba);

		return 0;

	}



	/* Emulate the mcrxr insn.  */

	if ((instword & PPC_INST_MCRXR_MASK) == PPC_INST_MCRXR) {

		int shift = (instword >> 21) & 0x1c;

		unsigned long msk = 0xf0000000UL >> shift;



		PPC_WARN_EMULATED(mcrxr);

		regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);

		regs->xer &= ~0xf0000000UL;

		return 0;

	}



	/* Emulate load/store string insn. */

	if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING)

	if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {

		PPC_WARN_EMULATED(string);

		return emulate_string_inst(regs, instword);

	}



	/* Emulate the popcntb (Population Count Bytes) instruction. */

	if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {

		PPC_WARN_EMULATED(popcntb);

		return emulate_popcntb_inst(regs, instword);

	}



	/* Emulate isel (Integer Select) instruction */

	if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {

		PPC_WARN_EMULATED(isel);

		return emulate_isel(regs, instword);

	}
@@ -984,6 +994,8 @@ void SoftwareEmulation(struct pt_regs *regs) 


#ifdef CONFIG_MATH_EMULATION

	errcode = do_mathemu(regs);

	if (errcode >= 0)

		PPC_WARN_EMULATED(math);



	switch (errcode) {

	case 0:
@@ -1005,6 +1017,9 @@ void SoftwareEmulation(struct pt_regs *regs) 


#elif defined(CONFIG_8XX_MINIMAL_FPEMU)

	errcode = Soft_emulate_8xx(regs);

	if (errcode >= 0)

		PPC_WARN_EMULATED(8xx);



	switch (errcode) {

	case 0:

		emulate_single_step(regs);
@@ -1088,6 +1103,7 @@ void altivec_assist_exception(struct pt_regs *regs) 


	flush_altivec_to_thread(current);



	PPC_WARN_EMULATED(altivec);

	err = emulate_altivec(regs);

	if (err == 0) {

		regs->nip += 4;		/* skip emulated instruction */
@@ -1286,3 +1302,79 @@ void kernel_bad_stack(struct pt_regs *regs) 
void __init trap_init(void)

{

}





#ifdef CONFIG_PPC_EMULATED_STATS



#define WARN_EMULATED_SETUP(type)	.type = { .name = #type }



struct ppc_emulated ppc_emulated = {

#ifdef CONFIG_ALTIVEC

	WARN_EMULATED_SETUP(altivec),

#endif

	WARN_EMULATED_SETUP(dcba),

	WARN_EMULATED_SETUP(dcbz),

	WARN_EMULATED_SETUP(fp_pair),

	WARN_EMULATED_SETUP(isel),

	WARN_EMULATED_SETUP(mcrxr),

	WARN_EMULATED_SETUP(mfpvr),

	WARN_EMULATED_SETUP(multiple),

	WARN_EMULATED_SETUP(popcntb),

	WARN_EMULATED_SETUP(spe),

	WARN_EMULATED_SETUP(string),

	WARN_EMULATED_SETUP(unaligned),

#ifdef CONFIG_MATH_EMULATION

	WARN_EMULATED_SETUP(math),

#elif defined(CONFIG_8XX_MINIMAL_FPEMU)

	WARN_EMULATED_SETUP(8xx),

#endif

#ifdef CONFIG_VSX

	WARN_EMULATED_SETUP(vsx),

#endif

};



u32 ppc_warn_emulated;



void ppc_warn_emulated_print(const char *type)

{

	if (printk_ratelimit())

		pr_warning("%s used emulated %s instruction\n", current->comm,

			   type);

}



static int __init ppc_warn_emulated_init(void)

{

	struct dentry *dir, *d;

	unsigned int i;

	struct ppc_emulated_entry *entries = (void *)&ppc_emulated;



	if (!powerpc_debugfs_root)

		return -ENODEV;



	dir = debugfs_create_dir("emulated_instructions",

				 powerpc_debugfs_root);

	if (!dir)

		return -ENOMEM;



	d = debugfs_create_u32("do_warn", S_IRUGO | S_IWUSR, dir,

			       &ppc_warn_emulated);

	if (!d)

		goto fail;



	for (i = 0; i < sizeof(ppc_emulated)/sizeof(*entries); i++) {

		d = debugfs_create_u32(entries[i].name, S_IRUGO | S_IWUSR, dir,

				       (u32 *)&entries[i].val.counter);

		if (!d)

			goto fail;

	}



	return 0;



fail:

	debugfs_remove_recursive(dir);

	return -ENOMEM;

}



device_initcall(ppc_warn_emulated_init);



#endif /* CONFIG_PPC_EMULATED_STATS */