[PATCH v4] powerpc: Keep track of emulated instructions
Geert Uytterhoeven
Geert.Uytterhoeven at sonycom.com
Mon May 18 22:10:05 EST 2009
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: Geert Uytterhoeven <Geert.Uytterhoeven at sonycom.com>
---
Tested on ppc64 (ps3) and ppc32 (sequoia) using mfpvr.
v4:
- Introduce CONFIG_PPC_EMULATED_STATS
v3:
- Add generic unaligned
- Switch from sysfs + sysctl to debugfs. All virtual files now show up under
/sys/kernel/debug/powerpc/emulated_instructions (assumed debugfs mounted on
/sys/kernel/debug)
- Enable the printing of rate-limited warnings by writing a non-zero value to
/sys/kernel/debug/powerpc/emulated_instructions/do_warn
- Switch from per-CPU to system-wide counters
- Always use 32-bit counters (was 64-bit on ppc64)
- Counters are writable, i.e. can be reset (by root)
v2:
- arch/powerpc/kernel/sysfs.c is now compiled on ppc32, so we can provide
counters in sysfs on ppc32, too,
- WARN_EMULATED() is a no-op if CONFIG_SYSCTL is disabled,
- Add warnings for altivec,
- Add warnings for recently introduced emulation of vsx and isel
instructions.
arch/powerpc/Kconfig.debug | 13 ++++
arch/powerpc/include/asm/emulated_ops.h | 73 +++++++++++++++++++++++
arch/powerpc/kernel/align.c | 20 +++++-
arch/powerpc/kernel/traps.c | 96 ++++++++++++++++++++++++++++++-
4 files changed, 196 insertions(+), 6 deletions(-)
create mode 100644 arch/powerpc/include/asm/emulated_ops.h
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index a1098e2..d79a902 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -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
diff --git a/arch/powerpc/include/asm/emulated_ops.h b/arch/powerpc/include/asm/emulated_ops.h
new file mode 100644
index 0000000..9154e85
--- /dev/null
+++ b/arch/powerpc/include/asm/emulated_ops.h
@@ -0,0 +1,73 @@
+/*
+ * 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 */
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index 5ffcfaa..a5b632e 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -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
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 678fbff..6a5b2b7 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -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 */
--
1.6.2.4
With kind regards,
Geert Uytterhoeven
Software Architect
Techsoft Centre
Technology and Software Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
Phone: +32 (0)2 700 8453
Fax: +32 (0)2 700 8622
E-mail: Geert.Uytterhoeven at sonycom.com
Internet: http://www.sony-europe.com/
A division of Sony Europe (Belgium) N.V.
VAT BE 0413.825.160 · RPR Brussels
Fortis · BIC GEBABEBB · IBAN BE41293037680010
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