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: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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 @@
/* 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 @@
#ifdef CONFIG_MATH_EMULATION
errcode = do_mathemu(regs);
+ if (errcode >= 0)
+ PPC_WARN_EMULATED(math);
switch (errcode) {
case 0:
@@ -1005,6 +1017,9 @@
#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 @@
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 __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 */