Re: [PATCH 3/3] powerpc: emulate_step test for load/store instructions

Add new selftest that test emulate_step for Normal, Floating Point,
Vector and Vector Scalar - load/store instructions. Test should run
at boot time if CONFIG_KPROBES_SANITY_TEST and CONFIG_PPC64 is set.

Sample log:

  [    0.762063] emulate_step smoke test: start.
  [    0.762219] emulate_step smoke test: ld             : PASS
  [    0.762434] emulate_step smoke test: lwz            : PASS
  [    0.762653] emulate_step smoke test: lwzx           : PASS
  [    0.762867] emulate_step smoke test: std            : PASS
  [    0.763082] emulate_step smoke test: ldarx / stdcx. : PASS
  [    0.763302] emulate_step smoke test: lfsx           : PASS
  [    0.763514] emulate_step smoke test: stfsx          : PASS
  [    0.763727] emulate_step smoke test: lfdx           : PASS
  [    0.763942] emulate_step smoke test: stfdx          : PASS
  [    0.764134] emulate_step smoke test: lvx            : PASS
  [    0.764349] emulate_step smoke test: stvx           : PASS
  [    0.764575] emulate_step smoke test: lxvd2x         : PASS
  [    0.764788] emulate_step smoke test: stxvd2x        : PASS
  [    0.764997] emulate_step smoke test: complete.

Signed-off-by: Ravi Bangoria <redacted>
---
 arch/powerpc/include/asm/sstep.h     |   8 +
 arch/powerpc/kernel/kprobes.c        |   2 +
 arch/powerpc/lib/Makefile            |   4 +
 arch/powerpc/lib/test_emulate_step.c | 439 +++++++++++++++++++++++++++++++++++
 4 files changed, 453 insertions(+)
 create mode 100644 arch/powerpc/lib/test_emulate_step.c

diff --git a/arch/powerpc/include/asm/sstep.h b/arch/powerpc/include/asm/sstep.h
index d3a42cc..d6d3630 100644
--- a/arch/powerpc/include/asm/sstep.h
+++ b/arch/powerpc/include/asm/sstep.h

@@ -87,3 +87,11 @@ struct instruction_op {

 extern int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
 			 unsigned int instr);
+
+#if defined(CONFIG_KPROBES_SANITY_TEST) && defined(CONFIG_PPC64)
+void test_emulate_step(void);
+#else
+static inline void test_emulate_step(void)
+{
+}
+#endif

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index e785cc9..01d8002 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c

@@ -544,6 +544,8 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)

 int __init arch_init_kprobes(void)
 {
+	test_emulate_step();
+
 	return register_kprobe(&trampoline_p);
 }

diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 309361e8..7d046ca 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile

@@ -35,3 +35,7 @@ obj-$(CONFIG_ALTIVEC)	+= xor_vmx.o
 CFLAGS_xor_vmx.o += -maltivec $(call cc-option,-mabi=altivec)

 obj-$(CONFIG_PPC64) += $(obj64-y)
+
+ifeq ($(CONFIG_PPC64), y)
+obj-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o
+endif

diff --git a/arch/powerpc/lib/test_emulate_step.c b/arch/powerpc/lib/test_emulate_step.c
new file mode 100644
index 0000000..887d1db
--- /dev/null
+++ b/arch/powerpc/lib/test_emulate_step.c

@@ -0,0 +1,439 @@
+/*
+ * test_emulate_step.c - simple sanity test for emulate_step load/store
+ *			 instructions
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would 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.
+ */
+
+#define pr_fmt(fmt) "emulate_step smoke test: " fmt
+
+#include <linux/ptrace.h>
+#include <asm/sstep.h>
+#include <asm/ppc-opcode.h>
+
+#define IMM_L(i)		((uintptr_t)(i) & 0xffff)
+
+/*
+ * Defined with TEST_ prefix so it does not conflict with other
+ * definitions.
+ */
+#define TEST_LD(r, base, i)	(PPC_INST_LD | ___PPC_RT(r) |		\
+					___PPC_RA(base) | IMM_L(i))
+#define TEST_LWZ(r, base, i)	(PPC_INST_LWZ | ___PPC_RT(r) |		\
+					___PPC_RA(base) | IMM_L(i))
+#define TEST_LWZX(t, a, b)	(PPC_INST_LWZX | ___PPC_RT(t) |		\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_STD(r, base, i)	(PPC_INST_STD | ___PPC_RS(r) |		\
+					___PPC_RA(base) | ((i) & 0xfffc))
+#define TEST_LDARX(t, a, b, eh)	(PPC_INST_LDARX | ___PPC_RT(t) |	\
+					___PPC_RA(a) | ___PPC_RB(b) |	\
+					__PPC_EH(eh))
+#define TEST_STDCX(s, a, b)	(PPC_INST_STDCX | ___PPC_RS(s) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_LFSX(t, a, b)	(PPC_INST_LFSX | ___PPC_RT(t) |		\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_STFSX(s, a, b)	(PPC_INST_STFSX | ___PPC_RS(s) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_LFDX(t, a, b)	(PPC_INST_LFDX | ___PPC_RT(t) |		\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_STFDX(s, a, b)	(PPC_INST_STFDX | ___PPC_RS(s) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_LVX(t, a, b)	(PPC_INST_LVX | ___PPC_RT(t) |		\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_STVX(s, a, b)	(PPC_INST_STVX | ___PPC_RS(s) |		\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_LXVD2X(s, a, b)	(PPC_INST_LXVD2X | VSX_XX1((s), R##a, 

R##b))
+#define TEST_STXVD2X(s, a, b)	(PPC_INST_STXVD2X | VSX_XX1((s), R##a, R##b))