[PATCH v3 2/2] powerpc: emulate_step tests for load/store instructions
From: Ravi Bangoria
Date: Tue Feb 14 2017 - 04:17:42 EST
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 <ravi.bangoria@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/ppc-opcode.h | 7 +
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 ++++++++++++++++++++++++++++++++++
5 files changed, 460 insertions(+)
create mode 100644 arch/powerpc/lib/test_emulate_step.c
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index d99bd44..e7d6d86 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -284,6 +284,13 @@
#define PPC_INST_BRANCH_COND 0x40800000
#define PPC_INST_LBZCIX 0x7c0006aa
#define PPC_INST_STBCIX 0x7c0007aa
+#define PPC_INST_LWZX 0x7c00002e
+#define PPC_INST_LFSX 0x7c00042e
+#define PPC_INST_STFSX 0x7c00052e
+#define PPC_INST_LFDX 0x7c0004ae
+#define PPC_INST_STFDX 0x7c0005ae
+#define PPC_INST_LVX 0x7c0000ce
+#define PPC_INST_STVX 0x7c0001ce
/* macros to insert fields into opcodes */
#define ___PPC_RA(a) (((a) & 0x1f) << 16)
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 fce05a3..5c5ae66 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -528,6 +528,8 @@ 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 0e649d7..ddc879d 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -33,3 +33,7 @@ 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))
+
+
+static void init_pt_regs(struct pt_regs *regs)
+{
+ static unsigned long msr;
+ static bool msr_cached;
+
+ memset(regs, 0, sizeof(struct pt_regs));
+
+ if (likely(msr_cached)) {
+ regs->msr = msr;
+ return;
+ }
+
+ asm volatile("mfmsr %0" : "=r"(regs->msr));
+
+ regs->msr |= MSR_FP;
+ regs->msr |= MSR_VEC;
+ regs->msr |= MSR_VSX;
+
+ msr = regs->msr;
+ msr_cached = true;
+}
+
+static void show_result(char *ins, char *result)
+{
+ pr_info("%-14s : %s\n", ins, result);
+}
+
+static void test_ld(void)
+{
+ struct pt_regs regs;
+ unsigned long a = 0x23;
+ int stepped = -1;
+
+ init_pt_regs(®s);
+ regs.gpr[3] = (unsigned long) &a;
+
+ /* ld r5, 0(r3) */
+ stepped = emulate_step(®s, TEST_LD(5, 3, 0));
+
+ if (stepped == 1 && regs.gpr[5] == a)
+ show_result("ld", "PASS");
+ else
+ show_result("ld", "FAIL");
+}
+
+static void test_lwz(void)
+{
+ struct pt_regs regs;
+ unsigned int a = 0x4545;
+ int stepped = -1;
+
+ init_pt_regs(®s);
+ regs.gpr[3] = (unsigned long) &a;
+
+ /* lwz r5, 0(r3) */
+ stepped = emulate_step(®s, TEST_LWZ(5, 3, 0));
+
+ if (stepped == 1 && regs.gpr[5] == a)
+ show_result("lwz", "PASS");
+ else
+ show_result("lwz", "FAIL");
+}
+
+static void test_lwzx(void)
+{
+ struct pt_regs regs;
+ unsigned int a[3] = {0x0, 0x0, 0x1234};
+ int stepped = -1;
+
+ init_pt_regs(®s);
+ regs.gpr[3] = (unsigned long) a;
+ regs.gpr[4] = 8;
+ regs.gpr[5] = 0x8765;
+
+ /* lwzx r5, r3, r4 */
+ stepped = emulate_step(®s, TEST_LWZX(5, 3, 4));
+ if (stepped == 1 && regs.gpr[5] == a[2])
+ show_result("lwzx", "PASS");
+ else
+ show_result("lwzx", "FAIL");
+}
+
+static void test_std(void)
+{
+ struct pt_regs regs;
+ unsigned long a = 0x1234;
+ int stepped = -1;
+
+ init_pt_regs(®s);
+ regs.gpr[3] = (unsigned long) &a;
+ regs.gpr[5] = 0x5678;
+
+ /* std r5, 0(r3) */
+ stepped = emulate_step(®s, TEST_STD(5, 3, 0));
+ if (stepped == 1 || regs.gpr[5] == a)
+ show_result("std", "PASS");
+ else
+ show_result("std", "FAIL");
+}
+
+static void test_ldarx_stdcx(void)
+{
+ struct pt_regs regs;
+ unsigned long a = 0x1234;
+ int stepped = -1;
+ unsigned long cr0_eq = 0x1 << 29; /* eq bit of CR0 */
+
+ init_pt_regs(®s);
+ asm volatile("mfcr %0" : "=r"(regs.ccr));
+
+
+ /*** ldarx ***/
+
+ regs.gpr[3] = (unsigned long) &a;
+ regs.gpr[4] = 0;
+ regs.gpr[5] = 0x5678;
+
+ /* ldarx r5, r3, r4, 0 */
+ stepped = emulate_step(®s, TEST_LDARX(5, 3, 4, 0));
+
+ /*
+ * Don't touch 'a' here. Touching 'a' can do Load/store
+ * of 'a' which result in failure of subsequent stdcx.
+ * Instead, use hardcoded value for comparison.
+ */
+ if (stepped <= 0 || regs.gpr[5] != 0x1234) {
+ show_result("ldarx / stdcx.", "FAIL (ldarx)");
+ return;
+ }
+
+
+ /*** stdcx. ***/
+
+ regs.gpr[5] = 0x9ABC;
+
+ /* stdcx. r5, r3, r4 */
+ stepped = emulate_step(®s, TEST_STDCX(5, 3, 4));
+
+ /*
+ * Two possible scenarios that indicates successful emulation
+ * of stdcx. :
+ * 1. Reservation is active and store is performed. In this
+ * case cr0.eq bit will be set to 1.
+ * 2. Reservation is not active and store is not performed.
+ * In this case cr0.eq bit will be set to 0.
+ */
+ if (stepped == 1 && ((regs.gpr[5] == a && (regs.ccr & cr0_eq))
+ || (regs.gpr[5] != a && !(regs.ccr & cr0_eq))))
+ show_result("ldarx / stdcx.", "PASS");
+ else
+ show_result("ldarx / stdcx.", "FAIL (stdcx.)");
+}
+
+#ifdef CONFIG_PPC_FPU
+static void test_lfsx_stfsx(void)
+{
+ struct pt_regs regs;
+ union {
+ float a;
+ int b;
+ } c;
+ int cached_b;
+ int stepped = -1;
+
+ init_pt_regs(®s);
+
+
+ /*** lfsx ***/
+
+ c.a = 123.45;
+ cached_b = c.b;
+
+ regs.gpr[3] = (unsigned long) &c.a;
+ regs.gpr[4] = 0;
+
+ /* lfsx frt10, r3, r4 */
+ stepped = emulate_step(®s, TEST_LFSX(10, 3, 4));
+
+ if (stepped == 1)
+ show_result("lfsx", "PASS");
+ else
+ show_result("lfsx", "FAIL");
+
+
+ /*** stfsx ***/
+
+ c.a = 678.91;
+
+ /* stfsx frs10, r3, r4 */
+ stepped = emulate_step(®s, TEST_STFSX(10, 3, 4));
+
+ if (stepped == 1 && c.b == cached_b)
+ show_result("stfsx", "PASS");
+ else
+ show_result("stfsx", "FAIL");
+}
+
+static void test_lfdx_stfdx(void)
+{
+ struct pt_regs regs;
+ union {
+ double a;
+ long b;
+ } c;
+ long cached_b;
+ int stepped = -1;
+
+ init_pt_regs(®s);
+
+
+ /*** lfdx ***/
+
+ c.a = 123456.78;
+ cached_b = c.b;
+
+ regs.gpr[3] = (unsigned long) &c.a;
+ regs.gpr[4] = 0;
+
+ /* lfdx frt10, r3, r4 */
+ stepped = emulate_step(®s, TEST_LFDX(10, 3, 4));
+
+ if (stepped == 1)
+ show_result("lfdx", "PASS");
+ else
+ show_result("lfdx", "FAIL");
+
+
+ /*** stfdx ***/
+
+ c.a = 987654.32;
+
+ /* stfdx frs10, r3, r4 */
+ stepped = emulate_step(®s, TEST_STFDX(10, 3, 4));
+
+ if (stepped == 1 && c.b == cached_b)
+ show_result("stfdx", "PASS");
+ else
+ show_result("stfdx", "FAIL");
+}
+#else
+static void test_lfsx_stfsx(void)
+{
+ show_result("lfsx", "SKIP (CONFIG_PPC_FPU is not set)");
+ show_result("stfsx", "SKIP (CONFIG_PPC_FPU is not set)");
+}
+
+static void test_lfdx_stfdx(void)
+{
+ show_result("lfdx", "SKIP (CONFIG_PPC_FPU is not set)");
+ show_result("stfdx", "SKIP (CONFIG_PPC_FPU is not set)");
+}
+#endif /* CONFIG_PPC_FPU */
+
+#ifdef CONFIG_ALTIVEC
+static void test_lvx_stvx(void)
+{
+ struct pt_regs regs;
+ union {
+ vector128 a;
+ u32 b[4];
+ } c;
+ u32 cached_b[4];
+ int stepped = -1;
+
+ init_pt_regs(®s);
+
+
+ /*** lvx ***/
+
+ cached_b[0] = c.b[0] = 923745;
+ cached_b[1] = c.b[1] = 2139478;
+ cached_b[2] = c.b[2] = 9012;
+ cached_b[3] = c.b[3] = 982134;
+
+ regs.gpr[3] = (unsigned long) &c.a;
+ regs.gpr[4] = 0;
+
+ /* lvx vrt10, r3, r4 */
+ stepped = emulate_step(®s, TEST_LVX(10, 3, 4));
+
+ if (stepped == 1)
+ show_result("lvx", "PASS");
+ else
+ show_result("lvx", "FAIL");
+
+
+ /*** stvx ***/
+
+ c.b[0] = 4987513;
+ c.b[1] = 84313948;
+ c.b[2] = 71;
+ c.b[3] = 498532;
+
+ /* stvx vrs10, r3, r4 */
+ stepped = emulate_step(®s, TEST_STVX(10, 3, 4));
+
+ if (stepped == 1 && cached_b[0] == c.b[0] && cached_b[1] == c.b[1] &&
+ cached_b[2] == c.b[2] && cached_b[3] == c.b[3])
+ show_result("stvx", "PASS");
+ else
+ show_result("stvx", "FAIL");
+}
+#else
+static void test_lvx_stvx(void)
+{
+ show_result("lvx", "SKIP (CONFIG_ALTIVEC is not set)");
+ show_result("stvx", "SKIP (CONFIG_ALTIVEC is not set)");
+}
+#endif /* CONFIG_ALTIVEC */
+
+#ifdef CONFIG_VSX
+static void test_lxvd2x_stxvd2x(void)
+{
+ struct pt_regs regs;
+ union {
+ vector128 a;
+ u32 b[4];
+ } c;
+ u32 cached_b[4];
+ int stepped = -1;
+
+ init_pt_regs(®s);
+
+
+ /*** lxvd2x ***/
+
+ cached_b[0] = c.b[0] = 18233;
+ cached_b[1] = c.b[1] = 34863571;
+ cached_b[2] = c.b[2] = 834;
+ cached_b[3] = c.b[3] = 6138911;
+
+ regs.gpr[3] = (unsigned long) &c.a;
+ regs.gpr[4] = 0;
+
+ /* lxvd2x vsr39, r3, r4 */
+ stepped = emulate_step(®s, TEST_LXVD2X(39, 3, 4));
+
+ if (stepped == 1)
+ show_result("lxvd2x", "PASS");
+ else
+ show_result("lxvd2x", "FAIL");
+
+
+ /*** stxvd2x ***/
+
+ c.b[0] = 21379463;
+ c.b[1] = 87;
+ c.b[2] = 374234;
+ c.b[3] = 4;
+
+ /* stxvd2x vsr39, r3, r4 */
+ stepped = emulate_step(®s, TEST_STXVD2X(39, 3, 4));
+
+ if (stepped == 1 && cached_b[0] == c.b[0] && cached_b[1] == c.b[1] &&
+ cached_b[2] == c.b[2] && cached_b[3] == c.b[3])
+ show_result("stxvd2x", "PASS");
+ else
+ show_result("stxvd2x", "FAIL");
+}
+#else
+static void test_lxvd2x_stxvd2x(void)
+{
+ show_result("lxvd2x", "SKIP (CONFIG_VSX is not set)");
+ show_result("stxvd2x", "SKIP (CONFIG_VSX is not set)");
+}
+#endif /* CONFIG_VSX */
+
+void test_emulate_step(void)
+{
+ pr_info("start.\n");
+ test_ld();
+ test_lwz();
+ test_lwzx();
+ test_std();
+ test_ldarx_stdcx();
+ test_lfsx_stfsx();
+ test_lfdx_stfdx();
+ test_lvx_stvx();
+ test_lxvd2x_stxvd2x();
+ pr_info("complete.\n");
+}
--
1.8.3.1