[PATCH RESEND 0/3] Fixes for kprobes test issues

[PATCH RESEND 0/3] Fixes for kprobes test issues

[Jon Medhurst]

This is a repost of my earlier kprobes fixes [1] updated for Linux 3.15.

Russell, if you're OK with these, do you want them in the patch tracker?
Or you can use the pull request below... Thanks.

The following changes since commit d6d211db37e75de2ddc3a4f979038c40df7cc79c:

  Linux 3.15-rc5 (2014-05-09 13:10:52 -0700)

are available in the git repository at:

  git://git.linaro.org/people/tixy/kernel.git kprobes-test-fixes

for you to fetch changes up to e5dfbe7b1cfe2c41111abfead8ecbefb46c0aba3:

  ARM: kprobes: Fix test code compilation errors for ARMv4 targets (2014-05-12 09:59:37 +0100)

----------------------------------------------------------------
Jon Medhurst (3):
      ARM: kprobes: Prevent known test failures stopping other tests running
      ARM: kprobes: Disallow instructions with PC and register specified shift
      ARM: kprobes: Fix test code compilation errors for ARMv4 targets

 arch/arm/kernel/kprobes-test-arm.c |   30 ++++++++++++++++++++----------
 arch/arm/kernel/kprobes-test.c     |   10 ++++++++++
 arch/arm/kernel/probes-arm.c       |    6 +++---
 3 files changed, 33 insertions(+), 13 deletions(-)


[1] http://www.spinics.net/lists/arm-kernel/msg314527.html

[PATCH RESEND 1/3] ARM: kprobes: Prevent known test failures stopping other tests running

[Jon Medhurst]

Due to a long-standing issue with Thumb symbol lookup [1] the jprobes
tests fail when built into a kernel compiled as Thumb mode. (They work
fine for ARM mode kernels or for Thumb when built as a loadable module.)

Rather than have this problem terminate testing prematurely lets instead
emit an error message and carry on with the main kprobes tests, delaying
the final failure report until the end.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2011-August/063026.html

Signed-off-by: Jon Medhurst <tixy@linaro.org>
---
 arch/arm/kernel/kprobes-test.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c
index 3796399..08d7312 100644
--- a/arch/arm/kernel/kprobes-test.c
+++ b/arch/arm/kernel/kprobes-test.c
@@ -225,6 +225,7 @@ static int pre_handler_called;
 static int post_handler_called;
 static int jprobe_func_called;
 static int kretprobe_handler_called;
+static int tests_failed;
 
 #define FUNC_ARG1 0x12345678
 #define FUNC_ARG2 0xabcdef
@@ -461,6 +462,13 @@ static int run_api_tests(long (*func)(long, long))
 
 	pr_info("    jprobe\n");
 	ret = test_jprobe(func);
+#if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE)
+	if (ret == -EINVAL) {
+		pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n");
+		tests_failed = ret;
+		ret = 0;
+	}
+#endif
 	if (ret < 0)
 		return ret;
 
@@ -1672,6 +1680,8 @@ static int __init run_all_tests(void)
 
 out:
 	if (ret == 0)
+		ret = tests_failed;
+	if (ret == 0)
 		pr_info("Finished kprobe tests OK\n");
 	else
 		pr_err("kprobe tests failed\n");
-- 
1.7.10.4

[PATCH RESEND 2/3] ARM: kprobes: Disallow instructions with PC and register specified shift

[Jon Medhurst]

ARM data processing instructions which have a register specified shift
are defined as UNPREDICTABLE if PC is used for any register, not just
the shift value as the code was previous assuming. This issue manifests
on A15 devices as either test case failures or undefined instructions
aborts.

Reported-by: David Long <dave.long@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
---
 arch/arm/kernel/kprobes-test-arm.c |   22 ++++++++++++----------
 arch/arm/kernel/probes-arm.c       |    6 +++---
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/kernel/kprobes-test-arm.c
index 9db4b65..e73f9cf 100644
--- a/arch/arm/kernel/kprobes-test-arm.c
+++ b/arch/arm/kernel/kprobes-test-arm.c
@@ -74,8 +74,6 @@ void kprobe_arm_test_cases(void)
 	TEST_RRR( op "lt" s "	r11, r",11,VAL1,", r",14,N(val),", asr r",7, 6,"")\
 	TEST_RR(  op "gt" s "	r12, r13"       ", r",14,val, ", ror r",14,7,"")\
 	TEST_RR(  op "le" s "	r14, r",0, val, ", r13"       ", lsl r",14,8,"")\
-	TEST_RR(  op s "	r12, pc"        ", r",14,val, ", ror r",14,7,"")\
-	TEST_RR(  op s "	r14, r",0, val, ", pc"        ", lsl r",14,8,"")\
 	TEST_R(   op "eq" s "	r0,  r",11,VAL1,", #0xf5")			\
 	TEST_R(   op "ne" s "	r11, r",0, VAL1,", #0xf5000000")		\
 	TEST_R(   op s "	r7,  r",8, VAL2,", #0x000af000")		\
@@ -103,8 +101,6 @@ void kprobe_arm_test_cases(void)
 	TEST_RRR( op "ge	r",11,VAL1,", r",14,N(val),", asr r",7, 6,"")	\
 	TEST_RR(  op "le	r13"       ", r",14,val, ", ror r",14,7,"")	\
 	TEST_RR(  op "gt	r",0, val, ", r13"       ", lsl r",14,8,"")	\
-	TEST_RR(  op "	pc"        ", r",14,val, ", ror r",14,7,"")		\
-	TEST_RR(  op "	r",0, val, ", pc"        ", lsl r",14,8,"")		\
 	TEST_R(   op "eq	r",11,VAL1,", #0xf5")				\
 	TEST_R(   op "ne	r",0, VAL1,", #0xf5000000")			\
 	TEST_R(   op "	r",8, VAL2,", #0x000af000")
@@ -125,7 +121,6 @@ void kprobe_arm_test_cases(void)
 	TEST_RR(  op "ge" s "	r11, r",11,N(val),", asr r",7, 6,"")	\
 	TEST_RR(  op "lt" s "	r12, r",11,val, ", ror r",14,7,"")	\
 	TEST_R(   op "gt" s "	r14, r13"       ", lsl r",14,8,"")	\
-	TEST_R(   op "le" s "	r14, pc"        ", lsl r",14,8,"")	\
 	TEST(     op "eq" s "	r0,  #0xf5")				\
 	TEST(     op "ne" s "	r11, #0xf5000000")			\
 	TEST(     op s "	r7,  #0x000af000")			\
@@ -159,12 +154,19 @@ void kprobe_arm_test_cases(void)
 	TEST_SUPPORTED("cmp	pc, #0x1000");
 	TEST_SUPPORTED("cmp	sp, #0x1000");
 
-	/* Data-processing with PC as shift*/
+	/* Data-processing with PC and a shift count in a register */
 	TEST_UNSUPPORTED(__inst_arm(0xe15c0f1e) "	@ cmp	r12, r14, asl pc")
 	TEST_UNSUPPORTED(__inst_arm(0xe1a0cf1e) "	@ mov	r12, r14, asl pc")
 	TEST_UNSUPPORTED(__inst_arm(0xe08caf1e) "	@ add	r10, r12, r14, asl pc")
-
-	/* Data-processing with PC as shift*/
+	TEST_UNSUPPORTED(__inst_arm(0xe151021f) "	@ cmp	r1, pc, lsl r2")
+	TEST_UNSUPPORTED(__inst_arm(0xe17f0211) "	@ cmn	pc, r1, lsl r2")
+	TEST_UNSUPPORTED(__inst_arm(0xe1a0121f) "	@ mov	r1, pc, lsl r2")
+	TEST_UNSUPPORTED(__inst_arm(0xe1a0f211) "	@ mov	pc, r1, lsl r2")
+	TEST_UNSUPPORTED(__inst_arm(0xe042131f) "	@ sub	r1, r2, pc, lsl r3")
+	TEST_UNSUPPORTED(__inst_arm(0xe1cf1312) "	@ bic	r1, pc, r2, lsl r3")
+	TEST_UNSUPPORTED(__inst_arm(0xe081f312) "	@ add	pc, r1, r2, lsl r3")
+
+	/* Data-processing with PC as a target and status registers updated */
 	TEST_UNSUPPORTED("movs	pc, r1")
 	TEST_UNSUPPORTED("movs	pc, r1, lsl r2")
 	TEST_UNSUPPORTED("movs	pc, #0x10000")
@@ -187,14 +189,14 @@ void kprobe_arm_test_cases(void)
 	TEST_BF_R ("add	pc, pc, r",14,2f-1f-8,"")
 	TEST_BF_R ("add	pc, r",14,2f-1f-8,", pc")
 	TEST_BF_R ("mov	pc, r",0,2f,"")
-	TEST_BF_RR("mov	pc, r",0,2f,", asl r",1,0,"")
+	TEST_BF_R ("add	pc, pc, r",14,(2f-1f-8)*2,", asr #1")
 	TEST_BB(   "sub	pc, pc, #1b-2b+8")
 #if __LINUX_ARM_ARCH__ == 6 && !defined(CONFIG_CPU_V7)
 	TEST_BB(   "sub	pc, pc, #1b-2b+8-2") /* UNPREDICTABLE before and after ARMv6 */
 #endif
 	TEST_BB_R( "sub	pc, pc, r",14, 1f-2f+8,"")
 	TEST_BB_R( "rsb	pc, r",14,1f-2f+8,", pc")
-	TEST_RR(   "add	pc, pc, r",10,-2,", asl r",11,1,"")
+	TEST_R(    "add	pc, pc, r",10,-2,", asl #1")
 #ifdef CONFIG_THUMB2_KERNEL
 	TEST_ARM_TO_THUMB_INTERWORK_R("add	pc, pc, r",0,3f-1f-8+1,"")
 	TEST_ARM_TO_THUMB_INTERWORK_R("sub	pc, r",0,3f+8+1,", #8")
diff --git a/arch/arm/kernel/probes-arm.c b/arch/arm/kernel/probes-arm.c
index 51a13a0..8eaef81 100644
--- a/arch/arm/kernel/probes-arm.c
+++ b/arch/arm/kernel/probes-arm.c
@@ -341,12 +341,12 @@ static const union decode_item arm_cccc_000x_table[] = {
 	/* CMP (reg-shift reg)	cccc 0001 0101 xxxx xxxx xxxx 0xx1 xxxx */
 	/* CMN (reg-shift reg)	cccc 0001 0111 xxxx xxxx xxxx 0xx1 xxxx */
 	DECODE_EMULATEX	(0x0f900090, 0x01100010, PROBES_DATA_PROCESSING_REG,
-						 REGS(ANY, 0, NOPC, 0, ANY)),
+						 REGS(NOPC, 0, NOPC, 0, NOPC)),
 
 	/* MOV (reg-shift reg)	cccc 0001 101x xxxx xxxx xxxx 0xx1 xxxx */
 	/* MVN (reg-shift reg)	cccc 0001 111x xxxx xxxx xxxx 0xx1 xxxx */
 	DECODE_EMULATEX	(0x0fa00090, 0x01a00010, PROBES_DATA_PROCESSING_REG,
-						 REGS(0, ANY, NOPC, 0, ANY)),
+						 REGS(0, NOPC, NOPC, 0, NOPC)),
 
 	/* AND (reg-shift reg)	cccc 0000 000x xxxx xxxx xxxx 0xx1 xxxx */
 	/* EOR (reg-shift reg)	cccc 0000 001x xxxx xxxx xxxx 0xx1 xxxx */
@@ -359,7 +359,7 @@ static const union decode_item arm_cccc_000x_table[] = {
 	/* ORR (reg-shift reg)	cccc 0001 100x xxxx xxxx xxxx 0xx1 xxxx */
 	/* BIC (reg-shift reg)	cccc 0001 110x xxxx xxxx xxxx 0xx1 xxxx */
 	DECODE_EMULATEX	(0x0e000090, 0x00000010, PROBES_DATA_PROCESSING_REG,
-						 REGS(ANY, ANY, NOPC, 0, ANY)),
+						 REGS(NOPC, NOPC, NOPC, 0, NOPC)),
 
 	DECODE_END
 };
-- 
1.7.10.4

[PATCH RESEND 3/3] ARM: kprobes: Fix test code compilation errors for ARMv4 targets

[Jon Medhurst]

Conditionally compile kprobes test cases for ARMv5 instructions to avoid
compilation errors with ARMv4 targets like:

/tmp/cc7Tx8ST.s:16740: Error: selected processor does not support ARM mode `clz r0,r0'

Signed-off-by: Jon Medhurst <tixy@linaro.org>
---
 arch/arm/kernel/kprobes-test-arm.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/kernel/kprobes-test-arm.c
index e73f9cf..cb14242 100644
--- a/arch/arm/kernel/kprobes-test-arm.c
+++ b/arch/arm/kernel/kprobes-test-arm.c
@@ -218,6 +218,7 @@ void kprobe_arm_test_cases(void)
 	TEST_BB_R("bx	r",7,2f,"")
 	TEST_BF_R("bxeq	r",14,2f,"")
 
+#if __LINUX_ARM_ARCH__ >= 5
 	TEST_R("clz	r0, r",0, 0x0,"")
 	TEST_R("clzeq	r7, r",14,0x1,"")
 	TEST_R("clz	lr, r",7, 0xffffffff,"")
@@ -339,6 +340,7 @@ void kprobe_arm_test_cases(void)
 	TEST_UNSUPPORTED(__inst_arm(0xe16f02e1) " @ smultt pc, r1, r2")
 	TEST_UNSUPPORTED(__inst_arm(0xe16002ef) " @ smultt r0, pc, r2")
 	TEST_UNSUPPORTED(__inst_arm(0xe1600fe1) " @ smultt r0, r1, pc")
+#endif
 
 	TEST_GROUP("Multiply and multiply-accumulate")
 
@@ -561,6 +563,7 @@ void kprobe_arm_test_cases(void)
 	TEST_UNSUPPORTED("ldrsht	r1, [r2], #48")
 #endif
 
+#if __LINUX_ARM_ARCH__ >= 5
 	TEST_RPR(  "strd	r",0, VAL1,", [r",1, 48,", -r",2,24,"]")
 	TEST_RPR(  "strccd	r",8, VAL2,", [r",13,0, ", r",12,48,"]")
 	TEST_RPR(  "strd	r",4, VAL1,", [r",2, 24,", r",3, 48,"]!")
@@ -597,6 +600,7 @@ void kprobe_arm_test_cases(void)
 	TEST_UNSUPPORTED(__inst_arm(0xe1efc3d0) "	@ ldrd r12, [pc, #48]!")
 	TEST_UNSUPPORTED(__inst_arm(0xe0c9f3d0) "	@ ldrd pc, [r9], #48")
 	TEST_UNSUPPORTED(__inst_arm(0xe0c9e3d0) "	@ ldrd lr, [r9], #48")
+#endif
 
 	TEST_GROUP("Miscellaneous")
 
@@ -1229,7 +1233,9 @@ void kprobe_arm_test_cases(void)
 	TEST_COPROCESSOR( "mrc"two"	0, 0, r0, cr0, cr0, 0")
 
 	COPROCESSOR_INSTRUCTIONS_ST_LD("",e)
+#if __LINUX_ARM_ARCH__ >= 5
 	COPROCESSOR_INSTRUCTIONS_MC_MR("",e)
+#endif
 	TEST_UNSUPPORTED("svc	0")
 	TEST_UNSUPPORTED("svc	0xffffff")
 
@@ -1289,7 +1295,9 @@ void kprobe_arm_test_cases(void)
 	TEST(	"blx	__dummy_thumb_subroutine_odd")
 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 
+#if __LINUX_ARM_ARCH__ >= 5
 	COPROCESSOR_INSTRUCTIONS_ST_LD("2",f)
+#endif
 #if __LINUX_ARM_ARCH__ >= 6
 	COPROCESSOR_INSTRUCTIONS_MC_MR("2",f)
 #endif
-- 
1.7.10.4