Thread (2 messages) flat view 2 messages, 2 authors, 2021-05-18

Re: [PATCH v2] ARM: kprobes: test-thumb: fix for LLVM_IAS=1

From: Jian Cai <hidden>
Date: 2021-05-18 00:02:56
Also in: lkml

Thanks for the patch. It looks good to me, and I double checked  ARM
architecture reference manual for V7 and can confirm the missing
operand in these instructions is not specified as optional.

Reviewed-by: Jian Cai <redacted>

On Mon, Mar 29, 2021 at 3:12 PM Nick Desaulniers
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
There's a few instructions that GAS infers operands but Clang doesn't;
from what I can tell the Arm ARM doesn't say these are optional.

F5.1.257 TBB, TBH T1 Halfword variant
F5.1.238 STREXD T1 variant
F5.1.84 LDREXD T1 variant

Link: https://github.com/ClangBuiltLinux/linux/issues/1309
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
See:
https://lore.kernel.org/linux-arm-kernel/CAMj1kXE5uw4+zV3JVpfA2drOD5TZVMs5a_E5wrrnzjEYc=E_fA@mail.gmail.com/ (local)
for what I'd consider V1. The previous issues with .w suffixes have been
fixed or have fixes pending in LLVM:
* BL+DBG:   https://reviews.llvm.org/D97236
* ORN/ORNS: https://reviews.llvm.org/D99538
* RSB/RSBS: https://reviews.llvm.org/D99542
I'd have expected the Arm ARM to use curly braces to denote optional
operands (see also "F5.1.167 RSB, RSBS (register)" for an example).

 arch/arm/probes/kprobes/test-thumb.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm/probes/kprobes/test-thumb.c b/arch/arm/probes/kprobes/test-thumb.c
index 456c181a7bfe..4e11f0b760f8 100644
--- a/arch/arm/probes/kprobes/test-thumb.c
+++ b/arch/arm/probes/kprobes/test-thumb.c
@@ -441,21 +441,21 @@ void kprobe_thumb32_test_cases(void)
                "3:     mvn     r0, r0  \n\t"
                "2:     nop             \n\t")

-       TEST_RX("tbh    [pc, r",7, (9f-(1f+4))>>1,"]",
+       TEST_RX("tbh    [pc, r",7, (9f-(1f+4))>>1,", lsl #1]",
                "9:                     \n\t"
                ".short (2f-1b-4)>>1    \n\t"
                ".short (3f-1b-4)>>1    \n\t"
                "3:     mvn     r0, r0  \n\t"
                "2:     nop             \n\t")

-       TEST_RX("tbh    [pc, r",12, ((9f-(1f+4))>>1)+1,"]",
+       TEST_RX("tbh    [pc, r",12, ((9f-(1f+4))>>1)+1,", lsl #1]",
                "9:                     \n\t"
                ".short (2f-1b-4)>>1    \n\t"
                ".short (3f-1b-4)>>1    \n\t"
                "3:     mvn     r0, r0  \n\t"
                "2:     nop             \n\t")

-       TEST_RRX("tbh   [r",1,9f, ", r",14,1,"]",
+       TEST_RRX("tbh   [r",1,9f, ", r",14,1,", lsl #1]",
                "9:                     \n\t"
                ".short (2f-1b-4)>>1    \n\t"
                ".short (3f-1b-4)>>1    \n\t"
@@ -468,10 +468,10 @@ void kprobe_thumb32_test_cases(void)

        TEST_UNSUPPORTED("strexb        r0, r1, [r2]")
        TEST_UNSUPPORTED("strexh        r0, r1, [r2]")
-       TEST_UNSUPPORTED("strexd        r0, r1, [r2]")
+       TEST_UNSUPPORTED("strexd        r0, r1, r2, [r2]")
        TEST_UNSUPPORTED("ldrexb        r0, [r1]")
        TEST_UNSUPPORTED("ldrexh        r0, [r1]")
-       TEST_UNSUPPORTED("ldrexd        r0, [r1]")
+       TEST_UNSUPPORTED("ldrexd        r0, r1, [r1]")

        TEST_GROUP("Data-processing (shifted register) and (modified immediate)")

--
2.31.0.291.g576ba9dcdaf-goog
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