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Substitute 'swpb' (swap byte) instruction with 'ldrexb/strexb', because 'swpb' needs to be enabled explicitly by the kernel, which is done by neither HW or FOC. When disabled, 'swpb' will cause an undefined instruction exception. Issue #1048
21 lines
757 B
Diff
21 lines
757 B
Diff
diff --git a/src/sys/arch/arm/include/lock.h b/sys/arch/arm/include/lock.h
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index c52a44f..3b4ba93 100644
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--- a/src/sys/arch/arm/include/lock.h
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+++ b/src/sys/arch/arm/include/lock.h
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@@ -119,8 +119,13 @@ __swp(__cpu_simple_lock_t __val, volatile __cpu_simple_lock_t *__ptr)
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return __rv;
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#else
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uint32_t __val32;
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- __asm volatile("swpb %0, %1, [%2]"
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- : "=&r" (__val32) : "r" (__val), "r" (__ptr) : "memory");
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+ __asm volatile(" 1: \n"
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+ " ldrexb %0, [%2] \n"
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+ " strexb r0, %1, [%2]\n"
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+ " teqeq r0, #0 \n"
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+ " bne 1b \n"
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+ : "=&r" (__val32) : "r" (__val), "r" (__ptr)
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+ : "memory", "r0");
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return __val32;
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#endif
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}
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