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https://github.com/cirosantilli/linux-kernel-module-cheat.git
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23 lines
598 B
C
23 lines
598 B
C
/* This is a worse version of scratch.c with hardcoded scratch.
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* https://github.com/cirosantilli/linux-kernel-module-cheat#gcc-inline-assembly-scratch-registers
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*/
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#include <assert.h>
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#include <inttypes.h>
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int main(void) {
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uint64_t in1 = 0xFFFFFFFF;
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uint64_t in2 = 1;
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uint64_t out;
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__asm__ (
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"mov %[in2], %%rax;" /* scratch = in2 */
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"add %[in1], %%rax;" /* scratch += in1 */
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"mov %%rax, %[out];" /* out = scratch */
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: [out] "=r" (out)
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: [in1] "r" (in1),
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[in2] "r" (in2)
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: "rax"
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);
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assert(out == 0x100000000);
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}
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