Re: [PATCH] selftests: vDSO: Also test counter in vdso_test_chacha

On Sun, Sep 01, 2024 at 08:08:13PM +0200, Jason A. Donenfeld wrote:

...

• reference_chacha20_blocks(output1, key, counter1, BLOCKS);
• __arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
• if (memcmp(output1, output2, sizeof(output1)) ||

•    memcmp(counter2, counter2, sizeof(counter1)))
  

• return KSFT_FAIL;
  

• reference_chacha20_blocks(output1, key, counter1, BLOCKS);
• __arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
• if (memcmp(output1, output2, sizeof(output1)) ||

•    memcmp(counter2, counter2, sizeof(counter1)))
  

• return KSFT_FAIL;
  

Why repeat these two stanzas?

Ah, from your commit message:

"The first test verifies that the function properly writes back the upper word, the second test verifies that the function properly reads back the upper word."