On Fri, May 30, 2014 at 3:54 PM, Chema Gonzalez [off-list ref] wrote:

On Thu, May 29, 2014 at 1:22 AM, Daniel Borkmann [off-list ref] wrote:

quoted

Also add a test for the scratch memory store that first fills
all slots and then sucessively reads all of them back adding
up to A, and eventually returning A. This and the previous
M[] test with alternating fill/spill will detect possible JIT
errors on M[].

Suggested-by: Alexei Starovoitov <redacted>
Signed-off-by: Daniel Borkmann <redacted>
Acked-by: Alexei Starovoitov <redacted>
---
 lib/test_bpf.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 1 deletion(-)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 3c4a1e3..2d0a0d1 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c

@@ -1493,7 +1493,7 @@ static struct bpf_test tests[] = {
                { },
        },
        {       /* Mainly checking JIT here. */
-               "M[]: STX + LDX",
+               "M[]: alt STX + LDX",
                .u.insns = {
                        BPF_STMT(BPF_LDX | BPF_IMM, 100),
                        BPF_STMT(BPF_STX, 0),

@@ -1582,6 +1582,79 @@ static struct bpf_test tests[] = {
                { },
                { { 0, 116 } },
        },
+       {       /* Mainly checking JIT here. */
+               "M[]: full STX + full LDX",
+               .u.insns = {
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xbadfeedb),

This is a nit: Could you please use numbers that are easily addable by
a 2-legged computer? For example, you could add 0x00000001,
0x00000004, 0x00000010, 0x00000040, 0x00000100, ..., and then the
addition should be 0x55555555.

Doing simple math will reduce quality of the test, since now this test is
not only checking M[] accesses, but also checks wrapping of 32-bit
arithmetic in interpreter and JITs as extra bonus.
Just take a look at div, mul, add tests.
They use crazy constants specifically to tests boundary conditions.

-Chema

quoted

+                       BPF_STMT(BPF_STX, 0),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xecabedae),
+                       BPF_STMT(BPF_STX, 1),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xafccfeaf),
+                       BPF_STMT(BPF_STX, 2),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xbffdcedc),
+                       BPF_STMT(BPF_STX, 3),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xfbbbdccb),
+                       BPF_STMT(BPF_STX, 4),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xfbabcbda),
+                       BPF_STMT(BPF_STX, 5),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xaedecbdb),
+                       BPF_STMT(BPF_STX, 6),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xadebbade),
+                       BPF_STMT(BPF_STX, 7),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xfcfcfaec),
+                       BPF_STMT(BPF_STX, 8),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xbcdddbdc),
+                       BPF_STMT(BPF_STX, 9),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xfeefdfac),
+                       BPF_STMT(BPF_STX, 10),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xcddcdeea),
+                       BPF_STMT(BPF_STX, 11),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xaccfaebb),
+                       BPF_STMT(BPF_STX, 12),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xbdcccdcf),
+                       BPF_STMT(BPF_STX, 13),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xaaedecde),
+                       BPF_STMT(BPF_STX, 14),
+                       BPF_STMT(BPF_LDX | BPF_IMM, 0xfaeacdad),
+                       BPF_STMT(BPF_STX, 15),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 0),
+                       BPF_STMT(BPF_MISC | BPF_TXA, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 1),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 2),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 3),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 4),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 5),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 6),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 7),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 8),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 9),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 10),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 11),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 12),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 13),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 14),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_LDX | BPF_MEM, 15),
+                       BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+                       BPF_STMT(BPF_RET | BPF_A, 0),
+               },
+               CLASSIC | FLAG_NO_DATA,
+               { },
+               { { 0, 0x2a5a5e5 } },
+       },
 };

 static struct net_device dev;
--
1.7.11.7

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