Readme update

README.md

@@ -19,9 +19,18 @@ pip3 install -r requirements.txt
 
 ```bash
 ./tests.py
-.
---------------------
-Ran 1 test in 0.010s
+...........WARNING:root:Can't convert BPF_LD_IMM64()
+DEBUG:root:
+Errors:
+  BPF_LD_IMM64                  : None
+Parse tree:
+call_expression:
+  identifier: BPF_LD_IMM64
+  argument_list:
+
+.........
+----------------------------------------------------------------------
+Ran 20 tests in 0.072s
 
 OK
 ```
@@ -33,6 +42,7 @@ Usage:
 ```bash
 usage: rewrite.py [--debug]
                   [--newlines]
+                  [--replace-st-mem]
                   file_name
 
 C code for converted test cases is printed to stdout.
@@ -43,6 +53,8 @@ positional arguments:
 options:
   --debug              print some debug info
   --newlines           add \n after each asm instruction
+  --replace-st-mem     replace BPF_ST_MEM insns with pairs
+                       of MOV/BPF_STX_MEM instructions.
 ```
 
 Example:
@@ -63,45 +75,44 @@ Output:
 #define MAX_ENTRIES 11
 
 struct test_val {
-	unsigned int index;
-	int foo[MAX_ENTRIES];
+        unsigned int index;
+        int foo[MAX_ENTRIES];
 };
 
 struct map_struct {
-	__uint(type, BPF_MAP_TYPE_HASH);
-	__uint(max_entries, 1);
-	__type(key, long long);
-	__type(value, struct test_val);
+        __uint(type, BPF_MAP_TYPE_HASH);
+        __uint(max_entries, 1);
+        __type(key, long long);
+        __type(value, struct test_val);
 } map_hash_48b SEC(".maps");
 
-/* invalid and of negative number */
+__description("invalid and of negative number")
+__failure __msg("R0 max value is outside of the allowed memory range")
+__failure_unpriv
+__flag(BPF_F_ANY_ALIGNMENT)
 SEC("socket")
-__naked
-__failure
-__msg("R0 max value is outside of the allowed memory range")
-__needs_efficient_unaligned_access
-void invalid_and_of_negative_number(void)
+__naked void invalid_and_of_negative_number(void)
 {
-	asm volatile (
-	"*(u64*)(r10 -8) = 0;"
-	"r2 = r10;"
-	"r2 += -8;"
-	"r1 = %[map_hash_48b] ll;"
-	"call %[bpf_map_lookup_elem];"
-	"if r0 == 0 goto l0_0;"
-	"r1 = *(u8*)(r0 +0);"
-	"r1 &= -4;"
-	"r1 <<= 2;"
-	"r0 += r1;"
-"l0_0:"
-	"*(u64*)(r0 +0) = %[test_val_foo_offset];"
-	"exit;"
-	:
-	: [test_val_foo_offset]"i"(offsetof(struct test_val, foo)),
-	  __imm(bpf_map_lookup_elem),
-	  __imm_addr(map_hash_48b)
-	: __clobber_all);
+        asm volatile (
+"       *(u64*)(r10 - 8) = 0;                           \
+        r2 = r10;                                       \
+        r2 += -8;                                       \
+        r1 = %[map_hash_48b] ll;                        \
+        call %[bpf_map_lookup_elem];                    \
+        if r0 == 0 goto l0_%=;                          \
+        r1 = *(u8*)(r0 + 0);                            \
+        r1 &= -4;                                       \
+        r1 <<= 2;                                       \
+        r0 += r1;                                       \
+l0_%=:                                                  \
+        // yes, label is misplaced in the original      \
+        *(u64*)(r0 + 0) = %[test_val_foo_offset];       \
+        exit;                                           \
+"       :
+        : [test_val_foo_offset]"i"(offsetof(struct test_val, foo)),
+          __imm(bpf_map_lookup_elem),
+          __imm_addr(map_hash_48b)
+        : __clobber_all);
 }
-
 ...
 ```