Messages in this thread | | | Date | Sun, 12 Aug 2012 12:32:47 -0400 | From | Cyril Chemparathy <> | Subject | Re: [PATCH v2 02/22] ARM: add self test for runtime patch mechanism |
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On 08/11/12 22:35, Nicolas Pitre wrote: > On Fri, 10 Aug 2012, Cyril Chemparathy wrote: > >> This patch adds basic sanity tests to ensure that the instruction patching >> results in valid instruction encodings. This is done by verifying the output >> of the patch process against a vector of assembler generated instructions at >> init time. >> >> Signed-off-by: Cyril Chemparathy <cyril@ti.com> >> --- [...] >> + __asm__ __volatile__ ( >> + " .irp shift1, 0, 6, 12, 18\n" >> + " .irp shift2, 0, 1, 2, 3, 4, 5\n" >> + " add r1, r2, #(0x41 << (\\shift1 + \\shift2))\n" >> + " .endr\n" >> + " .endr\n" > > > Maybe adding a "add r1, r2 #0x81 << 24" here might be a good thing since > this is the most used case but missing from the above. >
Indeed. I've now replaced this with something a bit more extensive. Does the following look better?
+struct patch_test_imm8 { + u16 imm; + u16 shift; + u32 insn; +}; + +static void __init __used __naked __patch_test_code_imm8(void) +{ + __asm__ __volatile__ ( + + /* a single test case */ + " .macro test_one, imm, sft\n" + " .hword \\imm\n" + " .hword \\sft\n" + " add r1, r2, #(\\imm << \\sft)\n" + " .endm\n" + + /* a sequence of tests at 'inc' increments of shift */ + " .macro test_seq, imm, sft, max, inc\n" + " test_one \\imm, \\sft\n" + " .if \\sft < \\max\n" + " test_seq \\imm, (\\sft + \\inc), \\max, \\inc\n" + " .endif\n" + " .endm\n" + + /* an empty record to mark the end */ + " .macro test_end\n" + " .hword 0, 0\n" + " .word 0\n" + " .endm\n" + + /* finally generate the test sequences */ + " test_seq 0x41, 0, 24, 1\n" + " test_seq 0x81, 0, 24, 2\n" + " test_end\n" + : : : + ); +} +
[...] >> + u32 test_code_addr = (u32)(&__patch_test_code_imm8); >> + u32 *test_code = (u32 *)(test_code_addr & ~0x3); > > Why this masking? With Thumb2 you may find functions starting at > halfword aligned addresses. Only the LSB (indicating thumb mode) should > be masked out. >
Fixed. Thanks.
Thanks -- Cyril.
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