Re: [PATCH v7 2/3] arm64: implement ftrace with regs
From: Julien Thierry <hidden>
Date: 2019-01-22 13:49:56
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On 22/01/2019 13:28, Torsten Duwe wrote:
On Tue, Jan 22, 2019 at 10:18:17AM +0000, Julien Thierry wrote:quoted
Hi Torsten, A few suggestions below.quoted
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +#define ARCH_SUPPORTS_FTRACE_OPS 1 +#define REC_IP_BRANCH_OFFSET AARCH64_INSN_SIZE +/* All we need is some magic value. Simply use "_mCount:" */Nit: Should the casing be "_mcount" ?No! The string makes it clear what it's supposed to be and the peculiar casing makes it unique and leaves no doubt were it came from. So whenever you see this register value in a crash dump you don't have to wonder about weird linkage errors, as it surely did not originate from a symtab.
Right, I had missed the point that the value below is actually the binary representation of that string. Things make more sense now, thanks.
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+#define MCOUNT_ADDR (0x5f6d436f756e743a) +#else +#define REC_IP_BRANCH_OFFSET 0 +#define MCOUNT_ADDR ((unsigned long)_mcount) +#endif +
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