Re: [RFC PATCH for 5.2 08/10] rseq/selftests: aarch64 code signature: handle big-endian environment
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: 2019-04-24 17:00:58
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linux-kselftest, lkml
----- On Apr 24, 2019, at 12:51 PM, Mark Rutland mark.rutland@arm.com wrote:
On Wed, Apr 24, 2019 at 05:45:38PM +0100, Will Deacon wrote:quoted
On Wed, Apr 24, 2019 at 11:25:00AM -0400, Mathieu Desnoyers wrote:quoted
+/* + * aarch64 -mbig-endian generates mixed endianness code vs data: + * little-endian code and big-endian data. Ensure the RSEQ_SIG signature + * matches code endianness. + */ +#define RSEQ_SIG_CODE 0xd428bc00 /* BRK #0x45E0. */ + +#ifdef __AARCH64EB__ +#define RSEQ_SIG_DATA 0x00bc28d4 /* BRK #0x45E0. */It would be neater to implement swab32 and use that with RSEQ_SIG_CODE,If possible, marginally neater than that would be using le32_to_cpu(RSEQ_SIG_CODE), without any ifdeffery necessary. It looks like that's defined in tools/include/linux/kernel.h, but I'm not sure if that gets pulled into your include path.
Considering that those RSEQ_SIG* define will end up in public bits/rseq.h headers within glibc, I'm tempted to keep the amount of dependencies on external headers to a minimum, if it's OK with you. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com