The following commit has been merged into the x86/fsgsbase branch of tip: Commit-ID: 8e259031c67a5ea0666428edb64c89e8c6ebd18e Gitweb: https://git.kernel.org/tip/8e259031c67a5ea0666428edb64c89e8c6ebd18e Author: Andy Lutomirski <[email protected]> AuthorDate: Fri, 26 Jun 2020 10:24:28 -07:00 Committer: Thomas Gleixner <[email protected]> CommitterDate: Wed, 01 Jul 2020 15:27:20 +02:00
selftests/x86/fsgsbase: Add a missing memory constraint The manual call to set_thread_area() via int $0x80 was missing any indication that the descriptor was a pointer, causing gcc to occasionally generate wrong code. Add the missing constraint. Signed-off-by: Andy Lutomirski <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Link: https://lkml.kernel.org/r/432968af67259ca92d68b774a731aff468eae610.1593192140.git.l...@kernel.org --- tools/testing/selftests/x86/fsgsbase.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index f47495d..9983195 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -285,7 +285,8 @@ static unsigned short load_gs(void) /* 32-bit set_thread_area */ long ret; asm volatile ("int $0x80" - : "=a" (ret) : "a" (243), "b" (low_desc) + : "=a" (ret), "+m" (*low_desc) + : "a" (243), "b" (low_desc) : "r8", "r9", "r10", "r11"); memcpy(&desc, low_desc, sizeof(desc)); munmap(low_desc, sizeof(desc));
