From 5f95843d51e7e0eb0d6ccea074f906214ef06fbc Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 28 Jun 2024 10:35:24 +0200 Subject: [PATCH] s390/hwcaps: Add documentation for HWCAP flags Describe that some HWCAP bits are reserved to avoid that they will be used by accident. Suggested-by: Stefan Liebler Reviewed-by: Stefan Liebler Acked-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev --- arch/s390/include/asm/elf.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h index 70a30ae258b7..8f2c23cc52b6 100644 --- a/arch/s390/include/asm/elf.h +++ b/arch/s390/include/asm/elf.h @@ -91,6 +91,14 @@ /* Keep this the last entry. */ #define R_390_NUM 61 +/* + * HWCAP flags - for AT_HWCAP + * + * Bits 32-63 are reserved for use by libc. + * Bit 31 is reserved and will be used by libc to determine if a second + * argument is passed to IFUNC resolvers. This will be implemented when + * there is a need for AT_HWCAP2. + */ enum { HWCAP_NR_ESAN3 = 0, HWCAP_NR_ZARCH = 1,