From 063bf5a7770f2f94abd28ba65b0c1723bd6fd027 Mon Sep 17 00:00:00 2001 From: "Cownie, James H" Date: Tue, 12 Jul 2016 16:35:43 +0000 Subject: [PATCH] getauxval.3: Correct AT_HWCAP result description The getauxval(3) man page describes the result for AT_HWCAP as "A pointer to a multibyte mask of bits", however the actual value returned is not a pointer, but simply the first 32 bits of the capabilities mask. This can be observed directly. Note the value shown for AT_HWCAP is a 32 bit value that is not a pointer (see AT_PHDR or AT_RANDOM for how pointers are shown). % LD_SHOW_AUXV=1 cat < /dev/null AT_SYSINFO_EHDR: 0x7fffe89fe000 AT_HWCAP: bfebfbff AT_PAGESZ: 4096 AT_CLKTCK: 100 AT_PHDR: 0x400040 AT_PHENT: 56 AT_PHNUM: 9 AT_BASE: 0x0 AT_FLAGS: 0x0 AT_ENTRY: 0x402634 AT_UID: 515 AT_EUID: 515 AT_GID: 114 AT_EGID: 114 AT_SECURE: 0 AT_RANDOM: 0x7fffe8917be9 AT_EXECFN: /usr/bin/cat AT_PLATFORM: x86_64 --- man3/getauxval.3 | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/man3/getauxval.3 b/man3/getauxval.3 index 85d7f41a9..b912e1cff 100644 --- a/man3/getauxval.3 +++ b/man3/getauxval.3 @@ -101,12 +101,13 @@ performed by the kernel. The real group ID of the thread. .TP .BR AT_HWCAP -A pointer to a multibyte mask of bits whose settings +A four byte long bit-mask whose settings indicate detailed processor capabilities. The contents of the bit mask are hardware dependent (for example, see the kernel source file .IR arch/x86/include/asm/cpufeature.h -for details relating to the Intel x86 architecture). +for details relating to the Intel x86 architecture; the value +returned is the first 32 bit word of the array described there). A human-readable version of the same information is available via .IR /proc/cpuinfo . .TP