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OpenCloudOS-Kernel/arch/x86/include/uapi/asm/hwcap2.h

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treewide: add "WITH Linux-syscall-note" to SPDX tag of uapi headers UAPI headers licensed under GPL are supposed to have exception "WITH Linux-syscall-note" so that they can be included into non-GPL user space application code. The exception note is missing in some UAPI headers. Some of them slipped in by the treewide conversion commit b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to files with no license"). Just run: $ git show --oneline b24413180f56 -- arch/x86/include/uapi/asm/ I believe they are not intentional, and should be fixed too. This patch was generated by the following script: git grep -l --not -e Linux-syscall-note --and -e SPDX-License-Identifier \ -- :arch/*/include/uapi/asm/*.h :include/uapi/ :^*/Kbuild | while read file do sed -i -e '/[[:space:]]OR[[:space:]]/s/\(GPL-[^[:space:]]*\)/(\1 WITH Linux-syscall-note)/g' \ -e '/[[:space:]]or[[:space:]]/s/\(GPL-[^[:space:]]*\)/(\1 WITH Linux-syscall-note)/g' \ -e '/[[:space:]]OR[[:space:]]/!{/[[:space:]]or[[:space:]]/!s/\(GPL-[^[:space:]]*\)/\1 WITH Linux-syscall-note/g}' $file done After this patch is applied, there are 5 UAPI headers that do not contain "WITH Linux-syscall-note". They are kept untouched since this exception applies only to GPL variants. $ git grep --not -e Linux-syscall-note --and -e SPDX-License-Identifier \ -- :arch/*/include/uapi/asm/*.h :include/uapi/ :^*/Kbuild include/uapi/drm/panfrost_drm.h:/* SPDX-License-Identifier: MIT */ include/uapi/linux/batman_adv.h:/* SPDX-License-Identifier: MIT */ include/uapi/linux/qemu_fw_cfg.h:/* SPDX-License-Identifier: BSD-3-Clause */ include/uapi/linux/vbox_err.h:/* SPDX-License-Identifier: MIT */ include/uapi/linux/virtio_iommu.h:/* SPDX-License-Identifier: BSD-3-Clause */ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-25 15:58:31 +08:00
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
x86/elf: Add HWCAP2 to expose ring 3 MONITOR/MWAIT Introduce ELF_HWCAP2 variable for x86 and reserve its bit 0 to expose the ring 3 MONITOR/MWAIT. HWCAP variables contain bitmasks which can be used by userspace applications to detect which instruction sets are supported by CPU. On x86 architecture information about CPU capabilities can be checked via CPUID instructions, unfortunately presence of ring 3 MONITOR/MWAIT feature cannot be checked this way. ELF_HWCAP cannot be used as well, because on x86 it is set to CPUID[1].EDX which means that all bits are reserved there. HWCAP2 approach was chosen because it reuses existing solution present in other architectures, so only minor modifications are required to the kernel and userspace applications. When ELF_HWCAP2 is defined kernel maps it to AT_HWCAP2 during the start of the application. This way the ring 3 MONITOR/MWAIT feature can be detected using getauxval() API in a simple and fast manner. ELF_HWCAP2 type is u32 to be consistent with x86 ELF_HWCAP type. Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: Piotr.Luc@intel.com Cc: dave.hansen@linux.intel.com Link: http://lkml.kernel.org/r/1484918557-15481-3-git-send-email-grzegorz.andrejczuk@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-01-20 21:22:34 +08:00
#ifndef _ASM_X86_HWCAP2_H
#define _ASM_X86_HWCAP2_H
/* MONITOR/MWAIT enabled in Ring 3 */
#define HWCAP2_RING3MWAIT (1 << 0)
x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 The kernel needs to explicitly enable FSGSBASE. So, the application needs to know if it can safely use these instructions. Just looking at the CPUID bit is not enough because it may be running in a kernel that does not enable the instructions. One way for the application would be to just try and catch the SIGILL. But that is difficult to do in libraries which may not want to overwrite the signal handlers of the main application. Enumerate the enabled FSGSBASE capability in bit 1 of AT_HWCAP2 in the ELF aux vector. AT_HWCAP2 is already used by PPC for similar purposes. The application can access it open coded or by using the getauxval() function in newer versions of glibc. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1557309753-24073-18-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-14-sashal@kernel.org
2020-05-29 04:13:59 +08:00
/* Kernel allows FSGSBASE instructions available in Ring 3 */
#define HWCAP2_FSGSBASE BIT(1)
x86/elf: Add HWCAP2 to expose ring 3 MONITOR/MWAIT Introduce ELF_HWCAP2 variable for x86 and reserve its bit 0 to expose the ring 3 MONITOR/MWAIT. HWCAP variables contain bitmasks which can be used by userspace applications to detect which instruction sets are supported by CPU. On x86 architecture information about CPU capabilities can be checked via CPUID instructions, unfortunately presence of ring 3 MONITOR/MWAIT feature cannot be checked this way. ELF_HWCAP cannot be used as well, because on x86 it is set to CPUID[1].EDX which means that all bits are reserved there. HWCAP2 approach was chosen because it reuses existing solution present in other architectures, so only minor modifications are required to the kernel and userspace applications. When ELF_HWCAP2 is defined kernel maps it to AT_HWCAP2 during the start of the application. This way the ring 3 MONITOR/MWAIT feature can be detected using getauxval() API in a simple and fast manner. ELF_HWCAP2 type is u32 to be consistent with x86 ELF_HWCAP type. Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: Piotr.Luc@intel.com Cc: dave.hansen@linux.intel.com Link: http://lkml.kernel.org/r/1484918557-15481-3-git-send-email-grzegorz.andrejczuk@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-01-20 21:22:34 +08:00
#endif