diff options
| author | Chang S. Bae <chang.seok.bae@intel.com> | 2020-05-28 16:13:56 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-18 15:47:04 +0200 |
| commit | eaad981291ee36efee15a5e515d4598ae94ace07 (patch) | |
| tree | 0e3621526e6d949461a6a25f0f704cac93a2c31d /arch/x86/include/asm/inst.h | |
| parent | 96b2371413e8f636a5f25c42a933af21c35a2a41 (diff) | |
x86/entry/64: Introduce the FIND_PERCPU_BASE macro
GSBASE is used to find per-CPU data in the kernel. But when GSBASE is
unknown, the per-CPU base can be found from the per_cpu_offset table with a
CPU NR. The CPU NR is extracted from the limit field of the CPUNODE entry
in GDT, or by the RDPID instruction. This is a prerequisite for using
FSGSBASE in the low level entry code.
Also, add the GAS-compatible RDPID macro as binutils 2.23 do not support
it. Support is added in version 2.27.
[ tglx: Massaged changelog ]
Suggested-by: H. Peter Anvin <hpa@zytor.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/1557309753-24073-12-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-11-sashal@kernel.org
Diffstat (limited to 'arch/x86/include/asm/inst.h')
| -rw-r--r-- | arch/x86/include/asm/inst.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/include/asm/inst.h b/arch/x86/include/asm/inst.h index f5a796da07f8..d063841a17e3 100644 --- a/arch/x86/include/asm/inst.h +++ b/arch/x86/include/asm/inst.h @@ -306,6 +306,21 @@ .endif MODRM 0xc0 movq_r64_xmm_opd1 movq_r64_xmm_opd2 .endm + +.macro RDPID opd + REG_TYPE rdpid_opd_type \opd + .if rdpid_opd_type == REG_TYPE_R64 + R64_NUM rdpid_opd \opd + .else + R32_NUM rdpid_opd \opd + .endif + .byte 0xf3 + .if rdpid_opd > 7 + PFX_REX rdpid_opd 0 + .endif + .byte 0x0f, 0xc7 + MODRM 0xc0 rdpid_opd 0x7 +.endm #endif #endif |