diff options
| author | Chang S. Bae <chang.seok.bae@intel.com> | 2019-05-08 03:02:26 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-06-22 11:38:54 +0200 |
| commit | 79e1932fa3cedd731ddbd6af111fe4db8ca109ae (patch) | |
| tree | 320046bbb343f2e9313a47c41c1a1dfe3587e2a2 /arch/x86/include | |
| parent | 1d07316b1363a004ed548c3759584f8e8b1e24e3 (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 2.21 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>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/1557309753-24073-12-git-send-email-chang.seok.bae@intel.com
Diffstat (limited to 'arch/x86/include')
| -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 |