summaryrefslogtreecommitdiff
path: root/arch/x86/entry/calling.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/entry/calling.h')
-rw-r--r--arch/x86/entry/calling.h40
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 4208c1e3f601..98e4d8886f11 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -6,6 +6,7 @@
#include <asm/percpu.h>
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
+#include <asm/inst.h>
/*
@@ -341,6 +342,12 @@ For 32-bit we have the following conventions - kernel is built with
#endif
.endm
+.macro SAVE_AND_SET_GSBASE scratch_reg:req save_reg:req
+ rdgsbase \save_reg
+ GET_PERCPU_BASE \scratch_reg
+ wrgsbase \scratch_reg
+.endm
+
#else /* CONFIG_X86_64 */
# undef UNWIND_HINT_IRET_REGS
# define UNWIND_HINT_IRET_REGS
@@ -351,3 +358,36 @@ For 32-bit we have the following conventions - kernel is built with
call stackleak_erase
#endif
.endm
+
+#ifdef CONFIG_SMP
+
+/*
+ * CPU/node NR is loaded from the limit (size) field of a special segment
+ * descriptor entry in GDT.
+ */
+.macro LOAD_CPU_AND_NODE_SEG_LIMIT reg:req
+ movq $__CPUNODE_SEG, \reg
+ lsl \reg, \reg
+.endm
+
+/*
+ * Fetch the per-CPU GSBASE value for this processor and put it in @reg.
+ * We normally use %gs for accessing per-CPU data, but we are setting up
+ * %gs here and obviously can not use %gs itself to access per-CPU data.
+ */
+.macro GET_PERCPU_BASE reg:req
+ ALTERNATIVE \
+ "LOAD_CPU_AND_NODE_SEG_LIMIT \reg", \
+ "RDPID \reg", \
+ X86_FEATURE_RDPID
+ andq $VDSO_CPUNODE_MASK, \reg
+ movq __per_cpu_offset(, \reg, 8), \reg
+.endm
+
+#else
+
+.macro GET_PERCPU_BASE reg:req
+ movq pcpu_unit_offsets(%rip), \reg
+.endm
+
+#endif /* CONFIG_SMP */