x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 137 insertions, 0 deletions

diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
new file mode 100644
index 000000000000..80860afffbdb
--- /dev/null
+++ b/arch/x86/include/asm/pda.h
@@ -0,0 +1,137 @@
+#ifndef ASM_X86__PDA_H
+#define ASM_X86__PDA_H
+
+#ifndef __ASSEMBLY__
+#include <linux/stddef.h>
+#include <linux/types.h>
+#include <linux/cache.h>
+#include <asm/page.h>
+
+/* Per processor datastructure. %gs points to it while the kernel runs */
+struct x8664_pda {
+	struct task_struct *pcurrent;	/* 0  Current process */
+	unsigned long data_offset;	/* 8 Per cpu data offset from linker
+					   address */
+	unsigned long kernelstack;	/* 16 top of kernel stack for current */
+	unsigned long oldrsp;		/* 24 user rsp for system call */
+	int irqcount;			/* 32 Irq nesting counter. Starts -1 */
+	unsigned int cpunumber;		/* 36 Logical CPU number */
+#ifdef CONFIG_CC_STACKPROTECTOR
+	unsigned long stack_canary;	/* 40 stack canary value */
+					/* gcc-ABI: this canary MUST be at
+					   offset 40!!! */
+#endif
+	char *irqstackptr;
+	short nodenumber;		/* number of current node (32k max) */
+	short in_bootmem;		/* pda lives in bootmem */
+	unsigned int __softirq_pending;
+	unsigned int __nmi_count;	/* number of NMI on this CPUs */
+	short mmu_state;
+	short isidle;
+	struct mm_struct *active_mm;
+	unsigned apic_timer_irqs;
+	unsigned irq0_irqs;
+	unsigned irq_resched_count;
+	unsigned irq_call_count;
+	unsigned irq_tlb_count;
+	unsigned irq_thermal_count;
+	unsigned irq_threshold_count;
+	unsigned irq_spurious_count;
+} ____cacheline_aligned_in_smp;
+
+extern struct x8664_pda **_cpu_pda;
+extern void pda_init(int);
+
+#define cpu_pda(i) (_cpu_pda[i])
+
+/*
+ * There is no fast way to get the base address of the PDA, all the accesses
+ * have to mention %fs/%gs.  So it needs to be done this Torvaldian way.
+ */
+extern void __bad_pda_field(void) __attribute__((noreturn));
+
+/*
+ * proxy_pda doesn't actually exist, but tell gcc it is accessed for
+ * all PDA accesses so it gets read/write dependencies right.
+ */
+extern struct x8664_pda _proxy_pda;
+
+#define pda_offset(field) offsetof(struct x8664_pda, field)
+
+#define pda_to_op(op, field, val)					\
+do {									\
+	typedef typeof(_proxy_pda.field) T__;				\
+	if (0) { T__ tmp__; tmp__ = (val); }	/* type checking */	\
+	switch (sizeof(_proxy_pda.field)) {				\
+	case 2:								\
+		asm(op "w %1,%%gs:%c2" :				\
+		    "+m" (_proxy_pda.field) :				\
+		    "ri" ((T__)val),					\
+		    "i"(pda_offset(field)));				\
+		break;							\
+	case 4:								\
+		asm(op "l %1,%%gs:%c2" :				\
+		    "+m" (_proxy_pda.field) :				\
+		    "ri" ((T__)val),					\
+		    "i" (pda_offset(field)));				\
+		break;							\
+	case 8:								\
+		asm(op "q %1,%%gs:%c2":					\
+		    "+m" (_proxy_pda.field) :				\
+		    "ri" ((T__)val),					\
+		    "i"(pda_offset(field)));				\
+		break;							\
+	default:							\
+		__bad_pda_field();					\
+	}								\
+} while (0)
+
+#define pda_from_op(op, field)			\
+({						\
+	typeof(_proxy_pda.field) ret__;		\
+	switch (sizeof(_proxy_pda.field)) {	\
+	case 2:					\
+		asm(op "w %%gs:%c1,%0" :	\
+		    "=r" (ret__) :		\
+		    "i" (pda_offset(field)),	\
+		    "m" (_proxy_pda.field));	\
+		break;				\
+	case 4:					\
+		asm(op "l %%gs:%c1,%0":		\
+		    "=r" (ret__):		\
+		    "i" (pda_offset(field)),	\
+		    "m" (_proxy_pda.field));	\
+		break;				\
+	case 8:					\
+		asm(op "q %%gs:%c1,%0":		\
+		    "=r" (ret__) :		\
+		    "i" (pda_offset(field)),	\
+		    "m" (_proxy_pda.field));	\
+		break;				\
+	default:				\
+		__bad_pda_field();		\
+	}					\
+	ret__;					\
+})
+
+#define read_pda(field)		pda_from_op("mov", field)
+#define write_pda(field, val)	pda_to_op("mov", field, val)
+#define add_pda(field, val)	pda_to_op("add", field, val)
+#define sub_pda(field, val)	pda_to_op("sub", field, val)
+#define or_pda(field, val)	pda_to_op("or", field, val)
+
+/* This is not atomic against other CPUs -- CPU preemption needs to be off */
+#define test_and_clear_bit_pda(bit, field)				\
+({									\
+	int old__;							\
+	asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"			\
+		     : "=r" (old__), "+m" (_proxy_pda.field)		\
+		     : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
+	old__;								\
+})
+
+#endif
+
+#define PDA_STACKOFFSET (5*8)
+
+#endif /* ASM_X86__PDA_H */