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Commit 64b163fa authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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x86/idt: Unify gate_struct handling for 32/64-bit kernels 



The first 32 bits of gate struct are the same for 32 and 64 bit kernels.

The 32-bit version uses desc_struct and no designated data structure,
so we need different accessors for 32 and 64 bit kernels.

Aside of that the macros which are necessary to build the 32-bit
gate descriptor are horrible to read.

Unify the gate structs and switch all code fiddling with it over.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064957.861974317@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 73285527

arch/x86/boot/compressed/eboot.c

+4 −4
Original line number Diff line number Diff line
@@ -1058,7 +1058,7 @@ struct boot_params *efi_main(struct efi_config *c, 
		desc->s = DESC_TYPE_CODE_DATA;

		desc->dpl = 0;

		desc->p = 1;

		desc->limit = 0xf;

		desc->limit1 = 0xf;

		desc->avl = 0;

		desc->l = 0;

		desc->d = SEG_OP_SIZE_32BIT;
@@ -1078,7 +1078,7 @@ struct boot_params *efi_main(struct efi_config *c, 
	desc->s = DESC_TYPE_CODE_DATA;

	desc->dpl = 0;

	desc->p = 1;

	desc->limit = 0xf;

	desc->limit1 = 0xf;

	desc->avl = 0;

	if (IS_ENABLED(CONFIG_X86_64)) {

		desc->l = 1;
@@ -1099,7 +1099,7 @@ struct boot_params *efi_main(struct efi_config *c, 
	desc->s = DESC_TYPE_CODE_DATA;

	desc->dpl = 0;

	desc->p = 1;

	desc->limit = 0xf;

	desc->limit1 = 0xf;

	desc->avl = 0;

	desc->l = 0;

	desc->d = SEG_OP_SIZE_32BIT;
@@ -1116,7 +1116,7 @@ struct boot_params *efi_main(struct efi_config *c, 
		desc->s = 0;

		desc->dpl = 0;

		desc->p = 1;

		desc->limit = 0x0;

		desc->limit1 = 0x0;

		desc->avl = 0;

		desc->l = 0;

		desc->d = 0;

arch/x86/include/asm/desc.h

+19 −26
Original line number Diff line number Diff line
@@ -84,33 +84,25 @@ static inline phys_addr_t get_cpu_gdt_paddr(unsigned int cpu) 
	return per_cpu_ptr_to_phys(get_cpu_gdt_rw(cpu));

}



#ifdef CONFIG_X86_64



static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,

			     unsigned dpl, unsigned ist, unsigned seg)

{

	gate->offset_low	= PTR_LOW(func);

	gate->offset_low	= (u16) func;

	gate->bits.p		= 1;

	gate->bits.dpl		= dpl;

	gate->bits.zero		= 0;

	gate->bits.type		= type;

	gate->offset_middle	= (u16) (func >> 16);

#ifdef CONFIG_X86_64

	gate->segment		= __KERNEL_CS;

	gate->ist		= ist;

	gate->p			= 1;

	gate->dpl		= dpl;

	gate->zero0		= 0;

	gate->zero1		= 0;

	gate->type		= type;

	gate->offset_middle	= PTR_MIDDLE(func);

	gate->offset_high	= PTR_HIGH(func);

}



	gate->bits.ist		= ist;

	gate->reserved		= 0;

	gate->offset_high	= (u32) (func >> 32);

#else

static inline void pack_gate(gate_desc *gate, unsigned char type,

			     unsigned long base, unsigned dpl, unsigned flags,

			     unsigned short seg)

{

	gate->a = (seg << 16) | (base & 0xffff);

	gate->b = (base & 0xffff0000) | (((0x80 | type | (dpl << 5)) & 0xff) << 8);

}



	gate->segment		= seg;

	gate->bits.ist		= 0;

#endif

}



static inline int desc_empty(const void *ptr)

{
@@ -186,7 +178,8 @@ static inline void pack_descriptor(struct desc_struct *desc, unsigned long base, 
}





static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned type, unsigned size)

static inline void set_tssldt_descriptor(void *d, unsigned long addr,

					 unsigned type, unsigned size)

{

#ifdef CONFIG_X86_64

	struct ldttss_desc64 *desc = d;
@@ -194,13 +187,13 @@ static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned t 
	memset(desc, 0, sizeof(*desc));



	desc->limit0		= size & 0xFFFF;

	desc->base0		= PTR_LOW(addr);

	desc->base1		= PTR_MIDDLE(addr) & 0xFF;

	desc->base0		= (u16) addr;

	desc->base1		= (addr >> 16) & 0xFF;

	desc->type		= type;

	desc->p			= 1;

	desc->limit1		= (size >> 16) & 0xF;

	desc->base2		= (PTR_MIDDLE(addr) >> 8) & 0xFF;

	desc->base3		= PTR_HIGH(addr);

	desc->base2		= (addr >> 24) & 0xFF;

	desc->base3		= (u32) (addr >> 32);

#else

	pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);

#endif

arch/x86/include/asm/desc_defs.h

+37 −20
Original line number Diff line number Diff line
@@ -47,20 +47,6 @@ enum { 
	GATE_TASK = 0x5,

};



/* 16byte gate */

struct gate_struct64 {

	u16 offset_low;

	u16 segment;

	unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;

	u16 offset_middle;

	u32 offset_high;

	u32 zero1;

} __attribute__((packed));



#define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF)

#define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF)

#define PTR_HIGH(x) ((unsigned long long)(x) >> 32)



enum {

	DESC_TSS = 0x9,

	DESC_LDT = 0x2,
@@ -77,20 +63,51 @@ struct ldttss_desc64 { 
	u32 zero1;

} __attribute__((packed));





#ifdef CONFIG_X86_64

typedef struct gate_struct64 gate_desc;

typedef struct ldttss_desc64 ldt_desc;

typedef struct ldttss_desc64 tss_desc;

#define gate_offset(g) ((g).offset_low | ((unsigned long)(g).offset_middle << 16) | ((unsigned long)(g).offset_high << 32))

#define gate_segment(g) ((g).segment)

#else

typedef struct desc_struct gate_desc;

typedef struct desc_struct ldt_desc;

typedef struct desc_struct tss_desc;

#define gate_offset(g)		(((g).b & 0xffff0000) | ((g).a & 0x0000ffff))

#define gate_segment(g)		((g).a >> 16)

#endif



struct idt_bits {

	u16		ist	: 3,

			zero	: 5,

			type	: 5,

			dpl	: 2,

			p	: 1;

} __attribute__((packed));



struct gate_struct {

	u16		offset_low;

	u16		segment;

	struct idt_bits	bits;

	u16		offset_middle;

#ifdef CONFIG_X86_64

	u32		offset_high;

	u32		reserved;

#endif

} __attribute__((packed));



typedef struct gate_struct gate_desc;



static inline unsigned long gate_offset(const gate_desc *g)

{

#ifdef CONFIG_X86_64

	return g->offset_low | ((unsigned long)g->offset_middle << 16) |

		((unsigned long) g->offset_high << 32);

#else

	return g->offset_low | ((unsigned long)g->offset_middle << 16);

#endif

}



static inline unsigned long gate_segment(const gate_desc *g)

{

	return g->segment;

}



struct desc_ptr {

	unsigned short size;

	unsigned long address;

arch/x86/kvm/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -8779,7 +8779,7 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu) 


		vector =  exit_intr_info & INTR_INFO_VECTOR_MASK;

		desc = (gate_desc *)vmx->host_idt_base + vector;

		entry = gate_offset(*desc);

		entry = gate_offset(desc);

		asm volatile(

#ifdef CONFIG_X86_64

			"mov %%" _ASM_SP ", %[sp]\n\t"

arch/x86/xen/enlighten_pv.c

+6 −6
Original line number Diff line number Diff line
@@ -584,12 +584,12 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val, 
{

	unsigned long addr;



	if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)

	if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)

		return 0;



	info->vector = vector;



	addr = gate_offset(*val);

	addr = gate_offset(val);

#ifdef CONFIG_X86_64

	/*

	 * Look for known traps using IST, and substitute them
@@ -622,16 +622,16 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val, 
		;

	else {

		/* Some other trap using IST? */

		if (WARN_ON(val->ist != 0))

		if (WARN_ON(val->bits.ist != 0))

			return 0;

	}

#endif	/* CONFIG_X86_64 */

	info->address = addr;



	info->cs = gate_segment(*val);

	info->flags = val->dpl;

	info->cs = gate_segment(val);

	info->flags = val->bits.dpl;

	/* interrupt gates clear IF */

	if (val->type == GATE_INTERRUPT)

	if (val->bits.type == GATE_INTERRUPT)

		info->flags |= 1 << 2;



	return 1;