Commit 718f5d00 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

x86/fpu: Use bitfield accessors for desc_struct 



desc_struct is a union of u32 fields and bitfields. The access to the u32
fields is done with magic macros.

Convert it to use the bitfields and replace the macro magic with parseable
inline functions.

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/20170828064958.042406718@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1dd439fe

arch/x86/math-emu/fpu_entry.c

+5 −6
Original line number Diff line number Diff line
@@ -147,7 +147,7 @@ void math_emulate(struct math_emu_info *info) 
		}



		code_descriptor = FPU_get_ldt_descriptor(FPU_CS);

		if (SEG_D_SIZE(code_descriptor)) {

		if (code_descriptor.d) {

			/* The above test may be wrong, the book is not clear */

			/* Segmented 32 bit protected mode */

			addr_modes.default_mode = SEG32;
@@ -155,11 +155,10 @@ void math_emulate(struct math_emu_info *info) 
			/* 16 bit protected mode */

			addr_modes.default_mode = PM16;

		}

		FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor);

		code_limit = code_base

		    + (SEG_LIMIT(code_descriptor) +

		       1) * SEG_GRANULARITY(code_descriptor)

		    - 1;

		FPU_EIP += code_base = seg_get_base(&code_descriptor);

		code_limit = seg_get_limit(&code_descriptor) + 1;

		code_limit *= seg_get_granularity(&code_descriptor);

		code_limit += code_base - 1;

		if (code_limit < code_base)

			code_limit = 0xffffffff;

	}

arch/x86/math-emu/fpu_system.h

+37 −11
Original line number Diff line number Diff line
@@ -34,17 +34,43 @@ static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg) 
	return ret;

}



#define SEG_D_SIZE(x)		((x).b & (3 << 21))

#define SEG_G_BIT(x)		((x).b & (1 << 23))

#define SEG_GRANULARITY(x)	(((x).b & (1 << 23)) ? 4096 : 1)

#define SEG_286_MODE(x)		((x).b & ( 0xff000000 | 0xf0000 | (1 << 23)))

#define SEG_BASE_ADDR(s)	(((s).b & 0xff000000) \

				 | (((s).b & 0xff) << 16) | ((s).a >> 16))

#define SEG_LIMIT(s)		(((s).b & 0xff0000) | ((s).a & 0xffff))

#define SEG_EXECUTE_ONLY(s)	(((s).b & ((1 << 11) | (1 << 9))) == (1 << 11))

#define SEG_WRITE_PERM(s)	(((s).b & ((1 << 11) | (1 << 9))) == (1 << 9))

#define SEG_EXPAND_DOWN(s)	(((s).b & ((1 << 11) | (1 << 10))) \

				 == (1 << 10))

#define SEG_TYPE_WRITABLE	(1U << 1)

#define SEG_TYPE_EXPANDS_DOWN	(1U << 2)

#define SEG_TYPE_EXECUTE	(1U << 3)

#define SEG_TYPE_EXPAND_MASK	(SEG_TYPE_EXPANDS_DOWN | SEG_TYPE_EXECUTE)

#define SEG_TYPE_EXECUTE_MASK	(SEG_TYPE_WRITABLE | SEG_TYPE_EXECUTE)



static inline unsigned long seg_get_base(struct desc_struct *d)

{

	unsigned long base = (unsigned long)d->base2 << 24;



	return base | ((unsigned long)d->base1 << 16) | d->base0;

}



static inline unsigned long seg_get_limit(struct desc_struct *d)

{

	return ((unsigned long)d->limit << 16) | d->limit0;

}



static inline unsigned long seg_get_granularity(struct desc_struct *d)

{

	return d->g ? 4096 : 1;

}



static inline bool seg_expands_down(struct desc_struct *d)

{

	return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN;

}



static inline bool seg_execute_only(struct desc_struct *d)

{

	return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE;

}



static inline bool seg_writable(struct desc_struct *d)

{

	return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE;

}



#define I387			(&current->thread.fpu.state)

#define FPU_info		(I387->soft.info)

arch/x86/math-emu/get_address.c

+9 −8
Original line number Diff line number Diff line
@@ -159,17 +159,18 @@ static long pm_address(u_char FPU_modrm, u_char segment, 
	}



	descriptor = FPU_get_ldt_descriptor(addr->selector);

	base_address = SEG_BASE_ADDR(descriptor);

	base_address = seg_get_base(&descriptor);

	address = base_address + offset;

	limit = base_address

	    + (SEG_LIMIT(descriptor) + 1) * SEG_GRANULARITY(descriptor) - 1;

	limit = seg_get_limit(&descriptor) + 1;

	limit *= seg_get_granularity(&descriptor);

	limit += base_address - 1;

	if (limit < base_address)

		limit = 0xffffffff;



	if (SEG_EXPAND_DOWN(descriptor)) {

		if (SEG_G_BIT(descriptor))

	if (seg_expands_down(&descriptor)) {

		if (descriptor.g) {

			seg_top = 0xffffffff;

		else {

		} else {

			seg_top = base_address + (1 << 20);

			if (seg_top < base_address)

				seg_top = 0xffffffff;
@@ -182,8 +183,8 @@ static long pm_address(u_char FPU_modrm, u_char segment, 
		    (address > limit) || (address < base_address) ? 0 :

		    ((limit - address) >= 254 ? 255 : limit - address + 1);

	}

	if (SEG_EXECUTE_ONLY(descriptor) ||

	    (!SEG_WRITE_PERM(descriptor) && (FPU_modrm & FPU_WRITE_BIT))) {

	if (seg_execute_only(&descriptor) ||

	    (!seg_writable(&descriptor) && (FPU_modrm & FPU_WRITE_BIT))) {

		access_limit = 0;

	}

	return address;

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