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Commit 117780ee authored by H. Peter Anvin's avatar H. Peter Anvin Committed by H. Peter Anvin
Browse files

x86, asm: use bool for bitops and other assembly outputs 



The gcc people have confirmed that using "bool" when combined with
inline assembly always is treated as a byte-sized operand that can be
assumed to be 0 or 1, which is exactly what the SET instruction
emits.  Change the output types and intermediate variables of as many
operations as practical to "bool".

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-3-git-send-email-hpa@linux.intel.com


Reviewed-by: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
parent 2823d4da

arch/x86/boot/bitops.h

+5 −3
Original line number Diff line number Diff line
@@ -16,14 +16,16 @@ 
#define BOOT_BITOPS_H

#define _LINUX_BITOPS_H		/* Inhibit inclusion of <linux/bitops.h> */



static inline int constant_test_bit(int nr, const void *addr)

#include <linux/types.h>



static inline bool constant_test_bit(int nr, const void *addr)

{

	const u32 *p = (const u32 *)addr;

	return ((1UL << (nr & 31)) & (p[nr >> 5])) != 0;

}

static inline int variable_test_bit(int nr, const void *addr)

static inline bool variable_test_bit(int nr, const void *addr)

{

	u8 v;

	bool v;

	const u32 *p = (const u32 *)addr;



	asm("btl %2,%1; setc %0" : "=qm" (v) : "m" (*p), "Ir" (nr));

arch/x86/boot/boot.h

+4 −4
Original line number Diff line number Diff line
@@ -176,16 +176,16 @@ static inline void wrgs32(u32 v, addr_t addr) 
}



/* Note: these only return true/false, not a signed return value! */

static inline int memcmp_fs(const void *s1, addr_t s2, size_t len)

static inline bool memcmp_fs(const void *s1, addr_t s2, size_t len)

{

	u8 diff;

	bool diff;

	asm volatile("fs; repe; cmpsb; setnz %0"

		     : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));

	return diff;

}

static inline int memcmp_gs(const void *s1, addr_t s2, size_t len)

static inline bool memcmp_gs(const void *s1, addr_t s2, size_t len)

{

	u8 diff;

	bool diff;

	asm volatile("gs; repe; cmpsb; setnz %0"

		     : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));

	return diff;

arch/x86/boot/string.c

+1 −1
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 


int memcmp(const void *s1, const void *s2, size_t len)

{

	u8 diff;

	bool diff;

	asm("repe; cmpsb; setnz %0"

	    : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));

	return diff;

arch/x86/include/asm/apm.h

+3 −3
Original line number Diff line number Diff line
@@ -45,11 +45,11 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in, 
		: "memory", "cc");

}



static inline u8 apm_bios_call_simple_asm(u32 func, u32 ebx_in,

static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,

					    u32 ecx_in, u32 *eax)

{

	int	cx, dx, si;

	u8	error;

	bool	error;



	/*

	 * N.B. We do NOT need a cld after the BIOS call

arch/x86/include/asm/archrandom.h

+8 −8
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ 
#ifdef CONFIG_ARCH_RANDOM



/* Instead of arch_get_random_long() when alternatives haven't run. */

static inline int rdrand_long(unsigned long *v)

static inline bool rdrand_long(unsigned long *v)

{

	int ok;

	asm volatile("1: " RDRAND_LONG "\n\t"
@@ -53,13 +53,13 @@ static inline int rdrand_long(unsigned long *v) 
		     "2:"

		     : "=r" (ok), "=a" (*v)

		     : "0" (RDRAND_RETRY_LOOPS));

	return ok;

	return !!ok;

}



/* A single attempt at RDSEED */

static inline bool rdseed_long(unsigned long *v)

{

	unsigned char ok;

	bool ok;

	asm volatile(RDSEED_LONG "\n\t"

		     "setc %0"

		     : "=qm" (ok), "=a" (*v));
@@ -67,7 +67,7 @@ static inline bool rdseed_long(unsigned long *v) 
}



#define GET_RANDOM(name, type, rdrand, nop)			\

static inline int name(type *v)					\

static inline bool name(type *v)				\

{								\

	int ok;							\

	alternative_io("movl $0, %0\n\t"			\
@@ -80,13 +80,13 @@ static inline int name(type *v) \ 
		       X86_FEATURE_RDRAND,                      \

		       ASM_OUTPUT2("=r" (ok), "=a" (*v)),       \

		       "0" (RDRAND_RETRY_LOOPS));		\

	return ok;						\

	return !!ok;						\

}



#define GET_SEED(name, type, rdseed, nop)			\

static inline int name(type *v)					\

static inline bool name(type *v)				\

{								\

	unsigned char ok;					\

	bool ok;						\

	alternative_io("movb $0, %0\n\t"			\

		       nop,					\

		       rdseed "\n\t"				\
@@ -119,7 +119,7 @@ GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4); 


#else



static inline int rdrand_long(unsigned long *v)

static inline bool rdrand_long(unsigned long *v)

{

	return 0;

}