Commit 75e2f0a6 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Ingo Molnar
Browse files

x86/fpu/math-emu: Fix possible uninitialized variable use 



When building the kernel with "make EXTRA_CFLAGS=...", this overrides
the "PARANOID" preprocessor macro defined in arch/x86/math-emu/Makefile,
and we run into a build warning:

  arch/x86/math-emu/reg_compare.c: In function ‘compare_i_st_st’:
  arch/x86/math-emu/reg_compare.c:254:6: error: ‘f’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

This fixes the implementation to work correctly even without the PARANOID
flag, and also fixes the Makefile to not use the EXTRA_CFLAGS variable
but instead use the ccflags-y variable in the Makefile that is meant
for this purpose.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Bill Metzenthen <billm@melbpc.org.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170719125310.2487451-3-arnd@arndb.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 11d8b058

arch/x86/math-emu/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -5,8 +5,8 @@ 
#DEBUG	= -DDEBUGGING

DEBUG	=

PARANOID = -DPARANOID

EXTRA_CFLAGS	:= $(PARANOID) $(DEBUG) -fno-builtin $(MATH_EMULATION)

EXTRA_AFLAGS	:= $(PARANOID)

ccflags-y += $(PARANOID) $(DEBUG) -fno-builtin $(MATH_EMULATION)

asflags-y += $(PARANOID)



# From 'C' language sources:

C_OBJS =fpu_entry.o errors.o \

arch/x86/math-emu/reg_compare.c

+8 −8
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ static int compare(FPU_REG const *b, int tagb) 
/* This function requires that st(0) is not empty */

int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag)

{

	int f = 0, c;

	int f, c;



	c = compare(loaded_data, loaded_tag);
@@ -189,12 +189,12 @@ int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag) 
		case COMP_No_Comp:

			f = SW_C3 | SW_C2 | SW_C0;

			break;

#ifdef PARANOID

		default:

#ifdef PARANOID

			EXCEPTION(EX_INTERNAL | 0x121);

#endif /* PARANOID */

			f = SW_C3 | SW_C2 | SW_C0;

			break;

#endif /* PARANOID */

		}

	setcc(f);

	if (c & COMP_Denormal) {
@@ -205,7 +205,7 @@ int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag) 


static int compare_st_st(int nr)

{

	int f = 0, c;

	int f, c;

	FPU_REG *st_ptr;



	if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
@@ -235,12 +235,12 @@ static int compare_st_st(int nr) 
		case COMP_No_Comp:

			f = SW_C3 | SW_C2 | SW_C0;

			break;

#ifdef PARANOID

		default:

#ifdef PARANOID

			EXCEPTION(EX_INTERNAL | 0x122);

#endif /* PARANOID */

			f = SW_C3 | SW_C2 | SW_C0;

			break;

#endif /* PARANOID */

		}

	setcc(f);

	if (c & COMP_Denormal) {
@@ -283,12 +283,12 @@ static int compare_i_st_st(int nr) 
	case COMP_No_Comp:

		f = X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF;

		break;

#ifdef PARANOID

	default:

#ifdef PARANOID

		EXCEPTION(EX_INTERNAL | 0x122);

#endif /* PARANOID */

		f = 0;

		break;

#endif /* PARANOID */

	}

	FPU_EFLAGS = (FPU_EFLAGS & ~(X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF)) | f;

	if (c & COMP_Denormal) {

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