From: tip-bot for Arnd Bergmann <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: hpa@zytor.com, linux-kernel@vger.kernel.org,
peterz@infradead.org, billm@melbpc.org.au, arnd@arndb.de,
torvalds@linux-foundation.org, tglx@linutronix.de,
mingo@kernel.org
Subject: [tip:x86/urgent] x86/fpu/math-emu: Fix possible uninitialized variable use
Date: Thu, 20 Jul 2017 03:25:08 -0700 [thread overview]
Message-ID: <tip-75e2f0a6b16141cb347f442033ec907380d4d66e@git.kernel.org> (raw)
In-Reply-To: <20170719125310.2487451-3-arnd@arndb.de>
Commit-ID: 75e2f0a6b16141cb347f442033ec907380d4d66e
Gitweb: http://git.kernel.org/tip/75e2f0a6b16141cb347f442033ec907380d4d66e
Author: Arnd Bergmann <arnd@arndb.de>
AuthorDate: Wed, 19 Jul 2017 14:53:00 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 20 Jul 2017 10:46:24 +0200
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: Arnd 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: Ingo Molnar <mingo@kernel.org>
---
arch/x86/math-emu/Makefile | 4 ++--
arch/x86/math-emu/reg_compare.c | 16 ++++++++--------
2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/arch/x86/math-emu/Makefile b/arch/x86/math-emu/Makefile
index 9b0c63b..1b2dac1 100644
--- a/arch/x86/math-emu/Makefile
+++ b/arch/x86/math-emu/Makefile
@@ -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 \
diff --git a/arch/x86/math-emu/reg_compare.c b/arch/x86/math-emu/reg_compare.c
index b77360f..19b33b5 100644
--- a/arch/x86/math-emu/reg_compare.c
+++ b/arch/x86/math-emu/reg_compare.c
@@ -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) {
next prev parent reply other threads:[~2017-07-20 10:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-19 12:52 [PATCH 0/8] x86: randconfig warning fixes Arnd Bergmann
2017-07-19 12:52 ` [PATCH 1/8] perf/x86: shut up false-positive -Wmaybe-uninitialized warning Arnd Bergmann
2017-07-20 10:24 ` [tip:x86/urgent] perf/x86: Shut " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 2/8] x86: math-emu: possible uninitialized variable use Arnd Bergmann
2017-07-20 10:25 ` tip-bot for Arnd Bergmann [this message]
2017-07-19 12:53 ` [PATCH 3/8] x86: math-emu: avoid bogus -Wint-in-bool-context warning Arnd Bergmann
2017-07-20 10:25 ` [tip:x86/urgent] x86/fpu/math-emu: Avoid " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 4/8] x86: io: add "memory" clobber to insb/insw/insl/outsb/outsw/outsl Arnd Bergmann
2017-07-19 19:25 ` Arnd Bergmann
2017-07-19 19:46 ` Linus Torvalds
2017-07-20 10:25 ` [tip:x86/urgent] x86/io: Add " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 5/8] x86: silence build with "make -s" Arnd Bergmann
2017-07-20 10:26 ` [tip:x86/urgent] x86/build: Silence the " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 6/8] x86: add MULTIUSER dependency for KVM Arnd Bergmann
2017-07-19 14:11 ` Radim Krčmář
2017-07-19 14:18 ` Arnd Bergmann
2017-07-19 16:13 ` Radim Krčmář
2017-07-23 13:41 ` Paolo Bonzini
2017-07-19 12:53 ` [PATCH 7/8] x86: add PCI dependency for PUNIT_ATOM_DEBUG Arnd Bergmann
2017-07-20 10:26 ` [tip:x86/urgent] x86/platform: Add " tip-bot for Arnd Bergmann
2017-07-19 12:53 ` [PATCH 8/8] x86: intel-mid: fix a format string overflow warning Arnd Bergmann
2017-07-20 10:27 ` [tip:x86/urgent] x86/platform/intel-mid: Fix " tip-bot for Arnd Bergmann
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