From 4c07f9046e48c3126978911239e20a5622ad0ad6 Mon Sep 17 00:00:00 2001 From: Roman Kagan Date: Mon, 17 Jul 2017 12:49:07 +0300 Subject: x86/mm, KVM: Fix warning when !CONFIG_PREEMPT_COUNT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A recent commit: d6e41f1151fe ("x86/mm, KVM: Teach KVM's VMX code that CR3 isn't a constant") introduced a VM_WARN_ON(!in_atomic()) which generates false positives on every VM entry on !CONFIG_PREEMPT_COUNT kernels. Replace it with a test for preemptible(), which appears to match the original intent and works across different CONFIG_PREEMPT* variations. Signed-off-by: Roman Kagan Cc: Andrew Morton Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dave Hansen Cc: Linus Torvalds Cc: Mel Gorman Cc: Michal Hocko Cc: Nadav Amit Cc: Nadav Amit Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Thomas Gleixner Cc: kvm@vger.kernel.org Cc: linux-mm@kvack.org Fixes: d6e41f1151fe ("x86/mm, KVM: Teach KVM's VMX code that CR3 isn't a constant") Signed-off-by: Ingo Molnar --- arch/x86/include/asm/mmu_context.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index ecfcb6643c9b..265c907d7d4c 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -293,7 +293,7 @@ static inline unsigned long __get_current_cr3_fast(void) unsigned long cr3 = __pa(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd); /* For now, be very restrictive about when this can be called. */ - VM_WARN_ON(in_nmi() || !in_atomic()); + VM_WARN_ON(in_nmi() || preemptible()); VM_BUG_ON(cr3 != __read_cr3()); return cr3; -- cgit v1.2.3 From 7206f9bf108eb9513d170c73f151367a1bdf3dbf Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 19 Jul 2017 14:53:02 +0200 Subject: x86/io: Add "memory" clobber to insb/insw/insl/outsb/outsw/outsl MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The x86 version of insb/insw/insl uses an inline assembly that does not have the target buffer listed as an output. This can confuse the compiler, leading it to think that a subsequent access of the buffer is uninitialized: drivers/net/wireless/wl3501_cs.c: In function ‘wl3501_mgmt_scan_confirm’: drivers/net/wireless/wl3501_cs.c:665:9: error: ‘sig.status’ is used uninitialized in this function [-Werror=uninitialized] drivers/net/wireless/wl3501_cs.c:668:12: error: ‘sig.cap_info’ may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/net/sb1000.c: In function 'sb1000_rx': drivers/net/sb1000.c:775:9: error: 'st[0]' is used uninitialized in this function [-Werror=uninitialized] drivers/net/sb1000.c:776:10: error: 'st[1]' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/net/sb1000.c:784:11: error: 'st[1]' may be used uninitialized in this function [-Werror=maybe-uninitialized] I tried to mark the exact input buffer as an output here, but couldn't figure it out. As suggested by Linus, marking all memory as clobbered however is good enough too. For the outs operations, I also add the memory clobber, to force the input to be written to local variables. This is probably already guaranteed by the "asm volatile", but it can't hurt to do this for symmetry. Suggested-by: Linus Torvalds Signed-off-by: Arnd Bergmann Acked-by: Linus Torvalds Cc: Borislav Petkov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tom Lendacky Link: http://lkml.kernel.org/r/20170719125310.2487451-5-arnd@arndb.de Link: https://lkml.org/lkml/2017/7/12/605 Signed-off-by: Ingo Molnar --- arch/x86/include/asm/io.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 7afb0e2f07f4..48febf07e828 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -328,13 +328,13 @@ static inline unsigned type in##bwl##_p(int port) \ static inline void outs##bwl(int port, const void *addr, unsigned long count) \ { \ asm volatile("rep; outs" #bwl \ - : "+S"(addr), "+c"(count) : "d"(port)); \ + : "+S"(addr), "+c"(count) : "d"(port) : "memory"); \ } \ \ static inline void ins##bwl(int port, void *addr, unsigned long count) \ { \ asm volatile("rep; ins" #bwl \ - : "+D"(addr), "+c"(count) : "d"(port)); \ + : "+D"(addr), "+c"(count) : "d"(port) : "memory"); \ } BUILDIO(b, b, char) -- cgit v1.2.3