From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54551) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S60t3-00031H-8D for qemu-devel@nongnu.org; Fri, 09 Mar 2012 09:34:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S60st-0003HT-0f for qemu-devel@nongnu.org; Fri, 09 Mar 2012 09:33:40 -0500 Received: from mnementh.archaic.org.uk ([81.2.115.146]:43330) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S60ss-0003GO-Oo for qemu-devel@nongnu.org; Fri, 09 Mar 2012 09:33:30 -0500 From: Peter Maydell Date: Fri, 9 Mar 2012 14:33:20 +0000 Message-Id: <1331303600-30715-1-git-send-email-peter.maydell@linaro.org> Subject: [Qemu-devel] [PATCH] cpu-all.h: Don't accidentally sign extend in g2h() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Riku Voipio , Alexander Graf , patches@linaro.org Cast the argument of the g2h() macro to a target_ulong so that it isn't accidentally sign-extended if it is a signed 32 bit type and long is a 64 bit type. In particular, this fixes a bug where it would return the wrong value for 32 bit guests on 64 bit hosts when passed in one of the arg* values from do_syscall() [which are all abi_long and thus signed types]. This could result in spurious failure of mlock(), among others. Signed-off-by: Peter Maydell --- This should be committed before Alex's patch to make mmap allocate downwards (http://patchwork.ozlabs.org/patch/144476/) because that hugely increases the chances that g2h will get passed a pointer that has the high bit set. cpu-all.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/cpu-all.h b/cpu-all.h index 80e6d42..a174532 100644 --- a/cpu-all.h +++ b/cpu-all.h @@ -197,7 +197,7 @@ extern unsigned long reserved_va; #endif /* All direct uses of g2h and h2g need to go away for usermode softmmu. */ -#define g2h(x) ((void *)((unsigned long)(x) + GUEST_BASE)) +#define g2h(x) ((void *)((unsigned long)(target_ulong)(x) + GUEST_BASE)) #if HOST_LONG_BITS <= TARGET_VIRT_ADDR_SPACE_BITS #define h2g_valid(x) 1 -- 1.7.1