From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x22f.google.com (mail-ob0-x22f.google.com [IPv6:2607:f8b0:4003:c01::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 32CE22C04FC for ; Fri, 1 Nov 2013 05:39:55 +1100 (EST) Received: by mail-ob0-f175.google.com with SMTP id wm4so3462046obc.6 for ; Thu, 31 Oct 2013 11:39:53 -0700 (PDT) From: Tom To: linuxppc-dev@lists.ozlabs.org Subject: [V2 PATCH 3/3] powerpc: Fix Unaligned LE Floating Point Loads and Stores Date: Thu, 31 Oct 2013 13:38:58 -0500 Message-Id: <1383244738-5986-4-git-send-email-tommusta@gmail.com> In-Reply-To: <1383244738-5986-1-git-send-email-tommusta@gmail.com> References: <1383244738-5986-1-git-send-email-tommusta@gmail.com> Cc: Tom Musta List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Tom Musta This patch addresses unaligned single precision floating point loads and stores in the single-step code. The old implementation improperly treated an 8 byte structure as an array of two 4 byte words, which is a classic little endian bug. Signed-off-by: Tom Musta --- arch/powerpc/lib/sstep.c | 52 +++++++++++++++++++++++++++++++++++---------- 1 files changed, 40 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index c8743e1..1cfd150 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -355,22 +355,36 @@ static int __kprobes do_fp_load(int rn, int (*func)(int, unsigned long), struct pt_regs *regs) { int err; - unsigned long val[sizeof(double) / sizeof(long)]; + union { + double dbl; + unsigned long ul[2]; + struct { +#ifdef __BIG_ENDIAN__ + unsigned _pad_; + unsigned word; +#endif +#ifdef __LITTLE_ENDIAN__ + unsigned word; + unsigned _pad_; +#endif + } single; + } data; unsigned long ptr; if (!address_ok(regs, ea, nb)) return -EFAULT; if ((ea & 3) == 0) return (*func)(rn, ea); - ptr = (unsigned long) &val[0]; + ptr = (unsigned long) &data.ul; if (sizeof(unsigned long) == 8 || nb == 4) { - err = read_mem_unaligned(&val[0], ea, nb, regs); - ptr += sizeof(unsigned long) - nb; + err = read_mem_unaligned(&data.ul[0], ea, nb, regs); + if (nb == 4) + ptr = (unsigned long)&(data.single.word); } else { /* reading a double on 32-bit */ - err = read_mem_unaligned(&val[0], ea, 4, regs); + err = read_mem_unaligned(&data.ul[0], ea, 4, regs); if (!err) - err = read_mem_unaligned(&val[1], ea + 4, 4, regs); + err = read_mem_unaligned(&data.ul[1], ea + 4, 4, regs); } if (err) return err; @@ -382,28 +396,42 @@ static int __kprobes do_fp_store(int rn, int (*func)(int, unsigned long), struct pt_regs *regs) { int err; - unsigned long val[sizeof(double) / sizeof(long)]; + union { + double dbl; + unsigned long ul[2]; + struct { +#ifdef __BIG_ENDIAN__ + unsigned _pad_; + unsigned word; +#endif +#ifdef __LITTLE_ENDIAN__ + unsigned word; + unsigned _pad_; +#endif + } single; + } data; unsigned long ptr; if (!address_ok(regs, ea, nb)) return -EFAULT; if ((ea & 3) == 0) return (*func)(rn, ea); - ptr = (unsigned long) &val[0]; + ptr = (unsigned long) &data.ul[0]; if (sizeof(unsigned long) == 8 || nb == 4) { - ptr += sizeof(unsigned long) - nb; + if (nb == 4) + ptr = (unsigned long)&(data.single.word); err = (*func)(rn, ptr); if (err) return err; - err = write_mem_unaligned(val[0], ea, nb, regs); + err = write_mem_unaligned(data.ul[0], ea, nb, regs); } else { /* writing a double on 32-bit */ err = (*func)(rn, ptr); if (err) return err; - err = write_mem_unaligned(val[0], ea, 4, regs); + err = write_mem_unaligned(data.ul[0], ea, 4, regs); if (!err) - err = write_mem_unaligned(val[1], ea + 4, 4, regs); + err = write_mem_unaligned(data.ul[1], ea + 4, 4, regs); } return err; } -- 1.7.1