From patchwork Thu Nov 15 05:49:26 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [3.5.yuz, extended, stable] Patch "ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels" has been added to staging queue From: Herton Ronaldo Krzesinski X-Patchwork-Id: 199170 Message-Id: <1352958566-16775-1-git-send-email-herton.krzesinski@canonical.com> To: Russell King Cc: kernel-team@lists.ubuntu.com Date: Thu, 15 Nov 2012 03:49:26 -0200 This is a note to let you know that I have just added a patch titled ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.yuz tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ >From 16d7899c2e7e39308cc736f1269103b6a77a5c28 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 9 Oct 2012 11:13:26 +0100 Subject: [PATCH] ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 upstream. Michael Olbrich reported that his test program fails when built with -O2 -mcpu=cortex-a8 -mfpu=neon, and a kernel which supports v6 and v7 CPUs: volatile int x = 2; volatile int64_t y = 2; int main() { volatile int a = 0; volatile int64_t b = 0; while (1) { a = (a + x) % (1 << 30); b = (b + y) % (1 << 30); assert(a == b); } } and two instances are run. When built for just v7 CPUs, this program works fine. It uses the "vadd.i64 d19, d18, d16" VFP instruction. It appears that we do not save the high-16 double VFP registers across context switches when the kernel is built for v6 CPUs. Fix that. Tested-By: Michael Olbrich Signed-off-by: Russell King Signed-off-by: Herton Ronaldo Krzesinski --- arch/arm/include/asm/vfpmacros.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 1.7.9.5 diff --git a/arch/arm/include/asm/vfpmacros.h b/arch/arm/include/asm/vfpmacros.h index 3d5fc41..bf53047 100644 --- a/arch/arm/include/asm/vfpmacros.h +++ b/arch/arm/include/asm/vfpmacros.h @@ -28,7 +28,7 @@ ldr \tmp, =elf_hwcap @ may not have MVFR regs ldr \tmp, [\tmp, #0] tst \tmp, #HWCAP_VFPv3D16 - ldceq p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d16-d31} + ldceql p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d16-d31} addne \base, \base, #32*4 @ step over unused register space #else VFPFMRX \tmp, MVFR0 @ Media and VFP Feature Register 0 @@ -52,7 +52,7 @@ ldr \tmp, =elf_hwcap @ may not have MVFR regs ldr \tmp, [\tmp, #0] tst \tmp, #HWCAP_VFPv3D16 - stceq p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d16-d31} + stceql p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d16-d31} addne \base, \base, #32*4 @ step over unused register space #else VFPFMRX \tmp, MVFR0 @ Media and VFP Feature Register 0