| Message ID | alpine.DEB.2.00.1210150523190.15973@utopia.booyaka.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Paul Walmsley <paul@pwsan.com> [121014 22:26]: > > After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix > saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board > started crashing during boot with omap2plus_defconfig: > > [ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB > [ 3.915954] mmcblk0: p1 > [ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM > [ 4.093719] Modules linked in: > [ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570) > [ 4.103149] PC is at vfp_reload_hw+0x1c/0x44 > [ 4.107666] LR is at __und_usr_fault_32+0x0/0x8 > > It turns out that the context save/restore fix unmasked a latent bug > in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make > VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is > booted on a pre-VFPv3 core, the code attempts to save and restore the > d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so > this results in an undefined instruction exception. The code didn't > crash before commit 846a136 because the save and restore code was > only touching d0-d15, present on all VFP. > > Fix by implementing a request from Russell King to add a new HWCAP > flag that affirmatively indicates the presence of the d16-d31 > registers: > > http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2 > > and some feedback from Måns to clarify the name of the HWCAP flag. > > Signed-off-by: Paul Walmsley <paul@pwsan.com> > Cc: Tony Lindgren <tony@atomide.com> > Cc: Russell King <rmk+kernel@arm.linux.org.uk> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Dave Martin <dave.martin@linaro.org> > Cc: Måns Rullgård <mans.rullgard@linaro.org> This fixes the error above on my 2430sdp: Tested-by: Tony Lindgren <tony@atomide.com>
On 10/15/2012 12:53 PM, Tony Lindgren wrote: > * Paul Walmsley <paul@pwsan.com> [121014 22:26]: >> >> After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix >> saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board >> started crashing during boot with omap2plus_defconfig: >> >> [ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB >> [ 3.915954] mmcblk0: p1 >> [ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM >> [ 4.093719] Modules linked in: >> [ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570) >> [ 4.103149] PC is at vfp_reload_hw+0x1c/0x44 >> [ 4.107666] LR is at __und_usr_fault_32+0x0/0x8 >> >> It turns out that the context save/restore fix unmasked a latent bug >> in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make >> VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is >> booted on a pre-VFPv3 core, the code attempts to save and restore the >> d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so >> this results in an undefined instruction exception. The code didn't >> crash before commit 846a136 because the save and restore code was >> only touching d0-d15, present on all VFP. >> >> Fix by implementing a request from Russell King to add a new HWCAP >> flag that affirmatively indicates the presence of the d16-d31 >> registers: >> >> http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2 >> >> and some feedback from Måns to clarify the name of the HWCAP flag. >> >> Signed-off-by: Paul Walmsley <paul@pwsan.com> >> Cc: Tony Lindgren <tony@atomide.com> >> Cc: Russell King <rmk+kernel@arm.linux.org.uk> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Dave Martin <dave.martin@linaro.org> >> Cc: Måns Rullgård <mans.rullgard@linaro.org> > > This fixes the error above on my 2430sdp: > > Tested-by: Tony Lindgren <tony@atomide.com> Fixes same error on 2420 H4. Tested-by: Jon Hunter <jon-hunter@ti.com> Cheers Jon
diff --git a/arch/arm/include/asm/vfpmacros.h b/arch/arm/include/asm/vfpmacros.h index 6a6f1e4..301c1db 100644 --- a/arch/arm/include/asm/vfpmacros.h +++ b/arch/arm/include/asm/vfpmacros.h @@ -27,9 +27,9 @@ #if __LINUX_ARM_ARCH__ <= 6 ldr \tmp, =elf_hwcap @ may not have MVFR regs ldr \tmp, [\tmp, #0] - tst \tmp, #HWCAP_VFPv3D16 - ldceql p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d16-d31} - addne \base, \base, #32*4 @ step over unused register space + tst \tmp, #HWCAP_VFPD32 + ldcnel p11, cr0, [\base],#32*4 @ FLDMIAD \base!, {d16-d31} + addeq \base, \base, #32*4 @ step over unused register space #else VFPFMRX \tmp, MVFR0 @ Media and VFP Feature Register 0 and \tmp, \tmp, #MVFR0_A_SIMD_MASK @ A_SIMD field @@ -51,9 +51,9 @@ #if __LINUX_ARM_ARCH__ <= 6 ldr \tmp, =elf_hwcap @ may not have MVFR regs ldr \tmp, [\tmp, #0] - tst \tmp, #HWCAP_VFPv3D16 - stceql p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d16-d31} - addne \base, \base, #32*4 @ step over unused register space + tst \tmp, #HWCAP_VFPD32 + stcnel p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d16-d31} + addeq \base, \base, #32*4 @ step over unused register space #else VFPFMRX \tmp, MVFR0 @ Media and VFP Feature Register 0 and \tmp, \tmp, #MVFR0_A_SIMD_MASK @ A_SIMD field diff --git a/arch/arm/include/uapi/asm/hwcap.h b/arch/arm/include/uapi/asm/hwcap.h index f254f65..3688fd1 100644 --- a/arch/arm/include/uapi/asm/hwcap.h +++ b/arch/arm/include/uapi/asm/hwcap.h @@ -18,11 +18,12 @@ #define HWCAP_THUMBEE (1 << 11) #define HWCAP_NEON (1 << 12) #define HWCAP_VFPv3 (1 << 13) -#define HWCAP_VFPv3D16 (1 << 14) +#define HWCAP_VFPv3D16 (1 << 14) /* also set for VFPv4-D16 */ #define HWCAP_TLS (1 << 15) #define HWCAP_VFPv4 (1 << 16) #define HWCAP_IDIVA (1 << 17) #define HWCAP_IDIVT (1 << 18) +#define HWCAP_VFPD32 (1 << 19) /* set if VFP has 32 regs (not 16) */ #define HWCAP_IDIV (HWCAP_IDIVA | HWCAP_IDIVT) diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index c834b32..3b44e0d 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -701,11 +701,14 @@ static int __init vfp_init(void) elf_hwcap |= HWCAP_VFPv3; /* - * Check for VFPv3 D16. CPUs in this configuration - * only have 16 x 64bit registers. + * Check for VFPv3 D16 and VFPv4 D16. CPUs in + * this configuration only have 16 x 64bit + * registers. */ if (((fmrx(MVFR0) & MVFR0_A_SIMD_MASK)) == 1) - elf_hwcap |= HWCAP_VFPv3D16; + elf_hwcap |= HWCAP_VFPv3D16; /* also v4-D16 */ + else + elf_hwcap |= HWCAP_VFPD32; } #endif /*
After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board started crashing during boot with omap2plus_defconfig: [ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB [ 3.915954] mmcblk0: p1 [ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM [ 4.093719] Modules linked in: [ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570) [ 4.103149] PC is at vfp_reload_hw+0x1c/0x44 [ 4.107666] LR is at __und_usr_fault_32+0x0/0x8 It turns out that the context save/restore fix unmasked a latent bug in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is booted on a pre-VFPv3 core, the code attempts to save and restore the d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so this results in an undefined instruction exception. The code didn't crash before commit 846a136 because the save and restore code was only touching d0-d15, present on all VFP. Fix by implementing a request from Russell King to add a new HWCAP flag that affirmatively indicates the presence of the d16-d31 registers: http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2 and some feedback from Måns to clarify the name of the HWCAP flag. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Tony Lindgren <tony@atomide.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Martin <dave.martin@linaro.org> Cc: Måns Rullgård <mans.rullgard@linaro.org> --- Thanks for the suggestion, Måns; certainly a readability improvement. arch/arm/include/asm/vfpmacros.h | 12 ++++++------ arch/arm/include/uapi/asm/hwcap.h | 3 ++- arch/arm/vfp/vfpmodule.c | 9 ++++++--- 3 files changed, 14 insertions(+), 10 deletions(-)