* [PATCH v2 01/15] xen/arm: Makefile: Sort the entries alphabetically
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 02/15] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h Julien Grall
` (13 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v2:
- Add Stefano's acked-by
---
xen/arch/arm/Makefile | 38 ++++++++++++++++++++------------------
xen/arch/arm/arm32/Makefile | 9 ++++-----
xen/arch/arm/arm64/Makefile | 12 +++++-------
xen/arch/arm/platforms/Makefile | 2 +-
4 files changed, 30 insertions(+), 31 deletions(-)
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index ead0cc0..8e0d2f6 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -4,42 +4,44 @@ subdir-y += platforms
subdir-$(CONFIG_ARM_64) += efi
subdir-$(CONFIG_ACPI) += acpi
-obj-$(EARLY_PRINTK) += early_printk.o
+obj-y += bootfdt.o
obj-y += cpu.o
+obj-y += decode.o
+obj-y += device.o
obj-y += domain.o
-obj-y += psci.o
-obj-y += vpsci.o
-obj-y += domctl.o
-obj-y += sysctl.o
obj-y += domain_build.o
-obj-y += gic.o gic-v2.o
+obj-y += domctl.o
+obj-$(EARLY_PRINTK) += early_printk.o
+obj-y += gic.o
+obj-y += gic-v2.o
obj-$(CONFIG_HAS_GICV3) += gic-v3.o
+obj-y += guestcopy.o
+obj-y += hvm.o
obj-y += io.o
obj-y += irq.o
obj-y += kernel.o
obj-y += mm.o
obj-y += p2m.o
obj-y += percpu.o
-obj-y += guestcopy.o
-obj-y += physdev.o
obj-y += platform.o
obj-y += platform_hypercall.o
+obj-y += physdev.o
+obj-y += processor.o
+obj-y += psci.o
obj-y += setup.o
-obj-y += bootfdt.o
-obj-y += time.o
-obj-y += smpboot.o
-obj-y += smp.o
obj-y += shutdown.o
+obj-y += smc.o
+obj-y += smp.o
+obj-y += smpboot.o
+obj-y += sysctl.o
+obj-y += time.o
obj-y += traps.o
-obj-y += vgic.o vgic-v2.o
+obj-y += vgic.o
+obj-y += vgic-v2.o
obj-$(CONFIG_ARM_64) += vgic-v3.o
obj-y += vtimer.o
+obj-y += vpsci.o
obj-y += vuart.o
-obj-y += hvm.o
-obj-y += device.o
-obj-y += decode.o
-obj-y += processor.o
-obj-y += smc.o
obj-$(CONFIG_XSPLICE) += xsplice.o
#obj-bin-y += ....o
diff --git a/xen/arch/arm/arm32/Makefile b/xen/arch/arm/arm32/Makefile
index df0e7de..b20db64 100644
--- a/xen/arch/arm/arm32/Makefile
+++ b/xen/arch/arm/arm32/Makefile
@@ -1,12 +1,11 @@
subdir-y += lib
+obj-$(EARLY_PRINTK) += debug.o
+obj-y += domctl.o
+obj-y += domain.o
obj-y += entry.o
obj-y += proc-v7.o proc-caxx.o
-
+obj-y += smpboot.o
obj-y += traps.o
-obj-y += domain.o
obj-y += vfp.o
-obj-y += smpboot.o
-obj-y += domctl.o
-obj-$(EARLY_PRINTK) += debug.o
diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
index c7243f5..39c6ac6 100644
--- a/xen/arch/arm/arm64/Makefile
+++ b/xen/arch/arm/arm64/Makefile
@@ -1,12 +1,10 @@
subdir-y += lib
+obj-y += cache.o
+obj-$(EARLY_PRINTK) += debug.o
+obj-y += domctl.o
+obj-y += domain.o
obj-y += entry.o
-
+obj-y += smpboot.o
obj-y += traps.o
-obj-y += domain.o
obj-y += vfp.o
-obj-y += smpboot.o
-obj-y += domctl.o
-obj-y += cache.o
-
-obj-$(EARLY_PRINTK) += debug.o
diff --git a/xen/arch/arm/platforms/Makefile b/xen/arch/arm/platforms/Makefile
index 3689eec..49fa683 100644
--- a/xen/arch/arm/platforms/Makefile
+++ b/xen/arch/arm/platforms/Makefile
@@ -3,8 +3,8 @@ obj-$(CONFIG_ARM_32) += brcm.o
obj-$(CONFIG_ARM_32) += exynos5.o
obj-$(CONFIG_ARM_32) += midway.o
obj-$(CONFIG_ARM_32) += omap5.o
-obj-$(CONFIG_ARM_32) += sunxi.o
obj-$(CONFIG_ARM_32) += rcar2.o
obj-$(CONFIG_ARM_64) += seattle.o
+obj-$(CONFIG_ARM_32) += sunxi.o
obj-$(CONFIG_ARM_64) += xgene-storm.o
obj-$(CONFIG_ARM_64) += xilinx-zynqmp.o
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 02/15] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-05-23 14:17 ` [PATCH v2 01/15] xen/arm: Makefile: Sort the entries alphabetically Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 03/15] xen/arm: Add macros to handle the MIDR Julien Grall
` (12 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
The header asm-arm/page.h makes use of the macro dsb defined in the header
asm-arm/system.h. Currently, the includer has to specify both of them.
This can be avoided by including asm-arm/system.h in asm-arm/page.h.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v2:
- Add Stefano's acked-by
---
xen/include/asm-arm/page.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index a94e978..05d9f82 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -84,6 +84,7 @@
#include <xen/errno.h>
#include <xen/types.h>
#include <xen/lib.h>
+#include <asm/system.h>
/* WARNING! Unlike the Intel pagetable code, where l1 is the lowest
* level and l4 is the root of the trie, the ARM pagetables follow ARM's
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 03/15] xen/arm: Add macros to handle the MIDR
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-05-23 14:17 ` [PATCH v2 01/15] xen/arm: Makefile: Sort the entries alphabetically Julien Grall
2016-05-23 14:17 ` [PATCH v2 02/15] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 04/15] xen/arm: Add cpu_hwcap bitmap Julien Grall
` (11 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
Add new macros to easily get different parts of the register and to
check if a given MIDR match a CPU model range. The latter will be really
useful to handle errata later.
The macros have been imported from the header
arch/arm64/include/asm/cputype.h in Linux v4.6-rc3.
Also remove MIDR_MASK which is unused.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v2:
- Add Stefano's acked-by
---
xen/include/asm-arm/processor.h | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 6789cd0..1b701c5 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -9,7 +9,40 @@
#include <public/arch-arm.h>
/* MIDR Main ID Register */
-#define MIDR_MASK 0xff0ffff0
+#define MIDR_REVISION_MASK 0xf
+#define MIDR_RESIVION(midr) ((midr) & MIDR_REVISION_MASK)
+#define MIDR_PARTNUM_SHIFT 4
+#define MIDR_PARTNUM_MASK (0xfff << MIDR_PARTNUM_SHIFT)
+#define MIDR_PARTNUM(midr) \
+ (((midr) & MIDR_PARTNUM_MASK) >> MIDR_PARTNUM_SHIFT)
+#define MIDR_ARCHITECTURE_SHIFT 16
+#define MIDR_ARCHITECTURE_MASK (0xf << MIDR_ARCHITECTURE_SHIFT)
+#define MIDR_ARCHITECTURE(midr) \
+ (((midr) & MIDR_ARCHITECTURE_MASK) >> MIDR_ARCHITECTURE_SHIFT)
+#define MIDR_VARIANT_SHIFT 20
+#define MIDR_VARIANT_MASK (0xf << MIDR_VARIANT_SHIFT)
+#define MIDR_VARIANT(midr) \
+ (((midr) & MIDR_VARIANT_MASK) >> MIDR_VARIANT_SHIFT)
+#define MIDR_IMPLEMENTOR_SHIFT 24
+#define MIDR_IMPLEMENTOR_MASK (0xff << MIDR_IMPLEMENTOR_SHIFT)
+#define MIDR_IMPLEMENTOR(midr) \
+ (((midr) & MIDR_IMPLEMENTOR_MASK) >> MIDR_IMPLEMENTOR_SHIFT)
+
+#define MIDR_CPU_MODEL(imp, partnum) \
+ (((imp) << MIDR_IMPLEMENTOR_SHIFT) | \
+ (0xf << MIDR_ARCHITECTURE_SHIFT) | \
+ ((partnum) << MIDR_PARTNUM_SHIFT))
+
+#define MIDR_CPU_MODEL_MASK \
+ (MIDR_IMPLEMENTOR_MASK | MIDR_PARTNUM_MASK | MIDR_ARCHITECTURE_MASK)
+
+#define MIDR_IS_CPU_MODEL_RANGE(midr, model, rv_min, rv_max) \
+({ \
+ u32 _model = (midr) & MIDR_CPU_MODEL_MASK; \
+ u32 _rv = (midr) & (MIDR_REVISION_MASK | MIDR_VARIANT_MASK); \
+ \
+ _model == (model) && _rv >= (rv_min) && _rv <= (rv_max); \
+})
/* MPIDR Multiprocessor Affinity Register */
#define _MPIDR_UP (30)
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 04/15] xen/arm: Add cpu_hwcap bitmap
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (2 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 03/15] xen/arm: Add macros to handle the MIDR Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-30 14:19 ` Stefano Stabellini
2016-05-23 14:17 ` [PATCH v2 05/15] xen/arm64: Add an helper to invalidate all instruction caches Julien Grall
` (10 subsequent siblings)
14 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
This will be used to know if a feature, which Xen cares, is available accross
all the CPUs.
This code is a light version of arch/arm64/kernel/cpufeature.c from
Linux v4.6-rc3.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
xen/arch/arm/Makefile | 1 +
xen/arch/arm/cpufeature.c | 34 ++++++++++++++++++++++++++++++++++
xen/include/asm-arm/cpufeature.h | 29 +++++++++++++++++++++++++++++
3 files changed, 64 insertions(+)
create mode 100644 xen/arch/arm/cpufeature.c
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 8e0d2f6..9122f78 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -6,6 +6,7 @@ subdir-$(CONFIG_ACPI) += acpi
obj-y += bootfdt.o
obj-y += cpu.o
+obj-y += cpufeature.o
obj-y += decode.o
obj-y += device.o
obj-y += domain.o
diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
new file mode 100644
index 0000000..7a1b56b
--- /dev/null
+++ b/xen/arch/arm/cpufeature.c
@@ -0,0 +1,34 @@
+/*
+ * Contains CPU feature definitions
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/config.h>
+#include <xen/types.h>
+#include <xen/init.h>
+#include <xen/smp.h>
+#include <asm/cpufeature.h>
+
+DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 7b519cd..2bebad1 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -35,6 +35,35 @@
#endif
#define cpu_has_security (boot_cpu_feature32(security) > 0)
+#define ARM_NCAPS 0
+
+#ifndef __ASSEMBLY__
+
+#include <xen/types.h>
+#include <xen/lib.h>
+#include <xen/bitops.h>
+
+extern DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
+
+static inline bool_t cpus_have_cap(unsigned int num)
+{
+ if ( num >= ARM_NCAPS )
+ return 0;
+
+ return test_bit(num, cpu_hwcaps);
+}
+
+static inline void cpus_set_cap(unsigned int num)
+{
+ if (num >= ARM_NCAPS)
+ printk(XENLOG_WARNING "Attempt to set an illegal CPU capability (%d >= %d)\n",
+ num, ARM_NCAPS);
+ else
+ __set_bit(num, cpu_hwcaps);
+}
+
+#endif /* __ASSEMBLY__ */
+
#endif
/*
* Local variables:
--
1.9.1
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http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 04/15] xen/arm: Add cpu_hwcap bitmap
2016-05-23 14:17 ` [PATCH v2 04/15] xen/arm: Add cpu_hwcap bitmap Julien Grall
@ 2016-05-30 14:19 ` Stefano Stabellini
0 siblings, 0 replies; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 14:19 UTC (permalink / raw)
To: Julien Grall
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara, xen-devel, wei.chen
On Mon, 23 May 2016, Julien Grall wrote:
> This will be used to know if a feature, which Xen cares, is available accross
> all the CPUs.
>
> This code is a light version of arch/arm64/kernel/cpufeature.c from
> Linux v4.6-rc3.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/cpufeature.c | 34 ++++++++++++++++++++++++++++++++++
> xen/include/asm-arm/cpufeature.h | 29 +++++++++++++++++++++++++++++
> 3 files changed, 64 insertions(+)
> create mode 100644 xen/arch/arm/cpufeature.c
>
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 8e0d2f6..9122f78 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -6,6 +6,7 @@ subdir-$(CONFIG_ACPI) += acpi
>
> obj-y += bootfdt.o
> obj-y += cpu.o
> +obj-y += cpufeature.o
> obj-y += decode.o
> obj-y += device.o
> obj-y += domain.o
> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
> new file mode 100644
> index 0000000..7a1b56b
> --- /dev/null
> +++ b/xen/arch/arm/cpufeature.c
> @@ -0,0 +1,34 @@
> +/*
> + * Contains CPU feature definitions
> + *
> + * Copyright (C) 2015 ARM Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <xen/config.h>
> +#include <xen/types.h>
> +#include <xen/init.h>
> +#include <xen/smp.h>
> +#include <asm/cpufeature.h>
> +
> +DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
> index 7b519cd..2bebad1 100644
> --- a/xen/include/asm-arm/cpufeature.h
> +++ b/xen/include/asm-arm/cpufeature.h
> @@ -35,6 +35,35 @@
> #endif
> #define cpu_has_security (boot_cpu_feature32(security) > 0)
>
> +#define ARM_NCAPS 0
> +
> +#ifndef __ASSEMBLY__
> +
> +#include <xen/types.h>
> +#include <xen/lib.h>
> +#include <xen/bitops.h>
> +
> +extern DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
> +
> +static inline bool_t cpus_have_cap(unsigned int num)
> +{
> + if ( num >= ARM_NCAPS )
> + return 0;
> +
> + return test_bit(num, cpu_hwcaps);
> +}
> +
> +static inline void cpus_set_cap(unsigned int num)
> +{
> + if (num >= ARM_NCAPS)
> + printk(XENLOG_WARNING "Attempt to set an illegal CPU capability (%d >= %d)\n",
> + num, ARM_NCAPS);
> + else
> + __set_bit(num, cpu_hwcaps);
> +}
> +
> +#endif /* __ASSEMBLY__ */
> +
> #endif
> /*
> * Local variables:
> --
> 1.9.1
>
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^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v2 05/15] xen/arm64: Add an helper to invalidate all instruction caches
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (3 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 04/15] xen/arm: Add cpu_hwcap bitmap Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 06/15] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header Julien Grall
` (9 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v2:
- Add Stefano's acked-by
---
xen/include/asm-arm/arm64/page.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/xen/include/asm-arm/arm64/page.h b/xen/include/asm-arm/arm64/page.h
index 29a32cf..fbdc8fb 100644
--- a/xen/include/asm-arm/arm64/page.h
+++ b/xen/include/asm-arm/arm64/page.h
@@ -24,6 +24,12 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
* inline asm operand) */
#define __clean_and_invalidate_dcache_one(R) "dc civac, %" #R ";"
+/* Invalidate all instruction caches in Inner Shareable domain to PoU */
+static inline void invalidate_icache(void)
+{
+ asm volatile ("ic ialluis");
+}
+
/*
* Flush all hypervisor mappings from the TLB of the local processor.
*
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 06/15] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (4 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 05/15] xen/arm64: Add an helper to invalidate all instruction caches Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 07/15] xen/arm: arm64: Reserve a brk immediate to fault on purpose Julien Grall
` (8 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
New immediates will be defined in the future. To keep track of the
immediates allocated, gather all of them in a separate header.
Also rename BRK_BUG_FRAME to BKR_BUG_FRAME_IMM.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v2:
- Add Stefano's reviewed-by
---
xen/arch/arm/traps.c | 2 +-
xen/include/asm-arm/arm64/brk.h | 26 ++++++++++++++++++++++++++
xen/include/asm-arm/arm64/bug.h | 5 ++---
3 files changed, 29 insertions(+), 4 deletions(-)
create mode 100644 xen/include/asm-arm/arm64/brk.h
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 1828ea1..c0325d5 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1205,7 +1205,7 @@ static void do_trap_brk(struct cpu_user_regs *regs, const union hsr hsr)
switch (hsr.brk.comment)
{
- case BRK_BUG_FRAME:
+ case BRK_BUG_FRAME_IMM:
if ( do_bug_frame(regs, regs->pc) )
goto die;
diff --git a/xen/include/asm-arm/arm64/brk.h b/xen/include/asm-arm/arm64/brk.h
new file mode 100644
index 0000000..7867b07
--- /dev/null
+++ b/xen/include/asm-arm/arm64/brk.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2016 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ASM_ARM_ARM64_BRK
+#define __ASM_ARM_ARM64_BRK
+
+/*
+ * #imm16 values used for BRK instruction generation
+ * 0x001: xen-mode BUG() and WARN() traps
+ */
+#define BRK_BUG_FRAME_IMM 1
+
+#endif /* !__ASM_ARM_ARM64_BRK */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/arm64/bug.h b/xen/include/asm-arm/arm64/bug.h
index 42b0e4f..59f664d 100644
--- a/xen/include/asm-arm/arm64/bug.h
+++ b/xen/include/asm-arm/arm64/bug.h
@@ -2,9 +2,8 @@
#define __ARM_ARM64_BUG_H__
#include <xen/stringify.h>
+#include <asm/arm64/brk.h>
-#define BRK_BUG_FRAME 1
-
-#define BUG_INSTR "brk " __stringify(BRK_BUG_FRAME)
+#define BUG_INSTR "brk " __stringify(BRK_BUG_FRAME_IMM)
#endif /* __ARM_ARM64_BUG_H__ */
--
1.9.1
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 07/15] xen/arm: arm64: Reserve a brk immediate to fault on purpose
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (5 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 06/15] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 08/15] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
` (7 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
It may not possible to return a proper error when encoding an
instruction. Instead, a handcrafted instruction will be returned.
Also, provide the encoding for the faulting instruction.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v2:
- Add Stefano's acked-by
---
xen/include/asm-arm/arm64/brk.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/xen/include/asm-arm/arm64/brk.h b/xen/include/asm-arm/arm64/brk.h
index 7867b07..04442c4 100644
--- a/xen/include/asm-arm/arm64/brk.h
+++ b/xen/include/asm-arm/arm64/brk.h
@@ -12,8 +12,21 @@
/*
* #imm16 values used for BRK instruction generation
* 0x001: xen-mode BUG() and WARN() traps
+ * 0x002: for triggering a fault on purpose (reserved)
*/
#define BRK_BUG_FRAME_IMM 1
+#define BRK_FAULT_IMM 2
+
+/*
+ * BRK instruction encoding
+ * The #imm16 value should be placed at bits[20:5] within BRK ins
+ */
+#define AARCH64_BREAK_MON 0xd4200000
+
+/*
+ * BRK instruction for provoking a fault on purpose
+ */
+#define AARCH64_BREAK_FAULT (AARCH64_BREAK_MON | (BRK_FAULT_IMM << 5))
#endif /* !__ASM_ARM_ARM64_BRK */
/*
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 08/15] xen/arm: arm64: Add helpers to decode and encode branch instructions
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (6 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 07/15] xen/arm: arm64: Reserve a brk immediate to fault on purpose Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-30 14:29 ` Stefano Stabellini
2016-05-23 14:17 ` [PATCH v2 09/15] xen/arm: Introduce alternative runtime patching Julien Grall
` (6 subsequent siblings)
14 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
We may need to update branch instruction when patching Xen.
The code has been imported from the files arch/arm64/kernel/insn.c
and arch/arm64/include/asm/insn.h in Linux v4.6.
Note that only the necessary helpers have been imported.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
Changes in v2:
- Re-sync with Linux v4.6
- Drop any reference to arm32
---
xen/arch/arm/arm64/Makefile | 1 +
xen/arch/arm/arm64/insn.c | 219 +++++++++++++++++++++++++++++++++++++++
xen/include/asm-arm/arm64/insn.h | 72 +++++++++++++
xen/include/asm-arm/insn.h | 20 ++++
4 files changed, 312 insertions(+)
create mode 100644 xen/arch/arm/arm64/insn.c
create mode 100644 xen/include/asm-arm/arm64/insn.h
create mode 100644 xen/include/asm-arm/insn.h
diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
index 39c6ac6..c1fa43f 100644
--- a/xen/arch/arm/arm64/Makefile
+++ b/xen/arch/arm/arm64/Makefile
@@ -5,6 +5,7 @@ obj-$(EARLY_PRINTK) += debug.o
obj-y += domctl.o
obj-y += domain.o
obj-y += entry.o
+obj-y += insn.o
obj-y += smpboot.o
obj-y += traps.o
obj-y += vfp.o
diff --git a/xen/arch/arm/arm64/insn.c b/xen/arch/arm/arm64/insn.c
new file mode 100644
index 0000000..12b4d96
--- /dev/null
+++ b/xen/arch/arm/arm64/insn.c
@@ -0,0 +1,219 @@
+/*
+ * Based on Linux v4.6 arch/arm64/kernel.ins.c
+ *
+ * Copyright (C) 2013 Huawei Ltd.
+ * Author: Jiang Liu <liuj97@gmail.com>
+ *
+ * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <xen/config.h>
+#include <xen/types.h>
+#include <xen/lib.h>
+#include <xen/errno.h>
+#include <xen/sizes.h>
+#include <xen/bitops.h>
+#include <asm/insn.h>
+#include <asm/arm64/insn.h>
+
+#define __kprobes
+#define pr_err(fmt, ...) printk(XENLOG_ERR fmt, ## __VA_ARGS__)
+
+bool aarch64_insn_is_branch_imm(u32 insn)
+{
+ return (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) ||
+ aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) ||
+ aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
+ aarch64_insn_is_bcond(insn));
+}
+
+static int __kprobes aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type,
+ u32 *maskp, int *shiftp)
+{
+ u32 mask;
+ int shift;
+
+ switch (type) {
+ case AARCH64_INSN_IMM_26:
+ mask = BIT(26) - 1;
+ shift = 0;
+ break;
+ case AARCH64_INSN_IMM_19:
+ mask = BIT(19) - 1;
+ shift = 5;
+ break;
+ case AARCH64_INSN_IMM_16:
+ mask = BIT(16) - 1;
+ shift = 5;
+ break;
+ case AARCH64_INSN_IMM_14:
+ mask = BIT(14) - 1;
+ shift = 5;
+ break;
+ case AARCH64_INSN_IMM_12:
+ mask = BIT(12) - 1;
+ shift = 10;
+ break;
+ case AARCH64_INSN_IMM_9:
+ mask = BIT(9) - 1;
+ shift = 12;
+ break;
+ case AARCH64_INSN_IMM_7:
+ mask = BIT(7) - 1;
+ shift = 15;
+ break;
+ case AARCH64_INSN_IMM_6:
+ case AARCH64_INSN_IMM_S:
+ mask = BIT(6) - 1;
+ shift = 10;
+ break;
+ case AARCH64_INSN_IMM_R:
+ mask = BIT(6) - 1;
+ shift = 16;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ *maskp = mask;
+ *shiftp = shift;
+
+ return 0;
+}
+
+#define ADR_IMM_HILOSPLIT 2
+#define ADR_IMM_SIZE SZ_2M
+#define ADR_IMM_LOMASK ((1 << ADR_IMM_HILOSPLIT) - 1)
+#define ADR_IMM_HIMASK ((ADR_IMM_SIZE >> ADR_IMM_HILOSPLIT) - 1)
+#define ADR_IMM_LOSHIFT 29
+#define ADR_IMM_HISHIFT 5
+
+u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn)
+{
+ u32 immlo, immhi, mask;
+ int shift;
+
+ switch (type) {
+ case AARCH64_INSN_IMM_ADR:
+ shift = 0;
+ immlo = (insn >> ADR_IMM_LOSHIFT) & ADR_IMM_LOMASK;
+ immhi = (insn >> ADR_IMM_HISHIFT) & ADR_IMM_HIMASK;
+ insn = (immhi << ADR_IMM_HILOSPLIT) | immlo;
+ mask = ADR_IMM_SIZE - 1;
+ break;
+ default:
+ if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
+ pr_err("aarch64_insn_decode_immediate: unknown immediate encoding %d\n",
+ type);
+ return 0;
+ }
+ }
+
+ return (insn >> shift) & mask;
+}
+
+u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
+ u32 insn, u64 imm)
+{
+ u32 immlo, immhi, mask;
+ int shift;
+
+ if (insn == AARCH64_BREAK_FAULT)
+ return AARCH64_BREAK_FAULT;
+
+ switch (type) {
+ case AARCH64_INSN_IMM_ADR:
+ shift = 0;
+ immlo = (imm & ADR_IMM_LOMASK) << ADR_IMM_LOSHIFT;
+ imm >>= ADR_IMM_HILOSPLIT;
+ immhi = (imm & ADR_IMM_HIMASK) << ADR_IMM_HISHIFT;
+ imm = immlo | immhi;
+ mask = ((ADR_IMM_LOMASK << ADR_IMM_LOSHIFT) |
+ (ADR_IMM_HIMASK << ADR_IMM_HISHIFT));
+ break;
+ default:
+ if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
+ pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",
+ type);
+ return AARCH64_BREAK_FAULT;
+ }
+ }
+
+ /* Update the immediate field. */
+ insn &= ~(mask << shift);
+ insn |= (imm & mask) << shift;
+
+ return insn;
+}
+
+/*
+ * Decode the imm field of a branch, and return the byte offset as a
+ * signed value (so it can be used when computing a new branch
+ * target).
+ */
+s32 aarch64_get_branch_offset(u32 insn)
+{
+ s32 imm;
+
+ if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) {
+ imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_26, insn);
+ return (imm << 6) >> 4;
+ }
+
+ if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
+ aarch64_insn_is_bcond(insn)) {
+ imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_19, insn);
+ return (imm << 13) >> 11;
+ }
+
+ if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) {
+ imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_14, insn);
+ return (imm << 18) >> 16;
+ }
+
+ /* Unhandled instruction */
+ BUG();
+}
+
+/*
+ * Encode the displacement of a branch in the imm field and return the
+ * updated instruction.
+ */
+u32 aarch64_set_branch_offset(u32 insn, s32 offset)
+{
+ if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn))
+ return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn,
+ offset >> 2);
+
+ if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
+ aarch64_insn_is_bcond(insn))
+ return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
+ offset >> 2);
+
+ if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn))
+ return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_14, insn,
+ offset >> 2);
+
+ /* Unhandled instruction */
+ BUG();
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 8
+ * indent-tabs-mode: t
+ * End:
+ */
diff --git a/xen/include/asm-arm/arm64/insn.h b/xen/include/asm-arm/arm64/insn.h
new file mode 100644
index 0000000..cfcdbe9
--- /dev/null
+++ b/xen/include/asm-arm/arm64/insn.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2013 Huawei Ltd.
+ * Author: Jiang Liu <liuj97@gmail.com>
+ *
+ * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ARCH_ARM_ARM64_INSN
+#define __ARCH_ARM_ARM64_INSN
+
+#include <xen/config.h>
+#include <xen/types.h>
+#include <xen/stdbool.h>
+
+enum aarch64_insn_imm_type {
+ AARCH64_INSN_IMM_ADR,
+ AARCH64_INSN_IMM_26,
+ AARCH64_INSN_IMM_19,
+ AARCH64_INSN_IMM_16,
+ AARCH64_INSN_IMM_14,
+ AARCH64_INSN_IMM_12,
+ AARCH64_INSN_IMM_9,
+ AARCH64_INSN_IMM_7,
+ AARCH64_INSN_IMM_6,
+ AARCH64_INSN_IMM_S,
+ AARCH64_INSN_IMM_R,
+ AARCH64_INSN_IMM_MAX
+};
+
+#define __AARCH64_INSN_FUNCS(abbr, mask, val) \
+static always_inline bool_t aarch64_insn_is_##abbr(u32 code) \
+{ return (code & (mask)) == (val); } \
+static always_inline u32 aarch64_insn_get_##abbr##_value(void) \
+{ return (val); }
+
+__AARCH64_INSN_FUNCS(b, 0xFC000000, 0x14000000)
+__AARCH64_INSN_FUNCS(bl, 0xFC000000, 0x94000000)
+__AARCH64_INSN_FUNCS(cbz, 0x7F000000, 0x34000000)
+__AARCH64_INSN_FUNCS(cbnz, 0x7F000000, 0x35000000)
+__AARCH64_INSN_FUNCS(tbz, 0x7F000000, 0x36000000)
+__AARCH64_INSN_FUNCS(tbnz, 0x7F000000, 0x37000000)
+__AARCH64_INSN_FUNCS(bcond, 0xFF000010, 0x54000000)
+
+bool aarch64_insn_is_branch_imm(u32 insn);
+
+u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn);
+u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
+ u32 insn, u64 imm);
+
+s32 aarch64_get_branch_offset(u32 insn);
+u32 aarch64_set_branch_offset(u32 insn, s32 offset);
+
+#endif /* !__ARCH_ARM_ARM64_INSN */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 8
+ * indent-tabs-mode: t
+ * End:
+ */
diff --git a/xen/include/asm-arm/insn.h b/xen/include/asm-arm/insn.h
new file mode 100644
index 0000000..a205ceb
--- /dev/null
+++ b/xen/include/asm-arm/insn.h
@@ -0,0 +1,20 @@
+#ifndef __ARCH_ARM_INSN
+#define __ARCH_ARM_INSN
+
+#include <xen/types.h>
+
+#if defined(CONFIG_ARM_64)
+# include <asm/arm64/insn.h>
+#else
+# error "unknown ARM variant"
+#endif
+
+#endif /* !__ARCH_ARM_INSN */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 8
+ * indent-tabs-mode: t
+ * End:
+ */
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 08/15] xen/arm: arm64: Add helpers to decode and encode branch instructions
2016-05-23 14:17 ` [PATCH v2 08/15] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
@ 2016-05-30 14:29 ` Stefano Stabellini
0 siblings, 0 replies; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 14:29 UTC (permalink / raw)
To: Julien Grall
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara, xen-devel, wei.chen
On Mon, 23 May 2016, Julien Grall wrote:
> We may need to update branch instruction when patching Xen.
>
> The code has been imported from the files arch/arm64/kernel/insn.c
> and arch/arm64/include/asm/insn.h in Linux v4.6.
>
> Note that only the necessary helpers have been imported.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
> Changes in v2:
> - Re-sync with Linux v4.6
> - Drop any reference to arm32
> ---
> xen/arch/arm/arm64/Makefile | 1 +
> xen/arch/arm/arm64/insn.c | 219 +++++++++++++++++++++++++++++++++++++++
> xen/include/asm-arm/arm64/insn.h | 72 +++++++++++++
> xen/include/asm-arm/insn.h | 20 ++++
> 4 files changed, 312 insertions(+)
> create mode 100644 xen/arch/arm/arm64/insn.c
> create mode 100644 xen/include/asm-arm/arm64/insn.h
> create mode 100644 xen/include/asm-arm/insn.h
>
> diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
> index 39c6ac6..c1fa43f 100644
> --- a/xen/arch/arm/arm64/Makefile
> +++ b/xen/arch/arm/arm64/Makefile
> @@ -5,6 +5,7 @@ obj-$(EARLY_PRINTK) += debug.o
> obj-y += domctl.o
> obj-y += domain.o
> obj-y += entry.o
> +obj-y += insn.o
> obj-y += smpboot.o
> obj-y += traps.o
> obj-y += vfp.o
> diff --git a/xen/arch/arm/arm64/insn.c b/xen/arch/arm/arm64/insn.c
> new file mode 100644
> index 0000000..12b4d96
> --- /dev/null
> +++ b/xen/arch/arm/arm64/insn.c
> @@ -0,0 +1,219 @@
> +/*
> + * Based on Linux v4.6 arch/arm64/kernel.ins.c
arch/arm64/kernel/insn.c ?
> + * Copyright (C) 2013 Huawei Ltd.
> + * Author: Jiang Liu <liuj97@gmail.com>
> + *
> + * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <xen/config.h>
> +#include <xen/types.h>
> +#include <xen/lib.h>
> +#include <xen/errno.h>
> +#include <xen/sizes.h>
> +#include <xen/bitops.h>
> +#include <asm/insn.h>
> +#include <asm/arm64/insn.h>
> +
> +#define __kprobes
> +#define pr_err(fmt, ...) printk(XENLOG_ERR fmt, ## __VA_ARGS__)
> +
> +bool aarch64_insn_is_branch_imm(u32 insn)
> +{
> + return (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) ||
> + aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) ||
> + aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
> + aarch64_insn_is_bcond(insn));
> +}
> +
> +static int __kprobes aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type,
> + u32 *maskp, int *shiftp)
> +{
> + u32 mask;
> + int shift;
> +
> + switch (type) {
> + case AARCH64_INSN_IMM_26:
> + mask = BIT(26) - 1;
> + shift = 0;
> + break;
> + case AARCH64_INSN_IMM_19:
> + mask = BIT(19) - 1;
> + shift = 5;
> + break;
> + case AARCH64_INSN_IMM_16:
> + mask = BIT(16) - 1;
> + shift = 5;
> + break;
> + case AARCH64_INSN_IMM_14:
> + mask = BIT(14) - 1;
> + shift = 5;
> + break;
> + case AARCH64_INSN_IMM_12:
> + mask = BIT(12) - 1;
> + shift = 10;
> + break;
> + case AARCH64_INSN_IMM_9:
> + mask = BIT(9) - 1;
> + shift = 12;
> + break;
> + case AARCH64_INSN_IMM_7:
> + mask = BIT(7) - 1;
> + shift = 15;
> + break;
> + case AARCH64_INSN_IMM_6:
> + case AARCH64_INSN_IMM_S:
> + mask = BIT(6) - 1;
> + shift = 10;
> + break;
> + case AARCH64_INSN_IMM_R:
> + mask = BIT(6) - 1;
> + shift = 16;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + *maskp = mask;
> + *shiftp = shift;
> +
> + return 0;
> +}
> +
> +#define ADR_IMM_HILOSPLIT 2
> +#define ADR_IMM_SIZE SZ_2M
> +#define ADR_IMM_LOMASK ((1 << ADR_IMM_HILOSPLIT) - 1)
> +#define ADR_IMM_HIMASK ((ADR_IMM_SIZE >> ADR_IMM_HILOSPLIT) - 1)
> +#define ADR_IMM_LOSHIFT 29
> +#define ADR_IMM_HISHIFT 5
> +
> +u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn)
> +{
> + u32 immlo, immhi, mask;
> + int shift;
> +
> + switch (type) {
> + case AARCH64_INSN_IMM_ADR:
> + shift = 0;
> + immlo = (insn >> ADR_IMM_LOSHIFT) & ADR_IMM_LOMASK;
> + immhi = (insn >> ADR_IMM_HISHIFT) & ADR_IMM_HIMASK;
> + insn = (immhi << ADR_IMM_HILOSPLIT) | immlo;
> + mask = ADR_IMM_SIZE - 1;
> + break;
> + default:
> + if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
> + pr_err("aarch64_insn_decode_immediate: unknown immediate encoding %d\n",
> + type);
> + return 0;
> + }
> + }
> +
> + return (insn >> shift) & mask;
> +}
> +
> +u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
> + u32 insn, u64 imm)
> +{
> + u32 immlo, immhi, mask;
> + int shift;
> +
> + if (insn == AARCH64_BREAK_FAULT)
> + return AARCH64_BREAK_FAULT;
> +
> + switch (type) {
> + case AARCH64_INSN_IMM_ADR:
> + shift = 0;
> + immlo = (imm & ADR_IMM_LOMASK) << ADR_IMM_LOSHIFT;
> + imm >>= ADR_IMM_HILOSPLIT;
> + immhi = (imm & ADR_IMM_HIMASK) << ADR_IMM_HISHIFT;
> + imm = immlo | immhi;
> + mask = ((ADR_IMM_LOMASK << ADR_IMM_LOSHIFT) |
> + (ADR_IMM_HIMASK << ADR_IMM_HISHIFT));
> + break;
> + default:
> + if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
> + pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",
> + type);
> + return AARCH64_BREAK_FAULT;
> + }
> + }
> +
> + /* Update the immediate field. */
> + insn &= ~(mask << shift);
> + insn |= (imm & mask) << shift;
> +
> + return insn;
> +}
> +
> +/*
> + * Decode the imm field of a branch, and return the byte offset as a
> + * signed value (so it can be used when computing a new branch
> + * target).
> + */
> +s32 aarch64_get_branch_offset(u32 insn)
> +{
> + s32 imm;
> +
> + if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) {
> + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_26, insn);
> + return (imm << 6) >> 4;
> + }
> +
> + if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
> + aarch64_insn_is_bcond(insn)) {
> + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_19, insn);
> + return (imm << 13) >> 11;
> + }
> +
> + if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) {
> + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_14, insn);
> + return (imm << 18) >> 16;
> + }
> +
> + /* Unhandled instruction */
> + BUG();
> +}
> +
> +/*
> + * Encode the displacement of a branch in the imm field and return the
> + * updated instruction.
> + */
> +u32 aarch64_set_branch_offset(u32 insn, s32 offset)
> +{
> + if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn))
> + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn,
> + offset >> 2);
> +
> + if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
> + aarch64_insn_is_bcond(insn))
> + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
> + offset >> 2);
> +
> + if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn))
> + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_14, insn,
> + offset >> 2);
> +
> + /* Unhandled instruction */
> + BUG();
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 8
> + * indent-tabs-mode: t
> + * End:
> + */
> diff --git a/xen/include/asm-arm/arm64/insn.h b/xen/include/asm-arm/arm64/insn.h
> new file mode 100644
> index 0000000..cfcdbe9
> --- /dev/null
> +++ b/xen/include/asm-arm/arm64/insn.h
> @@ -0,0 +1,72 @@
> +/*
> + * Copyright (C) 2013 Huawei Ltd.
> + * Author: Jiang Liu <liuj97@gmail.com>
> + *
> + * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +#ifndef __ARCH_ARM_ARM64_INSN
> +#define __ARCH_ARM_ARM64_INSN
> +
> +#include <xen/config.h>
> +#include <xen/types.h>
> +#include <xen/stdbool.h>
> +
> +enum aarch64_insn_imm_type {
> + AARCH64_INSN_IMM_ADR,
> + AARCH64_INSN_IMM_26,
> + AARCH64_INSN_IMM_19,
> + AARCH64_INSN_IMM_16,
> + AARCH64_INSN_IMM_14,
> + AARCH64_INSN_IMM_12,
> + AARCH64_INSN_IMM_9,
> + AARCH64_INSN_IMM_7,
> + AARCH64_INSN_IMM_6,
> + AARCH64_INSN_IMM_S,
> + AARCH64_INSN_IMM_R,
> + AARCH64_INSN_IMM_MAX
> +};
> +
> +#define __AARCH64_INSN_FUNCS(abbr, mask, val) \
> +static always_inline bool_t aarch64_insn_is_##abbr(u32 code) \
> +{ return (code & (mask)) == (val); } \
> +static always_inline u32 aarch64_insn_get_##abbr##_value(void) \
> +{ return (val); }
> +
> +__AARCH64_INSN_FUNCS(b, 0xFC000000, 0x14000000)
> +__AARCH64_INSN_FUNCS(bl, 0xFC000000, 0x94000000)
> +__AARCH64_INSN_FUNCS(cbz, 0x7F000000, 0x34000000)
> +__AARCH64_INSN_FUNCS(cbnz, 0x7F000000, 0x35000000)
> +__AARCH64_INSN_FUNCS(tbz, 0x7F000000, 0x36000000)
> +__AARCH64_INSN_FUNCS(tbnz, 0x7F000000, 0x37000000)
> +__AARCH64_INSN_FUNCS(bcond, 0xFF000010, 0x54000000)
> +
> +bool aarch64_insn_is_branch_imm(u32 insn);
> +
> +u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn);
> +u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
> + u32 insn, u64 imm);
> +
> +s32 aarch64_get_branch_offset(u32 insn);
> +u32 aarch64_set_branch_offset(u32 insn, s32 offset);
> +
> +#endif /* !__ARCH_ARM_ARM64_INSN */
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 8
> + * indent-tabs-mode: t
> + * End:
> + */
> diff --git a/xen/include/asm-arm/insn.h b/xen/include/asm-arm/insn.h
> new file mode 100644
> index 0000000..a205ceb
> --- /dev/null
> +++ b/xen/include/asm-arm/insn.h
> @@ -0,0 +1,20 @@
> +#ifndef __ARCH_ARM_INSN
> +#define __ARCH_ARM_INSN
> +
> +#include <xen/types.h>
> +
> +#if defined(CONFIG_ARM_64)
> +# include <asm/arm64/insn.h>
> +#else
> +# error "unknown ARM variant"
> +#endif
> +
> +#endif /* !__ARCH_ARM_INSN */
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 8
> + * indent-tabs-mode: t
> + * End:
> + */
> --
> 1.9.1
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v2 09/15] xen/arm: Introduce alternative runtime patching
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (7 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 08/15] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
` (5 subsequent siblings)
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
Some of the processor erratum will require to modify code sequence.
As those modifications may impact the performance, they should only
be enabled on affected cores. Furthermore, Xen may also want to take
advantage of new hardware features coming up with v8.1 and v8.2.
This patch adds an infrastructure to patch Xen during boot time
depending on the "features" available on the platform.
This code is based on the file arch/arm64/kernel/alternative.c in
Linux 4.6-rc3. Any references to arm64 have been dropped to make the
code as generic as possible.
When Xen is creating the page tables, all the executable sections
(.text and .init.text) will be marked read-only and then enforced by
setting SCTLR.WNX.
Whilst it might be possible to mark those entries read-only after
Xen has been patched, we would need extra care to avoid possible
TLBs conflicts (see D4-1732 in ARM DDI 0487A.i) as all
physical CPUs will be running.
All the physical CPUs have to be brought up before patching Xen because
each cores may have different errata/features which require code
patching. The only way to find them is to probe system registers on
each CPU.
To avoid extra complexity, it is possible to create a temporary
writeable mapping with vmap. This mapping will be used to write the
new instructions.
Lastly, runtime patching is currently not necessary for ARM32. So the
code is only enabled for ARM64.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
Changes in v2:
- Use hard tabs in Kconfig
- Update the copyright year
- Update the commit message to explain the extra mapping
---
xen/arch/arm/Kconfig | 5 +
xen/arch/arm/Makefile | 1 +
xen/arch/arm/alternative.c | 217 ++++++++++++++++++++++++++++++++++++++
xen/arch/arm/setup.c | 8 ++
xen/arch/arm/xen.lds.S | 7 ++
xen/include/asm-arm/alternative.h | 165 +++++++++++++++++++++++++++++
xen/include/asm-arm/arm64/insn.h | 16 +++
7 files changed, 419 insertions(+)
create mode 100644 xen/arch/arm/alternative.c
create mode 100644 xen/include/asm-arm/alternative.h
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 6231cd5..0141bd9 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -14,6 +14,7 @@ config ARM_64
def_bool y
depends on 64BIT
select HAS_GICV3
+ select ALTERNATIVE
config ARM
def_bool y
@@ -46,6 +47,10 @@ config ACPI
config HAS_GICV3
bool
+# Select ALTERNATIVE if the architecture supports runtime patching
+config ALTERNATIVE
+ bool
+
endmenu
source "common/Kconfig"
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 9122f78..2d330aa 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -4,6 +4,7 @@ subdir-y += platforms
subdir-$(CONFIG_ARM_64) += efi
subdir-$(CONFIG_ACPI) += acpi
+obj-$(CONFIG_ALTERNATIVE) += alternative.o
obj-y += bootfdt.o
obj-y += cpu.o
obj-y += cpufeature.o
diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
new file mode 100644
index 0000000..992fbb5
--- /dev/null
+++ b/xen/arch/arm/alternative.c
@@ -0,0 +1,217 @@
+/*
+ * alternative runtime patching
+ * inspired by the x86 version
+ *
+ * Copyright (C) 2014-2016 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/config.h>
+#include <xen/init.h>
+#include <xen/types.h>
+#include <xen/kernel.h>
+#include <xen/mm.h>
+#include <xen/vmap.h>
+#include <xen/smp.h>
+#include <xen/stop_machine.h>
+#include <asm/alternative.h>
+#include <asm/atomic.h>
+#include <asm/byteorder.h>
+#include <asm/cpufeature.h>
+#include <asm/insn.h>
+#include <asm/page.h>
+
+#define __ALT_PTR(a,f) (u32 *)((void *)&(a)->f + (a)->f)
+#define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset)
+#define ALT_REPL_PTR(a) __ALT_PTR(a, alt_offset)
+
+extern const struct alt_instr __alt_instructions[], __alt_instructions_end[];
+
+struct alt_region {
+ const struct alt_instr *begin;
+ const struct alt_instr *end;
+};
+
+/*
+ * Check if the target PC is within an alternative block.
+ */
+static bool_t branch_insn_requires_update(const struct alt_instr *alt,
+ unsigned long pc)
+{
+ unsigned long replptr;
+
+ if ( is_active_kernel_text(pc) )
+ return 1;
+
+ replptr = (unsigned long)ALT_REPL_PTR(alt);
+ if ( pc >= replptr && pc <= (replptr + alt->alt_len) )
+ return 0;
+
+ /*
+ * Branching into *another* alternate sequence is doomed, and
+ * we're not even trying to fix it up.
+ */
+ BUG();
+}
+
+static u32 get_alt_insn(const struct alt_instr *alt,
+ const u32 *insnptr, const u32 *altinsnptr)
+{
+ u32 insn;
+
+ insn = le32_to_cpu(*altinsnptr);
+
+ if ( insn_is_branch_imm(insn) )
+ {
+ s32 offset = insn_get_branch_offset(insn);
+ unsigned long target;
+
+ target = (unsigned long)altinsnptr + offset;
+
+ /*
+ * If we're branching inside the alternate sequence,
+ * do not rewrite the instruction, as it is already
+ * correct. Otherwise, generate the new instruction.
+ */
+ if ( branch_insn_requires_update(alt, target) )
+ {
+ offset = target - (unsigned long)insnptr;
+ insn = insn_set_branch_offset(insn, offset);
+ }
+ }
+
+ return insn;
+}
+
+static int __apply_alternatives(const struct alt_region *region)
+{
+ const struct alt_instr *alt;
+ const u32 *origptr, *replptr;
+ u32 *writeptr, *writemap;
+ mfn_t text_mfn = _mfn(virt_to_mfn(_stext));
+ unsigned int text_order = get_order_from_bytes(_end - _start);
+
+ printk("Patching kernel code\n");
+
+ /*
+ * The text section is read-only. So re-map Xen to be able to patch
+ * the code.
+ */
+ writemap = __vmap(&text_mfn, 1 << text_order, 1, 1, PAGE_HYPERVISOR,
+ VMAP_DEFAULT);
+ if ( !writemap )
+ {
+ printk("alternatives: Unable to map the text section\n");
+ return -ENOMEM;
+ }
+
+ for ( alt = region->begin; alt < region->end; alt++ )
+ {
+ u32 insn;
+ int i, nr_inst;
+
+ if ( !cpus_have_cap(alt->cpufeature) )
+ continue;
+
+ BUG_ON(alt->alt_len != alt->orig_len);
+
+ origptr = ALT_ORIG_PTR(alt);
+ writeptr = origptr - (u32 *)_start + writemap;
+ replptr = ALT_REPL_PTR(alt);
+
+ nr_inst = alt->alt_len / sizeof(insn);
+
+ for ( i = 0; i < nr_inst; i++ )
+ {
+ insn = get_alt_insn(alt, origptr + i, replptr + i);
+ *(writeptr + i) = cpu_to_le32(insn);
+ }
+
+ /* Ensure the new instructions reached the memory and nuke */
+ clean_and_invalidate_dcache_va_range(writeptr,
+ (sizeof (*writeptr) * nr_inst));
+ }
+
+ /* Nuke the instruction cache */
+ invalidate_icache();
+
+ vunmap(writemap);
+
+ return 0;
+}
+
+/*
+ * We might be patching the stop_machine state machine, so implement a
+ * really simple polling protocol here.
+ */
+static int __apply_alternatives_multi_stop(void *unused)
+{
+ static int patched = 0;
+ struct alt_region region = {
+ .begin = __alt_instructions,
+ .end = __alt_instructions_end,
+ };
+
+ /* We always have a CPU 0 at this point (__init) */
+ if ( smp_processor_id() )
+ {
+ while ( !read_atomic(&patched) )
+ cpu_relax();
+ isb();
+ }
+ else
+ {
+ int ret;
+
+ BUG_ON(patched);
+ ret = __apply_alternatives(®ion);
+ /* The patching is not expected to fail during boot. */
+ BUG_ON(ret != 0);
+
+ /* Barriers provided by the cache flushing */
+ write_atomic(&patched, 1);
+ }
+
+ return 0;
+}
+
+void __init apply_alternatives_all(void)
+{
+ int ret;
+
+ /* better not try code patching on a live SMP system */
+ ret = stop_machine_run(__apply_alternatives_multi_stop, NULL, NR_CPUS);
+
+ /* stop_machine_run should never fail at this stage of the boot */
+ BUG_ON(ret);
+}
+
+int apply_alternatives(void *start, size_t length)
+{
+ struct alt_region region = {
+ .begin = start,
+ .end = start + length,
+ };
+
+ return __apply_alternatives(®ion);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 09ff1ea..c4389ef 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -38,6 +38,7 @@
#include <xen/vmap.h>
#include <xen/libfdt/libfdt.h>
#include <xen/acpi.h>
+#include <asm/alternative.h>
#include <asm/page.h>
#include <asm/current.h>
#include <asm/setup.h>
@@ -834,6 +835,13 @@ void __init start_xen(unsigned long boot_phys_offset,
do_initcalls();
+ /*
+ * It needs to be called after do_initcalls to be able to use
+ * stop_machine (tasklets initialized via an initcall).
+ * XXX: Is it too late?
+ */
+ apply_alternatives_all();
+
/* Create initial domain 0. */
/* The vGIC for DOM0 is exactly emulating the hardware GIC */
config.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE;
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 1f010bd..80d9703 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -167,6 +167,13 @@ SECTIONS
*(.xsm_initcall.init)
__xsm_initcall_end = .;
} :text
+#ifdef CONFIG_ALTERNATIVE
+ .init.alternatives : {
+ __alt_instructions = .;
+ *(.altinstructions)
+ __alt_instructions_end = .;
+ }
+#endif
__init_end_efi = .;
. = ALIGN(STACK_SIZE);
__init_end = .;
diff --git a/xen/include/asm-arm/alternative.h b/xen/include/asm-arm/alternative.h
new file mode 100644
index 0000000..7e3a610
--- /dev/null
+++ b/xen/include/asm-arm/alternative.h
@@ -0,0 +1,165 @@
+#ifndef __ASM_ALTERNATIVE_H
+#define __ASM_ALTERNATIVE_H
+
+#include <asm/cpufeature.h>
+#include <xen/config.h>
+#include <xen/kconfig.h>
+
+#ifdef CONFIG_ALTERNATIVE
+
+#ifndef __ASSEMBLY__
+
+#include <xen/init.h>
+#include <xen/types.h>
+#include <xen/stringify.h>
+
+struct alt_instr {
+ s32 orig_offset; /* offset to original instruction */
+ s32 alt_offset; /* offset to replacement instruction */
+ u16 cpufeature; /* cpufeature bit set for replacement */
+ u8 orig_len; /* size of original instruction(s) */
+ u8 alt_len; /* size of new instruction(s), <= orig_len */
+};
+
+void __init apply_alternatives_all(void);
+int apply_alternatives(void *start, size_t length);
+
+#define ALTINSTR_ENTRY(feature) \
+ " .word 661b - .\n" /* label */ \
+ " .word 663f - .\n" /* new instruction */ \
+ " .hword " __stringify(feature) "\n" /* feature bit */ \
+ " .byte 662b-661b\n" /* source len */ \
+ " .byte 664f-663f\n" /* replacement len */
+
+/*
+ * alternative assembly primitive:
+ *
+ * If any of these .org directive fail, it means that insn1 and insn2
+ * don't have the same length. This used to be written as
+ *
+ * .if ((664b-663b) != (662b-661b))
+ * .error "Alternatives instruction length mismatch"
+ * .endif
+ *
+ * but most assemblers die if insn1 or insn2 have a .inst. This should
+ * be fixed in a binutils release posterior to 2.25.51.0.2 (anything
+ * containing commit 4e4d08cf7399b606 or c1baaddf8861).
+ */
+#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled) \
+ ".if "__stringify(cfg_enabled)" == 1\n" \
+ "661:\n\t" \
+ oldinstr "\n" \
+ "662:\n" \
+ ".pushsection .altinstructions,\"a\"\n" \
+ ALTINSTR_ENTRY(feature) \
+ ".popsection\n" \
+ ".pushsection .altinstr_replacement, \"a\"\n" \
+ "663:\n\t" \
+ newinstr "\n" \
+ "664:\n\t" \
+ ".popsection\n\t" \
+ ".org . - (664b-663b) + (662b-661b)\n\t" \
+ ".org . - (662b-661b) + (664b-663b)\n" \
+ ".endif\n"
+
+#define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...) \
+ __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg))
+
+#else
+
+#include <asm/asm_defns.h>
+
+.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
+ .word \orig_offset - .
+ .word \alt_offset - .
+ .hword \feature
+ .byte \orig_len
+ .byte \alt_len
+.endm
+
+.macro alternative_insn insn1, insn2, cap, enable = 1
+ .if \enable
+661: \insn1
+662: .pushsection .altinstructions, "a"
+ altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f
+ .popsection
+ .pushsection .altinstr_replacement, "ax"
+663: \insn2
+664: .popsection
+ .org . - (664b-663b) + (662b-661b)
+ .org . - (662b-661b) + (664b-663b)
+ .endif
+.endm
+
+/*
+ * Begin an alternative code sequence.
+ *
+ * The code that follows this macro will be assembled and linked as
+ * normal. There are no restrictions on this code.
+ */
+.macro alternative_if_not cap, enable = 1
+ .if \enable
+ .pushsection .altinstructions, "a"
+ altinstruction_entry 661f, 663f, \cap, 662f-661f, 664f-663f
+ .popsection
+661:
+ .endif
+.endm
+
+/*
+ * Provide the alternative code sequence.
+ *
+ * The code that follows this macro is assembled into a special
+ * section to be used for dynamic patching. Code that follows this
+ * macro must:
+ *
+ * 1. Be exactly the same length (in bytes) as the default code
+ * sequence.
+ *
+ * 2. Not contain a branch target that is used outside of the
+ * alternative sequence it is defined in (branches into an
+ * alternative sequence are not fixed up).
+ */
+.macro alternative_else
+662: .pushsection .altinstr_replacement, "ax"
+663:
+.endm
+
+/*
+ * Complete an alternative code sequence.
+ */
+.macro alternative_endif
+664: .popsection
+ .org . - (664b-663b) + (662b-661b)
+ .org . - (662b-661b) + (664b-663b)
+.endm
+
+#define _ALTERNATIVE_CFG(insn1, insn2, cap, cfg, ...) \
+ alternative_insn insn1, insn2, cap, IS_ENABLED(cfg)
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature));
+ *
+ * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature, CONFIG_FOO));
+ * N.B. If CONFIG_FOO is specified, but not selected, the whole block
+ * will be omitted, including oldinstr.
+ */
+#define ALTERNATIVE(oldinstr, newinstr, ...) \
+ _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1)
+
+#else /* !CONFIG_ALTERNATIVE */
+
+static inline void apply_alternatives_all(void)
+{
+}
+
+int apply_alternatives(void *start, size_t lenght)
+{
+ return 0;
+}
+
+#endif
+
+#endif /* __ASM_ALTERNATIVE_H */
diff --git a/xen/include/asm-arm/arm64/insn.h b/xen/include/asm-arm/arm64/insn.h
index cfcdbe9..6ce37be 100644
--- a/xen/include/asm-arm/arm64/insn.h
+++ b/xen/include/asm-arm/arm64/insn.h
@@ -61,6 +61,22 @@ u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
s32 aarch64_get_branch_offset(u32 insn);
u32 aarch64_set_branch_offset(u32 insn, s32 offset);
+/* Wrapper for common code */
+static inline bool insn_is_branch_imm(u32 insn)
+{
+ return aarch64_insn_is_branch_imm(insn);
+}
+
+static inline s32 insn_get_branch_offset(u32 insn)
+{
+ return aarch64_get_branch_offset(insn);
+}
+
+static inline u32 insn_set_branch_offset(u32 insn, s32 offset)
+{
+ return aarch64_set_branch_offset(insn, offset);
+}
+
#endif /* !__ARCH_ARM_ARM64_INSN */
/*
* Local variables:
--
1.9.1
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (8 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 09/15] xen/arm: Introduce alternative runtime patching Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-30 15:02 ` Stefano Stabellini
2016-05-23 14:17 ` [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen Julien Grall
` (4 subsequent siblings)
14 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
After each CPU has been started, we iterate through a list of CPU
errata to detect CPUs which need from hypervisor code patches.
For each bug there is a function which check if that a particular CPU is
affected. This needs to be done on every CPUs to cover heterogenous
system properly.
If a certain erratum has been detected, the capability bit will be set
and later the call to apply_alternatives() will trigger the actual code
patching.
The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
v4.6-rc3.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
Changes in v2:
- Use XENLOG_INFO for the loglevel of the message
---
xen/arch/arm/Makefile | 1 +
xen/arch/arm/cpuerrata.c | 26 ++++++++++++++++++++++++++
xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
xen/arch/arm/setup.c | 3 +++
xen/arch/arm/smpboot.c | 3 +++
xen/include/asm-arm/cpuerrata.h | 6 ++++++
xen/include/asm-arm/cpufeature.h | 15 +++++++++++++++
7 files changed, 70 insertions(+)
create mode 100644 xen/arch/arm/cpuerrata.c
create mode 100644 xen/include/asm-arm/cpuerrata.h
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 2d330aa..307578c 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -7,6 +7,7 @@ subdir-$(CONFIG_ACPI) += acpi
obj-$(CONFIG_ALTERNATIVE) += alternative.o
obj-y += bootfdt.o
obj-y += cpu.o
+obj-y += cpuerrata.o
obj-y += cpufeature.o
obj-y += decode.o
obj-y += device.o
diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
new file mode 100644
index 0000000..52d39f8
--- /dev/null
+++ b/xen/arch/arm/cpuerrata.c
@@ -0,0 +1,26 @@
+#include <xen/config.h>
+#include <asm/cpufeature.h>
+#include <asm/cpuerrata.h>
+
+#define MIDR_RANGE(model, min, max) \
+ .matches = is_affected_midr_range, \
+ .midr_model = model, \
+ .midr_range_min = min, \
+ .midr_range_max = max
+
+static bool_t __maybe_unused
+is_affected_midr_range(const struct arm_cpu_capabilities *entry)
+{
+ return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits, entry->midr_model,
+ entry->midr_range_min,
+ entry->midr_range_max);
+}
+
+static const struct arm_cpu_capabilities arm_errata[] = {
+ {},
+};
+
+void check_local_cpu_errata(void)
+{
+ update_cpu_capabilities(arm_errata, "enabled workaround for");
+}
diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
index 7a1b56b..088625b 100644
--- a/xen/arch/arm/cpufeature.c
+++ b/xen/arch/arm/cpufeature.c
@@ -24,6 +24,22 @@
DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
+void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
+ const char *info)
+{
+ int i;
+
+ for ( i = 0; caps[i].matches; i++ )
+ {
+ if ( !caps[i].matches(&caps[i]) )
+ continue;
+
+ if ( !cpus_have_cap(caps[i].capability) && caps[i].desc )
+ printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
+ cpus_set_cap(caps[i].capability);
+ }
+}
+
/*
* Local variables:
* mode: C
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index c4389ef..67eb13b 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -43,6 +43,7 @@
#include <asm/current.h>
#include <asm/setup.h>
#include <asm/gic.h>
+#include <asm/cpuerrata.h>
#include <asm/cpufeature.h>
#include <asm/platform.h>
#include <asm/procinfo.h>
@@ -171,6 +172,8 @@ static void __init processor_id(void)
}
processor_setup();
+
+ check_local_cpu_errata();
}
void dt_unreserved_regions(paddr_t s, paddr_t e,
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index c5109bf..3f5a77b 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -29,6 +29,7 @@
#include <xen/timer.h>
#include <xen/irq.h>
#include <xen/console.h>
+#include <asm/cpuerrata.h>
#include <asm/gic.h>
#include <asm/psci.h>
#include <asm/acpi.h>
@@ -316,6 +317,8 @@ void start_secondary(unsigned long boot_phys_offset,
local_irq_enable();
local_abort_enable();
+ check_local_cpu_errata();
+
printk(XENLOG_DEBUG "CPU %u booted.\n", smp_processor_id());
startup_cpu_idle_loop();
diff --git a/xen/include/asm-arm/cpuerrata.h b/xen/include/asm-arm/cpuerrata.h
new file mode 100644
index 0000000..8ffd7ba
--- /dev/null
+++ b/xen/include/asm-arm/cpuerrata.h
@@ -0,0 +1,6 @@
+#ifndef __ARM_CPUERRATA_H
+#define __ARM_CPUERRATA_H
+
+void check_local_cpu_errata(void);
+
+#endif /* __ARM_CPUERRATA_H */
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 2bebad1..fb57295 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -62,6 +62,21 @@ static inline void cpus_set_cap(unsigned int num)
__set_bit(num, cpu_hwcaps);
}
+struct arm_cpu_capabilities {
+ const char *desc;
+ u16 capability;
+ bool_t (*matches)(const struct arm_cpu_capabilities *);
+ union {
+ struct { /* To be used for eratum handling only */
+ u32 midr_model;
+ u32 midr_range_min, midr_range_max;
+ };
+ };
+};
+
+void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
+ const char *info);
+
#endif /* __ASSEMBLY__ */
#endif
--
1.9.1
_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-05-23 14:17 ` [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
@ 2016-05-30 15:02 ` Stefano Stabellini
2016-05-30 16:37 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 15:02 UTC (permalink / raw)
To: Julien Grall
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara, xen-devel, wei.chen
On Mon, 23 May 2016, Julien Grall wrote:
> After each CPU has been started, we iterate through a list of CPU
> errata to detect CPUs which need from hypervisor code patches.
>
> For each bug there is a function which check if that a particular CPU is
> affected. This needs to be done on every CPUs to cover heterogenous
> system properly.
>
> If a certain erratum has been detected, the capability bit will be set
> and later the call to apply_alternatives() will trigger the actual code
> patching.
>
> The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
> v4.6-rc3.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
>
> ---
> Changes in v2:
> - Use XENLOG_INFO for the loglevel of the message
> ---
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/cpuerrata.c | 26 ++++++++++++++++++++++++++
> xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
> xen/arch/arm/setup.c | 3 +++
> xen/arch/arm/smpboot.c | 3 +++
> xen/include/asm-arm/cpuerrata.h | 6 ++++++
> xen/include/asm-arm/cpufeature.h | 15 +++++++++++++++
> 7 files changed, 70 insertions(+)
> create mode 100644 xen/arch/arm/cpuerrata.c
> create mode 100644 xen/include/asm-arm/cpuerrata.h
>
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 2d330aa..307578c 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -7,6 +7,7 @@ subdir-$(CONFIG_ACPI) += acpi
> obj-$(CONFIG_ALTERNATIVE) += alternative.o
> obj-y += bootfdt.o
> obj-y += cpu.o
> +obj-y += cpuerrata.o
> obj-y += cpufeature.o
> obj-y += decode.o
> obj-y += device.o
> diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
> new file mode 100644
> index 0000000..52d39f8
> --- /dev/null
> +++ b/xen/arch/arm/cpuerrata.c
> @@ -0,0 +1,26 @@
> +#include <xen/config.h>
> +#include <asm/cpufeature.h>
> +#include <asm/cpuerrata.h>
> +
> +#define MIDR_RANGE(model, min, max) \
> + .matches = is_affected_midr_range, \
> + .midr_model = model, \
> + .midr_range_min = min, \
> + .midr_range_max = max
> +
> +static bool_t __maybe_unused
I would remove __maybe_unused given that you are going to use this
function in later patches.
> +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
> +{
> + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits, entry->midr_model,
> + entry->midr_range_min,
> + entry->midr_range_max);
> +}
> +
> +static const struct arm_cpu_capabilities arm_errata[] = {
> + {},
> +};
> +
> +void check_local_cpu_errata(void)
> +{
> + update_cpu_capabilities(arm_errata, "enabled workaround for");
> +}
update_cpu_capabilities should actually be called on arm64 only, right?
Given that runtime patching is unimplemented on arm32. I wouldn't want
to rely on the fact that we don't have any arm32 workarounds at the
moment.
> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
> index 7a1b56b..088625b 100644
> --- a/xen/arch/arm/cpufeature.c
> +++ b/xen/arch/arm/cpufeature.c
> @@ -24,6 +24,22 @@
>
> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>
> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> + const char *info)
The info parameter is unnecessary.
> +{
> + int i;
> +
> + for ( i = 0; caps[i].matches; i++ )
> + {
> + if ( !caps[i].matches(&caps[i]) )
> + continue;
> +
> + if ( !cpus_have_cap(caps[i].capability) && caps[i].desc )
> + printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
> + cpus_set_cap(caps[i].capability);
> + }
> +}
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index c4389ef..67eb13b 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -43,6 +43,7 @@
> #include <asm/current.h>
> #include <asm/setup.h>
> #include <asm/gic.h>
> +#include <asm/cpuerrata.h>
> #include <asm/cpufeature.h>
> #include <asm/platform.h>
> #include <asm/procinfo.h>
> @@ -171,6 +172,8 @@ static void __init processor_id(void)
> }
>
> processor_setup();
> +
> + check_local_cpu_errata();
> }
>
> void dt_unreserved_regions(paddr_t s, paddr_t e,
> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> index c5109bf..3f5a77b 100644
> --- a/xen/arch/arm/smpboot.c
> +++ b/xen/arch/arm/smpboot.c
> @@ -29,6 +29,7 @@
> #include <xen/timer.h>
> #include <xen/irq.h>
> #include <xen/console.h>
> +#include <asm/cpuerrata.h>
> #include <asm/gic.h>
> #include <asm/psci.h>
> #include <asm/acpi.h>
> @@ -316,6 +317,8 @@ void start_secondary(unsigned long boot_phys_offset,
> local_irq_enable();
> local_abort_enable();
>
> + check_local_cpu_errata();
> +
> printk(XENLOG_DEBUG "CPU %u booted.\n", smp_processor_id());
>
> startup_cpu_idle_loop();
> diff --git a/xen/include/asm-arm/cpuerrata.h b/xen/include/asm-arm/cpuerrata.h
> new file mode 100644
> index 0000000..8ffd7ba
> --- /dev/null
> +++ b/xen/include/asm-arm/cpuerrata.h
> @@ -0,0 +1,6 @@
> +#ifndef __ARM_CPUERRATA_H
> +#define __ARM_CPUERRATA_H
> +
> +void check_local_cpu_errata(void);
> +
> +#endif /* __ARM_CPUERRATA_H */
> diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
> index 2bebad1..fb57295 100644
> --- a/xen/include/asm-arm/cpufeature.h
> +++ b/xen/include/asm-arm/cpufeature.h
> @@ -62,6 +62,21 @@ static inline void cpus_set_cap(unsigned int num)
> __set_bit(num, cpu_hwcaps);
> }
>
> +struct arm_cpu_capabilities {
> + const char *desc;
> + u16 capability;
> + bool_t (*matches)(const struct arm_cpu_capabilities *);
> + union {
> + struct { /* To be used for eratum handling only */
> + u32 midr_model;
> + u32 midr_range_min, midr_range_max;
> + };
> + };
> +};
> +
> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> + const char *info);
> +
> #endif /* __ASSEMBLY__ */
>
> #endif
> --
> 1.9.1
>
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^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-05-30 15:02 ` Stefano Stabellini
@ 2016-05-30 16:37 ` Julien Grall
2016-05-31 9:27 ` Stefano Stabellini
0 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-30 16:37 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
Hi Stefano,
On 30/05/2016 16:02, Stefano Stabellini wrote:
> On Mon, 23 May 2016, Julien Grall wrote:
>> After each CPU has been started, we iterate through a list of CPU
>> errata to detect CPUs which need from hypervisor code patches.
>>
>> For each bug there is a function which check if that a particular CPU is
>> affected. This needs to be done on every CPUs to cover heterogenous
>> system properly.
>>
>> If a certain erratum has been detected, the capability bit will be set
>> and later the call to apply_alternatives() will trigger the actual code
>> patching.
>>
>> The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
>> v4.6-rc3.
>>
>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>>
>> ---
>> Changes in v2:
>> - Use XENLOG_INFO for the loglevel of the message
>> ---
>> xen/arch/arm/Makefile | 1 +
>> xen/arch/arm/cpuerrata.c | 26 ++++++++++++++++++++++++++
>> xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
>> xen/arch/arm/setup.c | 3 +++
>> xen/arch/arm/smpboot.c | 3 +++
>> xen/include/asm-arm/cpuerrata.h | 6 ++++++
>> xen/include/asm-arm/cpufeature.h | 15 +++++++++++++++
>> 7 files changed, 70 insertions(+)
>> create mode 100644 xen/arch/arm/cpuerrata.c
>> create mode 100644 xen/include/asm-arm/cpuerrata.h
>>
>> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
>> index 2d330aa..307578c 100644
>> --- a/xen/arch/arm/Makefile
>> +++ b/xen/arch/arm/Makefile
>> @@ -7,6 +7,7 @@ subdir-$(CONFIG_ACPI) += acpi
>> obj-$(CONFIG_ALTERNATIVE) += alternative.o
>> obj-y += bootfdt.o
>> obj-y += cpu.o
>> +obj-y += cpuerrata.o
>> obj-y += cpufeature.o
>> obj-y += decode.o
>> obj-y += device.o
>> diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
>> new file mode 100644
>> index 0000000..52d39f8
>> --- /dev/null
>> +++ b/xen/arch/arm/cpuerrata.c
>> @@ -0,0 +1,26 @@
>> +#include <xen/config.h>
>> +#include <asm/cpufeature.h>
>> +#include <asm/cpuerrata.h>
>> +
>> +#define MIDR_RANGE(model, min, max) \
>> + .matches = is_affected_midr_range, \
>> + .midr_model = model, \
>> + .midr_range_min = min, \
>> + .midr_range_max = max
>> +
>> +static bool_t __maybe_unused
>
> I would remove __maybe_unused given that you are going to use this
> function in later patches.
The user can decide to disable all the errata, so this function will be
unused.
Also, if I drop the __may_unused now, the compilation will fail because
nobody is use it so far.
>> +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
>> +{
>> + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits, entry->midr_model,
>> + entry->midr_range_min,
>> + entry->midr_range_max);
>> +}
>> +
>> +static const struct arm_cpu_capabilities arm_errata[] = {
>> + {},
>> +};
>> +
>> +void check_local_cpu_errata(void)
>> +{
>> + update_cpu_capabilities(arm_errata, "enabled workaround for");
>> +}
>
> update_cpu_capabilities should actually be called on arm64 only, right?
> Given that runtime patching is unimplemented on arm32. I wouldn't want
> to rely on the fact that we don't have any arm32 workarounds at the
> moment.
Whilst runtime patching is making use of the cpu features, not all the
features (or erratum) may require runtime patching.
So I deliberately keep this code enabled on ARM32.
>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>> index 7a1b56b..088625b 100644
>> --- a/xen/arch/arm/cpufeature.c
>> +++ b/xen/arch/arm/cpufeature.c
>> @@ -24,6 +24,22 @@
>>
>> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>
>> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
>> + const char *info)
>
> The info parameter is unnecessary.
It is used in the printk below:
printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
Regards,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-05-30 16:37 ` Julien Grall
@ 2016-05-31 9:27 ` Stefano Stabellini
2016-05-31 10:36 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-31 9:27 UTC (permalink / raw)
To: Julien Grall
Cc: Stefano Stabellini, wei.liu2, steve.capper, andre.przywara,
xen-devel, wei.chen
On Mon, 30 May 2016, Julien Grall wrote:
> Hi Stefano,
>
> On 30/05/2016 16:02, Stefano Stabellini wrote:
> > On Mon, 23 May 2016, Julien Grall wrote:
> > > After each CPU has been started, we iterate through a list of CPU
> > > errata to detect CPUs which need from hypervisor code patches.
> > >
> > > For each bug there is a function which check if that a particular CPU is
> > > affected. This needs to be done on every CPUs to cover heterogenous
> > > system properly.
> > >
> > > If a certain erratum has been detected, the capability bit will be set
> > > and later the call to apply_alternatives() will trigger the actual code
> > > patching.
> > >
> > > The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
> > > v4.6-rc3.
> > >
> > > Signed-off-by: Julien Grall <julien.grall@arm.com>
> > >
> > > ---
> > > Changes in v2:
> > > - Use XENLOG_INFO for the loglevel of the message
> > > ---
> > > xen/arch/arm/Makefile | 1 +
> > > xen/arch/arm/cpuerrata.c | 26 ++++++++++++++++++++++++++
> > > xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
> > > xen/arch/arm/setup.c | 3 +++
> > > xen/arch/arm/smpboot.c | 3 +++
> > > xen/include/asm-arm/cpuerrata.h | 6 ++++++
> > > xen/include/asm-arm/cpufeature.h | 15 +++++++++++++++
> > > 7 files changed, 70 insertions(+)
> > > create mode 100644 xen/arch/arm/cpuerrata.c
> > > create mode 100644 xen/include/asm-arm/cpuerrata.h
> > >
> > > diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> > > index 2d330aa..307578c 100644
> > > --- a/xen/arch/arm/Makefile
> > > +++ b/xen/arch/arm/Makefile
> > > @@ -7,6 +7,7 @@ subdir-$(CONFIG_ACPI) += acpi
> > > obj-$(CONFIG_ALTERNATIVE) += alternative.o
> > > obj-y += bootfdt.o
> > > obj-y += cpu.o
> > > +obj-y += cpuerrata.o
> > > obj-y += cpufeature.o
> > > obj-y += decode.o
> > > obj-y += device.o
> > > diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
> > > new file mode 100644
> > > index 0000000..52d39f8
> > > --- /dev/null
> > > +++ b/xen/arch/arm/cpuerrata.c
> > > @@ -0,0 +1,26 @@
> > > +#include <xen/config.h>
> > > +#include <asm/cpufeature.h>
> > > +#include <asm/cpuerrata.h>
> > > +
> > > +#define MIDR_RANGE(model, min, max) \
> > > + .matches = is_affected_midr_range, \
> > > + .midr_model = model, \
> > > + .midr_range_min = min, \
> > > + .midr_range_max = max
> > > +
> > > +static bool_t __maybe_unused
> >
> > I would remove __maybe_unused given that you are going to use this
> > function in later patches.
>
> The user can decide to disable all the errata, so this function will be
> unused.
>
> Also, if I drop the __may_unused now, the compilation will fail because nobody
> is use it so far.
Ah, I see.
> > > +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
> > > +{
> > > + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits,
> > > entry->midr_model,
> > > + entry->midr_range_min,
> > > + entry->midr_range_max);
> > > +}
> > > +
> > > +static const struct arm_cpu_capabilities arm_errata[] = {
> > > + {},
> > > +};
> > > +
> > > +void check_local_cpu_errata(void)
> > > +{
> > > + update_cpu_capabilities(arm_errata, "enabled workaround for");
> > > +}
> >
> > update_cpu_capabilities should actually be called on arm64 only, right?
> > Given that runtime patching is unimplemented on arm32. I wouldn't want
> > to rely on the fact that we don't have any arm32 workarounds at the
> > moment.
>
> Whilst runtime patching is making use of the cpu features, not all the
> features (or erratum) may require runtime patching.
>
> So I deliberately keep this code enabled on ARM32.
All right. But then what is stopping people from reading
docs/misc/arm/silicon-errata.txt and trying to use it on arm32?
> > > diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
> > > index 7a1b56b..088625b 100644
> > > --- a/xen/arch/arm/cpufeature.c
> > > +++ b/xen/arch/arm/cpufeature.c
> > > @@ -24,6 +24,22 @@
> > >
> > > DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
> > >
> > > +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> > > + const char *info)
> >
> > The info parameter is unnecessary.
>
> It is used in the printk below:
>
> printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
I know. Couldn't you just write the message directly below? It doesn't
look like that passing around that string is adding much value to the
code.
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-05-31 9:27 ` Stefano Stabellini
@ 2016-05-31 10:36 ` Julien Grall
2016-06-01 9:46 ` Stefano Stabellini
0 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-31 10:36 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
Hi Stefano,
On 31/05/16 10:27, Stefano Stabellini wrote:
> On Mon, 30 May 2016, Julien Grall wrote:
>> On 30/05/2016 16:02, Stefano Stabellini wrote:
>>> On Mon, 23 May 2016, Julien Grall wrote:
>>>> After each CPU has been started, we iterate through a list of CPU
>>>> errata to detect CPUs which need from hypervisor code patches.
>>>>
>>>> For each bug there is a function which check if that a particular CPU is
>>>> affected. This needs to be done on every CPUs to cover heterogenous
>>>> system properly.
>>>>
>>>> If a certain erratum has been detected, the capability bit will be set
>>>> and later the call to apply_alternatives() will trigger the actual code
>>>> patching.
>>>>
>>>> The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
>>>> v4.6-rc3.
>>>>
>>>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>>>>
>>>> ---
>>>> Changes in v2:
>>>> - Use XENLOG_INFO for the loglevel of the message
>>>> ---
>>>> xen/arch/arm/Makefile | 1 +
>>>> xen/arch/arm/cpuerrata.c | 26 ++++++++++++++++++++++++++
>>>> xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
>>>> xen/arch/arm/setup.c | 3 +++
>>>> xen/arch/arm/smpboot.c | 3 +++
>>>> xen/include/asm-arm/cpuerrata.h | 6 ++++++
>>>> xen/include/asm-arm/cpufeature.h | 15 +++++++++++++++
>>>> 7 files changed, 70 insertions(+)
>>>> create mode 100644 xen/arch/arm/cpuerrata.c
>>>> create mode 100644 xen/include/asm-arm/cpuerrata.h
>>>>
>>>> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
>>>> index 2d330aa..307578c 100644
>>>> --- a/xen/arch/arm/Makefile
>>>> +++ b/xen/arch/arm/Makefile
>>>> @@ -7,6 +7,7 @@ subdir-$(CONFIG_ACPI) += acpi
>>>> obj-$(CONFIG_ALTERNATIVE) += alternative.o
>>>> obj-y += bootfdt.o
>>>> obj-y += cpu.o
>>>> +obj-y += cpuerrata.o
>>>> obj-y += cpufeature.o
>>>> obj-y += decode.o
>>>> obj-y += device.o
>>>> diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
>>>> new file mode 100644
>>>> index 0000000..52d39f8
>>>> --- /dev/null
>>>> +++ b/xen/arch/arm/cpuerrata.c
>>>> @@ -0,0 +1,26 @@
>>>> +#include <xen/config.h>
>>>> +#include <asm/cpufeature.h>
>>>> +#include <asm/cpuerrata.h>
>>>> +
>>>> +#define MIDR_RANGE(model, min, max) \
>>>> + .matches = is_affected_midr_range, \
>>>> + .midr_model = model, \
>>>> + .midr_range_min = min, \
>>>> + .midr_range_max = max
>>>> +
>>>> +static bool_t __maybe_unused
>>>
>>> I would remove __maybe_unused given that you are going to use this
>>> function in later patches.
>>
>> The user can decide to disable all the errata, so this function will be
>> unused.
>>
>> Also, if I drop the __may_unused now, the compilation will fail because nobody
>> is use it so far.
>
> Ah, I see.
>
>
>>>> +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
>>>> +{
>>>> + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits,
>>>> entry->midr_model,
>>>> + entry->midr_range_min,
>>>> + entry->midr_range_max);
>>>> +}
>>>> +
>>>> +static const struct arm_cpu_capabilities arm_errata[] = {
>>>> + {},
>>>> +};
>>>> +
>>>> +void check_local_cpu_errata(void)
>>>> +{
>>>> + update_cpu_capabilities(arm_errata, "enabled workaround for");
>>>> +}
>>>
>>> update_cpu_capabilities should actually be called on arm64 only, right?
>>> Given that runtime patching is unimplemented on arm32. I wouldn't want
>>> to rely on the fact that we don't have any arm32 workarounds at the
>>> moment.
>>
>> Whilst runtime patching is making use of the cpu features, not all the
>> features (or erratum) may require runtime patching.
>>
>> So I deliberately keep this code enabled on ARM32.
>
> All right. But then what is stopping people from reading
> docs/misc/arm/silicon-errata.txt and trying to use it on arm32?
silicon-errata does not always mean runtime patching. It is possible to
workaround in a different way (see for instance #834220 or #852523) or
check a flag because it is not in hot path (such as erratum during the
initialization).
>
>>>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>>>> index 7a1b56b..088625b 100644
>>>> --- a/xen/arch/arm/cpufeature.c
>>>> +++ b/xen/arch/arm/cpufeature.c
>>>> @@ -24,6 +24,22 @@
>>>>
>>>> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>>>
>>>> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
>>>> + const char *info)
>>>
>>> The info parameter is unnecessary.
>>
>> It is used in the printk below:
>>
>> printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
>
> I know. Couldn't you just write the message directly below? It doesn't
> look like that passing around that string is adding much value to the
> code.
Because we will gain soon support of ARMv8.1 features which will use the
same function to update the capabilities.
Regards,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-05-31 10:36 ` Julien Grall
@ 2016-06-01 9:46 ` Stefano Stabellini
2016-06-01 12:47 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Stefano Stabellini @ 2016-06-01 9:46 UTC (permalink / raw)
To: Julien Grall
Cc: Stefano Stabellini, wei.liu2, steve.capper, andre.przywara,
xen-devel, wei.chen
On Tue, 31 May 2016, Julien Grall wrote:
> > > > > +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
> > > > > +{
> > > > > + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits,
> > > > > entry->midr_model,
> > > > > + entry->midr_range_min,
> > > > > + entry->midr_range_max);
> > > > > +}
> > > > > +
> > > > > +static const struct arm_cpu_capabilities arm_errata[] = {
> > > > > + {},
> > > > > +};
> > > > > +
> > > > > +void check_local_cpu_errata(void)
> > > > > +{
> > > > > + update_cpu_capabilities(arm_errata, "enabled workaround for");
> > > > > +}
> > > >
> > > > update_cpu_capabilities should actually be called on arm64 only, right?
> > > > Given that runtime patching is unimplemented on arm32. I wouldn't want
> > > > to rely on the fact that we don't have any arm32 workarounds at the
> > > > moment.
> > >
> > > Whilst runtime patching is making use of the cpu features, not all the
> > > features (or erratum) may require runtime patching.
> > >
> > > So I deliberately keep this code enabled on ARM32.
> >
> > All right. But then what is stopping people from reading
> > docs/misc/arm/silicon-errata.txt and trying to use it on arm32?
>
> silicon-errata does not always mean runtime patching. It is possible to
> workaround in a different way (see for instance #834220 or #852523) or check a
> flag because it is not in hot path (such as erratum during the
> initialization).
Fair enough. Can we at least add a line to the doc to explain that
runtime patching is left unimplemented on arm32?
> > > > > diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
> > > > > index 7a1b56b..088625b 100644
> > > > > --- a/xen/arch/arm/cpufeature.c
> > > > > +++ b/xen/arch/arm/cpufeature.c
> > > > > @@ -24,6 +24,22 @@
> > > > >
> > > > > DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
> > > > >
> > > > > +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> > > > > + const char *info)
> > > >
> > > > The info parameter is unnecessary.
> > >
> > > It is used in the printk below:
> > >
> > > printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
> >
> > I know. Couldn't you just write the message directly below? It doesn't
> > look like that passing around that string is adding much value to the
> > code.
>
> Because we will gain soon support of ARMv8.1 features which will use the same
> function to update the capabilities.
In that case I'd say make this patch sane, then add a paramter when
ARMv8.1 features are introduced.
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-06-01 9:46 ` Stefano Stabellini
@ 2016-06-01 12:47 ` Julien Grall
2016-06-02 11:43 ` Julien Grall
2016-06-02 11:45 ` Julien Grall
0 siblings, 2 replies; 38+ messages in thread
From: Julien Grall @ 2016-06-01 12:47 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
Hi Stefano,
On 01/06/16 10:46, Stefano Stabellini wrote:
> On Tue, 31 May 2016, Julien Grall wrote:
>>>>>> +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
>>>>>> +{
>>>>>> + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits,
>>>>>> entry->midr_model,
>>>>>> + entry->midr_range_min,
>>>>>> + entry->midr_range_max);
>>>>>> +}
>>>>>> +
>>>>>> +static const struct arm_cpu_capabilities arm_errata[] = {
>>>>>> + {},
>>>>>> +};
>>>>>> +
>>>>>> +void check_local_cpu_errata(void)
>>>>>> +{
>>>>>> + update_cpu_capabilities(arm_errata, "enabled workaround for");
>>>>>> +}
>>>>>
>>>>> update_cpu_capabilities should actually be called on arm64 only, right?
>>>>> Given that runtime patching is unimplemented on arm32. I wouldn't want
>>>>> to rely on the fact that we don't have any arm32 workarounds at the
>>>>> moment.
>>>>
>>>> Whilst runtime patching is making use of the cpu features, not all the
>>>> features (or erratum) may require runtime patching.
>>>>
>>>> So I deliberately keep this code enabled on ARM32.
>>>
>>> All right. But then what is stopping people from reading
>>> docs/misc/arm/silicon-errata.txt and trying to use it on arm32?
>>
>> silicon-errata does not always mean runtime patching. It is possible to
>> workaround in a different way (see for instance #834220 or #852523) or check a
>> flag because it is not in hot path (such as erratum during the
>> initialization).
>
> Fair enough. Can we at least add a line to the doc to explain that
> runtime patching is left unimplemented on arm32?
I can do that.
>
>
>>>>>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>>>>>> index 7a1b56b..088625b 100644
>>>>>> --- a/xen/arch/arm/cpufeature.c
>>>>>> +++ b/xen/arch/arm/cpufeature.c
>>>>>> @@ -24,6 +24,22 @@
>>>>>>
>>>>>> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>>>>>
>>>>>> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
>>>>>> + const char *info)
>>>>>
>>>>> The info parameter is unnecessary.
>>>>
>>>> It is used in the printk below:
>>>>
>>>> printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
>>>
>>> I know. Couldn't you just write the message directly below? It doesn't
>>> look like that passing around that string is adding much value to the
>>> code.
>>
>> Because we will gain soon support of ARMv8.1 features which will use the same
>> function to update the capabilities.
>
> In that case I'd say make this patch sane, then add a paramter when
> ARMv8.1 features are introduced.
I am not in favor of that. cpufeature.c is supposed to be an abstraction
to be used by both the features framework and the errata framework.
It sounds weird to have a message "errata:" in a file cpufeature.c.
Regards,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-06-01 12:47 ` Julien Grall
@ 2016-06-02 11:43 ` Julien Grall
2016-06-02 11:45 ` Julien Grall
1 sibling, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-06-02 11:43 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
On 01/06/16 13:47, Julien Grall wrote:
>>>>>>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>>>>>>> index 7a1b56b..088625b 100644
>>>>>>> --- a/xen/arch/arm/cpufeature.c
>>>>>>> +++ b/xen/arch/arm/cpufeature.c
>>>>>>> @@ -24,6 +24,22 @@
>>>>>>>
>>>>>>> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>>>>>>
>>>>>>> +void update_cpu_capabilities(const struct arm_cpu_capabilities
>>>>>>> *caps,
>>>>>>> + const char *info)
>>>>>>
>>>>>> The info parameter is unnecessary.
>>>>>
>>>>> It is used in the printk below:
>>>>>
>>>>> printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
>>>>
>>>> I know. Couldn't you just write the message directly below? It doesn't
>>>> look like that passing around that string is adding much value to the
>>>> code.
>>>
>>> Because we will gain soon support of ARMv8.1 features which will use
>>> the same
>>> function to update the capabilities.
>>
>> In that case I'd say make this patch sane, then add a paramter when
>> ARMv8.1 features are introduced.
>
> I am not in favor of that. cpufeature.c is supposed to be an abstraction
> to be used by both the features framework and the errata framework.
>
> It sounds weird to have a message "errata:" in a file cpufeature.c.
I thought a bit more, I will move the function to cpuerrata.c for the
time being.
Cheers,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
2016-06-01 12:47 ` Julien Grall
2016-06-02 11:43 ` Julien Grall
@ 2016-06-02 11:45 ` Julien Grall
1 sibling, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-06-02 11:45 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
On 01/06/16 13:47, Julien Grall wrote:
>>>>>>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>>>>>>> index 7a1b56b..088625b 100644
>>>>>>> --- a/xen/arch/arm/cpufeature.c
>>>>>>> +++ b/xen/arch/arm/cpufeature.c
>>>>>>> @@ -24,6 +24,22 @@
>>>>>>>
>>>>>>> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>>>>>>
>>>>>>> +void update_cpu_capabilities(const struct arm_cpu_capabilities
>>>>>>> *caps,
>>>>>>> + const char *info)
>>>>>>
>>>>>> The info parameter is unnecessary.
>>>>>
>>>>> It is used in the printk below:
>>>>>
>>>>> printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
>>>>
>>>> I know. Couldn't you just write the message directly below? It doesn't
>>>> look like that passing around that string is adding much value to the
>>>> code.
>>>
>>> Because we will gain soon support of ARMv8.1 features which will use
>>> the same
>>> function to update the capabilities.
>>
>> In that case I'd say make this patch sane, then add a paramter when
>> ARMv8.1 features are introduced.
>
> I am not in favor of that. cpufeature.c is supposed to be an abstraction
> to be used by both the features framework and the errata framework.
>
> It sounds weird to have a message "errata:" in a file cpufeature.c.
I thought a bit more, I will move the function to cpuerrata.c for the
time being.
Cheers,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (9 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:38 ` Andrew Cooper
2016-05-30 15:08 ` Stefano Stabellini
2016-05-23 14:17 ` [PATCH v2 12/15] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
` (3 subsequent siblings)
14 siblings, 2 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
The new document will help to keep track of all the erratum that Xen is
able to handle.
The text is based on the Linux doc in Documents/arm64/silicon-errata.txt.
Also list the current errata that Xen is aware of.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
docs/misc/arm/silicon-errata.txt | 45 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
create mode 100644 docs/misc/arm/silicon-errata.txt
diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
new file mode 100644
index 0000000..3f0d32b
--- /dev/null
+++ b/docs/misc/arm/silicon-errata.txt
@@ -0,0 +1,45 @@
+ Silicon Errata and Software Workarounds
+ =======================================
+
+It is an unfortunate fact of life that hardware is often produced with
+so-called "errata", which can cause it to deviate from the architecture
+under specific circumstances. For hardware produced by ARM, these
+errata are broadly classified into the following categories:
+
+ Category A: A critical error without a viable workaround.
+ Category B: A significant or critical error with an acceptable
+ workaround.
+ Category C: A minor error that is not expected to occur under normal
+ operation.
+
+For more information, consult one of the "Software Developers Errata
+Notice" documents available on infocenter.arm.com (registration
+required).
+
+As far as Xen is concerned, Category B errata may require some special
+treatment in the hypervisor. For example, avoiding a particular sequence
+of code, or configuring the processor in a particular way. A less common
+situation may require similar actions in order to declassify a Category A
+erratum into a Category C erratum. These are collectively known as
+"software workarounds" and are only required in the minority of cases
+(e.g. those cases that both require a non-secure workaround *and* can
+be triggered by Linux).
+
+For software workarounds that may adversely impact systems unaffected by
+the erratum in question, a Kconfig entry is added under "ARM errata
+workarounds via the alternatives framework". These are enabled by default
+and patched in at runtime when an affected CPU is detected. For
+less-intrusive workarounds, a Kconfig option is not available and the code
+is structured (preferably with a comment) in such a way that the erratum
+will not be hit.
+
+This approach can make it slightly onerous to determine exactly which
+errata are worked around in an arbitrary hypervisor source tree, so this
+file acts as a registry of software workarounds in the Xen hypervisor and
+will be updated when new workarounds are committed and backported to
+stable hypervisors.
+
+| Implementor | Component | Erratum ID | Kconfig |
++----------------+-----------------+-----------------+-------------------------+
+| ARM | Cortex-A15 | #766422 | N/A |
+| ARM | Cortex-A57 | #852523 | N/A |
--
1.9.1
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen
2016-05-23 14:17 ` [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen Julien Grall
@ 2016-05-23 14:38 ` Andrew Cooper
2016-05-24 9:13 ` Julien Grall
2016-05-30 15:08 ` Stefano Stabellini
1 sibling, 1 reply; 38+ messages in thread
From: Andrew Cooper @ 2016-05-23 14:38 UTC (permalink / raw)
To: Julien Grall, xen-devel
Cc: andre.przywara, sstabellini, wei.liu2, wei.chen, steve.capper
On 23/05/16 15:17, Julien Grall wrote:
> The new document will help to keep track of all the erratum that Xen is
> able to handle.
Just a grammar nit (which most native English speakers get wrong, given
its Latin roots)
An erratum, or Many errata.
In this case, I would suggest "... to keep track of each erratum Xen is
able to handle."
~Andrew
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen
2016-05-23 14:38 ` Andrew Cooper
@ 2016-05-24 9:13 ` Julien Grall
0 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-24 9:13 UTC (permalink / raw)
To: Andrew Cooper, xen-devel
Cc: andre.przywara, sstabellini, wei.liu2, wei.chen, steve.capper
Hi Andrew,
On 23/05/2016 15:38, Andrew Cooper wrote:
> On 23/05/16 15:17, Julien Grall wrote:
>> The new document will help to keep track of all the erratum that Xen is
>> able to handle.
>
> Just a grammar nit (which most native English speakers get wrong, given
> its Latin roots)
>
> An erratum, or Many errata.
I know about that. I was not sure whether it is "all + plural" or "all +
singular".
>
> In this case, I would suggest "... to keep track of each erratum Xen is
> able to handle."
I will update the commmit message.
Cheers,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen
2016-05-23 14:17 ` [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen Julien Grall
2016-05-23 14:38 ` Andrew Cooper
@ 2016-05-30 15:08 ` Stefano Stabellini
1 sibling, 0 replies; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 15:08 UTC (permalink / raw)
To: Julien Grall
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara, xen-devel, wei.chen
On Mon, 23 May 2016, Julien Grall wrote:
> The new document will help to keep track of all the erratum that Xen is
> able to handle.
>
> The text is based on the Linux doc in Documents/arm64/silicon-errata.txt.
>
> Also list the current errata that Xen is aware of.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> ---
> docs/misc/arm/silicon-errata.txt | 45 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
> create mode 100644 docs/misc/arm/silicon-errata.txt
>
> diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
> new file mode 100644
> index 0000000..3f0d32b
> --- /dev/null
> +++ b/docs/misc/arm/silicon-errata.txt
> @@ -0,0 +1,45 @@
> + Silicon Errata and Software Workarounds
> + =======================================
> +
> +It is an unfortunate fact of life that hardware is often produced with
> +so-called "errata", which can cause it to deviate from the architecture
> +under specific circumstances. For hardware produced by ARM, these
> +errata are broadly classified into the following categories:
> +
> + Category A: A critical error without a viable workaround.
> + Category B: A significant or critical error with an acceptable
> + workaround.
> + Category C: A minor error that is not expected to occur under normal
> + operation.
> +
> +For more information, consult one of the "Software Developers Errata
> +Notice" documents available on infocenter.arm.com (registration
> +required).
> +
> +As far as Xen is concerned, Category B errata may require some special
> +treatment in the hypervisor. For example, avoiding a particular sequence
> +of code, or configuring the processor in a particular way. A less common
> +situation may require similar actions in order to declassify a Category A
> +erratum into a Category C erratum. These are collectively known as
> +"software workarounds" and are only required in the minority of cases
> +(e.g. those cases that both require a non-secure workaround *and* can
> +be triggered by Linux).
^by Xen
> +For software workarounds that may adversely impact systems unaffected by
> +the erratum in question, a Kconfig entry is added under "ARM errata
> +workarounds via the alternatives framework". These are enabled by default
> +and patched in at runtime when an affected CPU is detected. For
> +less-intrusive workarounds, a Kconfig option is not available and the code
> +is structured (preferably with a comment) in such a way that the erratum
> +will not be hit.
> +
> +This approach can make it slightly onerous to determine exactly which
> +errata are worked around in an arbitrary hypervisor source tree, so this
> +file acts as a registry of software workarounds in the Xen hypervisor and
> +will be updated when new workarounds are committed and backported to
> +stable hypervisors.
> +
> +| Implementor | Component | Erratum ID | Kconfig |
> ++----------------+-----------------+-----------------+-------------------------+
> +| ARM | Cortex-A15 | #766422 | N/A |
> +| ARM | Cortex-A57 | #852523 | N/A |
> --
> 1.9.1
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v2 12/15] xen/arm: arm64: Add Cortex-A53 cache errata workaround
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (10 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 11/15] xen/arm: Document the errata implemented in Xen Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-24 2:46 ` Chenxiao Zhao
2016-05-23 14:17 ` [PATCH v2 13/15] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround Julien Grall
` (2 subsequent siblings)
14 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
The ARM errata 819472, 827319 and 824069 define the same workaround for
these hardware issues in certain Cortex-A53 parts.
The cache instructions "dc cvac" and "dc cvau" need to be upgraded to
"dc civac".
Use the alternative framework to replace those instructions only on
affected cores.
Whilst the errata affect cache instructions issued at any exception
level, it is not necessary to trap EL1/EL0 data cache instructions
access in order to upgrade them. Indeed the data cache corruption would
always be at the address used by the data cache instructions. Note that
this address could point to a shared memory between guests and the
hypervisors, however all the information present in it are be validated
before any use.
Therefore a malicious guest could only hurt itself. Note that all the
guests should implement/enable the workaround for the affected cores.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
docs/misc/arm/silicon-errata.txt | 3 ++
xen/arch/arm/Kconfig | 71 ++++++++++++++++++++++++++++++++++++++++
xen/arch/arm/arm64/cache.S | 54 ++++++++++++++++++++++++++++++
xen/arch/arm/cpuerrata.c | 17 ++++++++++
xen/include/asm-arm/arm64/page.h | 7 +++-
xen/include/asm-arm/cpufeature.h | 4 ++-
xen/include/asm-arm/processor.h | 6 ++++
7 files changed, 160 insertions(+), 2 deletions(-)
diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
index 3f0d32b..9a2983b 100644
--- a/docs/misc/arm/silicon-errata.txt
+++ b/docs/misc/arm/silicon-errata.txt
@@ -42,4 +42,7 @@ stable hypervisors.
| Implementor | Component | Erratum ID | Kconfig |
+----------------+-----------------+-----------------+-------------------------+
| ARM | Cortex-A15 | #766422 | N/A |
+| ARM | Cortex-A53 | #827319 | ARM64_ERRATUM_827319 |
+| ARM | Cortex-A53 | #824069 | ARM64_ERRATUM_824069 |
+| ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 |
| ARM | Cortex-A57 | #852523 | N/A |
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 0141bd9..a473d9c 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -53,6 +53,77 @@ config ALTERNATIVE
endmenu
+menu "ARM errata workaround via the alternative framework"
+ depends on ALTERNATIVE
+
+config ARM64_ERRATUM_827319
+ bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
+ default y
+ depends on ARM_64
+ help
+ This option adds an alternative code sequence to work around ARM
+ erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
+ master interface and an L2 cache.
+
+ Under certain conditions this erratum can cause a clean line eviction
+ to occur at the same time as another transaction to the same address
+ on the AMBA 5 CHI interface, which can cause data corruption if the
+ interconnect reorders the two transactions.
+
+ The workaround promotes data cache clean instructions to
+ data cache clean-and-invalidate.
+ Please note that this does not necessarily enable the workaround,
+ as it depends on the alternative framework, which will only patch
+ the kernel if an affected CPU is detected.
+
+ If unsure, say Y.
+
+config ARM64_ERRATUM_824069
+ bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
+ default y
+ depends on ARM_64
+ help
+ This option adds an alternative code sequence to work around ARM
+ erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
+ to a coherent interconnect.
+
+ If a Cortex-A53 processor is executing a store or prefetch for
+ write instruction at the same time as a processor in another
+ cluster is executing a cache maintenance operation to the same
+ address, then this erratum might cause a clean cache line to be
+ incorrectly marked as dirty.
+
+ The workaround promotes data cache clean instructions to
+ data cache clean-and-invalidate.
+ Please note that this option does not necessarily enable the
+ workaround, as it depends on the alternative framework, which will
+ only patch the kernel if an affected CPU is detected.
+
+ If unsure, say Y.
+
+config ARM64_ERRATUM_819472
+ bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
+ default y
+ depends on ARM_64
+ help
+ This option adds an alternative code sequence to work around ARM
+ erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
+ present when it is connected to a coherent interconnect.
+
+ If the processor is executing a load and store exclusive sequence at
+ the same time as a processor in another cluster is executing a cache
+ maintenance operation to the same address, then this erratum might
+ cause data corruption.
+
+ The workaround promotes data cache clean instructions to
+ data cache clean-and-invalidate.
+ Please note that this does not necessarily enable the workaround,
+ as it depends on the alternative framework, which will only patch
+ the kernel if an affected CPU is detected.
+
+ If unsure, say Y.
+endmenu
+
source "common/Kconfig"
source "drivers/Kconfig"
diff --git a/xen/arch/arm/arm64/cache.S b/xen/arch/arm/arm64/cache.S
index eff4e16..6e49e25 100644
--- a/xen/arch/arm/arm64/cache.S
+++ b/xen/arch/arm/arm64/cache.S
@@ -19,6 +19,8 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <asm/alternative.h>
+
/*
* dcache_line_size - get the minimum D-cache line size from the CTR register.
*/
@@ -30,6 +32,58 @@
.endm
/*
+<<<<<<< HEAD
+=======
+ * icache_line_size - get the minimum I-cache line size from the CTR register.
+ */
+ .macro icache_line_size, reg, tmp
+ mrs \tmp, ctr_el0 // read CTR
+ and \tmp, \tmp, #0xf // cache line size encoding
+ mov \reg, #4 // bytes per word
+ lsl \reg, \reg, \tmp // actual cache line size
+ .endm
+
+/*
+ * flush_icache_range(start,end)
+ *
+ * Ensure that the I and D caches are coherent within specified region.
+ * This is typically used when code has been written to a memory region,
+ * and will be executed.
+ *
+ * - start - virtual start address of region
+ * - end - virtual end address of region
+ */
+ENTRY(flush_icache_range)
+ dcache_line_size x2, x3
+ sub x3, x2, #1
+ bic x4, x0, x3
+1:
+alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
+ dc cvau, x4
+alternative_else
+ dc civac, x4
+alternative_endif
+ add x4, x4, x2
+ cmp x4, x1
+ b.lo 1b
+ dsb ish
+
+ icache_line_size x2, x3
+ sub x3, x2, #1
+ bic x4, x0, x3
+1:
+ ic ivau, x4 // invalidate I line PoU
+ add x4, x4, x2
+ cmp x4, x1
+ b.lo 1b
+ dsb ish
+ isb
+ mov x0, #0
+ ret
+ENDPROC(flush_icache_range)
+
+/*
+>>>>>>> 3b39ae7... xen/arm: arm64: Add Cortex-A53 cache errata workaround
* __flush_dcache_area(kaddr, size)
*
* Ensure that the data held in the page kaddr is written back to the
diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
index 52d39f8..211b520 100644
--- a/xen/arch/arm/cpuerrata.c
+++ b/xen/arch/arm/cpuerrata.c
@@ -17,6 +17,23 @@ is_affected_midr_range(const struct arm_cpu_capabilities *entry)
}
static const struct arm_cpu_capabilities arm_errata[] = {
+#if defined(CONFIG_ARM64_ERRATUM_827319) || \
+ defined(CONFIG_ARM64_ERRATUM_824069)
+ {
+ /* Cortex-A53 r0p[012] */
+ .desc = "ARM errata 827319, 824069",
+ .capability = ARM64_WORKAROUND_CLEAN_CACHE,
+ MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x02),
+ },
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_819472
+ {
+ /* Cortex-A53 r0[01] */
+ .desc = "ARM erratum 819472",
+ .capability = ARM64_WORKAROUND_CLEAN_CACHE,
+ MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x01),
+ },
+#endif
{},
};
diff --git a/xen/include/asm-arm/arm64/page.h b/xen/include/asm-arm/arm64/page.h
index fbdc8fb..79ef7bd 100644
--- a/xen/include/asm-arm/arm64/page.h
+++ b/xen/include/asm-arm/arm64/page.h
@@ -3,6 +3,8 @@
#ifndef __ASSEMBLY__
+#include <asm/alternative.h>
+
/* Write a pagetable entry */
static inline void write_pte(lpae_t *p, lpae_t pte)
{
@@ -18,7 +20,10 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
#define __invalidate_dcache_one(R) "dc ivac, %" #R ";"
/* Inline ASM to flush dcache on register R (may be an inline asm operand) */
-#define __clean_dcache_one(R) "dc cvac, %" #R ";"
+#define __clean_dcache_one(R) \
+ ALTERNATIVE("dc cvac, %" #R ";", \
+ "dc civac, %" #R ";", \
+ ARM64_WORKAROUND_CLEAN_CACHE) \
/* Inline ASM to clean and invalidate dcache on register R (may be an
* inline asm operand) */
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index fb57295..474a778 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -35,7 +35,9 @@
#endif
#define cpu_has_security (boot_cpu_feature32(security) > 0)
-#define ARM_NCAPS 0
+#define ARM64_WORKAROUND_CLEAN_CACHE 0
+
+#define ARM_NCAPS 1
#ifndef __ASSEMBLY__
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 1b701c5..4123951 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -44,6 +44,12 @@
_model == (model) && _rv >= (rv_min) && _rv <= (rv_max); \
})
+#define ARM_CPU_IMP_ARM 0x41
+
+#define ARM_CPU_PART_CORTEX_A53 0xD03
+
+#define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
+
/* MPIDR Multiprocessor Affinity Register */
#define _MPIDR_UP (30)
#define MPIDR_UP (_AC(1,U) << _MPIDR_UP)
--
1.9.1
_______________________________________________
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http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 12/15] xen/arm: arm64: Add Cortex-A53 cache errata workaround
2016-05-23 14:17 ` [PATCH v2 12/15] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
@ 2016-05-24 2:46 ` Chenxiao Zhao
2016-05-24 8:56 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Chenxiao Zhao @ 2016-05-24 2:46 UTC (permalink / raw)
To: Julien Grall, xen-devel
Cc: andre.przywara, sstabellini, wei.liu2, wei.chen, steve.capper
[-- Attachment #1.1: Type: text/plain, Size: 11304 bytes --]
On Mon, May 23, 2016 at 7:22 AM Julien Grall <julien.grall@arm.com> wrote:
> The ARM errata 819472, 827319 and 824069 define the same workaround for
> these hardware issues in certain Cortex-A53 parts.
>
> The cache instructions "dc cvac" and "dc cvau" need to be upgraded to
> "dc civac".
>
> Use the alternative framework to replace those instructions only on
> affected cores.
>
> Whilst the errata affect cache instructions issued at any exception
> level, it is not necessary to trap EL1/EL0 data cache instructions
> access in order to upgrade them. Indeed the data cache corruption would
> always be at the address used by the data cache instructions. Note that
> this address could point to a shared memory between guests and the
> hypervisors, however all the information present in it are be validated
> before any use.
>
> Therefore a malicious guest could only hurt itself. Note that all the
> guests should implement/enable the workaround for the affected cores.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> ---
> docs/misc/arm/silicon-errata.txt | 3 ++
> xen/arch/arm/Kconfig | 71
> ++++++++++++++++++++++++++++++++++++++++
> xen/arch/arm/arm64/cache.S | 54 ++++++++++++++++++++++++++++++
> xen/arch/arm/cpuerrata.c | 17 ++++++++++
> xen/include/asm-arm/arm64/page.h | 7 +++-
> xen/include/asm-arm/cpufeature.h | 4 ++-
> xen/include/asm-arm/processor.h | 6 ++++
> 7 files changed, 160 insertions(+), 2 deletions(-)
>
> diff --git a/docs/misc/arm/silicon-errata.txt
> b/docs/misc/arm/silicon-errata.txt
> index 3f0d32b..9a2983b 100644
> --- a/docs/misc/arm/silicon-errata.txt
> +++ b/docs/misc/arm/silicon-errata.txt
> @@ -42,4 +42,7 @@ stable hypervisors.
> | Implementor | Component | Erratum ID | Kconfig
> |
>
> +----------------+-----------------+-----------------+-------------------------+
> | ARM | Cortex-A15 | #766422 | N/A
> |
> +| ARM | Cortex-A53 | #827319 |
> ARM64_ERRATUM_827319 |
> +| ARM | Cortex-A53 | #824069 |
> ARM64_ERRATUM_824069 |
> +| ARM | Cortex-A53 | #819472 |
> ARM64_ERRATUM_819472 |
> | ARM | Cortex-A57 | #852523 | N/A
> |
> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
> index 0141bd9..a473d9c 100644
> --- a/xen/arch/arm/Kconfig
> +++ b/xen/arch/arm/Kconfig
> @@ -53,6 +53,77 @@ config ALTERNATIVE
>
> endmenu
>
> +menu "ARM errata workaround via the alternative framework"
> + depends on ALTERNATIVE
> +
> +config ARM64_ERRATUM_827319
> + bool "Cortex-A53: 827319: Data cache clean instructions might
> cause overlapping transactions to the interconnect"
> + default y
> + depends on ARM_64
> + help
> + This option adds an alternative code sequence to work around ARM
> + erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
> + master interface and an L2 cache.
> +
> + Under certain conditions this erratum can cause a clean line
> eviction
> + to occur at the same time as another transaction to the same
> address
> + on the AMBA 5 CHI interface, which can cause data corruption if
> the
> + interconnect reorders the two transactions.
> +
> + The workaround promotes data cache clean instructions to
> + data cache clean-and-invalidate.
> + Please note that this does not necessarily enable the workaround,
> + as it depends on the alternative framework, which will only patch
> + the kernel if an affected CPU is detected.
> +
> + If unsure, say Y.
> +
> +config ARM64_ERRATUM_824069
> + bool "Cortex-A53: 824069: Cache line might not be marked as clean
> after a CleanShared snoop"
> + default y
> + depends on ARM_64
> + help
> + This option adds an alternative code sequence to work around ARM
> + erratum 824069 on Cortex-A53 parts up to r0p2 when it is
> connected
> + to a coherent interconnect.
> +
> + If a Cortex-A53 processor is executing a store or prefetch for
> + write instruction at the same time as a processor in another
> + cluster is executing a cache maintenance operation to the same
> + address, then this erratum might cause a clean cache line to be
> + incorrectly marked as dirty.
> +
> + The workaround promotes data cache clean instructions to
> + data cache clean-and-invalidate.
> + Please note that this option does not necessarily enable the
> + workaround, as it depends on the alternative framework, which
> will
> + only patch the kernel if an affected CPU is detected.
> +
> + If unsure, say Y.
> +
> +config ARM64_ERRATUM_819472
> + bool "Cortex-A53: 819472: Store exclusive instructions might cause
> data corruption"
> + default y
> + depends on ARM_64
> + help
> + This option adds an alternative code sequence to work around ARM
> + erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
> + present when it is connected to a coherent interconnect.
> +
> + If the processor is executing a load and store exclusive
> sequence at
> + the same time as a processor in another cluster is executing a
> cache
> + maintenance operation to the same address, then this erratum
> might
> + cause data corruption.
> +
> + The workaround promotes data cache clean instructions to
> + data cache clean-and-invalidate.
> + Please note that this does not necessarily enable the workaround,
> + as it depends on the alternative framework, which will only patch
> + the kernel if an affected CPU is detected.
> +
> + If unsure, say Y.
> +endmenu
> +
> source "common/Kconfig"
>
> source "drivers/Kconfig"
> diff --git a/xen/arch/arm/arm64/cache.S b/xen/arch/arm/arm64/cache.S
> index eff4e16..6e49e25 100644
> --- a/xen/arch/arm/arm64/cache.S
> +++ b/xen/arch/arm/arm64/cache.S
> @@ -19,6 +19,8 @@
> * along with this program. If not, see <http://www.gnu.org/licenses/>.
> */
>
> +#include <asm/alternative.h>
> +
> /*
> * dcache_line_size - get the minimum D-cache line size from the CTR
> register.
> */
> @@ -30,6 +32,58 @@
> .endm
>
> /*
> +<<<<<<< HEAD
> +=======
> + * icache_line_size - get the minimum I-cache line size from the CTR
> register.
> + */
> + .macro icache_line_size, reg, tmp
> + mrs \tmp, ctr_el0 // read CTR
> + and \tmp, \tmp, #0xf // cache line size encoding
> + mov \reg, #4 // bytes per word
> + lsl \reg, \reg, \tmp // actual cache line size
> + .endm
> +
> +/*
> + * flush_icache_range(start,end)
> + *
> + * Ensure that the I and D caches are coherent within specified
> region.
> + * This is typically used when code has been written to a memory
> region,
> + * and will be executed.
> + *
> + * - start - virtual start address of region
> + * - end - virtual end address of region
> + */
> +ENTRY(flush_icache_range)
> + dcache_line_size x2, x3
> + sub x3, x2, #1
> + bic x4, x0, x3
> +1:
> +alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
> + dc cvau, x4
> +alternative_else
> + dc civac, x4
> +alternative_endif
> + add x4, x4, x2
> + cmp x4, x1
> + b.lo 1b
> + dsb ish
> +
> + icache_line_size x2, x3
> + sub x3, x2, #1
> + bic x4, x0, x3
> +1:
> + ic ivau, x4 // invalidate I line PoU
> + add x4, x4, x2
> + cmp x4, x1
> + b.lo 1b
> + dsb ish
> + isb
> + mov x0, #0
> + ret
> +ENDPROC(flush_icache_range)
> +
> +/*
> +>>>>>>> 3b39ae7... xen/arm: arm64: Add Cortex-A53 cache errata
workaround
>
Hi Julien,
This patch has a conflict, only can patched manually.
* __flush_dcache_area(kaddr, size)
> *
> * Ensure that the data held in the page kaddr is written back to the
> diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
> index 52d39f8..211b520 100644
> --- a/xen/arch/arm/cpuerrata.c
> +++ b/xen/arch/arm/cpuerrata.c
> @@ -17,6 +17,23 @@ is_affected_midr_range(const struct
> arm_cpu_capabilities *entry)
> }
>
> static const struct arm_cpu_capabilities arm_errata[] = {
> +#if defined(CONFIG_ARM64_ERRATUM_827319) || \
> + defined(CONFIG_ARM64_ERRATUM_824069)
> + {
> + /* Cortex-A53 r0p[012] */
> + .desc = "ARM errata 827319, 824069",
> + .capability = ARM64_WORKAROUND_CLEAN_CACHE,
> + MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x02),
> + },
> +#endif
> +#ifdef CONFIG_ARM64_ERRATUM_819472
> + {
> + /* Cortex-A53 r0[01] */
> + .desc = "ARM erratum 819472",
> + .capability = ARM64_WORKAROUND_CLEAN_CACHE,
> + MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x01),
> + },
> +#endif
> {},
> };
>
> diff --git a/xen/include/asm-arm/arm64/page.h
> b/xen/include/asm-arm/arm64/page.h
> index fbdc8fb..79ef7bd 100644
> --- a/xen/include/asm-arm/arm64/page.h
> +++ b/xen/include/asm-arm/arm64/page.h
> @@ -3,6 +3,8 @@
>
> #ifndef __ASSEMBLY__
>
> +#include <asm/alternative.h>
> +
> /* Write a pagetable entry */
> static inline void write_pte(lpae_t *p, lpae_t pte)
> {
> @@ -18,7 +20,10 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
> #define __invalidate_dcache_one(R) "dc ivac, %" #R ";"
>
> /* Inline ASM to flush dcache on register R (may be an inline asm
> operand) */
> -#define __clean_dcache_one(R) "dc cvac, %" #R ";"
> +#define __clean_dcache_one(R) \
> + ALTERNATIVE("dc cvac, %" #R ";", \
> + "dc civac, %" #R ";", \
> + ARM64_WORKAROUND_CLEAN_CACHE) \
>
> /* Inline ASM to clean and invalidate dcache on register R (may be an
> * inline asm operand) */
> diff --git a/xen/include/asm-arm/cpufeature.h
> b/xen/include/asm-arm/cpufeature.h
> index fb57295..474a778 100644
> --- a/xen/include/asm-arm/cpufeature.h
> +++ b/xen/include/asm-arm/cpufeature.h
> @@ -35,7 +35,9 @@
> #endif
> #define cpu_has_security (boot_cpu_feature32(security) > 0)
>
> -#define ARM_NCAPS 0
> +#define ARM64_WORKAROUND_CLEAN_CACHE 0
> +
> +#define ARM_NCAPS 1
>
> #ifndef __ASSEMBLY__
>
> diff --git a/xen/include/asm-arm/processor.h
> b/xen/include/asm-arm/processor.h
> index 1b701c5..4123951 100644
> --- a/xen/include/asm-arm/processor.h
> +++ b/xen/include/asm-arm/processor.h
> @@ -44,6 +44,12 @@
> _model == (model) && _rv >= (rv_min) && _rv <= (rv_max); \
> })
>
> +#define ARM_CPU_IMP_ARM 0x41
> +
> +#define ARM_CPU_PART_CORTEX_A53 0xD03
> +
> +#define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM,
> ARM_CPU_PART_CORTEX_A53)
> +
> /* MPIDR Multiprocessor Affinity Register */
> #define _MPIDR_UP (30)
> #define MPIDR_UP (_AC(1,U) << _MPIDR_UP)
> --
> 1.9.1
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>
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[-- Attachment #2: Type: text/plain, Size: 126 bytes --]
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^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v2 12/15] xen/arm: arm64: Add Cortex-A53 cache errata workaround
2016-05-24 2:46 ` Chenxiao Zhao
@ 2016-05-24 8:56 ` Julien Grall
0 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-24 8:56 UTC (permalink / raw)
To: Chenxiao Zhao, xen-devel
Cc: andre.przywara, sstabellini, wei.liu2, wei.chen, steve.capper
Hello,
Please configure your e-mail client to quote properly.
On 24/05/2016 03:46, Chenxiao Zhao wrote:
> On Mon, May 23, 2016 at 7:22 AM Julien Grall <julien.grall@arm.com
> <mailto:julien.grall@arm.com>> wrote:
> /*
> +<<<<<<< HEAD
> +=======
> + * icache_line_size - get the minimum I-cache line size from the
> CTR register.
> + */
> + .macro icache_line_size, reg, tmp
> + mrs \tmp, ctr_el0 // read CTR
> + and \tmp, \tmp, #0xf // cache line size
> encoding
> + mov \reg, #4 // bytes per word
> + lsl \reg, \reg, \tmp // actual cache line
> size
> + .endm
> +
> +/*
> + * flush_icache_range(start,end)
> + *
> + * Ensure that the I and D caches are coherent within specified
> region.
> + * This is typically used when code has been written to a
> memory region,
> + * and will be executed.
> + *
> + * - start - virtual start address of region
> + * - end - virtual end address of region
> + */
> +ENTRY(flush_icache_range)
> + dcache_line_size x2, x3
> + sub x3, x2, #1
> + bic x4, x0, x3
> +1:
> +alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
> + dc cvau, x4
> +alternative_else
> + dc civac, x4
> +alternative_endif
> + add x4, x4, x2
> + cmp x4, x1
> + b.lo 1b
> + dsb ish
> +
> + icache_line_size x2, x3
> + sub x3, x2, #1
> + bic x4, x0, x3
> +1:
> + ic ivau, x4 // invalidate I line PoU
> + add x4, x4, x2
> + cmp x4, x1
> + b.lo 1b
> + dsb ish
> + isb
> + mov x0, #0
> + ret
> +ENDPROC(flush_icache_range)
> +
> +/*
> +>>>>>>> 3b39ae7... xen/arm: arm64: Add Cortex-A53 cache errata
>
> workaround
> This patch has a conflict, only can patched manually.
Whilst this patch contain a conflict because I have not rebased
correctly, it applies without any issue and compile on ARM64.
This is because >>>> are part of the comments. I will sent a new version
of this patch.
Regards,
--
Julien Grall
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^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v2 13/15] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (11 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 12/15] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-23 14:17 ` [PATCH v2 14/15] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails Julien Grall
2016-05-23 14:17 ` [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
14 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
The ARM erratum 832075 applies to certain revisions of Cortex-A57, one
of the workarounds is to change device loads into using load-acquire
semantics.
Use the alternative framework to enable the workaround only on affected
cores.
Whilst a guest could trigger the deadlock, it can be broken when the
processor is receiving an interrupt. As the Xen scheduler will always setup
a timer (firing to every 1ms to 300ms depending on the running time
slice) on each processor, the deadlock would last only few milliseconds
and only affects the guest time slice.
Therefore a malicious guest could only hurt itself. Note that all the
guests should implement/enable the workaround for the affected cores.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
Changes in v2:
- Update the commit message to explain why it is not necessary
to take care of possible deadlock from the guest.
---
docs/misc/arm/silicon-errata.txt | 1 +
xen/arch/arm/Kconfig | 20 ++++++++++++++++++++
xen/arch/arm/cpuerrata.c | 9 +++++++++
xen/include/asm-arm/arm64/io.h | 21 +++++++++++++++++----
xen/include/asm-arm/cpufeature.h | 3 ++-
xen/include/asm-arm/processor.h | 2 ++
6 files changed, 51 insertions(+), 5 deletions(-)
diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
index 9a2983b..ab2e5bc 100644
--- a/docs/misc/arm/silicon-errata.txt
+++ b/docs/misc/arm/silicon-errata.txt
@@ -46,3 +46,4 @@ stable hypervisors.
| ARM | Cortex-A53 | #824069 | ARM64_ERRATUM_824069 |
| ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 |
| ARM | Cortex-A57 | #852523 | N/A |
+| ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index a473d9c..e26c4c8 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -122,6 +122,26 @@ config ARM64_ERRATUM_819472
the kernel if an affected CPU is detected.
If unsure, say Y.
+
+config ARM64_ERRATUM_832075
+ bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
+ default y
+ depends on ARM_64
+ help
+ This option adds an alternative code sequence to work around ARM
+ erratum 832075 on Cortex-A57 parts up to r1p2.
+
+ Affected Cortex-A57 parts might deadlock when exclusive load/store
+ instructions to Write-Back memory are mixed with Device loads.
+
+ The workaround is to promote device loads to use Load-Acquire
+ semantics.
+ Please note that this does not necessarily enable the workaround,
+ as it depends on the alternative framework, which will only patch
+ the kernel if an affected CPU is detected.
+
+ If unsure, say Y.
+
endmenu
source "common/Kconfig"
diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
index 211b520..48fc87a 100644
--- a/xen/arch/arm/cpuerrata.c
+++ b/xen/arch/arm/cpuerrata.c
@@ -34,6 +34,15 @@ static const struct arm_cpu_capabilities arm_errata[] = {
MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x01),
},
#endif
+#ifdef CONFIG_ARM64_ERRATUM_832075
+ {
+ /* Cortex-A57 r0p0 - r1p2 */
+ .desc = "ARM erratum 832075",
+ .capability = ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE,
+ MIDR_RANGE(MIDR_CORTEX_A57, 0x00,
+ (1 << MIDR_VARIANT_SHIFT) | 2),
+ },
+#endif
{},
};
diff --git a/xen/include/asm-arm/arm64/io.h b/xen/include/asm-arm/arm64/io.h
index f80156f..30bfc78 100644
--- a/xen/include/asm-arm/arm64/io.h
+++ b/xen/include/asm-arm/arm64/io.h
@@ -22,6 +22,7 @@
#include <asm/system.h>
#include <asm/byteorder.h>
+#include <asm/alternative.h>
/*
* Generic IO read/write. These perform native-endian accesses.
@@ -49,28 +50,40 @@ static inline void __raw_writeq(u64 val, volatile void __iomem *addr)
static inline u8 __raw_readb(const volatile void __iomem *addr)
{
u8 val;
- asm volatile("ldrb %w0, [%1]" : "=r" (val) : "r" (addr));
+ asm volatile(ALTERNATIVE("ldrb %w0, [%1]",
+ "ldarb %w0, [%1]",
+ ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
+ : "=r" (val) : "r" (addr));
return val;
}
static inline u16 __raw_readw(const volatile void __iomem *addr)
{
u16 val;
- asm volatile("ldrh %w0, [%1]" : "=r" (val) : "r" (addr));
+ asm volatile(ALTERNATIVE("ldrh %w0, [%1]",
+ "ldarh %w0, [%1]",
+ ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
+ : "=r" (val) : "r" (addr));
return val;
}
static inline u32 __raw_readl(const volatile void __iomem *addr)
{
u32 val;
- asm volatile("ldr %w0, [%1]" : "=r" (val) : "r" (addr));
+ asm volatile(ALTERNATIVE("ldr %w0, [%1]",
+ "ldar %w0, [%1]",
+ ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
+ : "=r" (val) : "r" (addr));
return val;
}
static inline u64 __raw_readq(const volatile void __iomem *addr)
{
u64 val;
- asm volatile("ldr %0, [%1]" : "=r" (val) : "r" (addr));
+ asm volatile(ALTERNATIVE("ldr %0, [%1]",
+ "ldar %0, [%1]",
+ ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)
+ : "=r" (val) : "r" (addr));
return val;
}
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 474a778..78e2263 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -36,8 +36,9 @@
#define cpu_has_security (boot_cpu_feature32(security) > 0)
#define ARM64_WORKAROUND_CLEAN_CACHE 0
+#define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1
-#define ARM_NCAPS 1
+#define ARM_NCAPS 2
#ifndef __ASSEMBLY__
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 4123951..a2c0dbe 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -47,8 +47,10 @@
#define ARM_CPU_IMP_ARM 0x41
#define ARM_CPU_PART_CORTEX_A53 0xD03
+#define ARM_CPU_PART_CORTEX_A57 0xD07
#define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
+#define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
/* MPIDR Multiprocessor Affinity Register */
#define _MPIDR_UP (30)
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v2 14/15] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (12 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 13/15] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-30 14:50 ` Stefano Stabellini
2016-05-23 14:17 ` [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
14 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
Based on ARM ARM (D4.5.3 in ARM DDI 0486A and B3.12.7 in ARM DDI 0406C.c),
a Stage 1 translation error has priority over a Stage 2 translation error.
Therefore gva_to_ipa can only fail if another vCPU is playing with the
page table.
Rather than injecting a custom fault, replay the instruction and let the
processor injecting the correct fault.
This is fine as Xen is handling all the pending softirqs
(see leave_hypervisor_tail) before returning to the guest. One of them
is the scheduler which could reschuled the vCPU.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
Changes in v2:
- Update commit message to explain why a guest cannot DoS the
hypervisor with it.
---
xen/arch/arm/traps.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index c0325d5..3acdba0 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2410,7 +2410,7 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
rc = gva_to_ipa(gva, &gpa, GV2M_READ);
if ( rc == -EFAULT )
- goto bad_insn_abort;
+ return; /* Try again */
}
rc = p2m_mem_access_check(gpa, gva, npfec);
@@ -2422,7 +2422,6 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
break;
}
-bad_insn_abort:
inject_iabt_exception(regs, gva, hsr.len);
}
@@ -2452,7 +2451,7 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
{
rc = gva_to_ipa(info.gva, &info.gpa, GV2M_READ);
if ( rc == -EFAULT )
- goto bad_data_abort;
+ return; /* Try again */
}
switch ( dabt.dfsc & 0x3f )
--
1.9.1
_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 14/15] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails
2016-05-23 14:17 ` [PATCH v2 14/15] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails Julien Grall
@ 2016-05-30 14:50 ` Stefano Stabellini
0 siblings, 0 replies; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 14:50 UTC (permalink / raw)
To: Julien Grall
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara, xen-devel, wei.chen
On Mon, 23 May 2016, Julien Grall wrote:
> Based on ARM ARM (D4.5.3 in ARM DDI 0486A and B3.12.7 in ARM DDI 0406C.c),
> a Stage 1 translation error has priority over a Stage 2 translation error.
>
> Therefore gva_to_ipa can only fail if another vCPU is playing with the
> page table.
>
> Rather than injecting a custom fault, replay the instruction and let the
> processor injecting the correct fault.
>
> This is fine as Xen is handling all the pending softirqs
> (see leave_hypervisor_tail) before returning to the guest. One of them
> is the scheduler which could reschuled the vCPU.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
> Changes in v2:
> - Update commit message to explain why a guest cannot DoS the
> hypervisor with it.
> ---
> xen/arch/arm/traps.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index c0325d5..3acdba0 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -2410,7 +2410,7 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
>
> rc = gva_to_ipa(gva, &gpa, GV2M_READ);
> if ( rc == -EFAULT )
> - goto bad_insn_abort;
> + return; /* Try again */
> }
>
> rc = p2m_mem_access_check(gpa, gva, npfec);
> @@ -2422,7 +2422,6 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
> break;
> }
>
> -bad_insn_abort:
> inject_iabt_exception(regs, gva, hsr.len);
> }
>
> @@ -2452,7 +2451,7 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
> {
> rc = gva_to_ipa(info.gva, &info.gpa, GV2M_READ);
> if ( rc == -EFAULT )
> - goto bad_data_abort;
> + return; /* Try again */
> }
>
> switch ( dabt.dfsc & 0x3f )
> --
> 1.9.1
>
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^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-23 14:17 [PATCH v2 00/15] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
` (13 preceding siblings ...)
2016-05-23 14:17 ` [PATCH v2 14/15] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails Julien Grall
@ 2016-05-23 14:17 ` Julien Grall
2016-05-30 15:11 ` Stefano Stabellini
14 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-23 14:17 UTC (permalink / raw)
To: xen-devel
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara,
Julien Grall, wei.chen
The ARM erratum applies to certain revisions of Cortex-A57. The
processor may report a Stage 2 translation fault as the result of
Stage 1 fault for load crossing a page boundary when there is a
permission fault or device memory fault at stage 1 and a translation
fault at Stage 2.
So Xen needs to check that Stage 1 translation does not generate a fault
before handling the Stage 2 fault. If it is a Stage 1 translation fault,
return to the guest to let the processor injecting the correct fault.
Only document it as this is already the behavior of the fault handlers.
Note that some optimization could be done to avoid unecessary translation
fault. This is because HPFAR_EL2 is valid for more use case. For the moment,
the code is left unmodified.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
docs/misc/arm/silicon-errata.txt | 1 +
xen/arch/arm/traps.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
index ab2e5bc..1ac365d 100644
--- a/docs/misc/arm/silicon-errata.txt
+++ b/docs/misc/arm/silicon-errata.txt
@@ -47,3 +47,4 @@ stable hypervisors.
| ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 |
| ARM | Cortex-A57 | #852523 | N/A |
| ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
+| ARM | Cortex-A57 | #834220 | N/A |
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 3acdba0..bbd5309 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2396,6 +2396,21 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
.kind = hsr.iabt.s1ptw ? npfec_kind_in_gpt : npfec_kind_with_gla
};
+ /*
+ * Erratum #834220: The processor may report a Stage 2
+ * translation fault as the result of Stage 1 fault for load
+ * crossing a page boundary when there is a permission fault or
+ * device memory alignment fault at Stage 1 and a translation
+ * fault at Stage 2.
+ *
+ * So Xen needs to check that the Stage 1 translation does not
+ * generate a fault before handling stage 2 fault. If it is a Stage
+ * 1 translation fault, return to the guest to let the processor
+ * injecting the correct fault.
+ *
+ * XXX: This can be optimized to avoid some unecessary
+ * translation.
+ */
if ( hsr.iabt.s1ptw )
gpa = get_faulting_ipa();
else
@@ -2445,6 +2460,21 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
info.gva = READ_SYSREG64(FAR_EL2);
#endif
+ /*
+ * Erratum #834220: The processor may report a Stage 2
+ * translation fault as the result of Stage 1 fault for load
+ * crossing a page boundary when there is a permission fault or
+ * device memory alignment fault at Stage 1 and a translation
+ * fault at Stage 2.
+ *
+ * So Xen needs to check that the Stage 1 translation does not
+ * generate a fault before handling stage 2 fault. If it is a Stage
+ * 1 translation fault, return to the guest to let the processor
+ * injecting the correct fault.
+ *
+ * XXX: This can be optimized to avoid some unecessary
+ * translation.
+ */
if ( dabt.s1ptw )
info.gpa = get_faulting_ipa();
else
--
1.9.1
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^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-23 14:17 ` [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
@ 2016-05-30 15:11 ` Stefano Stabellini
2016-05-30 16:15 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 15:11 UTC (permalink / raw)
To: Julien Grall
Cc: sstabellini, wei.liu2, steve.capper, andre.przywara, xen-devel, wei.chen
On Mon, 23 May 2016, Julien Grall wrote:
> The ARM erratum applies to certain revisions of Cortex-A57. The
> processor may report a Stage 2 translation fault as the result of
> Stage 1 fault for load crossing a page boundary when there is a
> permission fault or device memory fault at stage 1 and a translation
> fault at Stage 2.
>
> So Xen needs to check that Stage 1 translation does not generate a fault
> before handling the Stage 2 fault. If it is a Stage 1 translation fault,
> return to the guest to let the processor injecting the correct fault.
>
> Only document it as this is already the behavior of the fault handlers.
> Note that some optimization could be done to avoid unecessary translation
> fault. This is because HPFAR_EL2 is valid for more use case. For the moment,
> the code is left unmodified.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> ---
> docs/misc/arm/silicon-errata.txt | 1 +
> xen/arch/arm/traps.c | 30 ++++++++++++++++++++++++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
> index ab2e5bc..1ac365d 100644
> --- a/docs/misc/arm/silicon-errata.txt
> +++ b/docs/misc/arm/silicon-errata.txt
> @@ -47,3 +47,4 @@ stable hypervisors.
> | ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 |
> | ARM | Cortex-A57 | #852523 | N/A |
> | ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
> +| ARM | Cortex-A57 | #834220 | N/A |
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index 3acdba0..bbd5309 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -2396,6 +2396,21 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
> .kind = hsr.iabt.s1ptw ? npfec_kind_in_gpt : npfec_kind_with_gla
> };
>
> + /*
> + * Erratum #834220: The processor may report a Stage 2
> + * translation fault as the result of Stage 1 fault for load
> + * crossing a page boundary when there is a permission fault or
> + * device memory alignment fault at Stage 1 and a translation
> + * fault at Stage 2.
> + *
> + * So Xen needs to check that the Stage 1 translation does not
> + * generate a fault before handling stage 2 fault. If it is a Stage
> + * 1 translation fault, return to the guest to let the processor
> + * injecting the correct fault.
> + *
> + * XXX: This can be optimized to avoid some unecessary
> + * translation.
> + */
> if ( hsr.iabt.s1ptw )
> gpa = get_faulting_ipa();
> else
Please write the comment only once, maybe in do_trap_hypervisor before
the calls to do_trap_instr_abort_guest and do_trap_data_abort_guest.
> @@ -2445,6 +2460,21 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
> info.gva = READ_SYSREG64(FAR_EL2);
> #endif
>
> + /*
> + * Erratum #834220: The processor may report a Stage 2
> + * translation fault as the result of Stage 1 fault for load
> + * crossing a page boundary when there is a permission fault or
> + * device memory alignment fault at Stage 1 and a translation
> + * fault at Stage 2.
> + *
> + * So Xen needs to check that the Stage 1 translation does not
> + * generate a fault before handling stage 2 fault. If it is a Stage
> + * 1 translation fault, return to the guest to let the processor
> + * injecting the correct fault.
> + *
> + * XXX: This can be optimized to avoid some unecessary
> + * translation.
> + */
> if ( dabt.s1ptw )
> info.gpa = get_faulting_ipa();
> else
> --
> 1.9.1
>
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http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-30 15:11 ` Stefano Stabellini
@ 2016-05-30 16:15 ` Julien Grall
2016-05-30 16:19 ` Stefano Stabellini
0 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-30 16:15 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
Hi Stefano,
On 30/05/2016 16:11, Stefano Stabellini wrote:
> On Mon, 23 May 2016, Julien Grall wrote:
>> The ARM erratum applies to certain revisions of Cortex-A57. The
>> processor may report a Stage 2 translation fault as the result of
>> Stage 1 fault for load crossing a page boundary when there is a
>> permission fault or device memory fault at stage 1 and a translation
>> fault at Stage 2.
>>
>> So Xen needs to check that Stage 1 translation does not generate a fault
>> before handling the Stage 2 fault. If it is a Stage 1 translation fault,
>> return to the guest to let the processor injecting the correct fault.
>>
>> Only document it as this is already the behavior of the fault handlers.
>> Note that some optimization could be done to avoid unecessary translation
>> fault. This is because HPFAR_EL2 is valid for more use case. For the moment,
>> the code is left unmodified.
>>
>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>> ---
>> docs/misc/arm/silicon-errata.txt | 1 +
>> xen/arch/arm/traps.c | 30 ++++++++++++++++++++++++++++++
>> 2 files changed, 31 insertions(+)
>>
>> diff --git a/docs/misc/arm/silicon-errata.txt b/docs/misc/arm/silicon-errata.txt
>> index ab2e5bc..1ac365d 100644
>> --- a/docs/misc/arm/silicon-errata.txt
>> +++ b/docs/misc/arm/silicon-errata.txt
>> @@ -47,3 +47,4 @@ stable hypervisors.
>> | ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 |
>> | ARM | Cortex-A57 | #852523 | N/A |
>> | ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
>> +| ARM | Cortex-A57 | #834220 | N/A |
>> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
>> index 3acdba0..bbd5309 100644
>> --- a/xen/arch/arm/traps.c
>> +++ b/xen/arch/arm/traps.c
>> @@ -2396,6 +2396,21 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
>> .kind = hsr.iabt.s1ptw ? npfec_kind_in_gpt : npfec_kind_with_gla
>> };
>>
>> + /*
>> + * Erratum #834220: The processor may report a Stage 2
>> + * translation fault as the result of Stage 1 fault for load
>> + * crossing a page boundary when there is a permission fault or
>> + * device memory alignment fault at Stage 1 and a translation
>> + * fault at Stage 2.
>> + *
>> + * So Xen needs to check that the Stage 1 translation does not
>> + * generate a fault before handling stage 2 fault. If it is a Stage
>> + * 1 translation fault, return to the guest to let the processor
>> + * injecting the correct fault.
>> + *
>> + * XXX: This can be optimized to avoid some unecessary
>> + * translation.
>> + */
>> if ( hsr.iabt.s1ptw )
>> gpa = get_faulting_ipa();
>> else
>
> Please write the comment only once, maybe in do_trap_hypervisor before
> the calls to do_trap_instr_abort_guest and do_trap_data_abort_guest.
I wrote this comment at these two specific places because developers and
reviewers can spot directly that the code has been written in a specific
way to avoid an erratum.
If we happen to fix one place and not the other, the comment would still
be there. do_trap_hypervisor would be the wrong place for this comment
because it is "far away" in the code and will be less likely read.
I can shrink down the message. What about:
"Erratum #834220: Xen needs to check that the Stage 1 translation does
not generate a fault before handling Stage 2 fault. If it is a stage 1
translation fault, return to the guest to let the project injecting the
correct fault.
XXX: This can be optimized to avoid some unnecessary translation."
Regards,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-30 16:15 ` Julien Grall
@ 2016-05-30 16:19 ` Stefano Stabellini
2016-05-30 16:33 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-30 16:19 UTC (permalink / raw)
To: Julien Grall
Cc: Stefano Stabellini, wei.liu2, steve.capper, andre.przywara,
xen-devel, wei.chen
On Mon, 30 May 2016, Julien Grall wrote:
> Hi Stefano,
>
> On 30/05/2016 16:11, Stefano Stabellini wrote:
> > On Mon, 23 May 2016, Julien Grall wrote:
> > > The ARM erratum applies to certain revisions of Cortex-A57. The
> > > processor may report a Stage 2 translation fault as the result of
> > > Stage 1 fault for load crossing a page boundary when there is a
> > > permission fault or device memory fault at stage 1 and a translation
> > > fault at Stage 2.
> > >
> > > So Xen needs to check that Stage 1 translation does not generate a fault
> > > before handling the Stage 2 fault. If it is a Stage 1 translation fault,
> > > return to the guest to let the processor injecting the correct fault.
> > >
> > > Only document it as this is already the behavior of the fault handlers.
> > > Note that some optimization could be done to avoid unecessary translation
> > > fault. This is because HPFAR_EL2 is valid for more use case. For the
> > > moment,
> > > the code is left unmodified.
> > >
> > > Signed-off-by: Julien Grall <julien.grall@arm.com>
> > > ---
> > > docs/misc/arm/silicon-errata.txt | 1 +
> > > xen/arch/arm/traps.c | 30 ++++++++++++++++++++++++++++++
> > > 2 files changed, 31 insertions(+)
> > >
> > > diff --git a/docs/misc/arm/silicon-errata.txt
> > > b/docs/misc/arm/silicon-errata.txt
> > > index ab2e5bc..1ac365d 100644
> > > --- a/docs/misc/arm/silicon-errata.txt
> > > +++ b/docs/misc/arm/silicon-errata.txt
> > > @@ -47,3 +47,4 @@ stable hypervisors.
> > > | ARM | Cortex-A53 | #819472 |
> > > ARM64_ERRATUM_819472 |
> > > | ARM | Cortex-A57 | #852523 | N/A
> > > |
> > > | ARM | Cortex-A57 | #832075 |
> > > ARM64_ERRATUM_832075 |
> > > +| ARM | Cortex-A57 | #834220 | N/A
> > > |
> > > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> > > index 3acdba0..bbd5309 100644
> > > --- a/xen/arch/arm/traps.c
> > > +++ b/xen/arch/arm/traps.c
> > > @@ -2396,6 +2396,21 @@ static void do_trap_instr_abort_guest(struct
> > > cpu_user_regs *regs,
> > > .kind = hsr.iabt.s1ptw ? npfec_kind_in_gpt :
> > > npfec_kind_with_gla
> > > };
> > >
> > > + /*
> > > + * Erratum #834220: The processor may report a Stage 2
> > > + * translation fault as the result of Stage 1 fault for load
> > > + * crossing a page boundary when there is a permission fault or
> > > + * device memory alignment fault at Stage 1 and a translation
> > > + * fault at Stage 2.
> > > + *
> > > + * So Xen needs to check that the Stage 1 translation does not
> > > + * generate a fault before handling stage 2 fault. If it is a
> > > Stage
> > > + * 1 translation fault, return to the guest to let the processor
> > > + * injecting the correct fault.
> > > + *
> > > + * XXX: This can be optimized to avoid some unecessary
> > > + * translation.
> > > + */
> > > if ( hsr.iabt.s1ptw )
> > > gpa = get_faulting_ipa();
> > > else
> >
> > Please write the comment only once, maybe in do_trap_hypervisor before
> > the calls to do_trap_instr_abort_guest and do_trap_data_abort_guest.
>
> I wrote this comment at these two specific places because developers and
> reviewers can spot directly that the code has been written in a specific way
> to avoid an erratum.
>
> If we happen to fix one place and not the other, the comment would still be
> there. do_trap_hypervisor would be the wrong place for this comment because it
> is "far away" in the code and will be less likely read.
>
> I can shrink down the message. What about:
>
> "Erratum #834220: Xen needs to check that the Stage 1 translation does not
> generate a fault before handling Stage 2 fault. If it is a stage 1 translation
> fault, return to the guest to let the project injecting the correct fault.
>
> XXX: This can be optimized to avoid some unnecessary translation."
What about adding a lengthy and detailed description of the erratum
elsewhere and just having a one liner at the call sites, such as:
/* Erratum #834220: check Stage1 translation does not generate faults first! */
so that developers can easily grep for #834220 through the code to have
the full explanation?
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^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-30 16:19 ` Stefano Stabellini
@ 2016-05-30 16:33 ` Julien Grall
2016-05-31 9:34 ` Stefano Stabellini
0 siblings, 1 reply; 38+ messages in thread
From: Julien Grall @ 2016-05-30 16:33 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
On 30/05/2016 17:19, Stefano Stabellini wrote:
>> "Erratum #834220: Xen needs to check that the Stage 1 translation does not
>> generate a fault before handling Stage 2 fault. If it is a stage 1 translation
>> fault, return to the guest to let the project injecting the correct fault.
>>
>> XXX: This can be optimized to avoid some unnecessary translation."
>
> What about adding a lengthy and detailed description of the erratum
> elsewhere and just having a one liner at the call sites, such as:
I don't see any problem to have "lengthy" comment twice. It could
actually be 3 lines because the last one is a TODO.
I thought about merging some bits of do_trap_instr_abort_guest and
do_trap_data_abort_guest, but at first glance it is not that simple.
> /* Erratum #834220: check Stage1 translation does not generate faults first! */
>
> so that developers can easily grep for #834220 through the code to have
> the full explanation?
Where would you put the full explanation? do_trap_hypervisor does not
make sense because it does not deal with the erratum. When we will come
back in few months time, we will wonder why the comment is there.
Regards,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-30 16:33 ` Julien Grall
@ 2016-05-31 9:34 ` Stefano Stabellini
2016-05-31 10:39 ` Julien Grall
0 siblings, 1 reply; 38+ messages in thread
From: Stefano Stabellini @ 2016-05-31 9:34 UTC (permalink / raw)
To: Julien Grall
Cc: Stefano Stabellini, wei.liu2, steve.capper, andre.przywara,
xen-devel, wei.chen
On Mon, 30 May 2016, Julien Grall wrote:
> On 30/05/2016 17:19, Stefano Stabellini wrote:
> > > "Erratum #834220: Xen needs to check that the Stage 1 translation does not
> > > generate a fault before handling Stage 2 fault. If it is a stage 1
> > > translation
> > > fault, return to the guest to let the project injecting the correct fault.
> > >
> > > XXX: This can be optimized to avoid some unnecessary translation."
> >
> > What about adding a lengthy and detailed description of the erratum
> > elsewhere and just having a one liner at the call sites, such as:
>
> I don't see any problem to have "lengthy" comment twice. It could actually be
> 3 lines because the last one is a TODO.
In my experience comments tend to be modified and when it happens, not
all the instances get always updated. That's why I would prefer to have
only one good explanation somewhere and then references to it.
That said, they are just comments, even if they don't get properly
updated the code won't break because of that (not immediately at least).
So I am not going to be headstrong on this.
> I thought about merging some bits of do_trap_instr_abort_guest and
> do_trap_data_abort_guest, but at first glance it is not that simple.
>
> > /* Erratum #834220: check Stage1 translation does not generate faults first!
> > */
> >
> > so that developers can easily grep for #834220 through the code to have
> > the full explanation?
>
> Where would you put the full explanation? do_trap_hypervisor does not make
> sense because it does not deal with the erratum. When we will come back in few
> months time, we will wonder why the comment is there.
docs/misc/arm/silicon-errata.txt?
do_trap_instr_abort_guest or do_trap_data_abort_guest but not both (only
a reference in the other?
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* Re: [PATCH v2 15/15] xen/arm: arm64: Document Cortex-A57 erratum 834220
2016-05-31 9:34 ` Stefano Stabellini
@ 2016-05-31 10:39 ` Julien Grall
0 siblings, 0 replies; 38+ messages in thread
From: Julien Grall @ 2016-05-31 10:39 UTC (permalink / raw)
To: Stefano Stabellini
Cc: andre.przywara, wei.chen, wei.liu2, steve.capper, xen-devel
Hi Stefano,
On 31/05/16 10:34, Stefano Stabellini wrote:
> On Mon, 30 May 2016, Julien Grall wrote:
>> On 30/05/2016 17:19, Stefano Stabellini wrote:
>>>> "Erratum #834220: Xen needs to check that the Stage 1 translation does not
>>>> generate a fault before handling Stage 2 fault. If it is a stage 1
>>>> translation
>>>> fault, return to the guest to let the project injecting the correct fault.
>>>>
>>>> XXX: This can be optimized to avoid some unnecessary translation."
>>>
>>> What about adding a lengthy and detailed description of the erratum
>>> elsewhere and just having a one liner at the call sites, such as:
>>
>> I don't see any problem to have "lengthy" comment twice. It could actually be
>> 3 lines because the last one is a TODO.
>
> In my experience comments tend to be modified and when it happens, not
> all the instances get always updated. That's why I would prefer to have
> only one good explanation somewhere and then references to it.
>
> That said, they are just comments, even if they don't get properly
> updated the code won't break because of that (not immediately at least).
> So I am not going to be headstrong on this.
>
>
>> I thought about merging some bits of do_trap_instr_abort_guest and
>> do_trap_data_abort_guest, but at first glance it is not that simple.
>>
>>> /* Erratum #834220: check Stage1 translation does not generate faults first!
>>> */
>>>
>>> so that developers can easily grep for #834220 through the code to have
>>> the full explanation?
>>
>> Where would you put the full explanation? do_trap_hypervisor does not make
>> sense because it does not deal with the erratum. When we will come back in few
>> months time, we will wonder why the comment is there.
>
> docs/misc/arm/silicon-errata.txt?
> do_trap_instr_abort_guest or do_trap_data_abort_guest but not both (only
> a reference in the other?
silicon-errata.txt could be a good place.
Cheers,
--
Julien Grall
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