When the property "clock-frequency" is present in the DT timer node, it
means that the bootloader/firmware didn't correctly configure the
CNTFRQ/CNTFRQ_EL0 on each processor.
The best solution would be to fix the offending firmware/bootloader,
although it may not always be possible to modify and re-flash it.
As it's not possible to trap the register CNTFRQ/CNTFRQ_EL0, we have
to extend xen_arch_domainconfig to provide the timer frequency to the
toolstack when the property "clock-frequency" is present to the host DT
timer node. Then, a property "clock-frequency" will be created in the guest
DT timer node if the value is not 0.
We could have set the property in the guest DT no matter if the property
is present in the host DT. Although, we still want to let the guest
using CNTFRQ in normal case. After all, the property "clock-frequency"
is just a workaround for buggy firmware.
Also add a stub for fdt_property_u32 which is not present in libfdt <
1.4.0 used by distribution such as Debian Wheezy.
Signed-off-by: Julien Grall <julien.gr...@citrix.com>
Tested-by: Chris Brand <chris.br...@broadcom.com>
---
This patch requires to regenerate tools/configure.
Changes in v2:
- Typo in commit message
- Make the patch compiling on wheezy where fdt_property_u32 is
not present
---
tools/configure.ac | 4 ++++
tools/libxl/libxl_arm.c | 9 +++++++--
tools/libxl/libxl_libfdt_compat.h | 9 +++++++++
xen/arch/arm/domain.c | 2 +-
xen/arch/arm/time.c | 5 +++++
xen/arch/arm/vtimer.c | 4 +++-
xen/arch/arm/vtimer.h | 3 ++-
xen/include/asm-arm/time.h | 6 ++++++
xen/include/public/arch-arm.h | 14 ++++++++++++++
9 files changed, 51 insertions(+), 5 deletions(-)
diff --git a/tools/configure.ac b/tools/configure.ac
index 1a06ddf..2886cb5 100644
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -379,6 +379,10 @@ AS_IF([test "x$partial_dt" = "xy" ],
# * The prototype exists but the functions are not exposed. Don't ask why...
AC_CHECK_FUNCS([fdt_first_subnode fdt_next_subnode])
AC_CHECK_DECLS([fdt_first_subnode, fdt_next_subnode],,,[#include <libfdt.h>])
+
+# The helper fdt_property_u32 is only present in libfdt >= 1.4.0
+# It's an inline function, so only check if the declaration is present
+AC_CHECK_DECLS([fdt_property_u32],,,[#include <libfdt.h>])
esac
# Checks for header files.
diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
index 4fb5e26..f09c860 100644
--- a/tools/libxl/libxl_arm.c
+++ b/tools/libxl/libxl_arm.c
@@ -444,7 +444,9 @@ static int make_gicv3_node(libxl__gc *gc, void *fdt)
return 0;
}
-static int make_timer_node(libxl__gc *gc, void *fdt, const struct arch_info
*ainfo)
+static int make_timer_node(libxl__gc *gc, void *fdt,
+ const struct arch_info *ainfo,
+ uint32_t frequency)
{
int res;
gic_interrupt ints[3];
@@ -462,6 +464,9 @@ static int make_timer_node(libxl__gc *gc, void *fdt, const
struct arch_info *ain
res = fdt_property_interrupts(gc, fdt, ints, 3);
if (res) return res;
+ if ( frequency )
+ fdt_property_u32(fdt, "clock-frequency", frequency);
+
res = fdt_end_node(fdt);
if (res) return res;
@@ -805,7 +810,7 @@ next_resize:
goto out;
}
- FDT( make_timer_node(gc, fdt, ainfo) );
+ FDT( make_timer_node(gc, fdt, ainfo, xc_config->clock_frequency) );
FDT( make_hypervisor_node(gc, fdt, vers) );
if (pfdt)
diff --git a/tools/libxl/libxl_libfdt_compat.h
b/tools/libxl/libxl_libfdt_compat.h
index 53a5076..23230b5 100644
--- a/tools/libxl/libxl_libfdt_compat.h
+++ b/tools/libxl/libxl_libfdt_compat.h
@@ -61,6 +61,7 @@
#define LIBXL_LIBFDT_COMPAT_H
#include "libxl_internal.h"
+#include <libfdt.h>
#if !HAVE_DECL_FDT_FIRST_SUBNODE
_hidden int fdt_first_subnode(const void *fdt, int offset);
@@ -70,6 +71,14 @@ _hidden int fdt_first_subnode(const void *fdt, int offset);
_hidden int fdt_next_subnode(const void *fdt, int offset);
#endif
+#if !HAVE_DECL_FDT_PROPERTY_U32
+static inline int fdt_property_u32(void *fdt, const char *name, uint32_t val)
+{
+ uint32_t tmp = cpu_to_fdt32(val);
+ return fdt_property(fdt, name, &tmp, sizeof(tmp));
+}
+#endif
+
#endif
/*
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 24b8938..8b1bf5a 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -593,7 +593,7 @@ int arch_domain_create(struct domain *d, unsigned int
domcr_flags,
if ( (rc = domain_vgic_init(d, config->nr_spis)) != 0 )
goto fail;
- if ( (rc = domain_vtimer_init(d)) != 0 )
+ if ( (rc = domain_vtimer_init(d, config)) != 0 )
goto fail;
/*
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index ce6d3fd..5ded30c 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -42,6 +42,8 @@ uint64_t __read_mostly boot_count;
* register-mapped time source in the SoC. */
unsigned long __read_mostly cpu_khz; /* CPU clock frequency in kHz. */
+uint32_t __read_mostly timer_dt_clock_frequency;
+
static unsigned int timer_irq[MAX_TIMER_PPI];
unsigned int timer_get_irq(enum timer_ppi ppi)
@@ -86,7 +88,10 @@ void __init preinit_xen_time(void)
res = dt_property_read_u32(timer, "clock-frequency", &rate);
if ( res )
+ {
cpu_khz = rate / 1000;
+ timer_dt_clock_frequency = rate;
+ }
else
cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
diff --git a/xen/arch/arm/vtimer.c b/xen/arch/arm/vtimer.c
index 685bfea..1418092 100644
--- a/xen/arch/arm/vtimer.c
+++ b/xen/arch/arm/vtimer.c
@@ -60,11 +60,13 @@ static void virt_timer_expired(void *data)
perfc_incr(vtimer_virt_inject);
}
-int domain_vtimer_init(struct domain *d)
+int domain_vtimer_init(struct domain *d, struct xen_arch_domainconfig *config)
{
d->arch.phys_timer_base.offset = NOW();
d->arch.virt_timer_base.offset = READ_SYSREG64(CNTPCT_EL0);
+ config->clock_frequency = timer_dt_clock_frequency;
+
/* At this stage vgic_reserve_virq can't fail */
if ( is_hardware_domain(d) )
{
diff --git a/xen/arch/arm/vtimer.h b/xen/arch/arm/vtimer.h
index 6d2e46e..99e8145 100644
--- a/xen/arch/arm/vtimer.h
+++ b/xen/arch/arm/vtimer.h
@@ -20,7 +20,8 @@
#ifndef __ARCH_ARM_VTIMER_H__
#define __ARCH_ARM_VTIMER_H__
-extern int domain_vtimer_init(struct domain *d);
+extern int domain_vtimer_init(struct domain *d,
+ struct xen_arch_domainconfig *config);
extern int vcpu_vtimer_init(struct vcpu *v);
extern int vtimer_emulate(struct cpu_user_regs *regs, union hsr hsr);
extern int virt_timer_save(struct vcpu *v);
diff --git a/xen/include/asm-arm/time.h b/xen/include/asm-arm/time.h
index 039039a..d755f36 100644
--- a/xen/include/asm-arm/time.h
+++ b/xen/include/asm-arm/time.h
@@ -22,6 +22,12 @@ enum timer_ppi
MAX_TIMER_PPI = 4,
};
+/*
+ * Value of "clock-frequency" in the DT timer node if present.
+ * 0 means the property doesn't exist.
+ */
+extern uint32_t timer_dt_clock_frequency;
+
/* Get one of the timer IRQ number */
unsigned int timer_get_irq(enum timer_ppi ppi);
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index a320851..a819196 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -311,6 +311,20 @@ struct xen_arch_domainconfig {
uint8_t gic_version;
/* IN */
uint32_t nr_spis;
+ /*
+ * OUT
+ * Based on the property clock-frequency in the DT timer node.
+ * The property may be present when the bootloader/firmware doesn't
+ * set correctly CNTFRQ which hold the timer frequency.
+ *
+ * As it's not possible to trap this register, we have to replicate
+ * the value in the guest DT.
+ *
+ * = 0 => property not present
+ * > 0 => Value of the property
+ *
+ */
+ uint32_t clock_frequency;
};
#endif /* __XEN__ || __XEN_TOOLS__ */
--
2.1.4
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