Instead of comparing the name to a magic string, use archdata to
explicitly communicate whether the arch timer is suitable for
direct vdso access.
Signed-off-by: Scott Wood <oss@xxxxxxxxxxxx>
---
v4: new patch
I'm putting this after the other patches, in the hopes that if there
are issues with this patch, it doesn't hold up the others.
arch/arm/Kconfig | 1 +
arch/arm/include/asm/clocksource.h | 8 ++++++++
arch/arm/kernel/vdso.c | 2 +-
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/clocksource.h | 8 ++++++++
arch/arm64/kernel/vdso.c | 2 +-
drivers/clocksource/arm_arch_timer.c | 11 +++--------
7 files changed, 23 insertions(+), 10 deletions(-)
create mode 100644 arch/arm/include/asm/clocksource.h
create mode 100644 arch/arm64/include/asm/clocksource.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 90542db..dcdcd78 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1,6 +1,7 @@
config ARM
bool
default y
+ select ARCH_CLOCKSOURCE_DATA
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
diff --git a/arch/arm/include/asm/clocksource.h b/arch/arm/include/asm/clocksource.h
new file mode 100644
index 0000000..0b350a7
--- /dev/null
+++ b/arch/arm/include/asm/clocksource.h
@@ -0,0 +1,8 @@
+#ifndef _ASM_CLOCKSOURCE_H
+#define _ASM_CLOCKSOURCE_H
+
+struct arch_clocksource_data {
+ bool vdso_direct; /* Usable for direct VDSO access? */
+};
+
+#endif
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 994e971..a0affd1 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -270,7 +270,7 @@ static bool tk_is_cntvct(const struct timekeeper *tk)
if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
return false;
- if (strcmp(tk->tkr_mono.clock->name, "arch_sys_counter") != 0)
+ if (!tk->tkr_mono.clock->archdata.vdso_direct)
return false;
return true;
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5a0a691..24c4b2c 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -3,6 +3,7 @@ config ARM64
select ACPI_CCA_REQUIRED if ACPI
select ACPI_GENERIC_GSI if ACPI
select ACPI_REDUCED_HARDWARE_ONLY if ACPI
+ select ARCH_CLOCKSOURCE_DATA
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
diff --git a/arch/arm64/include/asm/clocksource.h b/arch/arm64/include/asm/clocksource.h
new file mode 100644
index 0000000..0b350a7
--- /dev/null
+++ b/arch/arm64/include/asm/clocksource.h
@@ -0,0 +1,8 @@
+#ifndef _ASM_CLOCKSOURCE_H
+#define _ASM_CLOCKSOURCE_H
+
+struct arch_clocksource_data {
+ bool vdso_direct; /* Usable for direct VDSO access? */
+};
+
+#endif
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 9fefb00..ee107f2 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -201,7 +201,7 @@ up_fail:
*/
void update_vsyscall(struct timekeeper *tk)
{
- u32 use_syscall = strcmp(tk->tkr_mono.clock->name, "arch_sys_counter");
+ u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
++vdso_data->tb_seq_count;
smp_wmb();
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index b857027..a5654a4 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -575,23 +575,18 @@ static void __init arch_counter_register(unsigned type)
else
arch_timer_read_counter = arch_counter_get_cntpct;
+ clocksource_counter.archdata.vdso_direct = true;
+
#ifdef CONFIG_FSL_ERRATUM_A008585
/*
* Don't use the vdso fastpath if errata require using
* the out-of-line counter accessor.
*/
if (static_branch_unlikely(&arch_timer_read_ool_enabled))
- clocksource_counter.name = "arch_sys_counter_ool";
+ clocksource_counter.archdata.vdso_direct = false;
#endif
} else {
arch_timer_read_counter = arch_counter_get_cntvct_mem;
-
- /* If the clocksource name is "arch_sys_counter" the
- * VDSO will attempt to read the CP15-based counter.
- * Ensure this does not happen when CP15-based
- * counter is not available.
- */
- clocksource_counter.name = "arch_mem_counter";
}
start_count = arch_timer_read_counter();
--
2.7.4
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