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vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter()

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MIPS already uses and S390 will need the vdso data pointer in
__arch_get_hw_counter().

This works nicely as long as the architecture does not support time
namespaces in the VDSO. With time namespaces enabled the regular
accessor to the vdso data pointer __arch_get_vdso_data() will return the
namespace specific VDSO data page for tasks which are part of a
non-root time namespace. This would cause the architectures which need
the vdso data pointer in __arch_get_hw_counter() to access the wrong
vdso data page.

Add a vdso_data pointer argument to __arch_get_hw_counter() and hand it in
from the call sites in the core code. For architectures which do not need
the data pointer in their counter accessor function the compiler will just
optimize it out.

Fix up all existing architecture implementations and make MIPS utilize the
pointer instead of invoking the accessor function.

No functional change and no change in the resulting object code (except
MIPS).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/draft-87wo2ekuzn.fsf@nanos.tec.linutronix.de
This commit is contained in:
Thomas Gleixner 2020-08-04 22:37:48 +02:00
parent 2324d50d05
commit 4c5a116ada
7 changed files with 15 additions and 9 deletions
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3
arch/arm/include/asm/vdso/gettimeofday.h
View File

@ -113,7 +113,8 @@ static inline bool arm_vdso_hres_capable(void)
}
#define __arch_vdso_hres_capable arm_vdso_hres_capable
static __always_inline u64 __arch_get_hw_counter(int clock_mode)
static __always_inline u64 __arch_get_hw_counter(int clock_mode,
const struct vdso_data *vd)
{
#ifdef CONFIG_ARM_ARCH_TIMER
u64 cycle_now;

3
arch/arm64/include/asm/vdso/compat_gettimeofday.h
View File

@ -103,7 +103,8 @@ int clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
return ret;
}
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
{
u64 res;

3
arch/arm64/include/asm/vdso/gettimeofday.h
View File

@ -64,7 +64,8 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
return ret;
}
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
{
u64 res;

5
arch/mips/include/asm/vdso/gettimeofday.h
View File

@ -167,7 +167,8 @@ static __always_inline u64 read_gic_count(const struct vdso_data *data)
#endif
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
{
#ifdef CONFIG_CSRC_R4K
if (clock_mode == VDSO_CLOCKMODE_R4K)
@ -175,7 +176,7 @@ static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
#endif
#ifdef CONFIG_CLKSRC_MIPS_GIC
if (clock_mode == VDSO_CLOCKMODE_GIC)
return read_gic_count(get_vdso_data());
return read_gic_count(vd);
#endif
/*
* Core checks mode already. So this raced against a concurrent

3
arch/riscv/include/asm/vdso/gettimeofday.h
View File

@ -60,7 +60,8 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
return ret;
}
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
{
/*
* The purpose of csr_read(CSR_TIME) is to trap the system into

3
arch/x86/include/asm/vdso/gettimeofday.h
View File

@ -241,7 +241,8 @@ static u64 vread_hvclock(void)
}
#endif
static inline u64 __arch_get_hw_counter(s32 clock_mode)
static inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
{
if (likely(clock_mode == VDSO_CLOCKMODE_TSC))
return (u64)rdtsc_ordered();

4
lib/vdso/gettimeofday.c
View File

@ -68,7 +68,7 @@ static int do_hres_timens(const struct vdso_data *vdns, clockid_t clk,
if (unlikely(!vdso_clocksource_ok(vd)))
return -1;
cycles = __arch_get_hw_counter(vd->clock_mode);
cycles = __arch_get_hw_counter(vd->clock_mode, vd);
if (unlikely(!vdso_cycles_ok(cycles)))
return -1;
ns = vdso_ts->nsec;
@ -138,7 +138,7 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
if (unlikely(!vdso_clocksource_ok(vd)))
return -1;
cycles = __arch_get_hw_counter(vd->clock_mode);
cycles = __arch_get_hw_counter(vd->clock_mode, vd);
if (unlikely(!vdso_cycles_ok(cycles)))
return -1;
ns = vdso_ts->nsec;