Merge tag 'timers-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timekeeping updates from Thomas Gleixner:
 "A set of timekeeping/VDSO updates:

   - Preparatory work to allow S390 to switch over to the generic VDSO
     implementation.

     S390 requires that the VDSO data pointer is handed in to the
     counter read function when time namespace support is enabled.
     Adding the pointer is a NOOP for all other architectures because
     the compiler is supposed to optimize that out when it is unused in
     the architecture specific inline. The change also solved a similar
     problem for MIPS which fortunately has time namespaces not yet
     enabled.

     S390 needs to update clock related VDSO data independent of the
     timekeeping updates. This was solved so far with yet another
     sequence counter in the S390 implementation. A better solution is
     to utilize the already existing VDSO sequence count for this. The
     core code now exposes helper functions which allow to serialize
     against the timekeeper code and against concurrent readers.

     S390 needs extra data for their clock readout function. The initial
     common VDSO data structure did not provide a way to add that. It
     now has an embedded architecture specific struct embedded which
     defaults to an empty struct.

     Doing this now avoids tree dependencies and conflicts post rc1 and
     allows all other architectures which work on generic VDSO support
     to work from a common upstream base.

   - A trivial comment fix"

* tag 'timers-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Delete repeated words in comments
  lib/vdso: Allow to add architecture-specific vdso data
  timekeeping/vsyscall: Provide vdso_update_begin/end()
  vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter()
This commit is contained in:
Linus Torvalds
2020-08-14 14:26:08 -07:00
15 changed files with 84 additions and 16 deletions

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