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authorLinus Torvalds <torvalds@linux-foundation.org>2024-05-14 19:27:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2024-05-14 19:27:40 +0300
commit2d9db778ddca079228ef10e60bceea06b34b0eaa (patch)
tree141de3fcc8b32a0d495b36f461b5875681f5011e /arch/powerpc
parent61deafa9ecf3f6d00c570774b0b38f439be543ac (diff)
parenta3825a7691585485e960cec04ce6667d176b7c67 (diff)
downloadlinux-2d9db778ddca079228ef10e60bceea06b34b0eaa.tar.xz
Merge tag 'timers-core-2024-05-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timers and timekeeping updates from Thomas Gleixner: "Core code: - Make timekeeping and VDSO time readouts resilent against math overflow: In guest context the kernel is prone to math overflow when the host defers the timer interrupt due to overload, malfunction or malice. This can be mitigated by checking the clocksource delta for the maximum deferrement which is readily available. If that value is exceeded then the code uses a slowpath function which can handle the multiplication overflow. This functionality is enabled unconditionally in the kernel, but made conditional in the VDSO code. The latter is conditional because it allows architectures to optimize the check so it is not causing performance regressions. On X86 this is achieved by reworking the existing check for negative TSC deltas as a negative delta obviously exceeds the maximum deferrement when it is evaluated as an unsigned value. That avoids two conditionals in the hotpath and allows to hide both the negative delta and the large delta handling in the same slow path. - Add an initial minimal ktime_t abstraction for Rust - The usual boring cleanups and enhancements Drivers: - Boring updates to device trees and trivial enhancements in various drivers" * tag 'timers-core-2024-05-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) clocksource/drivers/arm_arch_timer: Mark hisi_161010101_oem_info const clocksource/drivers/timer-ti-dm: Remove an unused field in struct dmtimer clocksource/drivers/renesas-ostm: Avoid reprobe after successful early probe clocksource/drivers/renesas-ostm: Allow OSTM driver to reprobe for RZ/V2H(P) SoC dt-bindings: timer: renesas: ostm: Document Renesas RZ/V2H(P) SoC rust: time: doc: Add missing C header links clocksource: Make the int help prompt unit readable in ncurses hrtimer: Rename __hrtimer_hres_active() to hrtimer_hres_active() timerqueue: Remove never used function timerqueue_node_expires() rust: time: Add Ktime vdso: Fix powerpc build U64_MAX undeclared error clockevents: Convert s[n]printf() to sysfs_emit() clocksource: Convert s[n]printf() to sysfs_emit() clocksource: Make watchdog and suspend-timing multiplication overflow safe timekeeping: Let timekeeping_cycles_to_ns() handle both under and overflow timekeeping: Make delta calculation overflow safe timekeeping: Prepare timekeeping_cycles_to_ns() for overflow safety timekeeping: Fold in timekeeping_delta_to_ns() timekeeping: Consolidate timekeeping helpers timekeeping: Refactor timekeeping helpers ...
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/vdso/gettimeofday.h26
1 files changed, 11 insertions, 15 deletions
diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h b/arch/powerpc/include/asm/vdso/gettimeofday.h
index 78302f6c2580..c6390890a60c 100644
--- a/arch/powerpc/include/asm/vdso/gettimeofday.h
+++ b/arch/powerpc/include/asm/vdso/gettimeofday.h
@@ -13,6 +13,17 @@
#define VDSO_HAS_TIME 1
+/*
+ * powerpc specific delta calculation.
+ *
+ * This variant removes the masking of the subtraction because the
+ * clocksource mask of all VDSO capable clocksources on powerpc is U64_MAX
+ * which would result in a pointless operation. The compiler cannot
+ * optimize it away as the mask comes from the vdso data and is not compile
+ * time constant.
+ */
+#define VDSO_DELTA_NOMASK 1
+
static __always_inline int do_syscall_2(const unsigned long _r0, const unsigned long _r3,
const unsigned long _r4)
{
@@ -104,21 +115,6 @@ static inline bool vdso_clocksource_ok(const struct vdso_data *vd)
}
#define vdso_clocksource_ok vdso_clocksource_ok
-/*
- * powerpc specific delta calculation.
- *
- * This variant removes the masking of the subtraction because the
- * clocksource mask of all VDSO capable clocksources on powerpc is U64_MAX
- * which would result in a pointless operation. The compiler cannot
- * optimize it away as the mask comes from the vdso data and is not compile
- * time constant.
- */
-static __always_inline u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
-{
- return (cycles - last) * mult;
-}
-#define vdso_calc_delta vdso_calc_delta
-
#ifndef __powerpc64__
static __always_inline u64 vdso_shift_ns(u64 ns, unsigned long shift)
{