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11c33ffb3a
__arch_counter_get_cntpct() and __arch_counter_get_cntvct() open-code
the same ECV-aware ALTERNATIVE block that arch_timer_read_cntpct_el0()
and arch_timer_read_cntvct_el0() already provide in the same header.
The two pairs are byte-for-byte identical except for the trailing
arch_counter_enforce_ordering() the __arch_counter_get_* variants add.
Replace the duplicated inline assembly in __arch_counter_get_cntpct()
and __arch_counter_get_cntvct() with calls to the corresponding helpers.
This mirrors commit 00b39d1509 ("arm64: vdso: Use
__arch_counter_get_cntvct()"), which removed similar duplication from
the vDSO, and keeps the system-counter read sequence in a single place,
reducing assembly code in the kernell
No functional change: the resulting inline assembly, alternatives, and
clobbers are unchanged; only the source-level expression of the read
moves into the existing helper.
Verified by rebuilding the consumers of these helpers before and after
the change and comparing the resulting disassembly:
- arch/arm64/kernel/vdso/vdso.so (final linked vDSO):
bit-identical (same sha256 across rebuilds)
- arch/arm64/kernel/vdso/vgettimeofday.o: identical disassembly
- arch/arm64/lib/delay.o: identical disassembly
- drivers/clocksource/arm_arch_timer.o: same 50 functions with
byte-identical instruction streams; only difference is function
ordering inside .text and NOP padding, with no opcodes added or
removed.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Will Deacon <will@kernel.org>