diff options
| author | Heiko Carstens <hca@linux.ibm.com> | 2025-02-07 15:48:59 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2025-03-04 17:18:06 +0100 |
| commit | f931f67cfc274682aecc9f727eecc89779fc47b7 (patch) | |
| tree | 4d92c5a78d8ca293f7c5bb44bf43cf1061a408c3 /arch/s390/boot/startup.c | |
| parent | a1a8da0dec77e0149b482698a2c1daab3a02ef7a (diff) | |
s390/time: Convert MACHINE_HAS_SCC to machine_has_scc()
Use static branch(es) to implement and use machine_has_scc() instead
of a runtime check via MACHINE_HAS_SCC.
This comes with a cleanup of early time initialization: the initial
tod_clock_base value is now passed via the bootdata mechanism, instead
of using absolute lowcore as transport vehicle from the decompressor
to the kernel.
Also the early tod clock initialization is moved to the decompressor
which allows to use a static branch with machine_has_scc() within the
kernel.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/boot/startup.c')
| -rw-r--r-- | arch/s390/boot/startup.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 8081f06ad258..1c7367a338cd 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -10,6 +10,7 @@ #include <asm/machine.h> #include <asm/cpu_mf.h> #include <asm/setup.h> +#include <asm/timex.h> #include <asm/kasan.h> #include <asm/kexec.h> #include <asm/sclp.h> @@ -35,6 +36,8 @@ unsigned long __bootdata_preserved(max_mappable); unsigned long __bootdata_preserved(page_noexec_mask); unsigned long __bootdata_preserved(segment_noexec_mask); unsigned long __bootdata_preserved(region_noexec_mask); +union tod_clock __bootdata_preserved(tod_clock_base); +u64 __bootdata_preserved(clock_comparator_max) = -1UL; u64 __bootdata_preserved(stfle_fac_list[16]); struct oldmem_data __bootdata_preserved(oldmem_data); @@ -46,6 +49,20 @@ void error(char *x) disabled_wait(); } +static void reset_tod_clock(void) +{ + union tod_clock clk; + + if (store_tod_clock_ext_cc(&clk) == 0) + return; + /* TOD clock not running. Set the clock to Unix Epoch. */ + if (set_tod_clock(TOD_UNIX_EPOCH) || store_tod_clock_ext_cc(&clk)) + disabled_wait(); + memset(&tod_clock_base, 0, sizeof(tod_clock_base)); + tod_clock_base.tod = TOD_UNIX_EPOCH; + get_lowcore()->last_update_clock = TOD_UNIX_EPOCH; +} + static void detect_facilities(void) { if (cpu_has_edat1()) @@ -60,6 +77,13 @@ static void detect_facilities(void) } if (IS_ENABLED(CONFIG_PCI) && test_facility(153)) set_machine_feature(MFEATURE_PCI_MIO); + reset_tod_clock(); + if (test_facility(139) && (tod_clock_base.tod >> 63)) { + /* Enable signed clock comparator comparisons */ + set_machine_feature(MFEATURE_SCC); + clock_comparator_max = -1UL >> 1; + local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SIGN_BIT); + } } static int cmma_test_essa(void) |