6.12-stable review patch. If anyone has any objections, please let me know.
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From: Huacai Chen chenhuacai@loongson.cn
commit ceb9155d058a11242aa0572875c44e9713b1a2be upstream.
Save and restore CSR.CNTC for hibernation which is similar to suspend.
For host this is unnecessary because sched clock is ensured continuous, but for kvm guest sched clock isn't enough because rdtime.d should also be continuous.
Host::rdtime.d = Host::CSR.CNTC + counter Guest::rdtime.d = Host::CSR.CNTC + Host::CSR.GCNTC + Guest::CSR.CNTC + counter
so,
Guest::rdtime.d = Host::rdtime.d + Host::CSR.GCNTC + Guest::CSR.CNTC
To ensure Guest::rdtime.d continuous, Host::rdtime.d should be at first continuous, while Host::CSR.GCNTC / Guest::CSR.CNTC is maintained by KVM.
Cc: stable@vger.kernel.org Signed-off-by: Xianglai Li lixianglai@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/kernel/time.c | 2 +- arch/loongarch/power/hibernate.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-)
--- a/arch/loongarch/kernel/time.c +++ b/arch/loongarch/kernel/time.c @@ -111,7 +111,7 @@ static unsigned long __init get_loops_pe return lpj; }
-static long init_offset __nosavedata; +static long init_offset;
void save_counter(void) { --- a/arch/loongarch/power/hibernate.c +++ b/arch/loongarch/power/hibernate.c @@ -2,6 +2,7 @@ #include <asm/fpu.h> #include <asm/loongson.h> #include <asm/sections.h> +#include <asm/time.h> #include <asm/tlbflush.h> #include <linux/suspend.h>
@@ -14,6 +15,7 @@ struct pt_regs saved_regs;
void save_processor_state(void) { + save_counter(); saved_crmd = csr_read32(LOONGARCH_CSR_CRMD); saved_prmd = csr_read32(LOONGARCH_CSR_PRMD); saved_euen = csr_read32(LOONGARCH_CSR_EUEN); @@ -26,6 +28,7 @@ void save_processor_state(void)
void restore_processor_state(void) { + sync_counter(); csr_write32(saved_crmd, LOONGARCH_CSR_CRMD); csr_write32(saved_prmd, LOONGARCH_CSR_PRMD); csr_write32(saved_euen, LOONGARCH_CSR_EUEN);