linux-yocto/arch/loongarch/power/hibernate.c
Huacai Chen e89bd983f3 LoongArch: Save and restore CSR.CNTC for hibernation
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>
2025-05-22 14:12:19 +02:00

66 lines
1.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <asm/fpu.h>
#include <asm/loongson.h>
#include <asm/sections.h>
#include <asm/time.h>
#include <asm/tlbflush.h>
#include <linux/suspend.h>
static u32 saved_crmd;
static u32 saved_prmd;
static u32 saved_euen;
static u32 saved_ecfg;
static u64 saved_pcpu_base;
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);
saved_ecfg = csr_read32(LOONGARCH_CSR_ECFG);
saved_pcpu_base = csr_read64(PERCPU_BASE_KS);
if (is_fpu_owner())
save_fp(current);
}
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);
csr_write32(saved_ecfg, LOONGARCH_CSR_ECFG);
csr_write64(saved_pcpu_base, PERCPU_BASE_KS);
if (is_fpu_owner())
restore_fp(current);
}
int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
unsigned long nosave_end_pfn = PFN_UP(__pa(&__nosave_end));
return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}
extern int swsusp_asm_suspend(void);
int swsusp_arch_suspend(void)
{
enable_pci_wakeup();
return swsusp_asm_suspend();
}
extern int swsusp_asm_resume(void);
int swsusp_arch_resume(void)
{
/* Avoid TLB mismatch during and after kernel resume */
local_flush_tlb_all();
return swsusp_asm_resume();
}