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| author | Heiko Carstens <hca@linux.ibm.com> | 2024-02-03 11:45:09 +0100 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2024-02-16 14:30:15 +0100 |
| commit | 419abc4d3828813b58d047da146f519eedaa395b (patch) | |
| tree | b358423efb377ffd2c050aab1ab2e41740ba44ab /arch/s390/kernel | |
| parent | 918c7cad66509c2170e38a088550fb4a525e0878 (diff) | |
| download | linux-next-419abc4d3828813b58d047da146f519eedaa395b.tar.gz linux-next-419abc4d3828813b58d047da146f519eedaa395b.zip | |
s390/fpu: convert FPU CIF flag to regular TIF flag
The FPU state, as represented by the CIF_FPU flag reflects the FPU state of
a task, not the CPU it is running on. Therefore convert the flag to a
regular TIF flag.
This removes the magic in switch_to() where a save_fpu_regs() call for the
currently (previous) running task sets the per-cpu CIF_FPU flag, which is
required to restore FPU register contents of the next task, when it returns
to user space.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
| -rw-r--r-- | arch/s390/kernel/entry.S | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/fpu.c | 6 | ||||
| -rw-r--r-- | arch/s390/kernel/process.c | 7 |
3 files changed, 5 insertions, 10 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 01c3b2d2821d..00f2e1741501 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -220,7 +220,7 @@ SYM_FUNC_START(__sie64a) oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now tm __SIE_PROG20+3(%r14),3 # last exit... jnz .Lsie_skip - TSTMSK __LC_CPU_FLAGS,_CIF_FPU + TSTMSK __SF_SIE_FLAGS(%r15),_TIF_FPU jo .Lsie_skip # exit if fp/vx regs changed lg %r14,__SF_SIE_CONTROL_PHYS(%r15) # get sie block phys addr BPEXIT __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST diff --git a/arch/s390/kernel/fpu.c b/arch/s390/kernel/fpu.c index 0a31408a46f3..12d6e9d97104 100644 --- a/arch/s390/kernel/fpu.c +++ b/arch/s390/kernel/fpu.c @@ -117,7 +117,7 @@ void __load_fpu_regs(void) load_vx_regs(regs); else load_fp_regs(regs); - clear_cpu_flag(CIF_FPU); + clear_thread_flag(TIF_FPU); } void load_fpu_regs(void) @@ -136,7 +136,7 @@ void save_fpu_regs(void) local_irq_save(flags); - if (test_cpu_flag(CIF_FPU)) + if (test_thread_flag(TIF_FPU)) goto out; state = ¤t->thread.fpu; @@ -147,7 +147,7 @@ void save_fpu_regs(void) save_vx_regs(regs); else save_fp_regs(regs); - set_cpu_flag(CIF_FPU); + set_thread_flag(TIF_FPU); out: local_irq_restore(flags); } diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c index b0578ea230e7..f4c355f080f2 100644 --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -88,7 +88,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { /* * Save the floating-point or vector register state of the current - * task and set the CIF_FPU flag to lazy restore the FPU register + * task and set the TIF_FPU flag to lazy restore the FPU register * state when returning to user space. */ save_fpu_regs(); @@ -196,11 +196,6 @@ void execve_tail(void) struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next) { - /* - * save_fpu_regs() sets the CIF_FPU flag, which enforces - * a restore of the floating point / vector registers as - * soon as the next task returns to user space. - */ save_fpu_regs(); save_access_regs(&prev->thread.acrs[0]); save_ri_cb(prev->thread.ri_cb); |