diff options
| author | Thomas Gleixner | 2021-06-23 14:02:11 +0200 |
|---|---|---|
| committer | Borislav Petkov | 2021-06-23 19:15:16 +0200 |
| commit | 371071131cd1032c1e9172c51234a2a324841cab (patch) | |
| tree | 0ca7ca1065a411917f11a58ad791d6c94c2e635b /arch/x86 | |
| parent | fa8c84b77a54bf3cf351c8b4b26a5aca27a14013 (diff) | |
x86/fpu: Use pkru_write_default() in copy_init_fpstate_to_fpregs()
There is no point in using copy_init_pkru_to_fpregs() which in turn calls
write_pkru(). write_pkru() tries to fiddle with the task's xstate buffer
for nothing because the XRSTOR[S](init_fpstate) just cleared the xfeature
flag in the xstate header which makes get_xsave_addr() fail.
It's a useless exercise anyway because the reinitialization activates the
FPU so before the task's xstate buffer can be used again a XRSTOR[S] must
happen which in turn dumps the PKRU value.
Get rid of the now unused copy_init_pkru_to_fpregs().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.732508792@linutronix.de
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/pkeys.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 3 | ||||
| -rw-r--r-- | arch/x86/mm/pkeys.c | 17 |
3 files changed, 1 insertions, 20 deletions
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h index 4128f647c755..5c7bcaa79623 100644 --- a/arch/x86/include/asm/pkeys.h +++ b/arch/x86/include/asm/pkeys.h @@ -124,7 +124,6 @@ extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val); extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val); -extern void copy_init_pkru_to_fpregs(void); static inline int vma_pkey(struct vm_area_struct *vma) { diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 3866954354a4..fedadcb04ba2 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -311,8 +311,7 @@ static inline void restore_fpregs_from_init_fpstate(u64 features_mask) else frstor(&init_fpstate.fsave); - if (cpu_feature_enabled(X86_FEATURE_OSPKE)) - copy_init_pkru_to_fpregs(); + pkru_write_default(); } /* diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index a02cfcf02d0d..fb171a5d7f33 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -10,7 +10,6 @@ #include <asm/cpufeature.h> /* boot_cpu_has, ... */ #include <asm/mmu_context.h> /* vma_pkey() */ -#include <asm/pkru.h> /* read/write_pkru() */ int __execute_only_pkey(struct mm_struct *mm) { @@ -125,22 +124,6 @@ u32 init_pkru_value = PKRU_AD_KEY( 1) | PKRU_AD_KEY( 2) | PKRU_AD_KEY( 3) | PKRU_AD_KEY(10) | PKRU_AD_KEY(11) | PKRU_AD_KEY(12) | PKRU_AD_KEY(13) | PKRU_AD_KEY(14) | PKRU_AD_KEY(15); -/* - * Called from the FPU code when creating a fresh set of FPU - * registers. This is called from a very specific context where - * we know the FPU registers are safe for use and we can use PKRU - * directly. - */ -void copy_init_pkru_to_fpregs(void) -{ - u32 init_pkru_value_snapshot = READ_ONCE(init_pkru_value); - /* - * Override the PKRU state that came from 'init_fpstate' - * with the baseline from the process. - */ - write_pkru(init_pkru_value_snapshot); -} - static ssize_t init_pkru_read_file(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { |