diff options
Diffstat (limited to 'arch/x86/mm/pkeys.c')
| -rw-r--r-- | arch/x86/mm/pkeys.c | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index 047a77f6a10c..1dcfc91c8f0c 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -18,6 +18,7 @@ #include <asm/cpufeature.h> /* boot_cpu_has, ... */ #include <asm/mmu_context.h> /* vma_pkey() */ +#include <asm/fpu/internal.h> /* init_fpstate */ int __execute_only_pkey(struct mm_struct *mm) { @@ -39,17 +40,12 @@ int __execute_only_pkey(struct mm_struct *mm) * dance to set PKRU if we do not need to. Check it * first and assume that if the execute-only pkey is * write-disabled that we do not have to set it - * ourselves. We need preempt off so that nobody - * can make fpregs inactive. + * ourselves. */ - preempt_disable(); if (!need_to_set_mm_pkey && - current->thread.fpu.initialized && !__pkru_allows_read(read_pkru(), execute_only_pkey)) { - preempt_enable(); return execute_only_pkey; } - preempt_enable(); /* * Set up PKRU so that it denies access for everything @@ -131,7 +127,6 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey * in the process's lifetime will not accidentally get access * to data which is pkey-protected later on. */ -static u32 init_pkru_value = PKRU_AD_KEY( 1) | PKRU_AD_KEY( 2) | PKRU_AD_KEY( 3) | PKRU_AD_KEY( 4) | PKRU_AD_KEY( 5) | PKRU_AD_KEY( 6) | PKRU_AD_KEY( 7) | PKRU_AD_KEY( 8) | PKRU_AD_KEY( 9) | @@ -148,13 +143,6 @@ void copy_init_pkru_to_fpregs(void) { u32 init_pkru_value_snapshot = READ_ONCE(init_pkru_value); /* - * Any write to PKRU takes it out of the XSAVE 'init - * state' which increases context switch cost. Avoid - * writing 0 when PKRU was already 0. - */ - if (!init_pkru_value_snapshot && !read_pkru()) - return; - /* * Override the PKRU state that came from 'init_fpstate' * with the baseline from the process. */ @@ -174,6 +162,7 @@ static ssize_t init_pkru_read_file(struct file *file, char __user *user_buf, static ssize_t init_pkru_write_file(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { + struct pkru_state *pk; char buf[32]; ssize_t len; u32 new_init_pkru; @@ -196,6 +185,10 @@ static ssize_t init_pkru_write_file(struct file *file, return -EINVAL; WRITE_ONCE(init_pkru_value, new_init_pkru); + pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU); + if (!pk) + return -EINVAL; + pk->pkru = new_init_pkru; return count; } |