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Diffstat (limited to 'arch/x86/mm/pkeys.c')
-rw-r--r--arch/x86/mm/pkeys.c21
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;
}