[patch V2 20/52] x86/fpu: Cleanup arch_set_user_pkey_access()

Thomas Gleixner
2021-06-14T16:38:55Z

The function is having a sanity check with a WARN_ON_ONCE() but happily
proceeds when the pkey argument is out of range.

Clean it up.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/fpu/xstate.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -887,11 +887,10 @@ EXPORT_SYMBOL_GPL(get_xsave_addr);
* rights for @pkey to @init_val.
*/
int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
- unsigned long init_val)
+ unsigned long init_val)
{
- u32 old_pkru;
- int pkey_shift = (pkey * PKRU_BITS_PER_PKEY);
- u32 new_pkru_bits = 0;
+ u32 old_pkru, new_pkru_bits = 0;
+ int pkey_shift;

/*
* This check implies XSAVE support. OSPKE only gets
@@ -905,7 +904,8 @@ int arch_set_user_pkey_access(struct tas
* values originating from in-kernel users. Complain
* if a bad value is observed.
*/
- WARN_ON_ONCE(pkey >= arch_max_pkey());
+ if (WARN_ON_ONCE(pkey >= arch_max_pkey()))
+ return -EINVAL;

/* Set the bits we need in PKRU: */
if (init_val & PKEY_DISABLE_ACCESS)
@@ -914,6 +914,7 @@ int arch_set_user_pkey_access(struct tas
new_pkru_bits |= PKRU_WD_BIT;

/* Shift the bits in to the correct place in PKRU for pkey: */
+ pkey_shift = pkey * PKRU_BITS_PER_PKEY;
new_pkru_bits <<= pkey_shift;

/* Get old PKRU and mask off any old bits in place: */