[patch V2 03/52] x86/pkeys: Revert a5eff7259790 ("x86/pkeys: Add PKRU value to init_fpstate")

Thomas Gleixner
2021-06-14T16:38:00Z

This cannot work and it's unclear how that ever made a difference.

init_fpstate.xsave.header.xfeatures is always 0 so get_xsave_addr() will
always return a NULL pointer, which will prevent storing the default PKRU
value in initfp_state.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: Fix subject
---
arch/x86/kernel/cpu/common.c | 5 -----
arch/x86/mm/pkeys.c | 6 ------
2 files changed, 11 deletions(-)

--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -466,8 +466,6 @@ static bool pku_disabled;

static __always_inline void setup_pku(struct cpuinfo_x86 *c)
{
- struct pkru_state *pk;
-
/* check the boot processor, plus compile options for PKU: */
if (!cpu_feature_enabled(X86_FEATURE_PKU))
return;
@@ -478,9 +476,6 @@ static __always_inline void setup_pku(st
return;

cr4_set_bits(X86_CR4_PKE);
- pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU);
- if (pk)
- pk->pkru = init_pkru_value;
/*
* Setting X86_CR4_PKE will cause the X86_FEATURE_OSPKE
* cpuid bit to be set. We need to ensure that we
--- 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/fpu/internal.h> /* init_fpstate */

int __execute_only_pkey(struct mm_struct *mm)
{
@@ -154,7 +153,6 @@ static ssize_t init_pkru_read_file(struc
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;
@@ -177,10 +175,6 @@ static ssize_t init_pkru_write_file(stru
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;
}