x86/pkeys: Revert a5eff7259790 ("x86/pkeys: Add PKRU value to init_fpstate")

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 init_fpstate.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121451.451391598@linutronix.de

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 9173dd4..dcbb11f 100644 (file)
--- 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(struct cpuinfo_x86 *c)
                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

diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index a2332ee..a840ac7 100644 (file)
--- 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(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;
@@ -177,10 +175,6 @@ 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;
 }