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x86/pkeys: Revert a5eff72597 ("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
This commit is contained in:
Thomas Gleixner 2021-06-23 14:01:29 +02:00 committed by Borislav Petkov
parent 9625895011
commit b3607269ff
2 changed files with 0 additions and 11 deletions
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5
arch/x86/kernel/cpu/common.c
View File

@ -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

6
arch/x86/mm/pkeys.c
View File

@ -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;
}