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Commit 65571693 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman
Browse files

x86/pkeys: Revert a5eff725 ("x86/pkeys: Add PKRU value to init_fpstate") 



commit b3607269ff57fd3c9690cb25962c5e4b91a0fd3b upstream.

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


Signed-off-by: default avatarThadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ea1b4c31

arch/x86/kernel/cpu/common.c

+0 −5
Original line number Diff line number Diff line
@@ -450,8 +450,6 @@ 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;
@@ -462,9 +460,6 @@ 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;

	/*

	 * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE

	 * cpuid bit to be set.  We need to ensure that we

arch/x86/mm/pkeys.c

+0 −6
Original line number Diff line number Diff line
@@ -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;

}