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x86/fpu/amx: Enable the AMX feature in 64-bit mode

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Add the AMX state components in XFEATURE_MASK_USER_SUPPORTED and the
TILE_DATA component to the dynamic states and update the permission check
table accordingly.

This is only effective on 64 bit kernels as for 32bit kernels
XFEATURE_MASK_TILE is defined as 0.

TILE_DATA is caller-saved state and the only dynamic state. Add build time
sanity check to ensure the assumption that every dynamic feature is caller-
saved.

Make AMX state depend on XFD as it is dynamic feature.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211021225527.10184-24-chang.seok.bae@intel.com
This commit is contained in:
Chang S. Bae 2021-10-21 15:55:27 -07:00 committed by Borislav Petkov
parent db3e7321b4
commit 2308ee57d9
4 changed files with 13 additions and 4 deletions
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5
arch/x86/include/asm/fpu/xstate.h
View File

@ -35,7 +35,8 @@
XFEATURE_MASK_Hi16_ZMM | \
XFEATURE_MASK_PKRU | \
XFEATURE_MASK_BNDREGS | \
XFEATURE_MASK_BNDCSR)
XFEATURE_MASK_BNDCSR | \
XFEATURE_MASK_XTILE)
/*
* Features which are restored when returning to user space.
@ -46,7 +47,7 @@
(XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
/* Features which are dynamically enabled for a process on request */
#define XFEATURE_MASK_USER_DYNAMIC 0ULL
#define XFEATURE_MASK_USER_DYNAMIC XFEATURE_MASK_XTILE_DATA
/* All currently supported supervisor features */
#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)

1
arch/x86/kernel/cpu/cpuid-deps.c
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@ -76,6 +76,7 @@ static const struct cpuid_dep cpuid_deps[] = {
{ X86_FEATURE_SGX1, X86_FEATURE_SGX },
{ X86_FEATURE_SGX2, X86_FEATURE_SGX1 },
{ X86_FEATURE_XFD, X86_FEATURE_XSAVES },
{ X86_FEATURE_AMX_TILE, X86_FEATURE_XFD },
{}
};

6
arch/x86/kernel/fpu/core.c
View File

@ -494,6 +494,12 @@ int fpu_clone(struct task_struct *dst, unsigned long clone_flags)
return 0;
}
/*
* If a new feature is added, ensure all dynamic features are
* caller-saved from here!
*/
BUILD_BUG_ON(XFEATURE_MASK_USER_DYNAMIC != XFEATURE_MASK_XTILE_DATA);
/*
* Save the default portion of the current FPU state into the
* clone. Assume all dynamic features to be defined as caller-

5
arch/x86/kernel/fpu/xstate.c
View File

@ -404,7 +404,8 @@ static __init void os_xrstor_booting(struct xregs_state *xstate)
XFEATURE_MASK_PKRU | \
XFEATURE_MASK_BNDREGS | \
XFEATURE_MASK_BNDCSR | \
XFEATURE_MASK_PASID)
XFEATURE_MASK_PASID | \
XFEATURE_MASK_XTILE)
/*
* setup the xstate image representing the init state
@ -1636,7 +1637,7 @@ static int __xstate_request_perm(u64 permitted, u64 requested)
* Permissions array to map facilities with more than one component
*/
static const u64 xstate_prctl_req[XFEATURE_MAX] = {
/* [XFEATURE_XTILE_DATA] = XFEATURE_MASK_XTILE, */
[XFEATURE_XTILE_DATA] = XFEATURE_MASK_XTILE_DATA,
};
static int xstate_request_perm(unsigned long idx)