The following commit has been merged into the x86/fpu branch of tip:
Commit-ID: 2308ee57d93d896618dd65c996429c9d3e469fe0
Gitweb: https://git.kernel.org/tip/2308ee57d93d896618dd65c996429c9d3e469fe0
Author: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
AuthorDate: Thu, 21 Oct 2021 15:55:27 -07:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 26 Oct 2021 10:53:03 +02:00
x86/fpu/amx: Enable the AMX feature in 64-bit mode
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@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/20211021225527.10184-24-chang.seok.bae@xxxxxxxxx
---
arch/x86/include/asm/fpu/xstate.h | 5 +++--
arch/x86/kernel/cpu/cpuid-deps.c | 1 +
arch/x86/kernel/fpu/core.c | 6 ++++++
arch/x86/kernel/fpu/xstate.c | 5 +++--
4 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 10adf13..0f8b90a 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -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)
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index d9ead9c..cb2fdd1 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -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 },
{}
};
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 12ca174..290836d 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -495,6 +495,12 @@ int fpu_clone(struct task_struct *dst, unsigned long clone_flags)
}
/*
+ * 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-
* saved, which enables skipping both the expansion of fpstate
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 987a07b..d288294 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -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)
|